glsl-diffuse-oren-nayar

glsl-diffuse-oren-nayar

The Oren-Nayar diffuse lighting model implemented in GLSL.

Example

#pragma glslify: orenNayar = require(glsl-diffuse-orenNayar)

uniform vec3 lightPosition, eyePosition;

varying vec3 surfacePosition, surfaceNormal;

void main() {
  //Light and view geometry
  vec3 lightDirection = normalize(lightPosition - surfacePosition);
  vec3 viewDirection = normalize(eyePosition - surfacePosition);

  //Surface properties
  vec3 normal = normalize(surfaceNormal);
  
  //Compute diffuse light intensity
  float power = orenNayar(
    lightDirection,
    viewDirection, 
    normal,
    0.3,
    0.7);

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

Usage

Install with npm:

npm install glsl-diffuse-oren-nayar

Then use with glslify.

API

#pragma glslify: orenNayar = require(glsl-diffuse-oren-nayar)

float orenNayar(vec3 lightDir, vec3 viewDir, vec3 normal, float roughness, float albedo)

Computes the diffuse intensity in the Lambertian model

• lightDir is a unit length vec3 pointing from the surface point toward the light
• viewDir is a unit length vec3 pointing toward the camera
• normal is the unit length surface normal at the sample point
• roughness is a parameter between 0 and 1 measuring the surface roughness. 0 for smooth, 1 for matte
• albedo measures the intensity of the diffuse reflection. Values >0.96 do not conserve energy

Returns A float representing the diffuse light intensity

License

(c) 2014 Mikola Lysenko. MIT License