webgl/texture/index.html - external/github.com/BinomialLLC/basis_universal - Git at Google

 <html>
 <head>
 <script src="renderer.js"></script>
 <script src="dxt-to-rgb565.js"></script>
 <script src="../transcoder/build/basis_transcoder.js"></script>
 <script type="text/javascript">
 function log(s) {
   var div = document.createElement('div');
   div.innerHTML = s;
   document.getElementById('logger').appendChild(div);
 }

 function logTime(desc, t) {
   log(t + 'ms ' + desc);
 }

 function isDef(v) {
   return typeof v != 'undefined';
 }

 function elem(id) {
   return document.getElementById(id);
 }

 formatTable = function(rows) {
   var colLengths = [];

   for (var i = 0; i < rows.length; i++) {
     var row = rows[i];
     for (var j = 0; j < row.length; j++) {
       if (colLengths.length <= j) colLengths.push(0);
       if (colLengths[j] < row[j].length) colLengths[j] = row[j].length;
     }
   }

   function formatRow(row) {
     var parts = [];
     for (var i = 0; i < colLengths.length; i++) {
       var s = row.length > i ? row[i] : '';
       var padding = (new Array(1 + colLengths[i] - s.length)).join(' ');
       if (s && s[0] >= '0' && s[0] <= '9') {
         // Right-align numbers.
         parts.push(padding + s);
       } else {
         parts.push(s + padding);
       }
     }
     return parts.join(' | ');
   }

   var width = 0;
   for (var i = 0; i < colLengths.length; i++) {
     width += colLengths[i];
     // Add another 3 for the separator.
     if (i != 0) width += 3;
   }

   var lines = [];
   lines.push(formatRow(rows[0]));
   lines.push((new Array(width + 1)).join('-'));
   for (var i = 1; i < rows.length; i++) {
     lines.push(formatRow(rows[i]));
   }

   return lines.join('\n');
 };


 function loadArrayBuffer(uri, callback) {
   log('Loading ' + uri + '...');
   var xhr = new XMLHttpRequest();
   xhr.responseType = "arraybuffer";
   xhr.open('GET', uri, true);
   xhr.onreadystatechange = function(e) {
     if (xhr.readyState == 4 && xhr.status == 200) {
       callback(xhr.response);
     }
   }
   xhr.send(null);
 }

 // ASTC format, from:
 // https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
 COMPRESSED_RGBA_ASTC_4x4_KHR = 0x93B0;

 // DXT formats, from:
 // http://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_s3tc/
 COMPRESSED_RGB_S3TC_DXT1_EXT  = 0x83F0;
 COMPRESSED_RGBA_S3TC_DXT1_EXT = 0x83F1;
 COMPRESSED_RGBA_S3TC_DXT3_EXT = 0x83F2;
 COMPRESSED_RGBA_S3TC_DXT5_EXT = 0x83F3;

 // BC7 format, from:
 // https://www.khronos.org/registry/webgl/extensions/EXT_texture_compression_bptc/
 COMPRESSED_RGBA_BPTC_UNORM = 0x8E8C;

 // ETC format, from:
 // https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_etc1/
 COMPRESSED_RGB_ETC1_WEBGL = 0x8D64;

 // PVRTC format, from:
 // https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_pvrtc/
 COMPRESSED_RGB_PVRTC_4BPPV1_IMG = 0x8C00;
 COMPRESSED_RGBA_PVRTC_4BPPV1_IMG = 0x8C02;

 // Same as the Module.transcoder_texture_format enum
 BASIS_FORMAT = {
   cTFETC1: 0,
   cTFETC2: 1,
   cTFBC1: 2,
   cTFBC3: 3,
   cTFBC4: 4,
   cTFBC5: 5,
   cTFBC7: 6,
   cTFPVRTC1_4_RGB: 8,
   cTFPVRTC1_4_RGBA: 9,
   cTFASTC_4x4: 10,
   cTFATC_RGB: 11,
   cTFATC_RGBA_INTERPOLATED_ALPHA: 12,
   cTFRGBA32: 13,
   cTFRGB565: 14,
   cTFBGR565: 15,
   cTFRGBA4444: 16,
   cTFFXT1_RGB: 17,
   cTFPVRTC2_4_RGB: 18,
   cTFPVRTC2_4_RGBA: 19,
   cTFETC2_EAC_R11: 20,
   cTFETC2_EAC_RG11: 21
 };

 BASIS_FORMAT_NAMES = {};
 for (var name in BASIS_FORMAT) {
   BASIS_FORMAT_NAMES[BASIS_FORMAT[name]] = name;
 }

 DXT_FORMAT_MAP = {};
 DXT_FORMAT_MAP[BASIS_FORMAT.cTFBC1] = COMPRESSED_RGB_S3TC_DXT1_EXT;
 DXT_FORMAT_MAP[BASIS_FORMAT.cTFBC3] = COMPRESSED_RGBA_S3TC_DXT5_EXT;
 DXT_FORMAT_MAP[BASIS_FORMAT.cTFBC7] = COMPRESSED_RGBA_BPTC_UNORM;

 var astcSupported = false;
 var etcSupported = false;
 var dxtSupported = false;
 var bc7Supported = false;
 var pvrtcSupported = false;
 var drawMode = 0;

 var tex, width, height, images, levels, have_alpha, alignedWidth, alignedHeight, format, displayWidth, displayHeight;

 function redraw()
 {
   if (!width)
    return;

   renderer.drawTexture(tex, displayWidth, displayHeight, drawMode);
 }

 function dumpBasisFileDesc(basisFile)
 {
   var basisFileDesc = basisFile.getFileDesc();

