gecko/content/canvas/src/WebGLContextGL.cpp

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 *   Mozilla Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2009
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Vladimir Vukicevic <vladimir@pobox.com> (original author)
 *   Mark Steele <mwsteele@gmail.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "WebGLContext.h"

#include "nsString.h"

#include "gfxImageSurface.h"
#include "gfxContext.h"
#include "gfxPlatform.h"
//#include "nsIDOMHTMLCanvasElement.h"

#include "nsContentUtils.h"
#include "nsDOMError.h"
#include "nsLayoutUtils.h"

#include "CanvasUtils.h"
#include "NativeJSContext.h"

#include "jstypedarray.h"

using namespace mozilla;

// XXX why is this broken?
#ifndef GL_BLEND_EQUATION
#define GL_BLEND_EQUATION 0x8009
#endif

static PRBool BaseTypeAndSizeFromUniformType(GLenum uType, GLenum *baseType, GLint *unitSize);

/* Helper macros for when we're just wrapping a gl method, so that
 * we can avoid having to type this 500 times.  Note that these MUST
 * NOT BE USED if we need to check any of the parameters.
 */

#define GL_SAME_METHOD_0(glname, name)                          \
NS_IMETHODIMP WebGLContext::name() {                            \
    MakeContextCurrent(); gl->f##glname(); return NS_OK;        \
}

#define GL_SAME_METHOD_1(glname, name, t1)          \
NS_IMETHODIMP WebGLContext::name(t1 a1) {           \
    MakeContextCurrent(); gl->f##glname(a1); return NS_OK;  \
}

#define GL_SAME_METHOD_2(glname, name, t1, t2)        \
NS_IMETHODIMP WebGLContext::name(t1 a1, t2 a2) {      \
    MakeContextCurrent(); gl->f##glname(a1,a2); return NS_OK;           \
}

#define GL_SAME_METHOD_3(glname, name, t1, t2, t3)      \
NS_IMETHODIMP WebGLContext::name(t1 a1, t2 a2, t3 a3) { \
    MakeContextCurrent(); gl->f##glname(a1,a2,a3); return NS_OK;        \
}

#define GL_SAME_METHOD_4(glname, name, t1, t2, t3, t4)         \
NS_IMETHODIMP WebGLContext::name(t1 a1, t2 a2, t3 a3, t4 a4) { \
    MakeContextCurrent(); gl->f##glname(a1,a2,a3,a4); return NS_OK;     \
}

#define GL_SAME_METHOD_5(glname, name, t1, t2, t3, t4, t5)            \
NS_IMETHODIMP WebGLContext::name(t1 a1, t2 a2, t3 a3, t4 a4, t5 a5) { \
    MakeContextCurrent(); gl->f##glname(a1,a2,a3,a4,a5); return NS_OK;  \
}

#define GL_SAME_METHOD_6(glname, name, t1, t2, t3, t4, t5, t6)          \
NS_IMETHODIMP WebGLContext::name(t1 a1, t2 a2, t3 a3, t4 a4, t5 a5, t6 a6) { \
    MakeContextCurrent(); gl->f##glname(a1,a2,a3,a4,a5,a6); return NS_OK; \
}

/* Helper function taking a BaseInterfaceType pointer and check that it matches the required concrete
 * implementation type (if it's non-null), that it's not null/deleted unless we allowed it to,
 * and obtain a pointer to the concrete object.
 *
 * By default, null (respectively: deleted) aInterface pointers are not allowed, but if you pass a
 * non-null isNull (respectively: isDeleted) pointer, then they become allowed and the value at
 * isNull (respecively isDeleted) is overwritten. In case of a null pointer, the resulting 
 */

template<class ConcreteObjectType, class BaseInterfaceType>
static PRBool
GetConcreteObject(BaseInterfaceType *aInterface,
                  ConcreteObjectType **aConcreteObject,
                  PRBool *isNull = 0,
                  PRBool *isDeleted = 0)
{
    if (!aInterface) {
        if (NS_LIKELY(isNull)) {
            // non-null isNull means that the caller will accept a null arg
            *isNull = PR_TRUE;
            if(isDeleted) *isDeleted = PR_FALSE;
            *aConcreteObject = 0;
            return PR_TRUE;
        } else {
            WebGLContext::LogMessage("Null object passed to WebGL function");
            return PR_FALSE;
        }
    }

    if (isNull) {
        *isNull = PR_FALSE;
    }

    nsresult rv;
    nsCOMPtr<ConcreteObjectType> tmp(do_QueryInterface(aInterface, &rv));
    if (NS_FAILED(rv)) {
        return PR_FALSE;
    }

    *aConcreteObject = tmp;

    if ((*aConcreteObject)->Deleted()) {
        if (NS_LIKELY(isDeleted)) {
            // non-null isDeleted means that the caller will accept a deleted arg
            *isDeleted = PR_TRUE;
            return PR_TRUE;
        } else {
            WebGLContext::LogMessage("Deleted object passed to WebGL function");
            return PR_FALSE;
        }
    }

    if (isDeleted)
      *isDeleted = PR_FALSE;

    return PR_TRUE;
}

/* Same as GetConcreteObject, and in addition gets the GL object name.
 * Null objects give the name 0.
 */
template<class ConcreteObjectType, class BaseInterfaceType>
static 
PRBool
GetConcreteObjectAndGLName(BaseInterfaceType *aInterface,
                           ConcreteObjectType **aConcreteObject,
                           GLuint *aGLObjectName,
                           PRBool *isNull = 0,
                           PRBool *isDeleted = 0)
{
    PRBool result = GetConcreteObject(aInterface, aConcreteObject, isNull, isDeleted);
    if(result == PR_FALSE) return PR_FALSE;
    *aGLObjectName = *aConcreteObject ? (*aConcreteObject)->GLName() : 0;
    return PR_TRUE;
}

/* Same as GetConcreteObjectAndGLName when you don't need the concrete object pointer.
 */
template<class ConcreteObjectType, class BaseInterfaceType>
static
PRBool
GetGLName(BaseInterfaceType *aInterface,
          GLuint *aGLObjectName,
          PRBool *isNull = 0,
          PRBool *isDeleted = 0)
{
    ConcreteObjectType *aConcreteObject;
    return GetConcreteObjectAndGLName(aInterface, &aConcreteObject, aGLObjectName, isNull, isDeleted);
}

/* Same as GetConcreteObject when you only want to check if the conversion succeeds.
 */
template<class ConcreteObjectType, class BaseInterfaceType>
static
PRBool
CheckConversion(BaseInterfaceType *aInterface,
                PRBool *isNull = 0,
                PRBool *isDeleted = 0)
{
  ConcreteObjectType *aConcreteObject;
  return GetConcreteObject(aInterface, &aConcreteObject, isNull, isDeleted);
}


//
//  WebGL API
//

/* readonly attribute nsIDOMHTMLCanvasElement canvas; */
NS_IMETHODIMP
WebGLContext::GetCanvas(nsIDOMHTMLCanvasElement **aCanvas)
{
    return NS_ERROR_NOT_IMPLEMENTED;
}


/* void present (); */
NS_IMETHODIMP
WebGLContext::Present()
{
    return NS_ERROR_NOT_IMPLEMENTED;
}

/* long sizeInBytes (in GLenum type); */
NS_IMETHODIMP
WebGLContext::SizeInBytes(GLenum type, PRInt32 *retval)
{
    if (type == LOCAL_GL_FLOAT) *retval = sizeof(float);
    if (type == LOCAL_GL_SHORT) *retval = sizeof(short);
    if (type == LOCAL_GL_UNSIGNED_SHORT) *retval = sizeof(unsigned short);
    if (type == LOCAL_GL_BYTE) *retval = 1;
    if (type == LOCAL_GL_UNSIGNED_BYTE) *retval = 1;
    if (type == LOCAL_GL_INT) *retval = sizeof(int);
    if (type == LOCAL_GL_UNSIGNED_INT) *retval = sizeof(unsigned int);
    if (type == LOCAL_GL_DOUBLE) *retval = sizeof(double);
    return NS_OK;
}

/* void GlActiveTexture (in PRUint32 texture); */
NS_IMETHODIMP
WebGLContext::ActiveTexture(PRUint32 texture)
{
    if (texture < LOCAL_GL_TEXTURE0 || texture >= LOCAL_GL_TEXTURE0+mBound2DTextures.Length())
        return NS_ERROR_DOM_SYNTAX_ERR;

    MakeContextCurrent();
    mActiveTexture = texture - LOCAL_GL_TEXTURE0;
    gl->fActiveTexture(texture);
    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::AttachShader(nsIWebGLProgram *pobj, nsIWebGLShader *shobj)
{
    GLuint progname, shadername;
    if (!GetGLName<WebGLProgram>(pobj, &progname) ||
        !GetGLName<WebGLShader>(shobj, &shadername))
    {
        return NS_ERROR_DOM_SYNTAX_ERR;
    }

    MakeContextCurrent();

    gl->fAttachShader(progname, shadername);

    return NS_OK;
}


NS_IMETHODIMP
WebGLContext::BindAttribLocation(nsIWebGLProgram *pobj, GLuint location, const nsAString& name)
{
    GLuint progname;
    if (!GetGLName<WebGLProgram>(pobj, &progname))
        return NS_ERROR_DOM_SYNTAX_ERR;

    if (name.IsEmpty())
        return ErrorMessage("glBindAttribLocation: name can't be null or empty!");

    MakeContextCurrent();

    gl->fBindAttribLocation(progname, location, NS_LossyConvertUTF16toASCII(name).get());

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::BindBuffer(GLenum target, nsIWebGLBuffer *bobj)
{
    GLuint bufname;
    WebGLBuffer* buf;
    PRBool isNull;
    if (!GetConcreteObjectAndGLName(bobj, &buf, &bufname, &isNull))
        return NS_ERROR_DOM_SYNTAX_ERR;

    //printf ("BindBuffer0: %04x\n", gl->fGetError());

    if (target == LOCAL_GL_ARRAY_BUFFER) {
        mBoundArrayBuffer = buf;
    } else if (target == LOCAL_GL_ELEMENT_ARRAY_BUFFER) {
        mBoundElementArrayBuffer = buf;
    } else {
        return ErrorMessage("glBindBuffer: invalid target!");
    }

    MakeContextCurrent();

    gl->fBindBuffer(target, bufname);

    //printf ("BindBuffer: %04x\n", gl->fGetError());

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::BindFramebuffer(GLenum target, nsIWebGLFramebuffer *fbobj)
{
    GLuint framebuffername;
    PRBool isNull;
    WebGLFramebuffer *wfb;

    if (target != LOCAL_GL_FRAMEBUFFER)
        return ErrorMessage("glBindFramebuffer: target must be GL_FRAMEBUFFER");

    if (!GetConcreteObjectAndGLName(fbobj, &wfb, &framebuffername, &isNull))
        return NS_ERROR_DOM_SYNTAX_ERR;

    MakeContextCurrent();

    gl->fBindFramebuffer(target, framebuffername);

    mBoundFramebuffer = wfb;

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::BindRenderbuffer(GLenum target, nsIWebGLRenderbuffer *rbobj)
{
    GLuint renderbuffername;
    PRBool isNull;
    WebGLRenderbuffer *wrb;

    if (!GetConcreteObjectAndGLName(rbobj, &wrb, &renderbuffername, &isNull))
        return NS_ERROR_DOM_SYNTAX_ERR;

    if (target != LOCAL_GL_RENDERBUFFER)
        return ErrorMessage("glBindRenderbuffer: target must be GL_RENDERBUFFER");

    MakeContextCurrent();

    gl->fBindRenderbuffer(target, renderbuffername);

    mBoundRenderbuffer = wrb;

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::BindTexture(GLenum target, nsIWebGLTexture *tobj)
{
    GLuint texturename;
    WebGLTexture *tex;
    PRBool isNull;
    if (!GetConcreteObjectAndGLName(tobj, &tex, &texturename, &isNull))
        return NS_ERROR_DOM_SYNTAX_ERR;

    if (target == LOCAL_GL_TEXTURE_2D) {
        mBound2DTextures[mActiveTexture] = tex;
    } else if (target == LOCAL_GL_TEXTURE_CUBE_MAP) {
        mBoundCubeMapTextures[mActiveTexture] = tex;
    } else {
        return ErrorMessage("glBindTexture: invalid target");
    }

    MakeContextCurrent();

    gl->fBindTexture(target, texturename);

    return NS_OK;
}

GL_SAME_METHOD_4(BlendColor, BlendColor, float, float, float, float)

GL_SAME_METHOD_1(BlendEquation, BlendEquation, PRUint32)

GL_SAME_METHOD_2(BlendEquationSeparate, BlendEquationSeparate, PRUint32, PRUint32)

GL_SAME_METHOD_2(BlendFunc, BlendFunc, PRUint32, PRUint32)

GL_SAME_METHOD_4(BlendFuncSeparate, BlendFuncSeparate, PRUint32, PRUint32, PRUint32, PRUint32)

