OrenNayer.GLSL

code:Usage.GLSL

// light vector, camera vector, material normal, roughness, albedo

float power = orenNayar(L, rd, N, .3, .7);

code:OrenNayer.GLSL

float orenNayarDiffuse(

vec3 lightDirection,

vec3 viewDirection,

vec3 surfaceNormal,

float roughness,

float albedo) {

float LdotV = dot(lightDirection, viewDirection);

float NdotL = dot(lightDirection, surfaceNormal);

float NdotV = dot(surfaceNormal, viewDirection);

float s = LdotV - NdotL * NdotV;

float t = mix(1.0, max(NdotL, NdotV), step(0.0, s));

float sigma2 = roughness * roughness;

float A = 1.0 + sigma2 * (albedo / (sigma2 + 0.13) + 0.5 / (sigma2 + 0.33));

float B = 0.45 * sigma2 / (sigma2 + 0.09);

return albedo * max(0.0, NdotL) * (A + B * s / t) / PI;

}