Shaders for showing DirectX coordinate conventions

coordinates.hlsl

static const float4 kPositions[] = {
    // A downard-pointing triangle near the viewer.
    float4(-1, 1, 0, 1),  // Red
    float4(1, 1, 0, 1),   // Green
    float4(0, -1, 0, 1),  // Blue

    // An upward-pointing triangle far from the viewer.
    float4(1, -1, .9, 1),   // Red
    float4(-1, -1, .9, 1),  // Green
    float4(0, 1, .9, 1),    // Blue
};

static const float4 kColors[] = {
    float4(1, 0, 0, 1),
    float4(0, 1, 0, 1),
    float4(0, 0, 1, 1),
};

ClipSpaceVertex main(uint index : SV_VertexId) {
  ClipSpaceVertex v;
  v.pos = kPositions[index % 6];
  v.color = kColors[index % 3];
  return v;
}