Fixes https://github.com/microsoft/vscode/issues/166158

addons/xterm-addon-canvas/src/BaseRenderLayer.ts

@@ -376,12 +376,12 @@ export abstract class BaseRenderLayer extends Disposable implements IRenderLayer
     this._ctx.save();
     this._clipRow(y);
     // Draw the image, use the bitmap if it's available
-    if (this._charAtlas.pages[glyph.texturePage].hasCanvasChanged) {
+    if (this._charAtlas.pages[glyph.texturePage].dirtyId !== this._bitmapGenerator[glyph.texturePage]?.dirtyId) {
       if (!this._bitmapGenerator[glyph.texturePage]) {
         this._bitmapGenerator[glyph.texturePage] = new BitmapGenerator(this._charAtlas.pages[glyph.texturePage].canvas);
       }
-      this._bitmapGenerator[glyph.texturePage]?.refresh();
-      this._charAtlas.pages[glyph.texturePage].hasCanvasChanged = false;
+      this._bitmapGenerator[glyph.texturePage]!.refresh();
+      this._bitmapGenerator[glyph.texturePage]!.dirtyId = this._charAtlas.pages[glyph.texturePage].dirtyId;
     }
     this._ctx.drawImage(
       this._bitmapGenerator[glyph.texturePage]?.bitmap || this._charAtlas!.pages[glyph.texturePage].canvas,
@@ -440,6 +440,7 @@ class BitmapGenerator {
   private _commitTimeout: number | undefined = undefined;
   private _bitmap: ImageBitmap | undefined = undefined;
   public get bitmap(): ImageBitmap | undefined { return this._bitmap; }
+  public dirtyId: number = -1;
 
   constructor(private readonly _canvas: HTMLCanvasElement) {
   }

addons/xterm-addon-webgl/src/GlyphRenderer.ts

@@ -3,7 +3,7 @@
  * @license MIT
  */
 
-import { createProgram, PROJECTION_MATRIX } from './WebglUtils';
+import { createProgram, GLTexture, PROJECTION_MATRIX } from './WebglUtils';
 import { IWebGL2RenderingContext, IWebGLVertexArrayObject, IRenderModel } from './Types';
 import { NULL_CELL_CODE } from 'common/buffer/Constants';
 import { Terminal } from 'xterm';
@@ -94,7 +94,7 @@ export class GlyphRenderer extends Disposable {
   private readonly _projectionLocation: WebGLUniformLocation;
   private readonly _resolutionLocation: WebGLUniformLocation;
   private readonly _textureLocation: WebGLUniformLocation;
-  private readonly _atlasTextures: WebGLTexture[];
+  private readonly _atlasTextures: GLTexture[];
   private readonly _attributesBuffer: WebGLBuffer;
 
   private _atlas: ITextureAtlas | undefined;
@@ -190,14 +190,14 @@ export class GlyphRenderer extends Disposable {
     // is ever drawn it will show characters as red rectangles.
     this._atlasTextures = [];
     for (let i = 0; i < TextureAtlas.maxAtlasPages; i++) {
-      const texture = throwIfFalsy(gl.createTexture());
-      this.register(toDisposable(() => gl.deleteTexture(texture)));
+      const glTexture = new GLTexture(throwIfFalsy(gl.createTexture()));
+      this.register(toDisposable(() => gl.deleteTexture(glTexture.texture)));
       gl.activeTexture(gl.TEXTURE0 + i);
-      gl.bindTexture(gl.TEXTURE_2D, texture);
+      gl.bindTexture(gl.TEXTURE_2D, glTexture.texture);
       gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
       gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
       gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 1, 1, 0, gl.RGBA, gl.UNSIGNED_BYTE, new Uint8Array([255, 0, 0, 255]));
-      this._atlasTextures[i] = texture;
+      this._atlasTextures[i] = glTexture;
     }
 
     // Allow drawing of transparent texture
@@ -348,8 +348,7 @@ export class GlyphRenderer extends Disposable {
 
