[pixel shader]
float4 main(float4 pos : SV_POSITION) : SV_TARGET
{
    if(pos.x > 200.0)
        return float4(0.1, 0.2, 0.3, 0.4);
    else
        return float4(0.9, 0.8, 0.7, 0.6);
}

[test]
draw quad
probe rect rgba (0, 0, 200, 480) (0.9, 0.8, 0.7, 0.6)
probe rect rgba (200, 0, 440, 480) (0.1, 0.2, 0.3, 0.4)