NS_IMETHODIMP
WebGLContext::BufferData(PRInt32 dummy)
{
    // this should never be called
    LogMessage("BufferData");
    return NS_ERROR_FAILURE;
}

NS_IMETHODIMP
WebGLContext::BufferData_size(GLenum target, GLsizei size, GLenum usage)
{
    WebGLBuffer *boundBuffer = NULL;

    if (target == LOCAL_GL_ARRAY_BUFFER) {
        boundBuffer = mBoundArrayBuffer;
    } else if (target == LOCAL_GL_ELEMENT_ARRAY_BUFFER) {
        boundBuffer = mBoundElementArrayBuffer;
    } else {
        return ErrorMessage("BufferData: invalid target");
    }

    if (boundBuffer == nsnull)
        return ErrorMessage("BufferData: no buffer bound!");

    MakeContextCurrent();

    // XXX what happens if BufferData fails? We probably shouldn't
    // update our size here then, right?
    boundBuffer->SetByteLength(size);
    gl->fBufferData(target, size, 0, usage);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::BufferData_buf(GLenum target, js::ArrayBuffer *wb, GLenum usage)
{
    WebGLBuffer *boundBuffer = NULL;

    if (target == LOCAL_GL_ARRAY_BUFFER) {
        boundBuffer = mBoundArrayBuffer;
    } else if (target == LOCAL_GL_ELEMENT_ARRAY_BUFFER) {
        boundBuffer = mBoundElementArrayBuffer;
    } else {
        return ErrorMessage("BufferData: invalid target");
    }

    if (boundBuffer == nsnull)
        return ErrorMessage("BufferData: no buffer bound!");

    MakeContextCurrent();

    boundBuffer->SetByteLength(wb->byteLength);
    gl->fBufferData(target, wb->byteLength, wb->data, usage);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::BufferData_array(GLenum target, js::TypedArray *wa, GLenum usage)
{
    WebGLBuffer *boundBuffer = NULL;

    if (target == LOCAL_GL_ARRAY_BUFFER) {
        boundBuffer = mBoundArrayBuffer;
    } else if (target == LOCAL_GL_ELEMENT_ARRAY_BUFFER) {
        boundBuffer = mBoundElementArrayBuffer;
    } else {
        return ErrorMessage("BufferData: invalid target");
    }

    if (boundBuffer == nsnull)
        return ErrorMessage("BufferData: no buffer bound!");

    MakeContextCurrent();

    boundBuffer->SetByteLength(wa->byteLength);
    gl->fBufferData(target, wa->byteLength, wa->data, usage);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::BufferSubData(PRInt32 dummy)
{
    return NS_ERROR_FAILURE;
}

NS_IMETHODIMP
WebGLContext::BufferSubData_buf(GLenum target, GLsizei offset, js::ArrayBuffer *wb)
{
    WebGLBuffer *boundBuffer = NULL;

    if (target == LOCAL_GL_ARRAY_BUFFER) {
        boundBuffer = mBoundArrayBuffer;
    } else if (target == LOCAL_GL_ELEMENT_ARRAY_BUFFER) {
        boundBuffer = mBoundElementArrayBuffer;
    } else {
        return ErrorMessage("BufferSubData: invalid target");
    }

    if (boundBuffer == nsnull)
        return ErrorMessage("BufferSubData: no buffer bound!");

    // XXX check for overflow
    if (offset + wb->byteLength > boundBuffer->ByteLength())
        return ErrorMessage("BufferSubData: data too big! Operation requires %d bytes, but buffer only has %d bytes.", offset, wb->byteLength, boundBuffer->ByteLength());

    MakeContextCurrent();

    gl->fBufferSubData(target, offset, wb->byteLength, wb->data);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::BufferSubData_array(GLenum target, GLsizei offset, js::TypedArray *wa)
{
    WebGLBuffer *boundBuffer = NULL;

    if (target == LOCAL_GL_ARRAY_BUFFER) {
        boundBuffer = mBoundArrayBuffer;
    } else if (target == LOCAL_GL_ELEMENT_ARRAY_BUFFER) {
        boundBuffer = mBoundElementArrayBuffer;
    } else {
        return ErrorMessage("BufferSubData: invalid target");
    }

    if (boundBuffer == nsnull)
        return ErrorMessage("BufferSubData: no buffer bound!");

    // XXX check for overflow
    if (offset + wa->byteLength > boundBuffer->ByteLength())
        return ErrorMessage("BufferSubData: data too big! Operation requires %d bytes, but buffer only has %d bytes.", offset, wa->byteLength, boundBuffer->ByteLength());

    MakeContextCurrent();

    gl->fBufferSubData(target, offset, wa->byteLength, wa->data);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::CheckFramebufferStatus(GLenum target, GLenum *retval)
{
    MakeContextCurrent();
    // XXX check target
    *retval = gl->fCheckFramebufferStatus(target);
    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::Clear(PRUint32 mask)
{
    MakeContextCurrent();
    gl->fClear(mask);
    Invalidate();

    return NS_OK;
}

GL_SAME_METHOD_4(ClearColor, ClearColor, float, float, float, float)

#ifdef USE_GLES2
GL_SAME_METHOD_1(ClearDepthf, ClearDepth, float)
#else
GL_SAME_METHOD_1(ClearDepth, ClearDepth, float)
#endif

GL_SAME_METHOD_1(ClearStencil, ClearStencil, PRInt32)

GL_SAME_METHOD_4(ColorMask, ColorMask, GLboolean, GLboolean, GLboolean, GLboolean)

NS_IMETHODIMP
WebGLContext::CopyTexImage2D(GLenum target,
                               GLint level,
                               GLenum internalformat,
                               GLint x,
                               GLint y,
                               GLsizei width,
                               GLsizei height,
                               GLint border)
{
    switch (target) {
        case LOCAL_GL_TEXTURE_2D:
        case LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_X:
        case LOCAL_GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
        case LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
        case LOCAL_GL_TEXTURE_CUBE_MAP_NEGATIVE_Y:
        case LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_Z:
        case LOCAL_GL_TEXTURE_CUBE_MAP_NEGATIVE_Z:
            break;
        default:
            return ErrorMessage("copyTexImage2D: unsupported target");
    }

    switch (internalformat) {
        case LOCAL_GL_RGB:
        case LOCAL_GL_RGBA:
        case LOCAL_GL_ALPHA:
        case LOCAL_GL_LUMINANCE:
        case LOCAL_GL_LUMINANCE_ALPHA:
            break;
        default:
            return ErrorMessage("copyTexImage2D: internal format not supported");
    }

    if (border != 0) {
        return ErrorMessage("copyTexImage2D: border != 0");
    }

    if (!CanvasUtils::CheckSaneSubrectSize(x,y,width, height, mWidth, mHeight)) {
        return ErrorMessage("copyTexImage2D: copied rectangle out of bounds");
    }

    MakeContextCurrent();

    gl->fCopyTexImage2D(target, level, internalformat, x, y, width, height, border);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::CopyTexSubImage2D(GLenum target,
                                  GLint level,
                                  GLint xoffset,
                                  GLint yoffset,
                                  GLint x,
                                  GLint y,
                                  GLsizei width,
                                  GLsizei height)
{
    switch (target) {
        case LOCAL_GL_TEXTURE_2D:
        case LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_X:
        case LOCAL_GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
        case LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
        case LOCAL_GL_TEXTURE_CUBE_MAP_NEGATIVE_Y:
        case LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_Z:
        case LOCAL_GL_TEXTURE_CUBE_MAP_NEGATIVE_Z:
            break;
        default:
            return ErrorMessage("copyTexSubImage2D: unsupported target");
    }

    if (!CanvasUtils::CheckSaneSubrectSize(x,y,width, height, mWidth, mHeight)) {
        return ErrorMessage("copyTexSubImage2D: copied rectangle out of bounds");
    }

    MakeContextCurrent();

    gl->fCopyTexSubImage2D(target, level, xoffset, yoffset, x, y, width, height);

    return NS_OK;
}


NS_IMETHODIMP
WebGLContext::CreateProgram(nsIWebGLProgram **retval)
{
    MakeContextCurrent();

    GLuint name = gl->fCreateProgram();

    WebGLProgram *prog = new WebGLProgram(name);
    if (prog) {
        NS_ADDREF(*retval = prog);
        mMapPrograms.Put(name, prog);
    } else {
        gl->fDeleteProgram(name);
    }

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::CreateShader(GLenum type, nsIWebGLShader **retval)
{
    MakeContextCurrent();

    GLuint name = gl->fCreateShader(type);

    WebGLShader *shader = new WebGLShader(name);
    if (shader) {
        NS_ADDREF(*retval = shader);
        mMapShaders.Put(name, shader);
    } else {
        gl->fDeleteShader(name);
    }

    return NS_OK;
}

GL_SAME_METHOD_1(CullFace, CullFace, GLenum)

NS_IMETHODIMP
WebGLContext::DeleteBuffer(nsIWebGLBuffer *bobj)
{
    GLuint bufname;
    WebGLBuffer *buf;
    PRBool isNull, isDeleted;
    if (!GetConcreteObjectAndGLName(bobj, &buf, &bufname, &isNull, &isDeleted))
        return NS_ERROR_DOM_SYNTAX_ERR;

    if (isNull || isDeleted) {
        return NS_OK;
    }

    MakeContextCurrent();

    gl->fDeleteBuffers(1, &bufname);
    buf->Delete();
    mMapBuffers.Remove(bufname);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::DeleteFramebuffer(nsIWebGLFramebuffer *fbobj)
{
    GLuint fbufname;
    WebGLFramebuffer *fbuf;
    PRBool isNull, isDeleted;
    if (!GetConcreteObjectAndGLName(fbobj, &fbuf, &fbufname, &isNull, &isDeleted))
        return NS_ERROR_DOM_SYNTAX_ERR;

    if (isNull || isDeleted) {
        return NS_OK;
    }

    MakeContextCurrent();

    gl->fDeleteFramebuffers(1, &fbufname);
    fbuf->Delete();
    mMapFramebuffers.Remove(fbufname);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::DeleteRenderbuffer(nsIWebGLRenderbuffer *rbobj)
{
    GLuint rbufname;
    WebGLRenderbuffer *rbuf;
    PRBool isNull, isDeleted;
    if (!GetConcreteObjectAndGLName(rbobj, &rbuf, &rbufname, &isNull, &isDeleted))
        return NS_ERROR_DOM_SYNTAX_ERR;

    if (isNull || isDeleted) {
        return NS_OK;
    }

    MakeContextCurrent();

    // XXX we need to track renderbuffer attachments; from glDeleteRenderbuffers man page:

    /*
            If a renderbuffer object that is currently bound is deleted, the binding reverts
            to 0 (the absence of any renderbuffer object). Additionally, special care
            must be taken when deleting a renderbuffer object if the image of the renderbuffer
            is attached to a framebuffer object. In this case, if the deleted renderbuffer object is
            attached to the currently bound framebuffer object, it is 
            automatically detached.  However, attachments to any other framebuffer objects are the
            responsibility of the application.
    */

    gl->fDeleteRenderbuffers(1, &rbufname);
    rbuf->Delete();
    mMapRenderbuffers.Remove(rbufname);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::DeleteTexture(nsIWebGLTexture *tobj)
{
    GLuint texname;
    WebGLTexture *tex;
    PRBool isNull, isDeleted;
    if (!GetConcreteObjectAndGLName(tobj, &tex, &texname, &isNull, &isDeleted))
        return NS_ERROR_DOM_SYNTAX_ERR;

    if (isNull || isDeleted) {
        return NS_OK;
    }

    MakeContextCurrent();

    gl->fDeleteTextures(1, &texname);
    tex->Delete();
    mMapTextures.Remove(texname);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::DeleteProgram(nsIWebGLProgram *pobj)
{
    GLuint progname;
    WebGLProgram *prog;
    PRBool isNull, isDeleted;
    if (!GetConcreteObjectAndGLName(pobj, &prog, &progname, &isNull, &isDeleted))
        return NS_ERROR_DOM_SYNTAX_ERR;

    if (isNull || isDeleted) {
        return NS_OK;
    }

    MakeContextCurrent();

    gl->fDeleteProgram(progname);
    prog->Delete();
    mMapPrograms.Remove(progname);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::DeleteShader(nsIWebGLShader *sobj)
{
    GLuint shadername;
    WebGLShader *shader;
    PRBool isNull, isDeleted;
    if (!GetConcreteObjectAndGLName(sobj, &shader, &shadername, &isNull, &isDeleted))
        return NS_ERROR_DOM_SYNTAX_ERR;

    if (isNull || isDeleted) {
        return NS_OK;
    }

    MakeContextCurrent();

    gl->fDeleteShader(shadername);
    shader->Delete();
    mMapShaders.Remove(shadername);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::DetachShader(nsIWebGLProgram *pobj, nsIWebGLShader *shobj)
{
    GLuint program, shader;
    if (!GetGLName<WebGLProgram>(pobj, &program) ||
        !GetGLName<WebGLShader>(shobj, &shader))
    {
        return NS_ERROR_DOM_SYNTAX_ERR;
    }