   log('------');
   log('getFileDesc():');
   log('version: ' + basisFileDesc.version);
   log('us per frame: ' + basisFileDesc.usPerFrame);
   log('total images: ' + basisFileDesc.totalImages);
   log('userdata0: ' + basisFileDesc.userdata0 + ' userdata1: ' + basisFileDesc.userdata1);
   log('texFormat: ' + basisFileDesc.texFormat);
   log('yFlipped: ' + basisFileDesc.yFlipped + ' hasAlphaSlices: ' + basisFileDesc.hasAlphaSlices);

   if (basisFileDesc.texFormat == Module.basis_tex_format.cETC1S.value)
   {
       log('numEndpoints: ' + basisFileDesc.numEndpoints);
       log('endpointPaletteOfs: ' + basisFileDesc.endpointPaletteOfs);
       log('endpointPaletteLen: ' + basisFileDesc.endpointPaletteLen);
       log('numSelectors: ' + basisFileDesc.numSelectors);
       log('selectorPaletteOfs: ' + basisFileDesc.selectorPaletteOfs);
       log('selectorPaletteLen: ' + basisFileDesc.selectorPaletteLen);
       log('tablesOfs: ' + basisFileDesc.tablesOfs);
       log('tablesLen: ' + basisFileDesc.tablesLen);
   }
   log('------');
   log('getImageDesc() for all images:');
   var image_index;
   for (image_index = 0; image_index < basisFileDesc.totalImages; image_index++)
   {
      log('image: ' + image_index);

      var basisImageDesc = basisFile.getImageDesc(image_index);

      log('origWidth: ' + basisImageDesc.origWidth + ' origWidth: ' + basisImageDesc.origHeight);
      log('numBlocksX: ' + basisImageDesc.numBlocksX + ' origWidth: ' + basisImageDesc.numBlocksY);
      log('numLevels: ' + basisImageDesc.numLevels);
      log('alphaFlag: ' + basisImageDesc.alphaFlag + ' iframeFlag: ' + basisImageDesc.iframeFlag);

      log('getImageLevelDesc() for all mipmap levels:');
      var level_index;
      for (level_index = 0; level_index < basisImageDesc.numLevels; level_index++)
      {
         var basisImageLevelDesc = basisFile.getImageLevelDesc(image_index, level_index);

         log('level: ' + level_index +
             ' rgb_file_offset: ' + basisImageLevelDesc.rgbFileOfs + ' rgb_file_len: ' + basisImageLevelDesc.rgbFileLen);

         if (basisFileDesc.hasAlphaSlices)
             log('alpha_file_offset: ' + basisImageLevelDesc.alphaFileOfs + ' alpha_file_len: ' + basisImageLevelDesc.alphaFileLen);
      }
   }

   log('------');
 }

 function dataLoaded(data)
 {
   log('Done loading .basis file, decoded header:');

   const { BasisFile, initializeBasis } = Module;
   initializeBasis();

   const startTime = performance.now();

   const basisFile = new BasisFile(new Uint8Array(data));

   width = basisFile.getImageWidth(0, 0);
   height = basisFile.getImageHeight(0, 0);
   images = basisFile.getNumImages();
   levels = basisFile.getNumLevels(0);
   has_alpha = basisFile.getHasAlpha();

   dumpBasisFileDesc(basisFile);

   if (!width || !height || !images || !levels) {
     console.warn('Invalid .basis file');
     basisFile.close();
     basisFile.delete();
     return;
   }

   // Note: If the file is UASTC, the preferred formats are ASTC/BC7.
   // If the file is ETC1S and doesn't have alpha, the preferred formats are ETC1 and BC1. For alpha, the preferred formats are ETC2, BC3 or BC7.

   var formatString = 'UNKNOWN';
   if (astcSupported)
   {
     formatString = 'ASTC';
     format = BASIS_FORMAT.cTFASTC_4x4;
   }
   else if (bc7Supported)
   {
     formatString = 'BC7';
     format = BASIS_FORMAT.cTFBC7;
   }
   else if (dxtSupported)
   {
     if (has_alpha)
     {
       formatString = 'BC3';
       format = BASIS_FORMAT.cTFBC3;
     }
     else
     {
       formatString = 'BC1';
       format = BASIS_FORMAT.cTFBC1;
     }
   }
   else if (pvrtcSupported)
   {
     if (has_alpha)
     {
       formatString = 'PVRTC1_RGBA';
       format = BASIS_FORMAT.cTFPVRTC1_4_RGBA;
     }
     else
     {
       formatString = 'PVRTC1_RGB';
       format = BASIS_FORMAT.cTFPVRTC1_4_RGB;
     }

     if (
          ((width & (width - 1)) != 0) || ((height & (height - 1)) != 0)
         )
     {
       log('ERROR: PVRTC1 requires square power of 2 textures');
     }
     if (width != height)
     {
       log('ERROR: PVRTC1 requires square power of 2 textures');
     }
   }
   else if (etcSupported)
   {
     formatString = 'ETC1';
     format = BASIS_FORMAT.cTFETC1;
   }
   else
   {
     formatString = 'RGB565';
     format = BASIS_FORMAT.cTFRGB565;
     log('Decoding .basis data to 565');
   }

   elem('format').innerText = formatString;

   log('format: ' + format);

   if (!basisFile.startTranscoding()) {
     log('startTranscoding failed');
     console.warn('startTranscoding failed');
     basisFile.close();
     basisFile.delete();
     return;
   }

   const isUncompressedFormat = Module.formatIsUncompressed(format);

   const blockWidth = isUncompressedFormat ? 1 : 4, blockHeight = isUncompressedFormat ? 1 : 4;

   const bytesPerBlockOrPixel = Module.getBytesPerBlockOrPixel(format);
   log('isUncompressedFormat: ' + isUncompressedFormat + ' bytesPerBlockOrPixel: ' + bytesPerBlockOrPixel);

   const dstSize = basisFile.getImageTranscodedSizeInBytes(0, 0, format);
   const dst = new Uint8Array(dstSize);

