Texture Compression (#143)

This PR introduces initial support for .KTX and .PVR contained
compressed textures. The format will be internally indicated.

examples/tests/tx-compression.ts

@@ -0,0 +1,62 @@
+/*
+ * If not stated otherwise in this file or this component's LICENSE file the
+ * following copyright and licenses apply:
+ *
+ * Copyright 2023 Comcast Cable Communications Management, LLC.
+ *
+ * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import type { ExampleSettings } from '../common/ExampleSettings.js';
+
+export default async function ({ renderer, testRoot }: ExampleSettings) {
+  renderer.createTextNode({
+    x: 100,
+    y: 100,
+    color: 0xffffffff,
+    alpha: 1.0,
+    text: 'etc1 compression in .pvr',
+    fontFamily: 'Ubuntu',
+    fontSize: 30,
+    parent: testRoot,
+  });
+
+  renderer.createNode({
+    x: 100,
+    y: 170,
+    width: 550,
+    height: 550,
+    src: '../assets/test-etc1.pvr',
+    parent: testRoot,
+  });
+
+  renderer.createTextNode({
+    x: 800,
+    y: 100,
+    color: 0xffffffff,
+    alpha: 1.0,
+    text: 's3tc compression in .ktx',
+    fontFamily: 'Ubuntu',
+    fontSize: 30,
+    parent: testRoot,
+  });
+
+  renderer.createNode({
+    x: 800,
+    y: 170,
+    width: 400,
+    height: 400,
+    src: '../assets/test-s3tc.ktx',
+    parent: testRoot,
+  });
+}

src/core/lib/WebGlContextWrapper.ts

@@ -335,7 +335,34 @@ export class WebGlContextWrapper {
       );
     }
   }
+  /**
+   * ```
+   * gl.compressedTexImage2D(gl.TEXTURE_2D, level, internalFormat, width, height, border, data);
+   * ```
+   *
+   * @remarks
+   * **WebGL Difference**: Bind target is always `gl.TEXTURE_2D`
+   */
 
+  compressedTexImage2D(
+    level: GLint,
+    internalformat: GLenum,
+    width: GLsizei,
+    height: GLsizei,
+    border: GLint,
+    data?: ArrayBufferView,
+  ): void {
+    const { gl } = this;
+    gl.compressedTexImage2D(
+      gl.TEXTURE_2D,
+      level,
+      internalformat,
+      width,
+      height,
+      border,
+      data as ArrayBufferView,
+    );
+  }
   /**
    * ```
    * gl.pixelStorei(pname, param);