    MakeContextCurrent();

    gl->fDetachShader(program, shader);

    return NS_OK;
}

GL_SAME_METHOD_1(DepthFunc, DepthFunc, GLenum)

GL_SAME_METHOD_1(DepthMask, DepthMask, GLboolean)

#ifdef USE_GLES2
GL_SAME_METHOD_2(DepthRangef, DepthRange, float, float)
#else
GL_SAME_METHOD_2(DepthRange, DepthRange, float, float)
#endif

// XXX arg check!
GL_SAME_METHOD_1(Disable, Disable, GLenum)

NS_IMETHODIMP
WebGLContext::DisableVertexAttribArray(GLuint index)
{
    if (index > mAttribBuffers.Length())
        return ErrorMessage("glDisableVertexAttribArray: index out of range");

    MakeContextCurrent();

    gl->fDisableVertexAttribArray(index);
    mAttribBuffers[index].enabled = PR_FALSE;

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::DrawArrays(GLenum mode, GLint offset, GLsizei count)
{
    switch (mode) {
        case LOCAL_GL_TRIANGLES:
        case LOCAL_GL_TRIANGLE_STRIP:
        case LOCAL_GL_TRIANGLE_FAN:
        case LOCAL_GL_POINTS:
        case LOCAL_GL_LINE_STRIP:
        case LOCAL_GL_LINE_LOOP:
        case LOCAL_GL_LINES:
            break;
        default:
            return ErrorMessage("drawArrays: invalid mode");
    }

    if (offset+count < offset || offset+count < count) {
        return ErrorMessage("drawArrays: overflow in offset+count");
    }

    if (!ValidateBuffers(offset+count))
        return NS_ERROR_INVALID_ARG;

    MakeContextCurrent();

    //printf ("DrawArrays0: %04x\n", gl->fGetError());

    gl->fDrawArrays(mode, offset, count);

    //printf ("DrawArrays: %04x\n", gl->fGetError());

    Invalidate();

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::DrawElements(GLenum mode, GLuint count, GLenum type, GLuint offset)
{
    int elementSize = 0;

    switch (mode) {
        case LOCAL_GL_TRIANGLES:
        case LOCAL_GL_TRIANGLE_STRIP:
        case LOCAL_GL_TRIANGLE_FAN:
        case LOCAL_GL_POINTS:
        case LOCAL_GL_LINE_STRIP:
        case LOCAL_GL_LINE_LOOP:
        case LOCAL_GL_LINES:
            break;
        default:
            return ErrorMessage("drawElements: invalid mode");
    }

    switch (type) {
        case LOCAL_GL_UNSIGNED_SHORT:
            elementSize = 2;
            if (offset % 2 != 0)
                return ErrorMessage("drawElements: invalid offset (must be a multiple of 2) for UNSIGNED_SHORT");
            break;

        case LOCAL_GL_UNSIGNED_BYTE:
            elementSize = 1;
            break;

        default:
            return ErrorMessage("drawElements: type must be UNSIGNED_SHORT or UNSIGNED_BYTE");
    }

    if (!mBoundElementArrayBuffer)
        return ErrorMessage("glDrawElements: must have element array buffer binding!");

    if (offset+count < offset || offset+count < count)
        return ErrorMessage("glDrawElements: overflow in offset+count");

    if (count*elementSize + offset > mBoundElementArrayBuffer->ByteLength())
        return ErrorMessage("glDrawElements: bound element array buffer is too small for given count and offset");

    MakeContextCurrent();

    // XXXmark fix validation
    // XXX either GLushort or GLubyte; just put this calculation as a method on the array object
#if 0
    GLuint maxindex = 0;
    GLushort *ubuf = (GLushort*) gl->fMapBuffer(LOCAL_GL_ELEMENT_ARRAY_BUFFER, LOCAL_GL_READ_ONLY);
    if (!ubuf)
        return ErrorMessage("glDrawElements: failed to map ELEMENT_ARRAY_BUFFER for validation!");

    ubuf += offset;

    // XXX cache results for this count,offset pair!
    for (PRUint32 i = 0; i < count; ++i)
        maxindex = NS_MAX(maxindex, *ubuf++);

    gl->fUnmapBuffer(LOCAL_GL_ELEMENT_ARRAY_BUFFER);

    if (!ValidateBuffers(maxindex))
        return ErrorMessage("glDrawElements: ValidateBuffers failed");
#endif

    gl->fDrawElements(mode, count, type, (GLvoid*) (offset));

    Invalidate();

    return NS_OK;
}

// XXX definitely need to validate this
GL_SAME_METHOD_1(Enable, Enable, PRUint32)

NS_IMETHODIMP
WebGLContext::EnableVertexAttribArray(GLuint index)
{
    if (index > mAttribBuffers.Length())
        return ErrorMessage("glEnableVertexAttribArray: index out of range");

    MakeContextCurrent();

    gl->fEnableVertexAttribArray(index);
    mAttribBuffers[index].enabled = PR_TRUE;

    return NS_OK;
}

// XXX need to track this -- see glDeleteRenderbuffer above and man page for DeleteRenderbuffers
NS_IMETHODIMP
WebGLContext::FramebufferRenderbuffer(GLenum target, GLenum attachment, GLenum rbtarget, nsIWebGLRenderbuffer *rbobj)
{
    GLuint renderbuffername;
    PRBool isNull;
    WebGLRenderbuffer *wrb;

    if (!GetConcreteObjectAndGLName(rbobj, &wrb, &renderbuffername, &isNull))
        return NS_ERROR_DOM_SYNTAX_ERR;

    if (target != LOCAL_GL_FRAMEBUFFER)
        return ErrorMessage("glFramebufferRenderbuffer: target must be GL_FRAMEBUFFER");

    if ((attachment < LOCAL_GL_COLOR_ATTACHMENT0 ||
         attachment >= LOCAL_GL_COLOR_ATTACHMENT0 + mFramebufferColorAttachments.Length()) &&
        attachment != LOCAL_GL_DEPTH_ATTACHMENT &&
        attachment != LOCAL_GL_STENCIL_ATTACHMENT)
    {
        return ErrorMessage("glFramebufferRenderbuffer: invalid attachment");
    }

    if (rbtarget != LOCAL_GL_RENDERBUFFER)
        return ErrorMessage("glFramebufferRenderbuffer: rbtarget must be GL_RENDERBUFFER");

    // dimensions are kept for readPixels primarily, function only uses COLOR_ATTACHMENT0
    if (mBoundFramebuffer && attachment == LOCAL_GL_COLOR_ATTACHMENT0)
        mBoundFramebuffer->setDimensions(wrb);

    MakeContextCurrent();

    gl->fFramebufferRenderbuffer(target, attachment, rbtarget, renderbuffername);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::FramebufferTexture2D(GLenum target,
                                   GLenum attachment,
                                   GLenum textarget,
                                   nsIWebGLTexture *tobj,
                                   GLint level)
{
    GLuint texturename;
    PRBool isNull;
    WebGLTexture *wtex;

    if (!GetConcreteObjectAndGLName(tobj, &wtex, &texturename, &isNull))
        return NS_ERROR_DOM_SYNTAX_ERR;

    if (target != LOCAL_GL_FRAMEBUFFER)
        return ErrorMessage("glFramebufferTexture2D: target must be GL_FRAMEBUFFER");

    if ((attachment < LOCAL_GL_COLOR_ATTACHMENT0 ||
         attachment >= LOCAL_GL_COLOR_ATTACHMENT0 + mFramebufferColorAttachments.Length()) &&
        attachment != LOCAL_GL_DEPTH_ATTACHMENT &&
        attachment != LOCAL_GL_STENCIL_ATTACHMENT)
        return ErrorMessage("glFramebufferTexture2D: invalid attachment");

    if (textarget != LOCAL_GL_TEXTURE_2D &&
        (textarget < LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_X ||
         textarget > LOCAL_GL_TEXTURE_CUBE_MAP_NEGATIVE_Z))
        return ErrorMessage("glFramebufferTexture2D: invalid textarget (only 2D or cube face)");

    if (level != 0)
        return ErrorMessage("glFramebufferTexture2D: level must be 0");

    // dimensions are kept for readPixels primarily, function only uses COLOR_ATTACHMENT0
    if (mBoundFramebuffer && attachment == LOCAL_GL_COLOR_ATTACHMENT0)
        mBoundFramebuffer->setDimensions(wtex);

    // XXXXX we need to store/reference this attachment!

    MakeContextCurrent();

    gl->fFramebufferTexture2D(target, attachment, textarget, texturename, level);

    return NS_OK;
}

GL_SAME_METHOD_0(Flush, Flush)

GL_SAME_METHOD_0(Finish, Finish)

GL_SAME_METHOD_1(FrontFace, FrontFace, GLenum)

GL_SAME_METHOD_1(GenerateMipmap, GenerateMipmap, GLenum)

// returns an object: { size: ..., type: ..., name: ... }
NS_IMETHODIMP
WebGLContext::GetActiveAttrib(nsIWebGLProgram *pobj, PRUint32 index, nsIWebGLActiveInfo **retval)
{
    GLuint progname;
    if (!GetGLName<WebGLProgram>(pobj, &progname))
        return NS_ERROR_DOM_SYNTAX_ERR;

    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    MakeContextCurrent();

    GLint len = 0;
    gl->fGetProgramiv(progname, LOCAL_GL_ACTIVE_ATTRIBUTE_MAX_LENGTH, &len);
    if (len == 0)
        return NS_ERROR_FAILURE;

    nsAutoArrayPtr<char> name(new char[len+1]);
    PRInt32 attrsize = 0;
    PRUint32 attrtype = 0;

    gl->fGetActiveAttrib(progname, index, len+1, &len, (GLint*) &attrsize, (GLuint*) &attrtype, name);
    if (attrsize == 0 || attrtype == 0)
        return NS_ERROR_FAILURE;

    JSObjectHelper retobj(&js);
    retobj.DefineProperty("size", attrsize);
    retobj.DefineProperty("type", attrtype);
    retobj.DefineProperty("name", name, len);

    js.SetRetVal(retobj);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::GetActiveUniform(nsIWebGLProgram *pobj, PRUint32 index, nsIWebGLActiveInfo **retval)
{
    GLuint progname;
    if (!GetGLName<WebGLProgram>(pobj, &progname))
        return NS_ERROR_DOM_SYNTAX_ERR;

    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    MakeContextCurrent();

    GLint len = 0;
    gl->fGetProgramiv(progname, LOCAL_GL_ACTIVE_UNIFORM_MAX_LENGTH, &len);
    if (len == 0)
        return NS_ERROR_FAILURE;

    nsAutoArrayPtr<char> name(new char[len+1]);
    PRInt32 attrsize = 0;
    PRUint32 attrtype = 0;

    gl->fGetActiveUniform(progname, index, len+1, &len, (GLint*) &attrsize, (GLenum*) &attrtype, name);
    if (attrsize == 0 || attrtype == 0)
        return NS_ERROR_FAILURE;

    JSObjectHelper retobj(&js);
    retobj.DefineProperty("size", attrsize);
    retobj.DefineProperty("type", attrtype);
    retobj.DefineProperty("name", name, len);

    js.SetRetVal(retobj.Object());

    return NS_OK;
}

// XXX fixme to return a IntArray
#if 0
NS_IMETHODIMP
WebGLContext::GetAttachedShaders(nsIWebGLProgram *pobj)
{
    nsresult rv;
    nsCOMPtr<WebGLProgram> prog = do_QueryInterface(pobj, &rv);
    if (NS_FAILED(rv))
        return NS_ERROR_DOM_SYNTAX_ERR;

    if (!prog || static_cast<WebGLProgram*>(prog)->Deleted())
        return ErrorMessage("%s: program is null or deleted!", __FUNCTION__);

    GLuint program = static_cast<WebGLProgram*>(prog)->GLName();

    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    MakeContextCurrent();

    GLint count = 0;
    gl->fGetProgramiv(program, LOCAL_GL_ATTACHED_SHADERS, &count);
    if (count == 0) {
        JSObject *empty = JS_NewArrayObject(js.ctx, 0, NULL);
        js.SetRetVal(empty);
        return NS_OK;
    }

    nsAutoArrayPtr<PRUint32> shaders(new PRUint32[count]);

    gl->fGetAttachedShaders(program, count, NULL, (GLuint*) shaders.get());

    JSObject *obj = NativeJSContext::ArrayToJSArray(js.ctx, shaders, count);

    js.AddGCRoot(obj, "GetAttachedShaders");
    js.SetRetVal(obj);
    js.ReleaseGCRoot(obj);

    return NS_OK;
}
#endif

NS_IMETHODIMP
WebGLContext::GetAttribLocation(nsIWebGLProgram *pobj,
                                const nsAString& name,
                                PRInt32 *retval)
{
    GLuint progname;
    if (!GetGLName<WebGLProgram>(pobj, &progname))
        return NS_ERROR_DOM_SYNTAX_ERR;

