Made readPixels consistent with the other faked readout functions.

lib/modifiedAPI.js

@@ -15,6 +15,8 @@
 	}
 	
 	const colorStatistics = require("./colorStatistics");
+	const logging = require("./logging");
+	const {copyCanvasToWebgl} = require("./webgl");
 	
 	// let Cu = require("chrome").Cu;
 	
@@ -101,6 +103,7 @@
 			return canvas;
 		}
 		catch (e){
+			logging.warning("Error while faking:", e);
 			return original;
 		}
 	}
@@ -363,34 +366,10 @@
 			fakeGenerator: function(prefs, notify, window, original){
 				return function readPixels(x, y, width, height, format, type, pixels){
 					if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
-						// not able to use the getFakeCanvas function because the context type is wrong...
 						notify.call(this, "fakedReadout");
-						var xPixels = pixels;
-						var ret = original.apply(this, window.Array.from(arguments));
-						var l = xPixels.length;
-						var ignoredColors = {};
-						if (prefs("ignoreFrequentColors")){
-							var statistic = colorStatistics.compute(pixels);
-							ignoredColors = statistic.getMaxColors(prefs("ignoreFrequentColors"));
-						}
-						var rng = randomSupply.getPixelRng(l, window, ignoredColors);
-						var fakeAlphaChannel = prefs("fakeAlphaChannel");
-						for (var i = 0; i < l; i += 4){
-							var [r, g, b, a] = rng(
-								xPixels[i + 0],
-								xPixels[i + 1],
-								xPixels[i + 2],
-								xPixels[i + 3],
-								i / 4
-							);
-							xPixels[i + 0] = r;
-							xPixels[i + 1] = g;
-							xPixels[i + 2] = b;
-							if (fakeAlphaChannel){
-								xPixels[i + 3] = a;
-							}
-						}
-						return ret;
+						var fakeCanvas = getFakeCanvas(window, this.canvas, prefs);
+						var {context} = copyCanvasToWebgl(window, fakeCanvas, this instanceof window.WebGLRenderingContext? "webgl": "webgl2");
+						return original.apply(context, window.Array.from(arguments));
 					}
 					else {
 						return original.apply(this, window.Array.from(arguments));