 //  log('getImageTranscodedSizeInBytes() returned ' + dstSize);

   // Use the low or high level transcoding API's. The high level API's require .basis files, while the low-level API's just work off blobs of memory and parameters.
   if (elem('ContainerIndependentTranscoding').checked)
   {
       // Always transcode the first image and the first mipmap level
       const image_index = 0;
       const level_index = 0;

       // Get the .basis file description
 	  var basisFileDesc = basisFile.getFileDesc();

 	  // Get the description of the file's first image (there could be multiple images, for texture arrays or videos)
       var basisImageDesc = basisFile.getImageDesc(image_index);

       // Get the description of this image's mipmap level
       var basisImageLevelDesc = basisFile.getImageLevelDesc(image_index, level_index);

       var status = false;

       // If we're transcoding to ETC1S, use the LowLevelETC1SImageTranscoder class. Otherwise use the transcodeUASTCImage() function.
       if (basisFileDesc.texFormat == Module.basis_tex_format.cETC1S.value)
       {
 	     // Create an instance of the LowLevelETC1SImageTranscoder class.
          const etc1s_transcoder = new Module.LowLevelETC1SImageTranscoder();

          // Create Uint8Array's pointing into the various bits of the .basis file holding the compressed data for the codebooks and the Huffman tables.
          var selectorPalette = new Uint8Array(data, basisFileDesc.selectorPaletteOfs, basisFileDesc.selectorPaletteLen);
          var endpointPalette = new Uint8Array(data, basisFileDesc.endpointPaletteOfs, basisFileDesc.endpointPaletteLen);
          var tables = new Uint8Array(data, basisFileDesc.tablesOfs, basisFileDesc.tablesLen);

          // Create a Uint8Array pointing to the image's compressed data.
 		 // If it's an opaque .basis file, there will only be RGB data. For transparant .basis files, each RGB slice will be immediately followed by an alpha slice.
 		 // Compressed ETC1S alpha data is guaranteed to immediately follow the RGB data (it's always at odd slices in the .basis file).
          var compData = new Uint8Array(data, basisImageLevelDesc.rgbFileOfs, basisImageLevelDesc.rgbFileLen + basisImageLevelDesc.alphaFileLen);

          // Decompress the palettes. This only has to be done once for each .basis file.
 		 var status = etc1s_transcoder.decodePalettes(basisFileDesc.numEndpoints, endpointPalette, basisFileDesc.numSelectors, selectorPalette);
          if (status)
          {
 			 // Decompress the Huffman tables. This only has to be done once for each .basis file.
              status = etc1s_transcoder.decodeTables(tables);
              if (status)
              {
 			    // Now transcode the image using the container independent transcode API. This API does not interpret any .basis file structures - only the compressed ETC1S data.
                 status = etc1s_transcoder.transcodeImage(
                     format,
                     dst, dstSize / bytesPerBlockOrPixel,
                     compData,
                     basisImageDesc.numBlocksX, basisImageDesc.numBlocksY, basisImageDesc.origWidth, basisImageDesc.origHeight, level_index,
                     0, basisImageLevelDesc.rgbFileLen, basisFileDesc.hasAlphaSlices ? basisImageLevelDesc.rgbFileLen : 0, basisImageLevelDesc.alphaFileLen,
                     0,
                     basisFileDesc.hasAlphaSlices,
                     basisFileDesc.isVideo,
                     0,
                     0);

                 if (!status)
                   log('transcodeImage() failed');
              }
              else
              {
                log('decodeTables() failed');
              }
          }
          else
          {
             log('decodePalettes() failed');
          }

          etc1s_transcoder.delete();

          if (!status)
          {
             log('etc1s_transcoder failed');
             console.warn('etc1s_transcoder failed');
             basisFile.close();
             basisFile.delete();
             return;
          }
          else
          {
             log('Successfully called etc1s_transcoder.transcodeImage()');
          }
       }
       else
       {
          // Create a Uint8Array pointing to the image's compressed data.
          var compData = new Uint8Array(data, basisImageLevelDesc.rgbFileOfs, basisImageLevelDesc.rgbFileLen);

          // Transcode the UASTC texture data to the desired output format.
          status = Module.transcodeUASTCImage(
             format,
             dst, dstSize / bytesPerBlockOrPixel,
             compData,
             basisImageDesc.numBlocksX, basisImageDesc.numBlocksY, basisImageDesc.origWidth, basisImageDesc.origHeight, level_index,
             0, basisImageLevelDesc.rgbFileLen,
             0,
             basisFileDesc.hasAlphaSlices,
             basisFileDesc.isVideo,
             0,
             0,
             -1, -1);

          if (!status)
          {
             log('transcodeUASTCImage() failed');
             console.warn('transcodeUASTCImage() failed');
             basisFile.close();
             basisFile.delete();
             return;
          }
          else
          {
             log('Successfully called transcodeUASTCImage()');
          }
       }
   }
   else
   {
     // Use the high-level transcode API, which requires a .basis file.
     if (!basisFile.transcodeImage(dst, 0, 0, format, 0, 0)) {
         log('basisFile.transcodeImage failed');
         console.warn('transcodeImage failed');
         basisFile.close();
         basisFile.delete();

