[require]
shader model >= 3.0

[pixel shader]
float4 main(float4 pos : sv_position) : sv_target
{
    // Shader models < 4 don't add 0.5 to sv_position, so this adjustment is required to get the
    // same outputs.
    pos.x = floor(pos.x) + 0.5;
    pos.y = floor(pos.y) + 0.5;

    pos /= 10.0;
    float nonlinear = pos.x * pos.y - pos.x * (pos.x + 0.5);
    float4 res = fwidth(nonlinear);

    // Each device may use either the coarse or the fine derivate, so use quantization.
    return round(30 * res);
}

[test]
todo(glsl) draw quad
todo(sm<4) probe (10, 10) rgba (8.0, 8.0, 8.0, 8.0)
todo(sm<4) probe (11, 10) rgba (8.0, 8.0, 8.0, 8.0)
todo(sm<4) probe (12, 10) rgba (10.0, 10.0, 10.0, 10.0)
todo(sm<4) probe (16, 16) rgba (12.0, 12.0, 12.0, 12.0)
todo(sm<4) probe (150, 150) rgba (92.0, 92.0, 92.0, 92.0)