src/core/lib/textureCompression.ts

@@ -0,0 +1,152 @@
+/*
+ * If not stated otherwise in this file or this component's LICENSE file the
+ * following copyright and licenses apply:
+ *
+ * Copyright 2023 Comcast Cable Communications Management, LLC.
+ *
+ * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { type TextureData } from '../textures/Texture.js';
+
+/**
+ * Tests if the given location is a compressed texture container
+ * @param url
+ * @remarks
+ * This function is used to determine if the given image url is a compressed
+ * and only supports the following extensions: .ktx and .pvr
+ * @returns
+ */
+export function isCompressedTextureContainer(url: string): boolean {
+  return /\.(ktx|pvr)$/.test(url);
+}
+
+/**
+ * Loads a compressed texture container
+ * @param url
+ * @returns
+ */
+export const loadCompressedTexture = async (
+  url: string,
+): Promise<TextureData> => {
+  const response = await fetch(url);
+  const arrayBuffer = await response.arrayBuffer();
+
+  if (url.indexOf('.ktx') !== -1) {
+    return loadKTXData(arrayBuffer);
+  }
+
+  return loadPVRData(arrayBuffer);
+};
+
+/**
+ * Loads a KTX texture container and returns the texture data
+ * @param buffer
+ * @returns
+ */
+const loadKTXData = async (buffer: ArrayBuffer): Promise<TextureData> => {
+  const view = new DataView(buffer);
+  const littleEndian = view.getUint32(12) === 16909060 ? true : false;
+  const mipmaps = [];
+
+  const data = {
+    glInternalFormat: view.getUint32(28, littleEndian),
+    pixelWidth: view.getUint32(36, littleEndian),
+    pixelHeight: view.getUint32(40, littleEndian),
+    numberOfMipmapLevels: view.getUint32(56, littleEndian),
+    bytesOfKeyValueData: view.getUint32(60, littleEndian),
+  };
+
+  let offset = 64;
+
+  // Key Value Pairs of data start at byte offset 64
+  // But the only known kvp is the API version, so skipping parsing.
+  offset += data.bytesOfKeyValueData;
+
+  for (let i = 0; i < data.numberOfMipmapLevels; i++) {
+    const imageSize = view.getUint32(offset);
+    offset += 4;
+
+    mipmaps.push(view.buffer.slice(offset, imageSize));
+    offset += imageSize;
+  }
+
+  return {
+    data: {
+      glInternalFormat: data.glInternalFormat,
+      mipmaps,
+      width: data.pixelWidth || 0,
+      height: data.pixelHeight || 0,
+      type: 'ktx',
+    },
+    premultiplyAlpha: false,
+  };
+};
+
+/**
+ * Loads a PVR texture container and returns the texture data
+ * @param buffer
+ * @returns
+ */
+const loadPVRData = async (buffer: ArrayBuffer): Promise<TextureData> => {
+  // pvr header length in 32 bits
+  const pvrHeaderLength = 13;
+  // for now only we only support: COMPRESSED_RGB_ETC1_WEBGL
+  const pvrFormatEtc1 = 0x8d64;
+  const pvrWidth = 7;
+  const pvrHeight = 6;
+  const pvrMipmapCount = 11;
+  const pvrMetadata = 12;
+  const arrayBuffer = buffer;
+  const header = new Int32Array(arrayBuffer, 0, pvrHeaderLength);
+
+  // @ts-expect-error Object possibly undefined
+  // eslint-disable-next-line @typescript-eslint/restrict-plus-operands
+  const dataOffset = header[pvrMetadata] + 52;
+  const pvrtcData = new Uint8Array(arrayBuffer, dataOffset);
+  const mipmaps = [];
+  const data = {
+    pixelWidth: header[pvrWidth],
+    pixelHeight: header[pvrHeight],
+    numberOfMipmapLevels: header[pvrMipmapCount] || 0,
+  };
+
+  let offset = 0;
+  let width = data.pixelWidth || 0;
+  let height = data.pixelHeight || 0;
+
+  for (let i = 0; i < data.numberOfMipmapLevels; i++) {
+    const level = ((width + 3) >> 2) * ((height + 3) >> 2) * 8;
+    const view = new Uint8Array(
+      arrayBuffer,
+      pvrtcData.byteOffset + offset,
+      level,
+    );
+
+    mipmaps.push(view);
+    offset += level;
+    width = width >> 1;
+    height = height >> 1;
+  }
+
+  return {
+    data: {
+      glInternalFormat: pvrFormatEtc1,
+      mipmaps: mipmaps,
+      width: data.pixelWidth || 0,
+      height: data.pixelHeight || 0,
+      type: 'pvr',
+    },
+    premultiplyAlpha: false,
+  };
+};

src/core/renderers/webgl/WebGlCoreCtxTexture.ts

@@ -168,6 +168,26 @@ export class WebGlCoreCtxTexture extends CoreContextTexture {
         glw.UNSIGNED_BYTE,
         TRANSPARENT_TEXTURE_DATA,
       );
+    } else if ('mipmaps' in textureData.data && textureData.data.mipmaps) {
+      const {
+        mipmaps,
+        width = 0,
+        height = 0,
+        type,
+        glInternalFormat,
+      } = textureData.data;
+      const view =
+        type === 'ktx'
+          ? new DataView(mipmaps[0] ?? new ArrayBuffer(0))
+          : (mipmaps[0] as unknown as ArrayBufferView);
+
+      glw.bindTexture(this._nativeCtxTexture);
+      glw.compressedTexImage2D(0, glInternalFormat, width, height, 0, view);
+
+      glw.texParameteri(glw.TEXTURE_WRAP_S, glw.CLAMP_TO_EDGE);
+      glw.texParameteri(glw.TEXTURE_WRAP_T, glw.CLAMP_TO_EDGE);
+      glw.texParameteri(glw.TEXTURE_MAG_FILTER, glw.LINEAR);
+      glw.texParameteri(glw.TEXTURE_MIN_FILTER, glw.LINEAR);
     } else {
       console.error(
         `WebGlCoreCtxTexture.onLoadRequest: Unexpected textureData returned`,

src/core/text-rendering/font-face-types/SdfTrFontFace/SdfTrFontFace.ts

@@ -98,7 +98,10 @@ export class SdfTrFontFace<
         });
         // We know `data` is defined here, because we just set it
         // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-        (this.shaper as FontShaper) = new SdfFontShaper(this.data!, this.glyphMap);
+        (this.shaper as FontShaper) = new SdfFontShaper(
+          this.data!,
+          this.glyphMap,
+        );
         this.checkLoaded();
       })
       .catch(console.error);

src/core/text-rendering/font-face-types/SdfTrFontFace/internal/SdfFontShaper.test.ts

