Need private packages and team management tools?Check out npm Teams »

glsl-specular-cook-torrance

2.0.1 • Public • Published

glsl-specular-cook-torrance

Computes the specular power in the Cook-Torrance model.

Example

#pragma glslify: cookTorranceSpec require(glsl-specular-cook-torrance) 
 
uniform vec3 eyePosition;
uniform vec3 lightPosition;
 
uniform float roughness, fresnel;
 
varying vec3 surfacePosition, surfaceNormal;
 
void main() {
  //Light and view geometry 
  vec3 viewDirection = normalize(eyePosition - surfacePosition);
  vec3 lightDirection = normalize(lightPosition - surfacePosition);
 
  //Surface properties 
  vec3 normal = normalize(surfaceNormal);
  
  //Compute specular power 
  float power = cookTorranceSpec(
    lightDirection, 
    viewDirection, 
    normal, 
    roughness,
    fresnel);
 
  gl_FragColor = vec4(power,power,power,1.0);
}

Usage

Install with npm:

npm install glsl-specular-phong

Then use with glslify.

API

#pragma glslify: 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 length vec3 pointing from the surface point toward the light
  • eyeDir is a unit length vec3 pointing from the surface point toward the camera
  • normal is the unit length surface normal at the sample point
  • roughness is the surface roughness parameter, between 0 and 1. 0 means surface is perfectly smooth, 1 means surface is matte
  • fresnel 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

Install

npm i glsl-specular-cook-torrance

DownloadsWeekly Downloads

59,360

Version

2.0.1

License

MIT

Last publish

Collaborators

  • avatar
  • avatar
  • avatar
  • avatar
  • avatar
  • avatar
  • avatar
  • avatar
  • avatar
  • avatar
  • avatar
  • avatar
  • avatar
  • avatar
  • avatar
  • avatar
  • avatar
  • avatar
  • avatar