gecko/gfx/thebes/gfx3DMatrix.h

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 * The Initial Developer of the Original Code is Oracle Corporation.
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 *   Bas Schouten <bschouten@mozilla.com>
 *   Matt Woodrow <mwoodrow@mozilla.com>
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#ifndef GFX_3DMATRIX_H
#define GFX_3DMATRIX_H

#include <gfxTypes.h>
#include <gfxPoint3D.h>
#include <gfxMatrix.h>

/**
 * This class represents a 3D transformation. The matrix is laid
 * out as follows:
 *
 * _11 _12 _13 _14
 * _21 _22 _23 _24
 * _31 _32 _33 _34
 * _41 _42 _43 _44
 *
 * This matrix is treated as row-major. Assuming we consider our vectors row
 * vectors, this matrix type will be identical in memory to the OpenGL and D3D
 * matrices. OpenGL matrices are column-major, however OpenGL also treats
 * vectors as column vectors, the double transposition makes everything work
 * out nicely.
 */
class THEBES_API gfx3DMatrix
{
public:
  /**
   * Create matrix.
   */
  gfx3DMatrix(void);

  /**
   * Matrix multiplication.
   */
  gfx3DMatrix operator*(const gfx3DMatrix &aMatrix) const;
  gfx3DMatrix& operator*=(const gfx3DMatrix &aMatrix);

  /**
   * Return true if this matrix and |aMatrix| are the same matrix.
   */
  bool operator==(const gfx3DMatrix& aMatrix) const;
  
  /**
   * Divide all values in the matrix by a scalar value
   */
  gfx3DMatrix& operator/=(gfxFloat scalar);

  /**
   * Create a 3D matrix from a gfxMatrix 2D affine transformation.
   *
   * \param aMatrix gfxMatrix 2D affine transformation.
   */
  static gfx3DMatrix From2D(const gfxMatrix &aMatrix);

  /**
   * Returns true if the matrix is isomorphic to a 2D affine transformation
   * (i.e. as obtained by From2D). If it is, optionally returns the 2D
   * matrix in aMatrix.
   */
  PRBool Is2D(gfxMatrix* aMatrix = nsnull) const;

  /**
   * Returns true if the matrix is the identity matrix. The most important
   * property we require is that gfx3DMatrix().IsIdentity() returns true.
   */
  PRBool IsIdentity() const;

  /**
   * Transforms a point according to this matrix.
   */
  gfxPoint Transform(const gfxPoint& point) const;

  /**
   * Transforms a rectangle according to this matrix
   */
  gfxRect TransformBounds(const gfxRect& rect) const;

  /** 
   * Transforms a 3D vector according to this matrix.
   */
  gfxPoint3D Transform3D(const gfxPoint3D& point) const;

  gfxPoint ProjectPoint(const gfxPoint& aPoint) const;
  gfxRect ProjectRectBounds(const gfxRect& aRect) const;


  /**
   * Inverts this matrix, if possible. Otherwise, the matrix is left
   * unchanged.
   */
  gfx3DMatrix& Invert();

  inline gfx3DMatrix Inverse() const
  {
    gfx3DMatrix temp = *this;
    temp.Invert();
    return temp;
  }

  /**
   * Returns a unit vector that is perpendicular to the plane formed
   * by transform the screen plane (z=0) by this matrix.
   */
  gfxPoint3D GetNormalVector() const;

  /**
   * Check if matrix is singular (no inverse exists).
   */
  PRBool IsSingular() const;

  /**
   * Create a translation matrix.
   *
   * \param aX Translation on X-axis.
   * \param aY Translation on Y-axis.
   * \param aZ Translation on Z-axis.
   */
  static gfx3DMatrix Translation(float aX, float aY, float aZ);

  /**
   * Create a scale matrix. Scales uniformly along all axes.
   *
   * \param aScale Scale factor
   */
  static gfx3DMatrix Scale(float aFactor);

  /**
   * Create a scale matrix.
   */
  static gfx3DMatrix Scale(float aX, float aY, float aZ);

private:

  gfxFloat Determinant() const;

public:

  /** Matrix elements */
  float _11, _12, _13, _14;
  float _21, _22, _23, _24;
  float _31, _32, _33, _34;
  float _41, _42, _43, _44;
};

#endif /* GFX_3DMATRIX_H */