    MakeContextCurrent();
    *retval = gl->fGetAttribLocation(progname, NS_LossyConvertUTF16toASCII(name).get());
    return NS_OK;
}

// XXX fixme to return objects correctly for programs/etc.
NS_IMETHODIMP
WebGLContext::GetParameter(PRUint32 pname)
{
    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    MakeContextCurrent();

    switch (pname) {
        //
        // String params
        //

        // XXX do we want to fake these?  Could be a problem to reveal this to web content
        case LOCAL_GL_VENDOR:
        case LOCAL_GL_RENDERER:
        case LOCAL_GL_VERSION:
        case LOCAL_GL_SHADING_LANGUAGE_VERSION:
        //case LOCAL_GL_EXTENSIONS:  // Not going to expose this

            break;

        //
        // Single-value params
        //

// int
        case LOCAL_GL_ARRAY_BUFFER_BINDING:
        case LOCAL_GL_ELEMENT_ARRAY_BUFFER_BINDING: // XXX really?
        case LOCAL_GL_CULL_FACE_MODE:
        case LOCAL_GL_FRONT_FACE:
        case LOCAL_GL_TEXTURE_BINDING_2D:
        case LOCAL_GL_TEXTURE_BINDING_CUBE_MAP:
        case LOCAL_GL_ACTIVE_TEXTURE:
        case LOCAL_GL_STENCIL_WRITEMASK:
        case LOCAL_GL_STENCIL_BACK_WRITEMASK:
        case LOCAL_GL_DEPTH_CLEAR_VALUE:
        case LOCAL_GL_STENCIL_CLEAR_VALUE:
        case LOCAL_GL_STENCIL_FUNC:
        case LOCAL_GL_STENCIL_VALUE_MASK:
        case LOCAL_GL_STENCIL_REF:
        case LOCAL_GL_STENCIL_FAIL:
        case LOCAL_GL_STENCIL_PASS_DEPTH_FAIL:
        case LOCAL_GL_STENCIL_PASS_DEPTH_PASS:
        case LOCAL_GL_STENCIL_BACK_FUNC:
        case LOCAL_GL_STENCIL_BACK_VALUE_MASK:
        case LOCAL_GL_STENCIL_BACK_REF:
        case LOCAL_GL_STENCIL_BACK_FAIL:
        case LOCAL_GL_STENCIL_BACK_PASS_DEPTH_FAIL:
        case LOCAL_GL_STENCIL_BACK_PASS_DEPTH_PASS:
        case LOCAL_GL_DEPTH_FUNC:
        case LOCAL_GL_BLEND_SRC_RGB:
        case LOCAL_GL_BLEND_SRC_ALPHA:
        case LOCAL_GL_BLEND_DST_RGB:
        case LOCAL_GL_BLEND_DST_ALPHA:
        case LOCAL_GL_BLEND_EQUATION_RGB:
        case LOCAL_GL_BLEND_EQUATION_ALPHA:
        //case LOCAL_GL_UNPACK_ALIGNMENT: // not supported
        //case LOCAL_GL_PACK_ALIGNMENT: // not supported
        case LOCAL_GL_CURRENT_PROGRAM:
        case LOCAL_GL_GENERATE_MIPMAP_HINT:
        case LOCAL_GL_SUBPIXEL_BITS:
        case LOCAL_GL_MAX_TEXTURE_SIZE:
        case LOCAL_GL_MAX_CUBE_MAP_TEXTURE_SIZE:
        case LOCAL_GL_MAX_ELEMENTS_INDICES:
        case LOCAL_GL_MAX_ELEMENTS_VERTICES:
        case LOCAL_GL_SAMPLE_BUFFERS:
        case LOCAL_GL_SAMPLES:
        //case LOCAL_GL_COMPRESSED_TEXTURE_FORMATS:
        //case LOCAL_GL_NUM_COMPRESSED_TEXTURE_FORMATS:
        //case LOCAL_GL_SHADER_BINARY_FORMATS:
        //case LOCAL_GL_NUM_SHADER_BINARY_FORMATS:
        case LOCAL_GL_MAX_VERTEX_ATTRIBS:
        case LOCAL_GL_MAX_VERTEX_UNIFORM_COMPONENTS:
        case LOCAL_GL_MAX_VARYING_FLOATS:
        case LOCAL_GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS:
        case LOCAL_GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS:
        case LOCAL_GL_MAX_TEXTURE_IMAGE_UNITS:
        case LOCAL_GL_MAX_FRAGMENT_UNIFORM_COMPONENTS:
        case LOCAL_GL_MAX_RENDERBUFFER_SIZE:
        case LOCAL_GL_RED_BITS:
        case LOCAL_GL_GREEN_BITS:
        case LOCAL_GL_BLUE_BITS:
        case LOCAL_GL_ALPHA_BITS:
        case LOCAL_GL_DEPTH_BITS:
        case LOCAL_GL_STENCIL_BITS:
        //case LOCAL_GL_IMPLEMENTATION_COLOR_READ_TYPE:
        //case LOCAL_GL_IMPLEMENTATION_COLOR_READ_FORMAT:
        case LOCAL_GL_RENDERBUFFER_BINDING:
        case LOCAL_GL_FRAMEBUFFER_BINDING:
        {
            PRInt32 iv = 0;
            gl->fGetIntegerv(pname, (GLint*) &iv);
            js.SetRetVal(iv);
        }
            break;

// float
        case LOCAL_GL_LINE_WIDTH:
        case LOCAL_GL_POLYGON_OFFSET_FACTOR:
        case LOCAL_GL_POLYGON_OFFSET_UNITS:
        case LOCAL_GL_SAMPLE_COVERAGE_VALUE:
        {
            float fv = 0;
            gl->fGetFloatv(pname, &fv);
            js.SetRetVal((double) fv);
        }
            break;
// bool
        case LOCAL_GL_SAMPLE_COVERAGE_INVERT:
        case LOCAL_GL_COLOR_WRITEMASK:
        case LOCAL_GL_DEPTH_WRITEMASK:
        ////case LOCAL_GL_SHADER_COMPILER: // pretty much must be true 
        {
            realGLboolean bv = 0;
            gl->fGetBooleanv(pname, &bv);
            js.SetBoolRetVal(bv);
        }
            break;

        //
        // Complex values
        //
        case LOCAL_GL_DEPTH_RANGE: // 2 floats
        case LOCAL_GL_ALIASED_POINT_SIZE_RANGE: // 2 floats
        case LOCAL_GL_ALIASED_LINE_WIDTH_RANGE: // 2 floats
        {
            float fv[2] = { 0 };
            gl->fGetFloatv(pname, &fv[0]);
            js.SetRetVal(fv, 2);
        }
            break;
        
        case LOCAL_GL_COLOR_CLEAR_VALUE: // 4 floats
        case LOCAL_GL_BLEND_COLOR: // 4 floats
        {
            float fv[4] = { 0 };
            gl->fGetFloatv(pname, &fv[0]);
            js.SetRetVal(fv, 4);
        }
            break;

        case LOCAL_GL_MAX_VIEWPORT_DIMS: // 2 ints
        {
            PRInt32 iv[2] = { 0 };
            gl->fGetIntegerv(pname, (GLint*) &iv[0]);
            js.SetRetVal(iv, 2);
        }
            break;

        case LOCAL_GL_SCISSOR_BOX: // 4 ints
        case LOCAL_GL_VIEWPORT: // 4 ints
        {
            PRInt32 iv[4] = { 0 };
            gl->fGetIntegerv(pname, (GLint*) &iv[0]);
            js.SetRetVal(iv, 4);
        }
            break;

        default:
            return NS_ERROR_NOT_IMPLEMENTED;
    }

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::GetBufferParameter(GLenum target, GLenum pname)
{
    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    MakeContextCurrent();

    switch (pname) {
        case LOCAL_GL_BUFFER_SIZE:
        case LOCAL_GL_BUFFER_USAGE:
        case LOCAL_GL_BUFFER_ACCESS:
        case LOCAL_GL_BUFFER_MAPPED:
        {
            PRInt32 iv = 0;
            gl->fGetBufferParameteriv(target, pname, (GLint*) &iv);
            js.SetRetVal(iv);
        }
            break;

        default:
            return NS_ERROR_NOT_IMPLEMENTED;
    }

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::GetFramebufferAttachmentParameter(GLenum target, GLenum attachment, GLenum pname)
{
    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    MakeContextCurrent();

    switch (attachment) {
        case LOCAL_GL_COLOR_ATTACHMENT0:
        case LOCAL_GL_DEPTH_ATTACHMENT:
        case LOCAL_GL_STENCIL_ATTACHMENT:
            break;
        default:
            return NS_ERROR_NOT_IMPLEMENTED;
    }

    switch (pname) {
        case LOCAL_GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE:
        case LOCAL_GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME:
        case LOCAL_GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL:
        case LOCAL_GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE:
        {
            PRInt32 iv = 0;
            gl->fGetFramebufferAttachmentParameteriv(target, attachment, pname, (GLint*) &iv);
            js.SetRetVal(iv);
        }
            break;

        default:
            return NS_ERROR_NOT_IMPLEMENTED;
    }

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::GetRenderbufferParameter(GLenum target, GLenum pname)
{
    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    MakeContextCurrent();

    switch (pname) {
        case LOCAL_GL_RENDERBUFFER_WIDTH:
        case LOCAL_GL_RENDERBUFFER_HEIGHT:
        case LOCAL_GL_RENDERBUFFER_INTERNAL_FORMAT:
        case LOCAL_GL_RENDERBUFFER_RED_SIZE:
        case LOCAL_GL_RENDERBUFFER_GREEN_SIZE:
        case LOCAL_GL_RENDERBUFFER_BLUE_SIZE:
        case LOCAL_GL_RENDERBUFFER_ALPHA_SIZE:
        case LOCAL_GL_RENDERBUFFER_DEPTH_SIZE:
        case LOCAL_GL_RENDERBUFFER_STENCIL_SIZE:
        {
            PRInt32 iv = 0;
            gl->fGetRenderbufferParameteriv(target, pname, (GLint*) &iv);
            js.SetRetVal(iv);
        }
            break;

        default:
            return NS_ERROR_NOT_IMPLEMENTED;
    }

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::CreateBuffer(nsIWebGLBuffer **retval)
{
    MakeContextCurrent();

    GLuint name;
    gl->fGenBuffers(1, &name);

    WebGLBuffer *globj = new WebGLBuffer(name);
    if (globj) {
        NS_ADDREF(*retval = globj);
        mMapBuffers.Put(name, globj);
    } else {
        gl->fDeleteBuffers(1, &name);
    }

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::CreateTexture(nsIWebGLTexture **retval)
{
    MakeContextCurrent();

    GLuint name;
    gl->fGenTextures(1, &name);

    WebGLTexture *globj = new WebGLTexture(name);
    if (globj) {
        NS_ADDREF(*retval = globj);
        mMapTextures.Put(name, globj);
    } else {
        gl->fDeleteTextures(1, &name);
    }

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::GetError(GLenum *_retval)
{
    MakeContextCurrent();
    *_retval = gl->fGetError();
    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::GetProgramParameter(nsIWebGLProgram *pobj, PRUint32 pname)
{
    GLuint progname;
    if (!GetGLName<WebGLProgram>(pobj, &progname))
        return NS_ERROR_DOM_SYNTAX_ERR;

    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    MakeContextCurrent();

    switch (pname) {
        case LOCAL_GL_CURRENT_PROGRAM:
        case LOCAL_GL_DELETE_STATUS:
        case LOCAL_GL_LINK_STATUS:
        case LOCAL_GL_VALIDATE_STATUS:
        case LOCAL_GL_ATTACHED_SHADERS:
        case LOCAL_GL_INFO_LOG_LENGTH:
        case LOCAL_GL_ACTIVE_UNIFORMS:
        case LOCAL_GL_ACTIVE_UNIFORM_MAX_LENGTH:
        case LOCAL_GL_ACTIVE_ATTRIBUTES:
        case LOCAL_GL_ACTIVE_ATTRIBUTE_MAX_LENGTH:
        {
            PRInt32 iv = 0;
            gl->fGetProgramiv(progname, pname, (GLint*) &iv);
            js.SetRetVal(iv);
        }
            break;

        default:
            return NS_ERROR_NOT_IMPLEMENTED;
    }

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::GetProgramInfoLog(nsIWebGLProgram *pobj, nsAString& retval)
{
    GLuint progname;
    if (!GetGLName<WebGLProgram>(pobj, &progname))
        return NS_ERROR_DOM_SYNTAX_ERR;

    MakeContextCurrent();