lib/webgl.js

@@ -0,0 +1,121 @@
+/* jslint moz: true */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+(function(){
+	"use strict";
+	
+	var logging = require("./logging");
+	
+	var scope;
+	if ((typeof exports) !== "undefined"){
+		scope = exports;
+	}
+	else {
+		window.scope.webgl = {};
+		scope = window.scope.webgl;
+	}
+	
+	scope.copyCanvasToWebgl = function copyCanvasToWebgl(window, canvas, webGLVersion = "webgl"){
+		var webGlCanvas = canvas.cloneNode(true);
+		var success;
+		var context =
+			window.HTMLCanvasElement.prototype.getContext.call(webGlCanvas, webGLVersion) ||
+			window.HTMLCanvasElement.prototype.getContext.call(webGlCanvas, "experimental-" + webGLVersion);
+		if (!context){
+			// unable to get a context...
+			logging.warning("unable to create webgl context.");
+			return {canvas: false, context: false};
+		}
+		
+		context.viewport(0, 0, webGlCanvas.width, webGlCanvas.height);
+
+		var program = context.createProgram();
+
+		var shader = context.createShader(context.VERTEX_SHADER);
+		var vertex = "attribute vec4 a_position;\nattribute vec2 a_texCoord;\nvarying vec2 v_texCoord;\nvoid main(){\n\tgl_Position = a_position;\n\tv_texCoord = a_texCoord;\n}";
+		context.shaderSource(shader, vertex);
+		context.compileShader(shader);
+		success = context.getShaderParameter(shader, context.COMPILE_STATUS);
+		if (!success){
+			context.deleteShader(shader);
+			logging.warning("webgl: failed to compile vertex shader.");
+			return {canvas: false, context: false};
+		}
+		context.attachShader(program, shader);
+		
+		var shader = context.createShader(context.FRAGMENT_SHADER);
+		var fragmenter = "precision mediump float;\nuniform sampler2D u_image;\nvarying vec2 v_texCoord;\nvoid main(){\n\tgl_FragColor = texture2D(u_image, v_texCoord);\n}"
+		context.shaderSource(shader, fragmenter);
+		context.compileShader(shader);
+		success = context.getShaderParameter(shader, context.COMPILE_STATUS);
+		if (!success){
+			context.deleteShader(shader);
+			logging.warning("webgl: failed to compile fragmenter shader.");
+			return {canvas: false, context: false};
+		}
+		context.attachShader(program, shader);
+		
+		context.linkProgram(program);
+		success = context.getProgramParameter(program, context.LINK_STATUS);
+		if (!success){
+			context.deleteProgram(program);
+			logging.warning("webgl: failed to link program.");
+			return {canvas: false, context: false};
+		}
+		
+		context.useProgram(program);
+		
+		var positionAttributeLocation = context.getAttribLocation(program, "a_position");
+		var positionBuffer = context.createBuffer();
+		context.bindBuffer(context.ARRAY_BUFFER, positionBuffer);
+		context.bufferData(context.ARRAY_BUFFER, new Float32Array([
+			-1,-1,
+			-1, 1,
+			 1,-1,
+			 1, 1,
+			-1, 1,
+			 1,-1
+			 
+		]), context.STATIC_DRAW);
+		
+		context.enableVertexAttribArray(positionAttributeLocation);
+		var size = 2;          // 2 components per iteration
+		var type = context.FLOAT;   // the data is 32bit floats
+		var normalize = false; // don't normalize the data
+		var stride = 0;        // 0 = move forward size * sizeof(type) each iteration to get the next position
+		var offset = 0;        // start at the beginning of the buffer
+		context.vertexAttribPointer( positionAttributeLocation, size, type, normalize, stride, offset);
+		
+		var texCoordLocation = context.getAttribLocation(program, "a_texCoord");
+		
+		// provide texture coordinates for the rectangle.
+		var texCoordBuffer = context.createBuffer();
+		context.bindBuffer(context.ARRAY_BUFFER, texCoordBuffer);
+		context.bufferData(context.ARRAY_BUFFER, new Float32Array([
+			0, 1,
+			0, 0,
+			1, 1,
+			1, 0,
+			0, 0,
+			1, 1
+		]), context.STATIC_DRAW);
+		context.enableVertexAttribArray(texCoordLocation);
+		context.vertexAttribPointer(texCoordLocation, 2, context.FLOAT, false, 0, 0);
+
+		var texture = context.createTexture();
+		context.bindTexture(context.TEXTURE_2D, texture);
+		context.texParameteri(context.TEXTURE_2D, context.TEXTURE_WRAP_S, context.CLAMP_TO_EDGE);
+		context.texParameteri(context.TEXTURE_2D, context.TEXTURE_WRAP_T, context.CLAMP_TO_EDGE);
+		context.texParameteri(context.TEXTURE_2D, context.TEXTURE_MIN_FILTER, context.NEAREST);
+		context.texParameteri(context.TEXTURE_2D, context.TEXTURE_MAG_FILTER, context.NEAREST);
+		context.texImage2D(context.TEXTURE_2D, 0, context.RGBA, context.RGBA, context.UNSIGNED_BYTE, canvas);
+
+		var primitiveType = context.TRIANGLES;
+		var offset = 0;
+		var count = 6;
+		context.drawArrays(primitiveType, offset, count);
+		
+		return {webGlCanvas, context};
+	};
+}());

manifest.json

@@ -22,6 +22,7 @@
 			"lib/logging.js",
 			
 			"lib/colorStatistics.js",
+			"lib/webgl.js",
 			"lib/modifiedAPI.js",
 			"lib/randomSupplies.js",
 			"lib/intercept.js",