redCanvasFormat();
  context.configure({
    device,
    format: presentationFormat,
    alphaMode: 'premultiplied',
  });

  const module = device.createShaderModule({
    code: `
      struct Uniforms {
        color: vec4f,
        matrix: mat3x3f,
      };

      struct Vertex {
        @location(0) position: vec2f,
      };

      struct VSOutput {
        @builtin(position) position: vec4f,
      };

      @group(0) @binding(0) var<uniform> uni: Uniforms;

      @vertex fn vs(vert: Vertex) -> VSOutput