    PRInt32 k = -1;
    gl->fGetProgramiv(progname, LOCAL_GL_INFO_LOG_LENGTH, (GLint*) &k);
    if (k == -1)
        return NS_ERROR_FAILURE;

    if (k == 0) {
        retval.Truncate();
        return NS_OK;
    }

    nsCAutoString log;
    log.SetCapacity(k);

    gl->fGetProgramInfoLog(progname, k, (GLint*) &k, (char*) log.BeginWriting());

    log.SetLength(k);

    CopyASCIItoUTF16(log, retval);

    return NS_OK;
}

/* DOMString glGetString (in GLenum name); */
NS_IMETHODIMP
WebGLContext::GetString(GLenum name, nsAString & _retval NS_OUTPARAM)
{
    return NS_ERROR_NOT_IMPLEMENTED;
}

/* XXX fix */
/* void texParameter (); */
NS_IMETHODIMP
WebGLContext::TexParameterf(GLenum target, GLenum pname, GLfloat param)
{
    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    if (js.argc != 3)
        return NS_ERROR_DOM_SYNTAX_ERR;

    MakeContextCurrent();

    gl->fTexParameterf (target, pname, param);

    return NS_OK;
}
NS_IMETHODIMP
WebGLContext::TexParameteri(GLenum target, GLenum pname, GLint param)
{
    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    if (js.argc != 3)
        return NS_ERROR_DOM_SYNTAX_ERR;

    MakeContextCurrent();

    gl->fTexParameteri (target, pname, param);

    return NS_OK;
}

#if 0
NS_IMETHODIMP
WebGLContext::TexParameter()
{
    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    if (js.argc != 3)
        return NS_ERROR_DOM_SYNTAX_ERR;

    jsuint targetVal;
    jsuint pnameVal;
    if (!::JS_ValueToECMAUint32(js.ctx, js.argv[0], &targetVal) ||
        !::JS_ValueToECMAUint32(js.ctx, js.argv[1], &pnameVal))
        return NS_ERROR_DOM_SYNTAX_ERR;

    if (targetVal != LOCAL_GL_TEXTURE_2D &&
        targetVal != LOCAL_GL_TEXTURE_CUBE_MAP)
    {
        return NS_ERROR_DOM_SYNTAX_ERR;
    }

    MakeContextCurrent();
    switch (pnameVal) {
        case LOCAL_GL_TEXTURE_MIN_FILTER: {
            jsuint ival;
            if (!::JS_ValueToECMAUint32(js.ctx, js.argv[2], &ival) ||
                (ival != LOCAL_GL_NEAREST &&
                 ival != LOCAL_GL_LINEAR &&
                 ival != LOCAL_GL_NEAREST_MIPMAP_NEAREST &&
                 ival != LOCAL_GL_LINEAR_MIPMAP_NEAREST &&
                 ival != LOCAL_GL_NEAREST_MIPMAP_LINEAR &&
                 ival != LOCAL_GL_LINEAR_MIPMAP_LINEAR))
                return NS_ERROR_DOM_SYNTAX_ERR;
            gl->fTexParameteri (targetVal, pnameVal, ival);
        }
            break;
        case LOCAL_GL_TEXTURE_MAG_FILTER: {
            jsuint ival;
            if (!::JS_ValueToECMAUint32(js.ctx, js.argv[2], &ival) ||
                (ival != LOCAL_GL_NEAREST &&
                 ival != LOCAL_GL_LINEAR))
                return NS_ERROR_DOM_SYNTAX_ERR;
            gl->fTexParameteri (targetVal, pnameVal, ival);
        }
            break;
        case LOCAL_GL_TEXTURE_WRAP_S:
        case LOCAL_GL_TEXTURE_WRAP_T: {
            jsuint ival;
            if (!::JS_ValueToECMAUint32(js.ctx, js.argv[2], &ival) ||
                (ival != LOCAL_GL_CLAMP &&
                 ival != LOCAL_GL_CLAMP_TO_EDGE &&
                 ival != LOCAL_GL_REPEAT))
                return NS_ERROR_DOM_SYNTAX_ERR;
            gl->fTexParameteri (targetVal, pnameVal, ival);
        }
            break;
        case LOCAL_GL_GENERATE_MIPMAP: {
            jsuint ival;
            if (js.argv[2] == JSVAL_TRUE)
                ival = 1;
            else if (js.argv[2] == JSVAL_FALSE)
                ival = 0;
            else if (!::JS_ValueToECMAUint32(js.ctx, js.argv[2], &ival) ||
                     (ival != 0 && ival != 1))
                return NS_ERROR_DOM_SYNTAX_ERR;
            gl->fTexParameteri (targetVal, pnameVal, ival);
        }
            break;
        case LOCAL_GL_TEXTURE_MAX_ANISOTROPY_EXT: {
#if 0
            if (GLEW_EXT_texture_filter_anisotropic) {
                jsdouble dval;
                if (!::JS_ValueToNumber(js.ctx, js.argv[2], &dval))
                    return NS_ERROR_DOM_SYNTAX_ERR;
                gl->fTexParameterf (targetVal, pnameVal, (float) dval);
            } else {
                return NS_ERROR_NOT_IMPLEMENTED;
            }
#else
            return NS_ERROR_NOT_IMPLEMENTED;
#endif
        }
            break;
        default:
            return NS_ERROR_DOM_SYNTAX_ERR;
    }

    return NS_OK;
}
#endif

NS_IMETHODIMP
WebGLContext::GetTexParameter(GLenum target, GLenum pname)
{
    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    MakeContextCurrent();

    switch (pname) {
        case LOCAL_GL_TEXTURE_MIN_FILTER:
        case LOCAL_GL_TEXTURE_MAG_FILTER:
        case LOCAL_GL_TEXTURE_WRAP_S:
        case LOCAL_GL_TEXTURE_WRAP_T:
        {
            float fv = 0;
            gl->fGetTexParameterfv(target, pname, (GLfloat*) &fv);
            js.SetRetVal(fv);
        }
            break;

        default:
            return NS_ERROR_NOT_IMPLEMENTED;
    }

    return NS_OK;
}

/* XXX fix */
/* any getUniform(in WebGLProgram program, in WebGLUniformLocation location) raises(DOMException); */
NS_IMETHODIMP
WebGLContext::GetUniform(nsIWebGLProgram *pobj, GLint location)
{
    GLuint progname;
    if (!GetGLName<WebGLProgram>(pobj, &progname))
        return NS_ERROR_DOM_SYNTAX_ERR;

    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    MakeContextCurrent();

    GLint uArraySize = 0;
    GLenum uType = 0;

    gl->fGetActiveUniform(progname, location, 0, NULL, &uArraySize, &uType, NULL);
    if (uArraySize == 0)
        return NS_ERROR_FAILURE;

    // glGetUniform needs to be called for each element of an array separately, so we don't
    // have to deal with uArraySize at all.

    GLenum baseType;
    GLint unitSize;
    if (!BaseTypeAndSizeFromUniformType(uType, &baseType, &unitSize))
        return NS_ERROR_FAILURE;

    // this should never happen
    if (unitSize > 16)
        return NS_ERROR_FAILURE;

    if (baseType == LOCAL_GL_FLOAT) {
        GLfloat fv[16];
        gl->fGetUniformfv(progname, location, fv);
        js.SetRetVal(fv, unitSize);
    } else if (baseType == LOCAL_GL_INT) {
        GLint iv[16];
        gl->fGetUniformiv(progname, location, iv);
        js.SetRetVal((PRInt32*)iv, unitSize);
    } else {
        js.SetRetValAsJSVal(JSVAL_NULL);
    }

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::GetUniformLocation(nsIWebGLProgram *pobj, const nsAString& name, GLint *retval)
{
    GLuint progname;
    if (!GetGLName<WebGLProgram>(pobj, &progname))
        return NS_ERROR_DOM_SYNTAX_ERR;

    MakeContextCurrent();
    *retval = gl->fGetUniformLocation(progname, NS_LossyConvertUTF16toASCII(name).get());
    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::GetVertexAttrib(GLuint index, GLenum pname)
{
    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    MakeContextCurrent();

    switch (pname) {
        // int
        case LOCAL_GL_VERTEX_ATTRIB_ARRAY_SIZE:
        case LOCAL_GL_VERTEX_ATTRIB_ARRAY_STRIDE:
        case LOCAL_GL_VERTEX_ATTRIB_ARRAY_TYPE:
        case LOCAL_GL_VERTEX_ATTRIB_ARRAY_ENABLED:
        case LOCAL_GL_VERTEX_ATTRIB_ARRAY_NORMALIZED:
        case LOCAL_GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING:
        {
            PRInt32 iv = 0;
            gl->fGetVertexAttribiv(index, pname, (GLint*) &iv);
            js.SetRetVal(iv);
        }
            break;

        case LOCAL_GL_CURRENT_VERTEX_ATTRIB:
        {
            GLfloat fv[4] = { 0 };
            gl->fGetVertexAttribfv(index, LOCAL_GL_CURRENT_VERTEX_ATTRIB, &fv[0]);
            js.SetRetVal(fv, 4);
        }
            break;

        // not supported; doesn't make sense to return a pointer unless we have some kind of buffer object abstraction
        case LOCAL_GL_VERTEX_ATTRIB_ARRAY_POINTER:
        default:
            return NS_ERROR_NOT_IMPLEMENTED;

    }

    return NS_OK;
}

/* GLuint getVertexAttribOffset (in GLuint index, in GLenum pname); */
NS_IMETHODIMP
WebGLContext::GetVertexAttribOffset(GLuint index, GLenum pname, GLuint *retval)
{
    return NS_ERROR_NOT_IMPLEMENTED;
}

NS_IMETHODIMP
WebGLContext::Hint(GLenum target, GLenum mode)
{
    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::IsBuffer(nsIWebGLBuffer *bobj, GLboolean *retval)
{
    PRBool isDeleted;
    *retval = CheckConversion<WebGLBuffer>(bobj, 0, &isDeleted) && !isDeleted;

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::IsFramebuffer(nsIWebGLFramebuffer *fbobj, GLboolean *retval)
{
    PRBool isDeleted;
    *retval = CheckConversion<WebGLFramebuffer>(fbobj, 0, &isDeleted) && !isDeleted;

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::IsProgram(nsIWebGLProgram *pobj, GLboolean *retval)
{
    PRBool isDeleted;
    *retval = CheckConversion<WebGLProgram>(pobj, 0, &isDeleted) && !isDeleted;

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::IsRenderbuffer(nsIWebGLRenderbuffer *rbobj, GLboolean *retval)
{
    PRBool isDeleted;
    *retval = CheckConversion<WebGLRenderbuffer>(rbobj, 0, &isDeleted) && !isDeleted;

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::IsShader(nsIWebGLShader *sobj, GLboolean *retval)
{
    PRBool isDeleted;
    *retval = CheckConversion<WebGLShader>(sobj, 0, &isDeleted) && !isDeleted;

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::IsTexture(nsIWebGLTexture *tobj, GLboolean *retval)
{
    PRBool isDeleted;
    *retval = CheckConversion<WebGLTexture>(tobj, 0, &isDeleted) && !isDeleted;

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::IsEnabled(GLenum k, GLboolean *retval)
{
    MakeContextCurrent();
    *retval = gl->fIsEnabled(k);
    return NS_OK;
}


GL_SAME_METHOD_1(LineWidth, LineWidth, float)

NS_IMETHODIMP
WebGLContext::LinkProgram(nsIWebGLProgram *pobj)
{
    GLuint progname;
    if (!GetGLName<WebGLProgram>(pobj, &progname))
        return NS_ERROR_DOM_SYNTAX_ERR;

    MakeContextCurrent();

    gl->fLinkProgram(progname);

    return NS_OK;
}

// XXX #if 0
NS_IMETHODIMP
WebGLContext::PixelStorei(GLenum pname, GLint param)
{
    if (pname != LOCAL_GL_PACK_ALIGNMENT &&
        pname != LOCAL_GL_UNPACK_ALIGNMENT)
        return NS_ERROR_INVALID_ARG;

    MakeContextCurrent();
    gl->fPixelStorei(pname, param);

    return NS_OK;
}
//#endif

GL_SAME_METHOD_2(PolygonOffset, PolygonOffset, float, float)

NS_IMETHODIMP
WebGLContext::ReadPixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type)
{
    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    if (mCanvasElement->IsWriteOnly() && !nsContentUtils::IsCallerTrustedForRead()) {
        LogMessage("readPixels: Not allowed");
        return NS_ERROR_DOM_SECURITY_ERR;
    }

    GLsizei boundWidth = mBoundFramebuffer ? mBoundFramebuffer->width() : mWidth;
    GLsizei boundHeight = mBoundFramebuffer ? mBoundFramebuffer->height() : mHeight;
    if (!CanvasUtils::CheckSaneSubrectSize(x, y, width, height, boundWidth, boundHeight))
        return ErrorMessage("readPixels: rectangle outside framebuffer");

