Cornell.osl || Open Shading Language || http://thhube.github.io/tutorials/osl/osl.html

Cornell.osl

// -- Cornell.osl - Generate the Cornell box material ---------------
#include "stdosl.h"

#define POS_Y normal(0.0, 1.0, 0.0)
#define NEG_Y normal(0.0, -1.0, 0.0)
#define EPSILON 1e-5

surface Cornell(output closure color bsdf = 0)
{
    color result = color(0, 1, 0);
    
    if (dot(N, POS_Y) < EPSILON) {
        result = color(1, 0, 0);
    }
    
    if (fabs(dot(N, NEG_Y)) < EPSILON) {
        result = color(1, 1, 1);
    }
    bsdf = result * diffuse(N);
}

// -- Glass.osl - Generate the glass material on Suzanne ------------
#include "stdosl.h"

#define IOR_THRESHOLD 1.000001

float FresnelDielectric(vector i, normal n, float eta)
{
    float c = fabs(dot(i, n));
    float g = eta * eta - 1 + c * c;
    float result = 1.0;
    
    if (g > 0) {
        g = sqrt(g);
        float a = (g - c) / (g + c);
        float b = (c * (g + c) - 1) / (c * (g + c) + 1);
        result = 0.5 * a * a * (1 + b * b);
    }
    
    return result;
}

surface Glass(
    color diffuse_col = 0.8, 
    float ior = 1.45, 
    output closure color bsdf = 0)
{
    float real_ior = max(ior, IOR_THRESHOLD);
    float eta = backfacing()? 1.0 / real_ior : real_ior;
    float fr = FresnelDielectric(I, N, eta);
    
    bsdf = diffuse_col * (fr * reflection(N) + (1.0 - fr) * refraction(N, eta));
}

// -- Metal.osl - Generate the metal reflection ---------------------
#include "stdosl.h"

surface Metal(
    color diffuse_col = 0.8,
    float roughness = 1.5,
    output closure color bsdf = 0) 
{
    bsdf = diffuse_col * reflection(N);
}

// -- Velvet.osl - Generate the velvet surface ----------------------
#include "stdosl.h"

surface Metal(
    color diffuse_col = 0.8,
    float roughness = 1.5,
    output closure color bsdf = 0) 
{
    bsdf = diffuse_col * reflection(N);
}