glsl-specular-beckmann

glsl-specular-beckmann

Computes the specular power from the Beckmann distribution

Example

#pragma glslify: beckmann = require(glsl-specular-beckmann)

uniform vec3 eyePosition;
uniform vec3 lightPosition;

uniform float roughness;

varying vec3 surfacePosition;
varying vec3 surfaceNormal;

void main() {
  vec3 eyeDirection = normalize(eyePosition - surfacePosition);
  vec3 lightDirection = normalize(lightPosition - surfacePosition);
  vec3 normal = normalize(surfaceNormal);

  float power = beckmann(lightDirection, viewDirection, normal, roughness);

  gl_FragColor = vec4(power,power,power,1.0);
}

Usage

Install with npm:

npm install glsl-specular-beckmann

Then use with glslify.

API

#pragma glslify: beckmann = require(glsl-specular-beckmann)

float beckmann(vec3 lightDir, vec3 eyeDir, vec3 normal, float shininess)

Computes the specular power in the Beckmann model

• 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 surface normal at the sample point
• roughness is a parameter between 0 and 1 measuring the surface roughness. Small values are shinier, larger values are rougher.

Returns A float representing the specular power

License

(c) 2014 Mikola Lysenko. MIT License