    PRUint32 size = 0;
    switch (format) {
      case LOCAL_GL_ALPHA:
        size = 1;
        break;
      case LOCAL_GL_RGB:
        size = 3;
        break;
      case LOCAL_GL_RGBA:
        size = 4;
        break;
      default:
        return ErrorMessage("readPixels: unsupported pixel format");
    }
    switch (type) {
//         case LOCAL_GL_UNSIGNED_SHORT_4_4_4_4:
//         case LOCAL_GL_UNSIGNED_SHORT_5_5_5_1:
//         case LOCAL_GL_UNSIGNED_SHORT_5_6_5:
      case LOCAL_GL_UNSIGNED_BYTE:
        break;
      default:
        return ErrorMessage("readPixels: unsupported pixel type");
    }

    MakeContextCurrent();

    PRUint32 len = width * height * size;
    JSObject *abufObject = js_CreateArrayBuffer(js.ctx, len);
    if (!abufObject)
        return NS_ERROR_FAILURE;
    js::ArrayBuffer *abuf = js::ArrayBuffer::fromJSObject(abufObject);

    gl->fReadPixels((GLint) x, (GLint) y, width, height, format, type, (GLvoid *) abuf->data);

    JSObject *retval = js_CreateTypedArrayWithBuffer(js.ctx, js::TypedArray::TYPE_UINT8, abufObject, 0, len);
    js.SetRetVal(retval);
    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::RenderbufferStorage(GLenum target, GLenum internalformat, GLsizei width, GLsizei height)
{
    if (mBoundRenderbuffer)
        mBoundRenderbuffer->setDimensions(width, height);

    MakeContextCurrent();
    gl->fRenderbufferStorage(target, internalformat, width, height);

    return NS_OK;
}

GL_SAME_METHOD_2(SampleCoverage, SampleCoverage, float, GLboolean)

GL_SAME_METHOD_4(Scissor, Scissor, GLint, GLint, GLsizei, GLsizei)

GL_SAME_METHOD_3(StencilFunc, StencilFunc, GLenum, GLint, GLuint)

GL_SAME_METHOD_4(StencilFuncSeparate, StencilFuncSeparate, GLenum, GLenum, GLint, GLuint)

GL_SAME_METHOD_1(StencilMask, StencilMask, GLuint)

GL_SAME_METHOD_2(StencilMaskSeparate, StencilMaskSeparate, GLenum, GLuint)

GL_SAME_METHOD_3(StencilOp, StencilOp, GLenum, GLenum, GLenum)

GL_SAME_METHOD_4(StencilOpSeparate, StencilOpSeparate, GLenum, GLenum, GLenum, GLenum)


nsresult
WebGLContext::DOMElementToImageSurface(nsIDOMElement *imageOrCanvas,
                                       gfxImageSurface **imageOut,
                                       PRBool flipY, PRBool premultiplyAlpha)
{
    gfxImageSurface *surf = nsnull;

    nsLayoutUtils::SurfaceFromElementResult res =
        nsLayoutUtils::SurfaceFromElement(imageOrCanvas,
                                          nsLayoutUtils::SFE_WANT_NEW_SURFACE | nsLayoutUtils::SFE_WANT_IMAGE_SURFACE);
    if (!res.mSurface)
        return NS_ERROR_FAILURE;

    CanvasUtils::DoDrawImageSecurityCheck(mCanvasElement, res.mPrincipal, res.mIsWriteOnly);

    if (res.mSurface->GetType() != gfxASurface::SurfaceTypeImage) {
        // SurfaceFromElement lied!
        return NS_ERROR_FAILURE;
    }

    surf = static_cast<gfxImageSurface*>(res.mSurface.get());

    PRInt32 width, height;
    width = res.mSize.width;
    height = res.mSize.height;

    if (width <= 0 || height <= 0)
        return NS_ERROR_FAILURE;

    if (surf->Format() == gfxASurface::ImageFormatARGB32) {
        PRUint8* src = surf->Data();
        PRUint8* dst = surf->Data();

        // this wants some SSE love

        for (int j = 0; j < height; j++) {
            src = surf->Data() + j * surf->Stride();
            // note that dst's stride is always tightly packed
            for (int i = 0; i < width; i++) {
#ifdef IS_LITTLE_ENDIAN
                PRUint8 b = *src++;
                PRUint8 g = *src++;
                PRUint8 r = *src++;
                PRUint8 a = *src++;
#else
                PRUint8 a = *src++;
                PRUint8 r = *src++;
                PRUint8 g = *src++;
                PRUint8 b = *src++;
#endif
                // Convert to non-premultiplied color
                if (a != 0) {
                    r = (r * 255) / a;
                    g = (g * 255) / a;
                    b = (b * 255) / a;
                }

                *dst++ = r;
                *dst++ = g;
                *dst++ = b;
                *dst++ = a;
            }
        }
    } else if (surf->Format() == gfxASurface::ImageFormatRGB24) {
        PRUint8* src = surf->Data();
        PRUint8* dst = surf->Data();

        // this wants some SSE love

        for (int j = 0; j < height; j++) {
            src = surf->Data() + j * surf->Stride();
            // note that dst's stride is always tightly packed
            for (int i = 0; i < width; i++) {
#ifdef IS_LITTLE_ENDIAN
                PRUint8 b = *src++;
                PRUint8 g = *src++;
                PRUint8 r = *src++;
                src++;
#else
                src++;
                PRUint8 r = *src++;
                PRUint8 g = *src++;
                PRUint8 b = *src++;
#endif

                *dst++ = r;
                *dst++ = g;
                *dst++ = b;
                *dst++ = 255;
            }
        }
    } else {
        return NS_ERROR_FAILURE;
    }

    if (flipY) {
        nsRefPtr<gfxImageSurface> tmpsurf = new gfxImageSurface(res.mSize,
                                                                gfxASurface::ImageFormatARGB32);
        if (!tmpsurf || tmpsurf->CairoStatus())
            return NS_ERROR_FAILURE;

        nsRefPtr<gfxContext> tmpctx = new gfxContext(tmpsurf);

        if (!tmpctx || tmpctx->HasError())
            return NS_ERROR_FAILURE;

        tmpctx->Translate(gfxPoint(0, res.mSize.height));
        tmpctx->Scale(1.0, -1.0);

        tmpctx->NewPath();
        tmpctx->Rectangle(gfxRect(0, 0, res.mSize.width, res.mSize.height));

        tmpctx->SetSource(res.mSurface);
        tmpctx->SetOperator(gfxContext::OPERATOR_SOURCE);
        tmpctx->Fill();

        NS_ADDREF(surf = tmpsurf);
        tmpctx = nsnull;
    }

    res.mSurface.forget();
    *imageOut = surf;

    return NS_OK;
}

#define GL_SIMPLE_ARRAY_METHOD(name, cnt, arrayType, ptrType)           \
NS_IMETHODIMP                                                           \
WebGLContext::name(PRInt32 dummy) {                                     \
     return NS_ERROR_NOT_IMPLEMENTED;                                   \
}                                                                       \
NS_IMETHODIMP                                                           \
WebGLContext::name##_array(GLint idx, js::TypedArray *wa)               \
{                                                                       \
    if (!wa || wa->type != js::TypedArray::arrayType)                   \
        return ErrorMessage("array must be " #arrayType);               \
    if (wa->length == 0 || wa->length % cnt != 0)                       \
        return ErrorMessage("array must be > 0 elements and have a length multiple of %d", cnt); \
    MakeContextCurrent();                                               \
    gl->f##name(idx, wa->length / cnt, (ptrType *)wa->data);            \
    return NS_OK;                                                       \
}

#define GL_SIMPLE_ARRAY_METHOD_NO_COUNT(name, cnt, arrayType, ptrType)  \
NS_IMETHODIMP                                                           \
WebGLContext::name(PRInt32 dummy) {                                     \
     return NS_ERROR_NOT_IMPLEMENTED;                                   \
}                                                                       \
NS_IMETHODIMP                                                           \
WebGLContext::name##_array(GLuint idx, js::TypedArray *wa)              \
{                                                                       \
    if (!wa || wa->type != js::TypedArray::arrayType)                   \
        return ErrorMessage("array must be " #arrayType);               \
    if (wa->length < cnt)                                               \
        return ErrorMessage("array must be >= %d elements", cnt);       \
    MakeContextCurrent();                                               \
    gl->f##name(idx, (ptrType *)wa->data);                              \
    return NS_OK;                                                       \
}

#define GL_SIMPLE_MATRIX_METHOD(name, dim, arrayType, ptrType)          \
NS_IMETHODIMP                                                           \
WebGLContext::name(PRInt32 dummy) {                                     \
     return NS_ERROR_NOT_IMPLEMENTED;                                   \
}                                                                       \
NS_IMETHODIMP                                                           \
WebGLContext::name##_array(GLint idx, GLboolean transpose, js::TypedArray *wa)  \
{                                                                       \
    if (!wa || wa->type != js::TypedArray::arrayType)                   \
        return ErrorMessage("array must be " #arrayType);               \
    if (wa->length == 0 || wa->length % (dim*dim) != 0)                 \
        return ErrorMessage("array must be > 0 elements and have a length multiple of %d", dim*dim); \
    MakeContextCurrent();                                               \
    gl->f##name(idx, wa->length / (dim*dim), transpose, (ptrType *)wa->data); \
    return NS_OK;                                                       \
}

GL_SAME_METHOD_2(Uniform1i, Uniform1i, GLint, GLint)
GL_SAME_METHOD_3(Uniform2i, Uniform2i, GLint, GLint, GLint)
GL_SAME_METHOD_4(Uniform3i, Uniform3i, GLint, GLint, GLint, GLint)
GL_SAME_METHOD_5(Uniform4i, Uniform4i, GLint, GLint, GLint, GLint, GLint)

GL_SAME_METHOD_2(Uniform1f, Uniform1f, GLint, GLfloat)
GL_SAME_METHOD_3(Uniform2f, Uniform2f, GLint, GLfloat, GLfloat)
GL_SAME_METHOD_4(Uniform3f, Uniform3f, GLint, GLfloat, GLfloat, GLfloat)
GL_SAME_METHOD_5(Uniform4f, Uniform4f, GLint, GLfloat, GLfloat, GLfloat, GLfloat)

GL_SIMPLE_ARRAY_METHOD(Uniform1iv, 1, TYPE_INT32, GLint)
GL_SIMPLE_ARRAY_METHOD(Uniform2iv, 2, TYPE_INT32, GLint)
GL_SIMPLE_ARRAY_METHOD(Uniform3iv, 3, TYPE_INT32, GLint)
GL_SIMPLE_ARRAY_METHOD(Uniform4iv, 4, TYPE_INT32, GLint)

GL_SIMPLE_ARRAY_METHOD(Uniform1fv, 1, TYPE_FLOAT32, GLfloat)
GL_SIMPLE_ARRAY_METHOD(Uniform2fv, 2, TYPE_FLOAT32, GLfloat)
GL_SIMPLE_ARRAY_METHOD(Uniform3fv, 3, TYPE_FLOAT32, GLfloat)
GL_SIMPLE_ARRAY_METHOD(Uniform4fv, 4, TYPE_FLOAT32, GLfloat)

GL_SIMPLE_MATRIX_METHOD(UniformMatrix2fv, 2, TYPE_FLOAT32, GLfloat)
GL_SIMPLE_MATRIX_METHOD(UniformMatrix3fv, 3, TYPE_FLOAT32, GLfloat)
GL_SIMPLE_MATRIX_METHOD(UniformMatrix4fv, 4, TYPE_FLOAT32, GLfloat)

GL_SAME_METHOD_2(VertexAttrib1f, VertexAttrib1f, PRUint32, GLfloat)
GL_SAME_METHOD_3(VertexAttrib2f, VertexAttrib2f, PRUint32, GLfloat, GLfloat)
GL_SAME_METHOD_4(VertexAttrib3f, VertexAttrib3f, PRUint32, GLfloat, GLfloat, GLfloat)
GL_SAME_METHOD_5(VertexAttrib4f, VertexAttrib4f, PRUint32, GLfloat, GLfloat, GLfloat, GLfloat)

GL_SIMPLE_ARRAY_METHOD_NO_COUNT(VertexAttrib1fv, 1, TYPE_FLOAT32, GLfloat)
GL_SIMPLE_ARRAY_METHOD_NO_COUNT(VertexAttrib2fv, 2, TYPE_FLOAT32, GLfloat)
GL_SIMPLE_ARRAY_METHOD_NO_COUNT(VertexAttrib3fv, 3, TYPE_FLOAT32, GLfloat)
GL_SIMPLE_ARRAY_METHOD_NO_COUNT(VertexAttrib4fv, 4, TYPE_FLOAT32, GLfloat)

NS_IMETHODIMP
WebGLContext::UseProgram(nsIWebGLProgram *pobj)
{
    WebGLProgram *prog;
    GLuint progname;
    if (!GetConcreteObjectAndGLName(pobj, &prog, &progname))
        return NS_ERROR_DOM_SYNTAX_ERR;

