Week 6 - Per-fragment Lighting

This week I completed a shader that uses the Blinn-Phong lighting model to light the scene. Below is a clip of the shader in action with 5 animated different colored lights.

                                        

Diffuse:

The diffuse component is essentially the intensity of light at a point on a plane/model. This is known as the Lambertian Reflection. Lambert's cosine law states that the instensity of light is proportional to the cosine of the angle formed between the light's direction and the surface normal.

Specular:

Using specular reflection in our model allows us to add specular highlights to our lighting model. Specular highlights are the bright spots on shiny objects when they are lit. In my lighting calculations I have chosen to go with the Blinn-Phong lighting model which bases the intensity of the specular component on the cosine angle of the half-vector and the normal.

Below is my GLSL shader function used to compute the total intensity and final color for one light.

vec3 returnTotalLight(Light light)

{

vec3 P = pos.xyz;//vertex positon

vec3 N = normalize(normal);//eye position in camera space

vec3 V = normalize(eye.xyz - P);//view direction

vec3 L = normalize(light.position - P);//light direction

vec3 H = normalize(L + V);//half vec for spec term

float specularLight = pow(max(dot(N,H),0), shininess);

float diffuseLight = max(dot(N,L),0);

vec3 diffuse = vec3(light.color *diffuseLight);

if(diffuseLight<=0)

{

specularLight = 0;

}

vec3 specular =vec3( light.color * specularLight);

return vec3(specular + diffuse);

};