Reflection Without Raytracing

Further to my recent IBL experience, I decided to write a simple texture-based 'surface' shader for use in situations where reflection is desired - A common work-around due to the expensive nature of raytracing...

/* Simple environment-mapping shader */

surface
envmap(float Ka = 1,
Kd = 1,
intensity = 1.0;
string texturename = "";
float blur = 0.01;)
{
point Nf = faceforward (normalize(N),I);

if (texturename != "")
{
Oi = Os;
Ci = Os * Cs * (Ka * ambient() + Kd * diffuse(Nf)) * (intensity * color environment(texturename, Nf, "blur", blur));
}
else
{
Oi = Os;
Ci = Os * Cs * (Ka * ambient() + Kd * diffuse(Nf));
}
}



While not perfect, as before, the result is reasonable (for my needs) and does offer a good foundation for me to build upon as my knowledge improves.

For fun, I added our existing 'envlight' shader to the scene to provide some AO goodness - Spot the difference...