    MakeContextCurrent();

    gl->fUseProgram(progname);

    mCurrentProgram = prog;

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::ValidateProgram(nsIWebGLProgram *pobj)
{
    GLuint progname;
    if (!GetGLName<WebGLProgram>(pobj, &progname))
        return NS_ERROR_DOM_SYNTAX_ERR;

    MakeContextCurrent();

    gl->fValidateProgram(progname);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::CreateFramebuffer(nsIWebGLFramebuffer **retval)
{
    MakeContextCurrent();

    GLuint name;
    gl->fGenFramebuffers(1, &name);

    WebGLFramebuffer *globj = new WebGLFramebuffer(name);
    if (globj) {
        NS_ADDREF(*retval = globj);
        mMapFramebuffers.Put(name, globj);
    } else {
        gl->fDeleteFramebuffers(1, &name);
    }

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::CreateRenderbuffer(nsIWebGLRenderbuffer **retval)
{
    MakeContextCurrent();

    GLuint name;
    gl->fGenRenderbuffers(1, &name);

    WebGLRenderbuffer *globj = new WebGLRenderbuffer(name);
    if (globj) {
        NS_ADDREF(*retval = globj);
        mMapRenderbuffers.Put(name, globj);
    } else {
        gl->fDeleteRenderbuffers(1, &name);
    }

    return NS_OK;
}

GL_SAME_METHOD_4(Viewport, Viewport, PRInt32, PRInt32, PRInt32, PRInt32)

NS_IMETHODIMP
WebGLContext::CompileShader(nsIWebGLShader *sobj)
{
    GLuint shadername;
    if (!GetGLName<WebGLShader>(sobj, &shadername))
        return NS_ERROR_DOM_SYNTAX_ERR;

    MakeContextCurrent();

    gl->fCompileShader(shadername);

    return NS_OK;
}


NS_IMETHODIMP
WebGLContext::GetShaderParameter(nsIWebGLShader *sobj, GLenum pname)
{
    GLuint shadername;
    if (!GetGLName<WebGLShader>(sobj, &shadername))
        return NS_ERROR_DOM_SYNTAX_ERR;

    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    MakeContextCurrent();

    switch (pname) {
        case LOCAL_GL_SHADER_TYPE:
        case LOCAL_GL_DELETE_STATUS:
        case LOCAL_GL_COMPILE_STATUS:
        case LOCAL_GL_INFO_LOG_LENGTH:
        case LOCAL_GL_SHADER_SOURCE_LENGTH:
        {
            PRInt32 iv = 0;
            gl->fGetShaderiv(shadername, pname, (GLint*) &iv);
            js.SetRetVal(iv);
        }
            break;

        default:
            return NS_ERROR_NOT_IMPLEMENTED;
    }

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::GetShaderInfoLog(nsIWebGLShader *sobj, nsAString& retval)
{
    GLuint shadername;
    if (!GetGLName<WebGLShader>(sobj, &shadername))
        return NS_ERROR_DOM_SYNTAX_ERR;

    MakeContextCurrent();

    PRInt32 k = -1;
    gl->fGetShaderiv(shadername, LOCAL_GL_INFO_LOG_LENGTH, (GLint*) &k);
    if (k == -1)
        return NS_ERROR_FAILURE;

    if (k == 0) {
        retval.Truncate();
        return NS_OK;
    }

    nsCAutoString log;
    log.SetCapacity(k);

    gl->fGetShaderInfoLog(shadername, k, (GLint*) &k, (char*) log.BeginWriting());

    log.SetLength(k);

    CopyASCIItoUTF16(log, retval);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::GetShaderSource(nsIWebGLShader *sobj, nsAString& retval)
{
    GLuint shadername;
    if (!GetGLName<WebGLShader>(sobj, &shadername))
        return NS_ERROR_DOM_SYNTAX_ERR;

    MakeContextCurrent();

    GLint slen = -1;
    gl->fGetShaderiv(shadername, LOCAL_GL_SHADER_SOURCE_LENGTH, &slen);
    if (slen == -1)
        return NS_ERROR_FAILURE;

    if (slen == 0) {
        retval.Truncate();
        return NS_OK;
    }

    nsCAutoString src;
    src.SetCapacity(slen);

    gl->fGetShaderSource(shadername, slen, NULL, (char*) src.BeginWriting());

    src.SetLength(slen);

    CopyASCIItoUTF16(src, retval);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::ShaderSource(nsIWebGLShader *sobj, const nsAString& source)
{
    GLuint shadername;
    if (!GetGLName<WebGLShader>(sobj, &shadername))
        return NS_ERROR_DOM_SYNTAX_ERR;
    
    MakeContextCurrent();

    NS_LossyConvertUTF16toASCII asciisrc(source);
    const char *p = asciisrc.get();

    gl->fShaderSource(shadername, 1, &p, NULL);
    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::VertexAttribPointer(GLuint index, GLint size, GLenum type,
                                  GLboolean normalized, GLuint stride,
                                  GLuint offset)
{
    if (mBoundArrayBuffer == nsnull)
        return ErrorMessage("glvertexattribpointer: must have GL_ARRAY_BUFFER binding!");

    if (index >= mAttribBuffers.Length())
        return ErrorMessage("glVertexAttribPointer: index out of range - %d >= %d", index, mAttribBuffers.Length());

    if (size < 1 || size > 4)
        return ErrorMessage("glVertexAttribPointer: invalid element size");

    /* XXX make work with bufferSubData & heterogeneous types 
    if (type != mBoundArrayBuffer->GLType())
        return ErrorMessage("glVertexAttribPointer: type must match bound VBO type: %d != %d", type, mBoundArrayBuffer->GLType());
    */

    // XXX 0 stride?
    //if (stride < (GLuint) size)
    //    return ErrorMessage("glVertexAttribPointer: stride must be >= size!");

    WebGLVertexAttribData &vd = mAttribBuffers[index];

    vd.buf = mBoundArrayBuffer;
    vd.stride = stride;
    vd.size = size;
    vd.offset = offset;

    MakeContextCurrent();

    gl->fVertexAttribPointer(index, size, type, normalized,
                             stride,
                             (void*) (offset));

    return NS_OK;
}

PRBool
WebGLContext::ValidateGL()
{
    // make sure that the opengl stuff that we need is supported
    GLint val = 0;

    // XXX this exposes some strange latent bug; what's going on?
    //MakeContextCurrent();

    gl->fGetIntegerv(LOCAL_GL_MAX_VERTEX_ATTRIBS, &val);
    if (val == 0) {
        LogMessage("GL_MAX_VERTEX_ATTRIBS is 0!");
        return PR_FALSE;
    }

    mAttribBuffers.SetLength(val);

    //fprintf(stderr, "GL_MAX_VERTEX_ATTRIBS: %d\n", val);

    // Note: GL_MAX_TEXTURE_UNITS is fixed at 4 for most desktop hardware,
    // even though the hardware supports much more.  The
    // GL_MAX_{COMBINED_}TEXTURE_IMAGE_UNITS value is the accurate
    // value.  For GLES2, GL_MAX_TEXTURE_UNITS is still correct.
    gl->fGetIntegerv(LOCAL_GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS, &val);
    if (val == 0) {
        LogMessage("GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS is 0!");
        return PR_FALSE;
    }

    mBound2DTextures.SetLength(val);
    mBoundCubeMapTextures.SetLength(val);

    //fprintf(stderr, "GL_MAX_TEXTURE_UNITS: %d\n", val);

    gl->fGetIntegerv(LOCAL_GL_MAX_COLOR_ATTACHMENTS, &val);
    mFramebufferColorAttachments.SetLength(val);

#ifdef DEBUG_vladimir
    gl->fGetIntegerv(LOCAL_GL_IMPLEMENTATION_COLOR_READ_FORMAT, &val);
    fprintf(stderr, "GL_IMPLEMENTATION_COLOR_READ_FORMAT: 0x%04x\n", val);

    gl->fGetIntegerv(LOCAL_GL_IMPLEMENTATION_COLOR_READ_TYPE, &val);
    fprintf(stderr, "GL_IMPLEMENTATION_COLOR_READ_TYPE: 0x%04x\n", val);
#endif

#ifndef USE_GLES2
    // gl_PointSize is always available in ES2 GLSL
    gl->fEnable(LOCAL_GL_VERTEX_PROGRAM_POINT_SIZE);
#endif

    return PR_TRUE;
}

NS_IMETHODIMP
WebGLContext::TexImage2D(PRInt32 dummy)
{
    return NS_ERROR_FAILURE;
}

nsresult
WebGLContext::TexImage2D_base(GLenum target, GLint level, GLenum internalformat,
                              GLsizei width, GLsizei height, GLint border,
                              GLenum format, GLenum type,
                              void *data, PRUint32 byteLength)
{
    switch (target) {
        case LOCAL_GL_TEXTURE_2D:
        case LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_X:
        case LOCAL_GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
        case LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
        case LOCAL_GL_TEXTURE_CUBE_MAP_NEGATIVE_Y:
        case LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_Z:
        case LOCAL_GL_TEXTURE_CUBE_MAP_NEGATIVE_Z:
            break;
        default:
            return ErrorMessage("texImage2D: unsupported target");
    }

    if (level < 0)
        return ErrorMessage("texImage2D: level must be >= 0");

    switch (internalformat) {
        case LOCAL_GL_RGB:
        case LOCAL_GL_RGBA:
        case LOCAL_GL_ALPHA:
        case LOCAL_GL_LUMINANCE:
        case LOCAL_GL_LUMINANCE_ALPHA:
            break;
        default:
            return ErrorMessage("texImage2D: internal format not supported");
    }

    if (width < 0 || height < 0)
        return ErrorMessage("texImage2D: width and height must be >= 0!");

    if (border != 0)
        return ErrorMessage("texImage2D: border must be 0");

    // number of bytes per pixel
    uint32 bufferPixelSize = 0;
    switch (format) {
        case LOCAL_GL_RED:
        case LOCAL_GL_GREEN:
        case LOCAL_GL_BLUE:
        case LOCAL_GL_ALPHA:
        case LOCAL_GL_LUMINANCE:
            bufferPixelSize = 1;
            break;
        case LOCAL_GL_LUMINANCE_ALPHA:
            bufferPixelSize = 2;
            break;
        case LOCAL_GL_RGB:
            bufferPixelSize = 3;
            break;
        case LOCAL_GL_RGBA:
            bufferPixelSize = 4;
            break;
        default:
            return ErrorMessage("texImage2D: pixel format not supported");
    }

    switch (type) {
        case LOCAL_GL_BYTE:
        case LOCAL_GL_UNSIGNED_BYTE:
            break;
        case LOCAL_GL_SHORT:
        case LOCAL_GL_UNSIGNED_SHORT:
            bufferPixelSize *= 2;
            break;
        case LOCAL_GL_INT:
        case LOCAL_GL_UNSIGNED_INT:
        case LOCAL_GL_FLOAT:
            bufferPixelSize *= 4;
            break;
        case LOCAL_GL_UNSIGNED_SHORT_4_4_4_4:
        case LOCAL_GL_UNSIGNED_SHORT_5_5_5_1:
        case LOCAL_GL_UNSIGNED_SHORT_5_6_5:
            bufferPixelSize *= 2;
            break;
        default:
            return ErrorMessage("texImage2D: invalid type argument");
    }

    // XXX overflow!
    uint32 bytesNeeded = width * height * bufferPixelSize;

    if (byteLength && byteLength < bytesNeeded)
        return ErrorMessage("texImage2D: not enough data for operation (need %d, have %d)", bytesNeeded, byteLength);

    MakeContextCurrent();

    if (byteLength) {
        gl->fTexImage2D(target, level, internalformat, width, height, border, format, type, data);
    } else {
        // We need some zero pages, because GL doesn't guarantee the
        // contents of a texture allocated with NULL data.
        // Hopefully calloc will just mmap zero pages here.
        void *tempZeroData = calloc(1, bytesNeeded);
        if (!tempZeroData)
            return ErrorMessage("texImage2D: could not allocate %d bytes", bytesNeeded);

        gl->fTexImage2D(target, level, internalformat, width, height, border, format, type, tempZeroData);

        free(tempZeroData);
    }

    if (mBound2DTextures[mActiveTexture])
        mBound2DTextures[mActiveTexture]->setDimensions(width, height);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::TexImage2D_buf(GLenum target, GLint level, GLenum internalformat,
                             GLsizei width, GLsizei height, GLint border,
                             GLenum format, GLenum type,
                             js::ArrayBuffer *pixels)
{
    return TexImage2D_base(target, level, internalformat, width, height, border, format, type,
                           pixels ? pixels->data : 0,
                           pixels ? pixels->byteLength : 0);
}

NS_IMETHODIMP
WebGLContext::TexImage2D_array(GLenum target, GLint level, GLenum internalformat,
                               GLsizei width, GLsizei height, GLint border,
                               GLenum format, GLenum type,
                               js::TypedArray *pixels)
{
    return TexImage2D_base(target, level, internalformat, width, height, border, format, type,
                           pixels ? pixels->data : 0,
                           pixels ? pixels->byteLength : 0);
}

