ScreenQuadVertexShader.metal

constant float4x4 quadVertices = float4x4(float4( -1.0, -1.0, 0.0, 1.0 ),
                                          float4(  1.0, -1.0, 0.0, 1.0 ),
                                          float4( -1.0,  1.0, 0.0, 1.0 ),
                                          float4(  1.0,  1.0, 0.0, 1.0 ));

constant float4x2 quadTextureCoordinates = float4x2(float2( 1.0, 1.0 ),
                                                    float2( 0.0, 1.0 ),
                                                    float2( 1.0, 0.0 ),
                                                    float2( 0.0, 0.0 ));

vertex ScreenQuadVertex screenQuadVertex(uint vertex_id [[vertex_id]],
                                         const constant Uniforms& uniforms [[buffer(0)]])
{
    ScreenQuadVertex outVertex;
    outVertex.position = quadVertices[vertex_id];
    outVertex.position.x *= uniforms.aspectRatioAdjustment;
    outVertex.texcoord = quadTextureCoordinates[vertex_id];
    
    return outVertex;
}