Canvas API. There are still a number of things to do:

samples/openglui/src/openglui_raytrace.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // This sample is based upon the Ray Tracer sample by Jonas Sicking at:
 // http://www.khronos.org/webgl/wiki/Demo_Repository
 
 /**
  * A sample GL application.
  */
-library raytrace;
+library openglui_raytrace;
 
 import 'gl.dart';
 import 'dart:math' as Math;
 
+WebGLRenderingContext gl = null;
+
 // Note: The first line of the fragment shader ("precision mediump float")
 // is not portable. It is required for WebGL and OpenGL ES. Desktop OpenGL
 // does not use precision specifiers. Some desktop systems treat this as a
 // no-op and some treat it as a syntax error. In particular, this line needs
 // to be removed to this this shader on a MAc.
 const FRAGMENT_PROGRAM = """
 // TODO(vsm): Remove this ifdef.  It's a temporary workaround to get
 // this sample running on the Mac desktop emulator.
 #ifdef GL_ES
   precision mediump float;
@@ skipping 266 matching lines @@
   var cameraPersp = 6.0;
   var up = new Vector(0.0, 1.0, 0.0);
   var cameraDir = normalize(vectSub(cameraTo, cameraFrom));
 
   var cameraLeft = normalize(crossProd(cameraDir, up));
   var cameraUp = normalize(crossProd(cameraLeft, cameraDir));
   // cameraFrom + cameraDir * cameraPersp
   var cameraCenter = vectAdd(cameraFrom, vectMul(cameraDir, cameraPersp));
 
   // cameraCenter + cameraUp + cameraLeft * ratio
-  var cameraTopLeft  = vectAdd(vectAdd(cameraCenter, cameraUp),
-             vectMul(cameraLeft, ratio));
-  var cameraBotLeft  = vectAdd(vectSub(cameraCenter, cameraUp),
-             vectMul(cameraLeft, ratio));
-  var cameraTopRight = vectSub(vectAdd(cameraCenter, cameraUp),
-             vectMul(cameraLeft, ratio));
-  var cameraBotRight = vectSub(vectSub(cameraCenter, cameraUp),
-             vectMul(cameraLeft, ratio));
+log("cameraLeft = ${cameraLeft}");
+log("ratio = ${ratio}");
+  var vl = vectMul(cameraLeft, ratio);
+  var cameraTopLeft  = vectAdd(vectAdd(cameraCenter, cameraUp), vl);
+             //vectMul(cameraLeft, ratio));
+  var cameraBotLeft  = vectAdd(vectSub(cameraCenter, cameraUp), vl);
+             //vectMul(cameraLeft, ratio));
+  var cameraTopRight = vectSub(vectAdd(cameraCenter, cameraUp), vl);
+             //vectMul(cameraLeft, ratio));
+  var cameraBotRight = vectSub(vectSub(cameraCenter, cameraUp), vl);
+             //vectMul(cameraLeft, ratio));
 
   var corners = [];
   pushVec(cameraTopRight, corners);
   pushVec(cameraTopLeft, corners);
   pushVec(cameraBotRight, corners);
   pushVec(cameraBotLeft, corners);
 
   gl.bufferData(WebGLRenderingContext.ARRAY_BUFFER, wrapVertices(corners),
       WebGLRenderingContext.STATIC_DRAW);
 
   gl.uniform3f(cameraPos, cameraFrom.x, cameraFrom.y, cameraFrom.z);
   gl.uniform3f(sphere1Center, x1, y1, z1);
   gl.uniform3f(sphere2Center, x2, y2, z2);
   gl.uniform3f(sphere3Center, x3, y3, z3);
 
   gl.drawArrays(WebGLRenderingContext.TRIANGLE_STRIP, 0, 4);
 
   t += 0.03;
   if (t > Math.PI * 200) {
     t -= Math.PI * 200;
   }
 }
 
-void setup(int width, int height) {
+void setup(canvas, int w, int h) {
+  if (canvas == null) {
+    canvas = new CanvasElement(width: w, height: h);
+  }
+  gl = canvas.getContext("experimental-webgl");
   initShaders();
   gl.clearColor(0.0, 0.0, 0.0, 1.0);
   gl.clearDepth(1.0);
   initBuffers();
-  resize(width, height);
+  resize(w, h);
+  log("Done setup");
 }
 
 void resize(int width, int height) {
+  gl.viewport(0, 0, width, height);
   ratio = width / height;
-  gl.viewport(0, 0, width, height);
   t -= 0.03;
   drawScene();
 }
 
 void update() {
   drawScene();
 }
 
-/*
-TODO(gram): below are the current entry points for input events for the
-native code version. We need to integrate these somehow with the WebGL
-version:
+onMotionDown(num when, num x, num y) {
+}
 
-onMotionDown(num when, num x, num y) {}
-onMotionUp(num when, num x, num y) {}
-onMotionMove(num when, num x, num y) {}
-onMotionCancel(num when, num x, num y) {}
-onMotionOutside(num when, num x, num y) {}
-onMotionPointerDown(num when, num x, num y) {}
-onMotionPointerUp(num when, num x, num y) {}
-onKeyDown(num when, int flags, int keycode, int metastate, int repeat) {}
-onKeyUp(num when, int flags, int keycode, int metastate, int repeat) {}
-onKeyMultiple(num when, int flags, int keycode, int metastate, int repeat) {
-}
-*/
-