NS_IMETHODIMP
WebGLContext::TexImage2D_dom(GLenum target, GLint level,
                             nsIDOMElement *elt,
                             GLboolean flipY, GLboolean premultiplyAlpha)
{
    nsRefPtr<gfxImageSurface> isurf;

    nsresult rv = DOMElementToImageSurface(elt, getter_AddRefs(isurf),
                                           flipY, premultiplyAlpha);
    if (NS_FAILED(rv))
        return rv;

    return TexImage2D_base(target, level, LOCAL_GL_RGBA,
                           isurf->Width(), isurf->Height(), 0,
                           LOCAL_GL_RGBA, LOCAL_GL_UNSIGNED_BYTE,
                           isurf->Data(), isurf->Stride() * isurf->Height());
}

NS_IMETHODIMP
WebGLContext::TexSubImage2D(PRInt32 dummy)
{
    return NS_ERROR_FAILURE;
}

nsresult
WebGLContext::TexSubImage2D_base(GLenum target, GLint level,
                                 GLint xoffset, GLint yoffset,
                                 GLsizei width, GLsizei height,
                                 GLenum format, GLenum type,
                                 void *pixels, PRUint32 byteLength)
{
    switch (target) {
        case LOCAL_GL_TEXTURE_2D:
        case LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_X:
        case LOCAL_GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
        case LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
        case LOCAL_GL_TEXTURE_CUBE_MAP_NEGATIVE_Y:
        case LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_Z:
        case LOCAL_GL_TEXTURE_CUBE_MAP_NEGATIVE_Z:
            break;
        default:
            return ErrorMessage("texSubImage2D: unsupported target");
    }

    if (level < 0)
        return ErrorMessage("texSubImage2D: level must be >= 0");

    if (width <= 0 || height <= 0)
        return ErrorMessage("texSubImage2D: width and height must be > 0!");

    // number of bytes per pixel
    uint32 bufferPixelSize = 0;
    switch (format) {
        case LOCAL_GL_RED:
        case LOCAL_GL_GREEN:
        case LOCAL_GL_BLUE:
        case LOCAL_GL_ALPHA:
        case LOCAL_GL_LUMINANCE:
            bufferPixelSize = 1;
            break;
        case LOCAL_GL_LUMINANCE_ALPHA:
            bufferPixelSize = 2;
            break;
        case LOCAL_GL_RGB:
            bufferPixelSize = 3;
            break;
        case LOCAL_GL_RGBA:
            bufferPixelSize = 4;
            break;
        default:
            return ErrorMessage("texImage2D: pixel format not supported");
    }

    switch (type) {
        case LOCAL_GL_BYTE:
        case LOCAL_GL_UNSIGNED_BYTE:
            break;
        case LOCAL_GL_SHORT:
        case LOCAL_GL_UNSIGNED_SHORT:
            bufferPixelSize *= 2;
            break;
        case LOCAL_GL_INT:
        case LOCAL_GL_UNSIGNED_INT:
        case LOCAL_GL_FLOAT:
            bufferPixelSize *= 4;
            break;
        case LOCAL_GL_UNSIGNED_SHORT_4_4_4_4:
        case LOCAL_GL_UNSIGNED_SHORT_5_5_5_1:
        case LOCAL_GL_UNSIGNED_SHORT_5_6_5:
            bufferPixelSize *= 2;
            break;
        default:
            return ErrorMessage("texImage2D: invalid type argument");
    }

    // XXX overflow!
    uint32 bytesNeeded = width * height * bufferPixelSize;

    if (byteLength < bytesNeeded)
        return ErrorMessage("texSubImage2D: not enough data for operation (need %d, have %d)", bytesNeeded, byteLength);

    MakeContextCurrent();

    gl->fTexSubImage2D(target, level, xoffset, yoffset, width, height, format, type, pixels);

    return NS_OK;
}

NS_IMETHODIMP
WebGLContext::TexSubImage2D_buf(GLenum target, GLint level,
                                GLint xoffset, GLint yoffset,
                                GLsizei width, GLsizei height,
                                GLenum format, GLenum type,
                                js::ArrayBuffer *pixels)
{
    if (!pixels)
        return ErrorMessage("texSubImage2D: pixels must not be null!");

    return TexSubImage2D_base(target, level, xoffset, yoffset,
                              width, height, format, type,
                              pixels->data, pixels->byteLength);
}

NS_IMETHODIMP
WebGLContext::TexSubImage2D_array(GLenum target, GLint level,
                                  GLint xoffset, GLint yoffset,
                                  GLsizei width, GLsizei height,
                                  GLenum format, GLenum type,
                                  js::TypedArray *pixels)
{
    if (!pixels)
        return ErrorMessage("texSubImage2D: pixels must not be null!");

    return TexSubImage2D_base(target, level, xoffset, yoffset,
                              width, height, format, type,
                              pixels->data, pixels->byteLength);
}

NS_IMETHODIMP
WebGLContext::TexSubImage2D_dom(GLenum target, GLint level,
                                GLint xoffset, GLint yoffset,
                                GLsizei width, GLsizei height,
                                nsIDOMElement *elt,
                                GLboolean flipY, GLboolean premultiplyAlpha)
{
    nsRefPtr<gfxImageSurface> isurf;

    nsresult rv = DOMElementToImageSurface(elt, getter_AddRefs(isurf),
                                           flipY, premultiplyAlpha);
    if (NS_FAILED(rv))
        return rv;

    return TexSubImage2D_base(target, level,
                              xoffset, yoffset,
                              width, height,
                              LOCAL_GL_RGBA, LOCAL_GL_UNSIGNED_BYTE,
                              isurf->Data(), isurf->Stride() * isurf->Height());
}

#if 0
// ImageData getImageData (in float x, in float y, in float width, in float height);
NS_IMETHODIMP
WebGLContext::GetImageData(PRUint32 x, PRUint32 y, PRUint32 w, PRUint32 h)
{
    // disabled due to win32 linkage issues with thebes symbols and NS_RELEASE
    return NS_ERROR_FAILURE;

#if 0
    NativeJSContext js;
    if (NS_FAILED(js.error))
        return js.error;

    if (js.argc != 4) return NS_ERROR_INVALID_ARG;
    
    if (!mGLPbuffer ||
        !mGLPbuffer->ThebesSurface())
        return NS_ERROR_FAILURE;

    if (!mCanvasElement)
        return NS_ERROR_FAILURE;

    if (mCanvasElement->IsWriteOnly() && !IsCallerTrustedForRead()) {
        // XXX ERRMSG we need to report an error to developers here! (bug 329026)
        return NS_ERROR_DOM_SECURITY_ERR;
    }

    JSContext *ctx = js.ctx;

    if (!CanvasUtils::CheckSaneSubrectSize (x, y, w, h, mWidth, mHeight))
        return NS_ERROR_DOM_SYNTAX_ERR;

    nsAutoArrayPtr<PRUint8> surfaceData (new (std::nothrow) PRUint8[w * h * 4]);
    int surfaceDataStride = w*4;
    int surfaceDataOffset = 0;

    if (!surfaceData)
        return NS_ERROR_OUT_OF_MEMORY;

    nsRefPtr<gfxImageSurface> tmpsurf = new gfxImageSurface(surfaceData,
                                                            gfxIntSize(w, h),
                                                            w * 4,
                                                            gfxASurface::ImageFormatARGB32);
    if (!tmpsurf || tmpsurf->CairoStatus())
        return NS_ERROR_FAILURE;

    nsRefPtr<gfxContext> tmpctx = new gfxContext(tmpsurf);

    if (!tmpctx || tmpctx->HasError())
        return NS_ERROR_FAILURE;

    nsRefPtr<gfxASurface> surf = mGLPbuffer->ThebesSurface();
    nsRefPtr<gfxPattern> pat = CanvasGLThebes::CreatePattern(surf);
    gfxMatrix m;
    m.Translate(gfxPoint(x, mGLPbuffer->Height()-y));
    m.Scale(1.0, -1.0);
    pat->SetMatrix(m);

    // XXX I don't want to use PixelSnapped here, but layout doesn't guarantee
    // pixel alignment for this stuff!
    tmpctx->NewPath();
    tmpctx->PixelSnappedRectangleAndSetPattern(gfxRect(0, 0, w, h), pat);
    tmpctx->SetOperator(gfxContext::OPERATOR_SOURCE);
    tmpctx->Fill();

    tmpctx = nsnull;
    tmpsurf = nsnull;

    PRUint32 len = w * h * 4;
    if (len > (((PRUint32)0xfff00000)/sizeof(jsval)))
        return NS_ERROR_INVALID_ARG;

    nsAutoArrayPtr<jsval> jsvector(new (std::nothrow) jsval[w * h * 4]);
    if (!jsvector)
        return NS_ERROR_OUT_OF_MEMORY;
    jsval *dest = jsvector.get();
    PRUint8 *row;
    for (PRUint32 j = 0; j < h; j++) {
        row = surfaceData + surfaceDataOffset + (surfaceDataStride * j);
        for (PRUint32 i = 0; i < w; i++) {
            // XXX Is there some useful swizzle MMX we can use here?
            // I guess we have to INT_TO_JSVAL still
#ifdef IS_LITTLE_ENDIAN
            PRUint8 b = *row++;
            PRUint8 g = *row++;
            PRUint8 r = *row++;
            PRUint8 a = *row++;
#else
            PRUint8 a = *row++;
            PRUint8 r = *row++;
            PRUint8 g = *row++;
            PRUint8 b = *row++;
#endif
            // Convert to non-premultiplied color
            if (a != 0) {
                r = (r * 255) / a;
                g = (g * 255) / a;
                b = (b * 255) / a;
            }

            *dest++ = INT_TO_JSVAL(r);
            *dest++ = INT_TO_JSVAL(g);
            *dest++ = INT_TO_JSVAL(b);
            *dest++ = INT_TO_JSVAL(a);
        }
    }

    JSObject *dataArray = JS_NewArrayObject(ctx, w*h*4, jsvector);
    if (!dataArray)
        return NS_ERROR_OUT_OF_MEMORY;

    JSObjectHelper retobj(&js);
    retobj.DefineProperty("width", w);
    retobj.DefineProperty("height", h);
    retobj.DefineProperty("data", dataArray);

    js.SetRetVal(retobj);

    return NS_OK;
#endif
}
#endif

PRBool
BaseTypeAndSizeFromUniformType(GLenum uType, GLenum *baseType, GLint *unitSize)
{
        switch (uType) {
        case LOCAL_GL_INT:
        case LOCAL_GL_INT_VEC2:
        case LOCAL_GL_INT_VEC3:
        case LOCAL_GL_INT_VEC4:
        case LOCAL_GL_SAMPLER_2D:
        case LOCAL_GL_SAMPLER_CUBE:
            *baseType = LOCAL_GL_INT;
            break;
        case LOCAL_GL_FLOAT:
        case LOCAL_GL_FLOAT_VEC2:
        case LOCAL_GL_FLOAT_VEC3:
        case LOCAL_GL_FLOAT_VEC4:
        case LOCAL_GL_FLOAT_MAT2:
        case LOCAL_GL_FLOAT_MAT3:
        case LOCAL_GL_FLOAT_MAT4:
            *baseType = LOCAL_GL_FLOAT;
            break;
        case LOCAL_GL_BOOL:
        case LOCAL_GL_BOOL_VEC2:
        case LOCAL_GL_BOOL_VEC3:
        case LOCAL_GL_BOOL_VEC4:
            *baseType = LOCAL_GL_INT; // pretend these are int
            break;
        default:
            return PR_FALSE;
    }

    switch (uType) {
        case LOCAL_GL_INT:
        case LOCAL_GL_FLOAT:
        case LOCAL_GL_BOOL:
        case LOCAL_GL_SAMPLER_2D:
        case LOCAL_GL_SAMPLER_CUBE:
            *unitSize = 1;
            break;
        case LOCAL_GL_INT_VEC2:
        case LOCAL_GL_FLOAT_VEC2:
        case LOCAL_GL_BOOL_VEC2:
            *unitSize = 2;
            break;
        case LOCAL_GL_INT_VEC3:
        case LOCAL_GL_FLOAT_VEC3:
        case LOCAL_GL_BOOL_VEC3:
            *unitSize = 3;
            break;
        case LOCAL_GL_INT_VEC4:
        case LOCAL_GL_FLOAT_VEC4:
        case LOCAL_GL_BOOL_VEC4:
            *unitSize = 4;
            break;
        case LOCAL_GL_FLOAT_MAT2:
            *unitSize = 4;
            break;
        case LOCAL_GL_FLOAT_MAT3:
            *unitSize = 9;
            break;
        case LOCAL_GL_FLOAT_MAT4:
            *unitSize = 16;
            break;
        default:
            return PR_FALSE;
    }

    return PR_TRUE;
}