generalize context proxying to support not just 2d contexts

emcc

@@ -1830,7 +1830,7 @@ try:
     js_target = unsuffixed(target) + '.js'
     base_js_target = os.path.basename(js_target)
     if proxy_to_worker:
-      html.write(shell.replace('{{{ SCRIPT }}}', '<script>' + open(shared.path_from_root('src', 'proxyClient.js')).read().replace('{{{ filename }}}', target_basename) + '</script>'))
+      html.write(shell.replace('{{{ SCRIPT }}}', '<script>' + open(shared.path_from_root('src', 'webGLClient.js')).read() + '\n' + open(shared.path_from_root('src', 'proxyClient.js')).read().replace('{{{ filename }}}', target_basename) + '</script>'))
       shutil.move(final, js_target)
     elif not Compression.on:
       # Normal code generation path

src/jsifier.js

@@ -1899,6 +1899,7 @@ function JSify(data, functionsOnly) {
       print('}');
     }
     if (PROXY_TO_WORKER) {
+      print(read('webGLWorker.js'));
       print(read('proxyWorker.js'));
     }
     if (RUNTIME_TYPE_INFO) {

src/proxyClient.js

@@ -1,8 +1,6 @@
 
 // proxy to/from worker
 
-Module.ctx = Module.canvas.getContext('2d');
-
 // render
 
 var renderFrameData = null;
@@ -31,6 +29,7 @@ var worker = new Worker('{{{ filename }}}.js');
 var workerResponded = false;
 
 worker.onmessage = function worker_onmessage(event) {
+  //console.log(JSON.stringify(event.data));
   if (!workerResponded) {
     workerResponded = true;
     if (Module.setStatus) Module.setStatus('');
@@ -52,6 +51,10 @@ worker.onmessage = function worker_onmessage(event) {
     }
     case 'canvas': {
       switch (data.op) {
+        case 'getContext': {
+          Module.ctx = Module.canvas.getContext(data.type);
+          break;
+        }
         case 'resize': {
           Module.canvas.width = data.width;
           Module.canvas.height = data.height;

src/proxyWorker.js

@@ -43,24 +43,28 @@ document.createElement = function document_createElement(what) {
         }
       };
       canvas.getContext = function canvas_getContext(type) {
-        assert(type == '2d');
-        return {
-          getImageData: function(x, y, w, h) {
-            assert(x == 0 && y == 0 && w == canvas.width && h == canvas.height);
-            canvas.ensureData();
-            return {
-              width: canvas.data.width,
-              height: canvas.data.height,
-              data: new Uint8Array(canvas.data.data) // TODO: can we avoid this copy?
-            };
-          },
-          putImageData: function(image, x, y) {
-            canvas.ensureData();
-            assert(x == 0 && y == 0 && image.width == canvas.width && image.height == canvas.height);
-            canvas.data.data.set(image.data); // TODO: can we avoid this copy?
-            postMessage({ target: 'canvas', op: 'render', image: canvas.data });
-          }
-        };
+        postMessage({ target: 'canvas', op: 'getContext', type: type });
+        if (type === '2d') {
+          return {
+            getImageData: function(x, y, w, h) {
+              assert(x == 0 && y == 0 && w == canvas.width && h == canvas.height);
+              canvas.ensureData();
+              return {
+                width: canvas.data.width,
+                height: canvas.data.height,
+                data: new Uint8Array(canvas.data.data) // TODO: can we avoid this copy?
+              };
+            },
+            putImageData: function(image, x, y) {
+              canvas.ensureData();
+              assert(x == 0 && y == 0 && image.width == canvas.width && image.height == canvas.height);
+              canvas.data.data.set(image.data); // TODO: can we avoid this copy?
+              postMessage({ target: 'canvas', op: 'render', image: canvas.data });
+            }
+          };
+        } else {
+          return new WebGLWorker();
+        }
       };
       canvas.boundingClientRect = {};
       canvas.getBoundingClientRect = function canvas_getBoundingClientRect() {

src/webGLClient.js

@@ -0,0 +1,2 @@
+// WebGLWorker client code
+

src/webGLWorker.js

@@ -0,0 +1,2 @@
+// WebGLWorker worker code
+