Cg Lighting Function

This a cool lighting function written in Nvidia Cg. It's pretty generalistic, its basically just a normal sum of the ambient + emissive + diffuse + specular. It can be the same for per pixel or vertex lighting.

struct Material
{
float4 Ka;
float4 Ke;
float4 Kd;
float4 Ks;
float shininess;
};

struct Light
{
float3 position;
float4 diffuseColor;
float4 specularColor;
};

float4 lighting(Material material,
Light light,
float4 globalAmbient,
float4 position,
float3 normal,
float3 eyePosition)
{
//Normalize the normal
normal = normalize(normal);

//Compute the ambient light
float4 ambient = globalAmbient * material.Ka;

//Compute the emissive term
float4 emissive = material.Ke;

//Compute the diffuse term
float3 lightVector = normalize(light.position - position);
float diffuseLight = max(dot(normal, lightVector), 0);
float4 diffuse = material.Kd * light.diffuseColor * diffuseLight;

//Compute the specular term
float3 viewVector = normalize(eyePosition - position);
float3 halfAngleVector = normalize(lightVector + viewVector);
float specularLight = pow(max(dot(normal, halfAngleVector), 0), material.shininess);
if(diffuseLight <= 0) specularLight = 0; float4 specular = material.Ks * light.specularColor * specularLight; return ambient + emissive + diffuse + specular; }

That´s it

I'm using Ogre for this trials, so i'm also supplying the Ogre .material and .program files, as well as some cg shaders using this function in a PerPixel, Vertex and FixedPipeline Contexts. Any doubts or critics go fuck yourself, do you think i'm your mother?


Material File

Program File

Lighting.cg

PerPixel.cg

PerVertex.cg

Also check some pics, it's the same model ( a low tessellated sphere ), with the same texture applied. You can quickly see the difference in both quality and the frame rate penalty.