From 6d7a9fc22a55d1cebe71fdd6475ba3af2e9a1a5a Mon Sep 17 00:00:00 2001
From: kkapsner <github@mail.kkapsner.de>
Date: Mon, 26 Dec 2016 14:36:01 +0100
Subject: [PATCH] Removed bug with faking webgl and added readPixels for
 webgl2.

Fixes #96 and #97.
---
 lib/intercept.js   | 92 +++++++++++++++++++++++-----------------------
 lib/modifiedAPI.js | 25 ++++++++-----
 2 files changed, 63 insertions(+), 54 deletions(-)

diff --git a/lib/intercept.js b/lib/intercept.js
index b78bb08..26268d9 100644
--- a/lib/intercept.js
+++ b/lib/intercept.js
@@ -26,56 +26,58 @@
 		if (siteStatus.mode !== "allow"){
 			apiNames.forEach(function(name){
 				var changedFunction = changedFunctions[name];
-				var original = window.wrappedJSObject[changedFunction.object].prototype[name];
-				
 				if (changedFunction.getStatus(undefined, siteStatus).active){
-					Object.defineProperty(
-						window.wrappedJSObject[changedFunction.object].prototype,
-						name,
-						{
-							enumerable: true,
-							configureable: false,
-							get: function(){
-								if (!window.location.href){
-									return undef;
-								}
-								var error = new Error();
-								if (checkStack(error.stack)){
-									return original;
-								}
-								var funcStatus = changedFunction.getStatus(this, siteStatus);
-								
-								if (funcStatus.active){
-									if (funcStatus.mode === "ask"){
-										funcStatus.mode = ask({window: window, type: changedFunction.type, canvas: this, errorStack: error.stack});
+					(Array.isArray(changedFunction.object)? changedFunction.object: [changedFunction.object]).forEach(function(object){
+						var original = window.wrappedJSObject[object].prototype[name];
+					
+						Object.defineProperty(
+							window.wrappedJSObject[object].prototype,
+							name,
+							{
+								enumerable: true,
+								configureable: false,
+								get: function(){
+									if (!window.location.href){
+										return undef;
 									}
-									switch (funcStatus.mode){
-										case "allow":
-											return original;
-										case "fake":
-											setRandomSupplyByType(prefs("rng"));
-											var fake = changedFunction.fakeGenerator(prefs, function(messageId){
-												notify({url: window.location.href, errorStack: error.stack, messageId});
-											}, original);
-											switch (fake){
-												case true:
-													return original;
-												case false:
-													return undef;
-												default:
-													return exportFunction(fake, window.wrappedJSObject);
-											}
-										//case "block":
-										default:
-											return undef;
+									var error = new Error();
+									if (checkStack(error.stack)){
+										return original;
+									}
+									var funcStatus = changedFunction.getStatus(this, siteStatus);
+									
+									if (funcStatus.active){
+										if (funcStatus.mode === "ask"){
+											funcStatus.mode = ask({window: window, type: changedFunction.type, canvas: this, errorStack: error.stack});
+										}
+										switch (funcStatus.mode){
+											case "allow":
+												return original;
+											case "fake":
+												setRandomSupplyByType(prefs("rng"));
+												var fake = changedFunction.fakeGenerator(prefs, function(messageId){
+													notify({url: window.location.href, errorStack: error.stack, messageId});
+												}, original);
+												switch (fake){
+													case true:
+														return original;
+													case false:
+														return undef;
+													default:
+														return exportFunction(fake, window.wrappedJSObject);
+												}
+											//case "block":
+											default:
+												return undef;
+										}
+									}
+									else {
+										return original;
 									}
-								}
-								else {
-									return original;
 								}
 							}
-						}
-					);
+						);
+					});
 				}
 			});
 		}
diff --git a/lib/modifiedAPI.js b/lib/modifiedAPI.js
index f95821f..3f74878 100644
--- a/lib/modifiedAPI.js
+++ b/lib/modifiedAPI.js
@@ -17,30 +17,37 @@
 			window.HTMLCanvasElement.prototype.getContext.call(canvas, "experimental-webgl2");
 	}
 	function getImageData(window, context){
+		var imageData;
+		var source;
 		if (context instanceof window.CanvasRenderingContext2D){
-			return window.CanvasRenderingContext2D.prototype.getImageData.call(context, 0, 0, context.canvas.width, context.canvas.height);
+			imageData = window.CanvasRenderingContext2D.prototype.getImageData.call(context, 0, 0, context.canvas.width, context.canvas.height);
+			source = imageData.data;
 		}
 		else {
 			var imageData  = new window.wrappedJSObject.ImageData(context.canvas.width, context.canvas.height);
+			var source = new Uint8Array(imageData.data.length);
 			window.WebGLRenderingContext.prototype.readPixels.call(
 				context,
 				0, 0, context.canvas.width, context.canvas.height,
 				context.RGBA, context.UNSIGNED_BYTE,
-				imageData.data
+				source
 			);
-			return imageData;
 		}
+		return {
+			imageData,
+			source
+		};
 	}
 	
 	function getFakeCanvas(window, original){
 		var context = getContext(window, original);
-		var imageData = getImageData(window, context);
-		var data = imageData.data;
-		var l = data.length;
+		var {imageData, source} = getImageData(window, context);
+		var desc = imageData.data;
+		var l = desc.length;
 		var rng = randomSupply.getRng(l, window);
 		
-		for (var i = 0; i < l; i += 1){
-			data[i] = rng(data[i], i);
+		for (var i = 0; i < l; i += 10){
+			desc[i] = rng(source[i], i);
 		}
 		var canvas = original.cloneNode(true);
 		context = window.HTMLCanvasElement.prototype.getContext.call(canvas, "2d");
@@ -249,7 +256,7 @@
 				status.active = hasType(status, "readout") || hasType(status, "input");
 				return status;
 			},
-			object: "WebGLRenderingContext",
+			object: ["WebGLRenderingContext", "WebGL2RenderingContext"],
 			fakeGenerator: function(prefs, notify){
 				return function readPixels(x, y, width, height, format, type, pixels){
 					// not able to use the getFakeCanvas function because the context type is wrong...