         return;
     }
   }

   const elapsed = performance.now() - startTime;

   basisFile.close();
   basisFile.delete();

   log('width: ' + width);
   log('height: ' + height);
   log('images: ' + images);
   log('first image mipmap levels: ' + levels);
   log('has_alpha: ' + has_alpha);
   logTime('transcoding time', elapsed.toFixed(2));

   alignedWidth = (width + 3) & ~3;
   alignedHeight = (height + 3) & ~3;

   displayWidth = alignedWidth;
   displayHeight = alignedHeight;

   var canvas = elem('canvas');
   canvas.width = alignedWidth;
   canvas.height = alignedHeight;

   if (format === BASIS_FORMAT.cTFASTC_4x4)
   {
     tex = renderer.createCompressedTexture(dst, alignedWidth, alignedHeight, COMPRESSED_RGBA_ASTC_4x4_KHR);
   }
   else if ((format === BASIS_FORMAT.cTFBC3) || (format === BASIS_FORMAT.cTFBC1) || (format == BASIS_FORMAT.cTFBC7))
   {
      tex = renderer.createCompressedTexture(dst, alignedWidth, alignedHeight, DXT_FORMAT_MAP[format]);
   }
   else if (format === BASIS_FORMAT.cTFETC1)
   {
     tex = renderer.createCompressedTexture(dst, alignedWidth, alignedHeight, COMPRESSED_RGB_ETC1_WEBGL);
   }
   else if (format === BASIS_FORMAT.cTFPVRTC1_4_RGB)
   {
     tex = renderer.createCompressedTexture(dst, alignedWidth, alignedHeight, COMPRESSED_RGB_PVRTC_4BPPV1_IMG);
   }
   else if (format === BASIS_FORMAT.cTFPVRTC1_4_RGBA)
   {
     tex = renderer.createCompressedTexture(dst, alignedWidth, alignedHeight, COMPRESSED_RGBA_PVRTC_4BPPV1_IMG);
   }
   else
   {
    canvas.width = width;
    canvas.height = height;
    displayWidth = width;
    displayHeight = height;

    // Create 565 texture.
    var dstTex = new Uint16Array(width * height);

    // Convert the array of bytes to an array of uint16's.
    var pix = 0;
    for (var y = 0; y < height; y++)
       for (var x = 0; x < width; x++, pix++)
          dstTex[pix] = dst[2 * pix + 0] | (dst[2 * pix + 1] << 8);

    tex = renderer.createRgb565Texture(dstTex, width, height);
   }

   redraw();
 }

 function runLoadFile() {
   elem('logger').innerHTML = '';
   loadArrayBuffer(elem('file').value, dataLoaded);
 }

 function alphaBlend() { drawMode = 0; redraw(); }
 function viewRGB() { drawMode = 1; redraw(); }
 function viewAlpha() { drawMode = 2; redraw(); }

 </script>
 </head>
 <body>
   <br>
   <div style="font-size: 24pt; font-weight: bold">
     .basis->Compressed texture transcoder test
   </div>

   <br>This demo uses the Basis C++ transcoder (compiled to Javascript using Emscripten) to transcode a .basis file to <b id='format'>FORMAT</b>
   <br>Thanks to Evan Parker for providing <a href="https://github.com/toji/webgl-texture-utils">webgl-texture-utils</a> and this test bed.
   <br>
   <br>
       .basis file:
       <input id="file" type="text" size=30 value="assets/kodim03.basis"></input>
       <input type="button" value="Run!" onclick="runLoadFile()"></input>
   <br>
   <br>
       <input type="button" value="Alpha blend" onclick="alphaBlend()"></input>
       <input type="button" value="View RGB" onclick="viewRGB()"></input>
      <input type="button" value="View Alpha" onclick="viewAlpha()"></input>

   <br>
   <br>
       Use Container Independent Transcoding API's:
       <input type="checkbox" id="ContainerIndependentTranscoding">

   <div style="position:absolute; left: 525px; top:130px; font-size: 20pt; font-weight: bold; color: red">
     <div id="no-compressed-tex" style="display: none; width: 768px; font-size: 20pt; font-weight: bold; color: red">
       NOTE: Your browser does not support several compressed texture format, so using RGB565.
     </div>
     <canvas id='canvas'></canvas>
   </div>
   <br><br>
   <div id='logger'></div>
 </body>
 <script>
   BASIS({onRuntimeInitialized : () => {
     var gl = elem('canvas').getContext('webgl');

     astcSupported = !!gl.getExtension('WEBGL_compressed_texture_astc');
     etcSupported = !!gl.getExtension('WEBGL_compressed_texture_etc1');
     dxtSupported = !!gl.getExtension('WEBGL_compressed_texture_s3tc');
     pvrtcSupported = !!(gl.getExtension('WEBGL_compressed_texture_pvrtc')) || !!(gl.getExtension('WEBKIT_WEBGL_compressed_texture_pvrtc'));
     bc7Supported = !!gl.getExtension('EXT_texture_compression_bptc');

