Only copy used parts of texture atlas

This will slow as the page gets filled but this simple change improves start up quite a bit
microsoft · Aug 16, 2024 · aef2733 · aef2733
1 parent ec59051
commit aef2733
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Showing 3 changed files with 12 additions and 4 deletions.
diff --git a/src/vs/editor/browser/view/gpu/atlas/atlas.ts b/src/vs/editor/browser/view/gpu/atlas/atlas.ts
@@ -39,6 +39,7 @@ export interface ITextureAtlasAllocator {
 
 export interface IReadableTextureAtlasPage {
 	readonly version: number;
+	readonly usedArea: Readonly<IBoundingBox>;
 	readonly glyphs: IterableIterator<ITextureAtlasGlyph>;
 	readonly source: OffscreenCanvas;
 	getUsagePreview(): Promise<Blob>;

diff --git a/src/vs/editor/browser/view/gpu/atlas/textureAtlasPage.ts b/src/vs/editor/browser/view/gpu/atlas/textureAtlasPage.ts
@@ -6,7 +6,7 @@
 import { Event } from 'vs/base/common/event';
 import { Disposable, toDisposable } from 'vs/base/common/lifecycle';
 import { TwoKeyMap } from 'vs/base/common/map';
-import type { IReadableTextureAtlasPage, ITextureAtlasAllocator, ITextureAtlasGlyph } from 'vs/editor/browser/view/gpu/atlas/atlas';
+import type { IBoundingBox, IReadableTextureAtlasPage, ITextureAtlasAllocator, ITextureAtlasGlyph } from 'vs/editor/browser/view/gpu/atlas/atlas';
 import { TextureAtlasShelfAllocator } from 'vs/editor/browser/view/gpu/atlas/textureAtlasShelfAllocator';
 import { TextureAtlasSlabAllocator } from 'vs/editor/browser/view/gpu/atlas/textureAtlasSlabAllocator';
 import type { GlyphRasterizer } from 'vs/editor/browser/view/gpu/raster/glyphRasterizer';
@@ -16,6 +16,11 @@ import { IThemeService } from 'vs/platform/theme/common/themeService';
 export class TextureAtlasPage extends Disposable implements IReadableTextureAtlasPage {
 	private _version: number = 0;
 
+	private _usedArea: IBoundingBox = { left: 0, top: 0, right: 0, bottom: 0 };
+	public get usedArea(): Readonly<IBoundingBox> {
+		return this._usedArea;
+	}
+
 	/**
 	 * The version of the texture atlas. This is incremented every time the page's texture changes.
 	 */
@@ -82,7 +87,10 @@ export class TextureAtlasPage extends Disposable implements IReadableTextureAtla
 		const glyph = this._allocator.allocate(chars, tokenFg, rasterizedGlyph)!;
 		this._glyphMap.set(chars, tokenFg, glyph);
 		this._glyphInOrderSet.add(glyph);
+
 		this._version++;
+		this._usedArea.right = Math.max(this._usedArea.right, glyph.x + glyph.w);
+		this._usedArea.bottom = Math.max(this._usedArea.bottom, glyph.y + glyph.h);
 
 		if (this._logService.getLevel() === LogLevel.Trace) {
 			this._logService.trace('New glyph', {

diff --git a/src/vs/editor/browser/view/gpu/gpuViewLayer.ts b/src/vs/editor/browser/view/gpu/gpuViewLayer.ts
@@ -326,11 +326,10 @@ export class GpuViewLayerRenderer<T extends IVisibleLine> {
 				entryOffset += SpriteInfoStorageBufferInfo.Size;
 			}
 			this._device.queue.writeBuffer(this._glyphStorageBuffer[layerIndex], 0, values);
-			// TODO: Draw only dirty regions
 			this._device.queue.copyExternalImageToTexture(
 				{ source: page.source },
-				{ texture: this._atlasGpuTexture, origin: { x: 0, y: 0, z: layerIndex } },
-				{ width: page.source.width, height: page.source.height },
+				{ texture: this._atlasGpuTexture, origin: { x: page.usedArea.left, y: page.usedArea.top, z: layerIndex } },
+				{ width: page.usedArea.right - page.usedArea.left, height: page.usedArea.bottom - page.usedArea.top },
 			);
 			this._atlasGpuTextureVersions[layerIndex] = page.version;
 		}