uniform float4 N;
uniform half4 colorGreen, colorRed;

half4 main(float2 xy) {
    // Scalar facefoward has to be polyfilled, which produces an I*NRef expression. Test that this
    // avoids compile-time eval that would overflow for just those parameters.
    float huge = faceforward(N.x, 1e30, 1e30);
    // Scalar reflect also is implemented from scratch, producing a 2*N*I*N expression.
    huge = reflect(1e30, 1e30);
    // mod introduces division in its polyfill
    huge = mod(0, 0);
    return huge > 0 ? colorGreen : colorRed;
}