    // HACK HACK - for testing uncompressed
    //astcSupported = false;
    //etcSupported = false;
    //dxtSupported = false;
    //bc7Supported = false;
    //pvrtcSupported = false;

     window.renderer = new Renderer(gl);

     elem('file').addEventListener('keydown', function(e) {
       if (e.keyCode == 13) {
         runLoadFile();
       }
     }, false);

     if (!(astcSupported || etcSupported || dxtSupported || pvrtcSupported))
     {
 //      elem('nodxt').style.display = 'block';
     }

     runLoadFile();
   }}).then(module => window.Module = module);
 </script>
 </html>
	<html>
	<head>
	<script src="renderer.js"></script>
	<script src="dxt-to-rgb565.js"></script>
	<script src="../transcoder/build/basis_transcoder.js"></script>
	<script type="text/javascript">
	function log(s) {
	var div = document.createElement('div');
	div.innerHTML = s;
	document.getElementById('logger').appendChild(div);
	}

	function logTime(desc, t) {
	log(t + 'ms ' + desc);
	}

	function isDef(v) {
	return typeof v != 'undefined';
	}

	function elem(id) {
	return document.getElementById(id);
	}

	formatTable = function(rows) {
	var colLengths = [];

	for (var i = 0; i < rows.length; i++) {
	var row = rows[i];
	for (var j = 0; j < row.length; j++) {
	if (colLengths.length <= j) colLengths.push(0);
	if (colLengths[j] < row[j].length) colLengths[j] = row[j].length;
	}
	}

	function formatRow(row) {
	var parts = [];
	for (var i = 0; i < colLengths.length; i++) {
	var s = row.length > i ? row[i] : '';
	var padding = (new Array(1 + colLengths[i] - s.length)).join(' ');
	if (s && s[0] >= '0' && s[0] <= '9') {
	// Right-align numbers.
	parts.push(padding + s);
	} else {
	parts.push(s + padding);
	}
	}
	return parts.join(' \| ');
	}

	var width = 0;
	for (var i = 0; i < colLengths.length; i++) {
	width += colLengths[i];
	// Add another 3 for the separator.
	if (i != 0) width += 3;
	}

	var lines = [];
	lines.push(formatRow(rows[0]));
	lines.push((new Array(width + 1)).join('-'));
	for (var i = 1; i < rows.length; i++) {
	lines.push(formatRow(rows[i]));
	}

	return lines.join('\n');
	};


	function loadArrayBuffer(uri, callback) {
	log('Loading ' + uri + '...');
	var xhr = new XMLHttpRequest();
	xhr.responseType = "arraybuffer";
	xhr.open('GET', uri, true);
	xhr.onreadystatechange = function(e) {
	if (xhr.readyState == 4 && xhr.status == 200) {
	callback(xhr.response);
	}
	}
	xhr.send(null);
	}

	// ASTC format, from:
	// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_astc/
	COMPRESSED_RGBA_ASTC_4x4_KHR = 0x93B0;

	// DXT formats, from:
	// http://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_s3tc/
	COMPRESSED_RGB_S3TC_DXT1_EXT = 0x83F0;
	COMPRESSED_RGBA_S3TC_DXT1_EXT = 0x83F1;
	COMPRESSED_RGBA_S3TC_DXT3_EXT = 0x83F2;
	COMPRESSED_RGBA_S3TC_DXT5_EXT = 0x83F3;

	// BC7 format, from:
	// https://www.khronos.org/registry/webgl/extensions/EXT_texture_compression_bptc/
	COMPRESSED_RGBA_BPTC_UNORM = 0x8E8C;

	// ETC format, from:
	// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_etc1/
	COMPRESSED_RGB_ETC1_WEBGL = 0x8D64;

	// PVRTC format, from:
	// https://www.khronos.org/registry/webgl/extensions/WEBGL_compressed_texture_pvrtc/
	COMPRESSED_RGB_PVRTC_4BPPV1_IMG = 0x8C00;
	COMPRESSED_RGBA_PVRTC_4BPPV1_IMG = 0x8C02;

	// Same as the Module.transcoder_texture_format enum
	BASIS_FORMAT = {
	cTFETC1: 0,
	cTFETC2: 1,
	cTFBC1: 2,
	cTFBC3: 3,
	cTFBC4: 4,
	cTFBC5: 5,
	cTFBC7: 6,
	cTFPVRTC1_4_RGB: 8,
	cTFPVRTC1_4_RGBA: 9,
	cTFASTC_4x4: 10,
	cTFATC_RGB: 11,
	cTFATC_RGBA_INTERPOLATED_ALPHA: 12,
	cTFRGBA32: 13,
	cTFRGB565: 14,
	cTFBGR565: 15,
	cTFRGBA4444: 16,
	cTFFXT1_RGB: 17,
	cTFPVRTC2_4_RGB: 18,
	cTFPVRTC2_4_RGBA: 19,
	cTFETC2_EAC_R11: 20,
	cTFETC2_EAC_RG11: 21
	};

	BASIS_FORMAT_NAMES = {};
	for (var name in BASIS_FORMAT) {
	BASIS_FORMAT_NAMES[BASIS_FORMAT[name]] = name;
	}

	DXT_FORMAT_MAP = {};
	DXT_FORMAT_MAP[BASIS_FORMAT.cTFBC1] = COMPRESSED_RGB_S3TC_DXT1_EXT;
	DXT_FORMAT_MAP[BASIS_FORMAT.cTFBC3] = COMPRESSED_RGBA_S3TC_DXT5_EXT;
	DXT_FORMAT_MAP[BASIS_FORMAT.cTFBC7] = COMPRESSED_RGBA_BPTC_UNORM;

	var astcSupported = false;
	var etcSupported = false;
	var dxtSupported = false;
	var bc7Supported = false;
	var pvrtcSupported = false;
	var drawMode = 0;

	var tex, width, height, images, levels, have_alpha, alignedWidth, alignedHeight, format, displayWidth, displayHeight;

	function redraw()
	{
	if (!width)
	return;

	renderer.drawTexture(tex, displayWidth, displayHeight, drawMode);
	}

	function dumpBasisFileDesc(basisFile)
	{
	var basisFileDesc = basisFile.getFileDesc();