@@ -34,7 +34,10 @@ sdfData.chars.forEach((glyph) => {
 
 describe('SdfFontShaper', () => {
   it('should be able to shape text.', () => {
-    const shaper = new SdfFontShaper(sdfData as unknown as SdfFontData, glyphMap);
+    const shaper = new SdfFontShaper(
+      sdfData as unknown as SdfFontData,
+      glyphMap,
+    );
     const peekableCodepoints = new PeekableIterator(
       getUnicodeCodepoints('Hi!'),
     );
@@ -88,7 +91,10 @@ describe('SdfFontShaper', () => {
   });
 
   it('should be able to shape text that we know have kerning pairs.', () => {
-    const shaper = new SdfFontShaper(sdfData as unknown as SdfFontData, glyphMap);
+    const shaper = new SdfFontShaper(
+      sdfData as unknown as SdfFontData,
+      glyphMap,
+    );
     const peekableCodepoints = new PeekableIterator(
       getUnicodeCodepoints('WeVo'),
     );
@@ -130,8 +136,10 @@ describe('SdfFontShaper', () => {
   });
 
   it('should be able to shape text with letterSpacing.', () => {
-
-    const shaper = new SdfFontShaper(sdfData as unknown as SdfFontData, glyphMap);
+    const shaper = new SdfFontShaper(
+      sdfData as unknown as SdfFontData,
+      glyphMap,
+    );
     const peekableCodepoints = new PeekableIterator(
       getUnicodeCodepoints('We!'),
     );

src/core/text-rendering/font-face-types/SdfTrFontFace/internal/SdfFontShaper.ts

@@ -39,7 +39,10 @@ export class SdfFontShaper extends FontShaper {
   private readonly glyphMap: Map<number, SdfFontData['chars'][0]>;
   private readonly kernings: KerningTable;
 
-  constructor(data: SdfFontData, glyphMap: Map<number, SdfFontData['chars'][0]>) {
+  constructor(
+    data: SdfFontData,
+    glyphMap: Map<number, SdfFontData['chars'][0]>,
+  ) {
     super();
     this.data = data;
     this.glyphMap = glyphMap;

src/core/text-rendering/renderers/SdfTextRenderer/internal/measureText.test.ts

@@ -33,7 +33,10 @@ sdfData.chars.forEach((glyph) => {
 describe('measureText', () => {
   it('should measure text width', () => {
     const PERIOD_WIDTH = 10.332;
-    const shaper = new SdfFontShaper(sdfData as unknown as SdfFontData, glyphMap);
+    const shaper = new SdfFontShaper(
+      sdfData as unknown as SdfFontData,
+      glyphMap,
+    );
     expect(measureText('', { letterSpacing: 0 }, shaper)).toBe(0);
     expect(measureText('.', { letterSpacing: 0 }, shaper)).toBe(PERIOD_WIDTH);
     expect(measureText('..', { letterSpacing: 0 }, shaper)).toBeCloseTo(

src/core/textures/ImageTexture.ts

@@ -19,6 +19,10 @@
 
 import type { CoreTextureManager } from '../CoreTextureManager.js';
 import { Texture, type TextureData } from './Texture.js';
+import {
+  isCompressedTextureContainer,
+  loadCompressedTexture,
+} from '../lib/textureCompression.js';
 
 /**
  * Properties of the {@link ImageTexture}
@@ -84,6 +88,11 @@ export class ImageTexture extends Texture {
       };
     }
 
+    // Handle compressed textures
+    if (isCompressedTextureContainer(src)) {
+      return loadCompressedTexture(src);
+    }
+
     if (this.txManager.imageWorkerManager.imageWorkersEnabled) {
       return await this.txManager.imageWorkerManager.getImage(
         src,