A reusable GLSL directional light function.

The simplest case is to simply use:

dot(normal, direction) * light

But this module also takes into account specualrity as well.

view demo

Exports vec3 directional_light(), which takes the following arguments:

• vec3 normal: This point's normal vector.
• vec3 light: The light color.
• vec3 surface: The color of the material/surface being drawn.
• vec3 lightDirection: The direction of the light to cast – normalized.
• mat4 modelMatrix: The model matrix.
• mat4 viewMatrix: The view matrix.
• vec3 viewPosition: The position of the camera in world space.

If you wish to include specular lighting too, simply add these two extra parameters when calling the function:

• float shininess: Set to lower values for matte, higher for gloss.
• float specularity: The amount by which to scale the specular light cast on the object.

MIT. See LICENSE.md for details.