	log('------');
	log('getFileDesc():');
	log('version: ' + basisFileDesc.version);
	log('us per frame: ' + basisFileDesc.usPerFrame);
	log('total images: ' + basisFileDesc.totalImages);
	log('userdata0: ' + basisFileDesc.userdata0 + ' userdata1: ' + basisFileDesc.userdata1);
	log('texFormat: ' + basisFileDesc.texFormat);
	log('yFlipped: ' + basisFileDesc.yFlipped + ' hasAlphaSlices: ' + basisFileDesc.hasAlphaSlices);

	if (basisFileDesc.texFormat == Module.basis_tex_format.cETC1S.value)
	{
	log('numEndpoints: ' + basisFileDesc.numEndpoints);
	log('endpointPaletteOfs: ' + basisFileDesc.endpointPaletteOfs);
	log('endpointPaletteLen: ' + basisFileDesc.endpointPaletteLen);
	log('numSelectors: ' + basisFileDesc.numSelectors);
	log('selectorPaletteOfs: ' + basisFileDesc.selectorPaletteOfs);
	log('selectorPaletteLen: ' + basisFileDesc.selectorPaletteLen);
	log('tablesOfs: ' + basisFileDesc.tablesOfs);
	log('tablesLen: ' + basisFileDesc.tablesLen);
	}
	log('------');
	log('getImageDesc() for all images:');
	var image_index;
	for (image_index = 0; image_index < basisFileDesc.totalImages; image_index++)
	{
	log('image: ' + image_index);

	var basisImageDesc = basisFile.getImageDesc(image_index);

	log('origWidth: ' + basisImageDesc.origWidth + ' origWidth: ' + basisImageDesc.origHeight);
	log('numBlocksX: ' + basisImageDesc.numBlocksX + ' origWidth: ' + basisImageDesc.numBlocksY);
	log('numLevels: ' + basisImageDesc.numLevels);
	log('alphaFlag: ' + basisImageDesc.alphaFlag + ' iframeFlag: ' + basisImageDesc.iframeFlag);

	log('getImageLevelDesc() for all mipmap levels:');
	var level_index;
	for (level_index = 0; level_index < basisImageDesc.numLevels; level_index++)
	{
	var basisImageLevelDesc = basisFile.getImageLevelDesc(image_index, level_index);

	log('level: ' + level_index +
	' rgb_file_offset: ' + basisImageLevelDesc.rgbFileOfs + ' rgb_file_len: ' + basisImageLevelDesc.rgbFileLen);

	if (basisFileDesc.hasAlphaSlices)
	log('alpha_file_offset: ' + basisImageLevelDesc.alphaFileOfs + ' alpha_file_len: ' + basisImageLevelDesc.alphaFileLen);
	}
	}

	log('------');
	}

	function dataLoaded(data)
	{
	log('Done loading .basis file, decoded header:');

	const { BasisFile, initializeBasis } = Module;
	initializeBasis();

	const startTime = performance.now();

	const basisFile = new BasisFile(new Uint8Array(data));

	width = basisFile.getImageWidth(0, 0);
	height = basisFile.getImageHeight(0, 0);
	images = basisFile.getNumImages();
	levels = basisFile.getNumLevels(0);
	has_alpha = basisFile.getHasAlpha();

	dumpBasisFileDesc(basisFile);

	if (!width \|\| !height \|\| !images \|\| !levels) {
	console.warn('Invalid .basis file');
	basisFile.close();
	basisFile.delete();
	return;
	}

	// Note: If the file is UASTC, the preferred formats are ASTC/BC7.
	// If the file is ETC1S and doesn't have alpha, the preferred formats are ETC1 and BC1. For alpha, the preferred formats are ETC2, BC3 or BC7.

	var formatString = 'UNKNOWN';
	if (astcSupported)
	{
	formatString = 'ASTC';
	format = BASIS_FORMAT.cTFASTC_4x4;
	}
	else if (bc7Supported)
	{
	formatString = 'BC7';
	format = BASIS_FORMAT.cTFBC7;
	}
	else if (dxtSupported)
	{
	if (has_alpha)
	{
	formatString = 'BC3';
	format = BASIS_FORMAT.cTFBC3;
	}
	else
	{
	formatString = 'BC1';
	format = BASIS_FORMAT.cTFBC1;
	}
	}
	else if (pvrtcSupported)
	{
	if (has_alpha)
	{
	formatString = 'PVRTC1_RGBA';
	format = BASIS_FORMAT.cTFPVRTC1_4_RGBA;
	}
	else
	{
	formatString = 'PVRTC1_RGB';
	format = BASIS_FORMAT.cTFPVRTC1_4_RGB;
	}

	if (
	((width & (width - 1)) != 0) \|\| ((height & (height - 1)) != 0)
	)
	{
	log('ERROR: PVRTC1 requires square power of 2 textures');
	}
	if (width != height)
	{
	log('ERROR: PVRTC1 requires square power of 2 textures');
	}
	}
	else if (etcSupported)
	{
	formatString = 'ETC1';
	format = BASIS_FORMAT.cTFETC1;
	}
	else
	{
	formatString = 'RGB565';
	format = BASIS_FORMAT.cTFRGB565;
	log('Decoding .basis data to 565');
	}

	elem('format').innerText = formatString;

	log('format: ' + format);

	if (!basisFile.startTranscoding()) {
	log('startTranscoding failed');
	console.warn('startTranscoding failed');
	basisFile.close();
	basisFile.delete();
	return;
	}

	const isUncompressedFormat = Module.formatIsUncompressed(format);

	const blockWidth = isUncompressedFormat ? 1 : 4, blockHeight = isUncompressedFormat ? 1 : 4;

	const bytesPerBlockOrPixel = Module.getBytesPerBlockOrPixel(format);
	log('isUncompressedFormat: ' + isUncompressedFormat + ' bytesPerBlockOrPixel: ' + bytesPerBlockOrPixel);

	const dstSize = basisFile.getImageTranscodedSizeInBytes(0, 0, format);
	const dst = new Uint8Array(dstSize);

