Multiple canvas example

README.md

@@ -5,6 +5,7 @@ Small examples WebGPU usage.
 - [Triangle](https://tsherif.github.io/webgpu-examples/triangle.html): Creating vertex buffers and drawing a triangle.
 - [Cube](https://tsherif.github.io/webgpu-examples/cube.html): Creating a texture from an ImageBitmap, setting up vertex and uniform buffers, and animating a 3D cube.
 - [Particles](https://tsherif.github.io/webgpu-examples/particles.html): Simulating gravity on instanced particles using a compute shader.
+- [Multiple Canvases](https://tsherif.github.io/webgpu-examples/multi-canvas.html): Rendering to multiple canvases with a single device instance.
 
 Examples currently only run in Chrome without special flags. See the [Implementation Status](https://github.com/gpuweb/gpuweb/wiki/Implementation-Status) page for updates on support. 
 

cube.html

@@ -103,7 +103,6 @@
     const viewMatrix = mat4.create();
     const modelMatrix = mat4.create();
     const viewProjectionMatrix = mat4.create();
-    const mvpMatrix = mat4.create();
     const rotation = [0, 0, 0];
 
     mat4.perspective(projectionMatrix, Math.PI / 2, canvas.width / canvas.height, 0.1, 10.0)