glsl-specular-cook-torrance
Computes the specular power in the Cook-Torrance model.
Example
# cookTorranceSpec = require(glsl-specular-cook-torrance) uniform vec3 eyePosition;uniform vec3 lightPosition; uniform float roughness, fresnel; varying vec3 surfacePosition, surfaceNormal; void
Usage
Install with npm:
npm install glsl-specular-phong
Then use with glslify.
API
# cookTorrance = require(glsl-specular-cook-torrance)
float cookTorrance(vec3 lightDir, vec3 eyeDir, vec3 normal, float roughness, float fresnel)
Computes the specular power in the Cook-Torrance
lightDir
is a unit lengthvec3
pointing from the surface point toward the lighteyeDir
is a unit lengthvec3
pointing from the surface point toward the cameranormal
is the unit length surface normal at the sample pointroughness
is the surface roughness parameter, between 0 and 1. 0 means surface is perfectly smooth, 1 means surface is mattefresnel
the Fresnel exponent. 0 = no Fresnel, higher values create a rim effect around objects
Returns A float
representing the specular power
Note Unlike the usual Cook-Torrance model, the light power is not scaled by 1/(normal . lightDirection). This avoids an unnecessary numerically unstable division, but requires modifying how diffuse light is calculated.
License
(c) 2014 Mikola Lysenko. MIT License