	// log('getImageTranscodedSizeInBytes() returned ' + dstSize);

	// Use the low or high level transcoding API's. The high level API's require .basis files, while the low-level API's just work off blobs of memory and parameters.
	if (elem('ContainerIndependentTranscoding').checked)
	{
	// Always transcode the first image and the first mipmap level
	const image_index = 0;
	const level_index = 0;

	// Get the .basis file description
	var basisFileDesc = basisFile.getFileDesc();

	// Get the description of the file's first image (there could be multiple images, for texture arrays or videos)
	var basisImageDesc = basisFile.getImageDesc(image_index);

	// Get the description of this image's mipmap level
	var basisImageLevelDesc = basisFile.getImageLevelDesc(image_index, level_index);

	var status = false;

	// If we're transcoding to ETC1S, use the LowLevelETC1SImageTranscoder class. Otherwise use the transcodeUASTCImage() function.
	if (basisFileDesc.texFormat == Module.basis_tex_format.cETC1S.value)
	{
	// Create an instance of the LowLevelETC1SImageTranscoder class.
	const etc1s_transcoder = new Module.LowLevelETC1SImageTranscoder();

	// Create Uint8Array's pointing into the various bits of the .basis file holding the compressed data for the codebooks and the Huffman tables.
	var selectorPalette = new Uint8Array(data, basisFileDesc.selectorPaletteOfs, basisFileDesc.selectorPaletteLen);
	var endpointPalette = new Uint8Array(data, basisFileDesc.endpointPaletteOfs, basisFileDesc.endpointPaletteLen);
	var tables = new Uint8Array(data, basisFileDesc.tablesOfs, basisFileDesc.tablesLen);

	// Create a Uint8Array pointing to the image's compressed data.
	// If it's an opaque .basis file, there will only be RGB data. For transparant .basis files, each RGB slice will be immediately followed by an alpha slice.
	// Compressed ETC1S alpha data is guaranteed to immediately follow the RGB data (it's always at odd slices in the .basis file).
	var compData = new Uint8Array(data, basisImageLevelDesc.rgbFileOfs, basisImageLevelDesc.rgbFileLen + basisImageLevelDesc.alphaFileLen);

	// Decompress the palettes. This only has to be done once for each .basis file.
	var status = etc1s_transcoder.decodePalettes(basisFileDesc.numEndpoints, endpointPalette, basisFileDesc.numSelectors, selectorPalette);
	if (status)
	{
	// Decompress the Huffman tables. This only has to be done once for each .basis file.
	status = etc1s_transcoder.decodeTables(tables);
	if (status)
	{
	// Now transcode the image using the container independent transcode API. This API does not interpret any .basis file structures - only the compressed ETC1S data.
	status = etc1s_transcoder.transcodeImage(
	format,
	dst, dstSize / bytesPerBlockOrPixel,
	compData,
	basisImageDesc.numBlocksX, basisImageDesc.numBlocksY, basisImageDesc.origWidth, basisImageDesc.origHeight, level_index,
	0, basisImageLevelDesc.rgbFileLen, basisFileDesc.hasAlphaSlices ? basisImageLevelDesc.rgbFileLen : 0, basisImageLevelDesc.alphaFileLen,
	0,
	basisFileDesc.hasAlphaSlices,
	basisFileDesc.isVideo,
	0,
	0);

	if (!status)
	log('transcodeImage() failed');
	}
	else
	{
	log('decodeTables() failed');
	}
	}
	else
	{
	log('decodePalettes() failed');
	}

	etc1s_transcoder.delete();

	if (!status)
	{
	log('etc1s_transcoder failed');
	console.warn('etc1s_transcoder failed');
	basisFile.close();
	basisFile.delete();
	return;
	}
	else
	{
	log('Successfully called etc1s_transcoder.transcodeImage()');
	}
	}
	else
	{
	// Create a Uint8Array pointing to the image's compressed data.
	var compData = new Uint8Array(data, basisImageLevelDesc.rgbFileOfs, basisImageLevelDesc.rgbFileLen);

	// Transcode the UASTC texture data to the desired output format.
	status = Module.transcodeUASTCImage(
	format,
	dst, dstSize / bytesPerBlockOrPixel,
	compData,
	basisImageDesc.numBlocksX, basisImageDesc.numBlocksY, basisImageDesc.origWidth, basisImageDesc.origHeight, level_index,
	0, basisImageLevelDesc.rgbFileLen,
	0,
	basisFileDesc.hasAlphaSlices,
	basisFileDesc.isVideo,
	0,
	0,
	-1, -1);

	if (!status)
	{
	log('transcodeUASTCImage() failed');
	console.warn('transcodeUASTCImage() failed');
	basisFile.close();
	basisFile.delete();
	return;
	}
	else
	{
	log('Successfully called transcodeUASTCImage()');
	}
	}
	}
	else
	{
	// Use the high-level transcode API, which requires a .basis file.
	if (!basisFile.transcodeImage(dst, 0, 0, format, 0, 0)) {
	log('basisFile.transcodeImage failed');
	console.warn('transcodeImage failed');
	basisFile.close();
	basisFile.delete();