     // Bind the atlas page texture if they have changed
     for (let i = 0; i < this._atlas.pages.length; i++) {
-      if (this._atlas.pages[i].hasCanvasChanged) {
-        this._atlas.pages[i].hasCanvasChanged = false;
+      if (this._atlas.pages[i].dirtyId !== this._atlasTextures[i].dirtyId) {
         this._bindAtlasPageTexture(gl, this._atlas, i);
       }
     }
@@ -360,18 +359,19 @@ export class GlyphRenderer extends Disposable {
 
   public setAtlas(atlas: ITextureAtlas): void {
     this._atlas = atlas;
-    for (let i = 0; i < atlas.pages.length; i++) {
-      this._bindAtlasPageTexture(this._gl, atlas, i);
+    for (const glTexture of this._atlasTextures) {
+      glTexture.dirtyId = -1;
     }
   }
 
   private _bindAtlasPageTexture(gl: IWebGL2RenderingContext, atlas: ITextureAtlas, i: number): void {
     gl.activeTexture(gl.TEXTURE0 + i);
-    gl.bindTexture(gl.TEXTURE_2D, this._atlasTextures[i]);
+    gl.bindTexture(gl.TEXTURE_2D, this._atlasTextures[i].texture);
     gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
     gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
     gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, atlas.pages[i].canvas);
     gl.generateMipmap(gl.TEXTURE_2D);
+    this._atlasTextures[i].dirtyId = atlas.pages[i].dirtyId;
   }
 
   public setDimensions(dimensions: IRenderDimensions): void {

addons/xterm-addon-webgl/src/WebglUtils.ts

@@ -51,3 +51,13 @@ export function expandFloat32Array(source: Float32Array, max: number): Float32Ar
   }
   return newArray;
 }
+
+export class GLTexture {
+  public texture: WebGLTexture;
+  public dirtyId: number;
+
+  constructor(texture: WebGLTexture) {
+    this.texture = texture;
+    this.dirtyId = -1;
+  }
+}

src/browser/renderer/shared/TextureAtlas.ts

@@ -61,7 +61,7 @@ export class TextureAtlas implements ITextureAtlas {
 
   // The texture that the atlas is drawn to
   private _pages: AtlasPage[] = [];
-  public get pages(): { canvas: HTMLCanvasElement, hasCanvasChanged: boolean }[] { return this._pages; }
+  public get pages(): { canvas: HTMLCanvasElement, dirtyId: number }[] { return this._pages; }
 
   // The set of atlas pages that can be written to
   private _activePages: AtlasPage[] = [];
@@ -179,7 +179,7 @@ export class TextureAtlas implements ITextureAtlas {
 
         // Merge into the new page
         const mergedPage = this._mergePages(mergingPages, mergedPageIndex);
-        mergedPage.hasCanvasChanged = true;
+        mergedPage.dirtyId++;
 
         // Replace the first _merging_ page with the _merged_ page
         this._pages[mergedPageIndex] = mergedPage;
@@ -238,7 +238,7 @@ export class TextureAtlas implements ITextureAtlas {
       for (const g of adjustingPage.glyphs) {
         g.texturePage--;
       }
-      adjustingPage.hasCanvasChanged = true;
+      adjustingPage.dirtyId++;
     }
   }
 
@@ -826,7 +826,7 @@ export class TextureAtlas implements ITextureAtlas {
       rasterizedGlyph.size.y
     );
     activePage.addGlyph(rasterizedGlyph);
-    activePage.hasCanvasChanged = true;
+    activePage.dirtyId++;
 
     return rasterizedGlyph;
   }
@@ -936,10 +936,9 @@ class AtlasPage {
   }
 
   /**
-   * Whether the canvas of the atlas page has changed, this is only set to true by the atlas, the
-   * user of the boolean is required to reset its value to false.
+   * Used to check whether the canvas of the atlas page has changed.
    */
-  public hasCanvasChanged = false;
+  public dirtyId = 0;
 
   // Texture atlas current positioning data. The texture packing strategy used is to fill from
   // left-to-right and top-to-bottom. When the glyph being written is less than half of the current
@@ -982,7 +981,7 @@ class AtlasPage {
     this.currentRow.y = 0;
     this.currentRow.height = 0;
     this.fixedRows.length = 0;
-    this.hasCanvasChanged = true;
+    this.dirtyId++;
   }
 }
 

src/browser/renderer/shared/Types.d.ts

@@ -87,7 +87,7 @@ export interface IRenderer extends IDisposable {
 }
 
 export interface ITextureAtlas extends IDisposable {
-  readonly pages: { canvas: HTMLCanvasElement, hasCanvasChanged: boolean }[];
+  readonly pages: { canvas: HTMLCanvasElement, dirtyId: number }[];
 
   onAddTextureAtlasCanvas: IEvent<HTMLCanvasElement>;
   onRemoveTextureAtlasCanvas: IEvent<HTMLCanvasElement>;