// This is C2E2f_passthru from "The Cg Tutorial" (Addison-Wesley, ISBN
// 0321194969) by Randima Fernando and Mark J. Kilgard.  See page 53.

struct fregm_Output {
  float4 color : COLOR;
};

fregm_Output fregm_shader(	float2 texCoord : TEXCOORD0,
							float4 position : TEXCOORD1,
							float3 normal	: TEXCOORD2,
							float4 color	: COLOR,

							uniform float3 globalAmbient,
							uniform float3 lightColor,
							uniform float3 lightPosition,
							uniform float3 eyePosition,
							uniform float3 Ke,
							uniform float3 Ka,
							uniform float3 Kd,
							uniform float3 Ks,
							uniform float  shininess)
{
	fregm_Output OUT;

	float3 P = position.xyz;
	float3 N = normalize(normal);

	// Compute the emissive term
	float3 emissive = Ke;

	// Compute the ambient term
	float3 ambient = Ka * globalAmbient;

	// Compute the diffuse term
	float3 L = normalize(lightPosition - P);
	float diffuseLight = max(dot(N, L), 0);
	float3 diffuse = Kd * lightColor * diffuseLight;

	// Compute the specular term
	float3 V = normalize(eyePosition - P);
	float3 H = normalize(L + V);
	float specularLight = pow(max(dot(N, H), 0),
                              shininess);

	if (diffuseLight <= 0) specularLight = 0;
//	float3 specular = Ks * lightColor * specularLight;
	float3 specular = Ks * specularLight;

	OUT.color.xyz = emissive + ambient + diffuse + specular;
	OUT.color.w = 1.0;

	return OUT;

}