	return;
	}
	}

	const elapsed = performance.now() - startTime;

	basisFile.close();
	basisFile.delete();

	log('width: ' + width);
	log('height: ' + height);
	log('images: ' + images);
	log('first image mipmap levels: ' + levels);
	log('has_alpha: ' + has_alpha);
	logTime('transcoding time', elapsed.toFixed(2));

	alignedWidth = (width + 3) & ~3;
	alignedHeight = (height + 3) & ~3;

	displayWidth = alignedWidth;
	displayHeight = alignedHeight;

	var canvas = elem('canvas');
	canvas.width = alignedWidth;
	canvas.height = alignedHeight;

	if (format === BASIS_FORMAT.cTFASTC_4x4)
	{
	tex = renderer.createCompressedTexture(dst, alignedWidth, alignedHeight, COMPRESSED_RGBA_ASTC_4x4_KHR);
	}
	else if ((format === BASIS_FORMAT.cTFBC3) \|\| (format === BASIS_FORMAT.cTFBC1) \|\| (format == BASIS_FORMAT.cTFBC7))
	{
	tex = renderer.createCompressedTexture(dst, alignedWidth, alignedHeight, DXT_FORMAT_MAP[format]);
	}
	else if (format === BASIS_FORMAT.cTFETC1)
	{
	tex = renderer.createCompressedTexture(dst, alignedWidth, alignedHeight, COMPRESSED_RGB_ETC1_WEBGL);
	}
	else if (format === BASIS_FORMAT.cTFPVRTC1_4_RGB)
	{
	tex = renderer.createCompressedTexture(dst, alignedWidth, alignedHeight, COMPRESSED_RGB_PVRTC_4BPPV1_IMG);
	}
	else if (format === BASIS_FORMAT.cTFPVRTC1_4_RGBA)
	{
	tex = renderer.createCompressedTexture(dst, alignedWidth, alignedHeight, COMPRESSED_RGBA_PVRTC_4BPPV1_IMG);
	}
	else
	{
	canvas.width = width;
	canvas.height = height;
	displayWidth = width;
	displayHeight = height;

	// Create 565 texture.
	var dstTex = new Uint16Array(width * height);

	// Convert the array of bytes to an array of uint16's.
	var pix = 0;
	for (var y = 0; y < height; y++)
	for (var x = 0; x < width; x++, pix++)
	dstTex[pix] = dst[2 * pix + 0] \| (dst[2 * pix + 1] << 8);

	tex = renderer.createRgb565Texture(dstTex, width, height);
	}

	redraw();
	}

	function runLoadFile() {
	elem('logger').innerHTML = '';
	loadArrayBuffer(elem('file').value, dataLoaded);
	}

	function alphaBlend() { drawMode = 0; redraw(); }
	function viewRGB() { drawMode = 1; redraw(); }
	function viewAlpha() { drawMode = 2; redraw(); }

	</script>
	</head>
	<body>
	<br>
	<div style="font-size: 24pt; font-weight: bold">
	.basis->Compressed texture transcoder test
	</div>

	<br>This demo uses the Basis C++ transcoder (compiled to Javascript using Emscripten) to transcode a .basis file to <b id='format'>FORMAT</b>
	<br>Thanks to Evan Parker for providing <a href="https://github.com/toji/webgl-texture-utils">webgl-texture-utils</a> and this test bed.
	<br>
	<br>
	.basis file:
	<input id="file" type="text" size=30 value="assets/kodim03.basis"></input>
	<input type="button" value="Run!" onclick="runLoadFile()"></input>
	<br>
	<br>
	<input type="button" value="Alpha blend" onclick="alphaBlend()"></input>
	<input type="button" value="View RGB" onclick="viewRGB()"></input>
	<input type="button" value="View Alpha" onclick="viewAlpha()"></input>

	<br>
	<br>
	Use Container Independent Transcoding API's:
	<input type="checkbox" id="ContainerIndependentTranscoding">

	<div style="position:absolute; left: 525px; top:130px; font-size: 20pt; font-weight: bold; color: red">
	<div id="no-compressed-tex" style="display: none; width: 768px; font-size: 20pt; font-weight: bold; color: red">
	NOTE: Your browser does not support several compressed texture format, so using RGB565.
	</div>
	<canvas id='canvas'></canvas>
	</div>
	<br><br>
	<div id='logger'></div>
	</body>
	<script>
	BASIS({onRuntimeInitialized : () => {
	var gl = elem('canvas').getContext('webgl');

	astcSupported = !!gl.getExtension('WEBGL_compressed_texture_astc');
	etcSupported = !!gl.getExtension('WEBGL_compressed_texture_etc1');
	dxtSupported = !!gl.getExtension('WEBGL_compressed_texture_s3tc');
	pvrtcSupported = !!(gl.getExtension('WEBGL_compressed_texture_pvrtc')) \|\| !!(gl.getExtension('WEBKIT_WEBGL_compressed_texture_pvrtc'));
	bc7Supported = !!gl.getExtension('EXT_texture_compression_bptc');

	// HACK HACK - for testing uncompressed
	//astcSupported = false;
	//etcSupported = false;
	//dxtSupported = false;
	//bc7Supported = false;
	//pvrtcSupported = false;

	window.renderer = new Renderer(gl);

	elem('file').addEventListener('keydown', function(e) {
	if (e.keyCode == 13) {
	runLoadFile();
	}
	}, false);

	if (!(astcSupported \|\| etcSupported \|\| dxtSupported \|\| pvrtcSupported))
	{
	// elem('nodxt').style.display = 'block';
	}

	runLoadFile();
	}}).then(module => window.Module = module);
	</script>
	</html>