用可编程渲染管线实现phone光照模型

float4x4 matViewProjection;
float4 Light_Position;
float4 Light_Attenuation;
float4 Light_Color;
float4 Ambient_Color;
float4 vViewPosition;
float alpha;

struct VS_INPUT
{
float4 Position : POSITION0;
float3 Normal : NORMAL0;
float2 Texcoord : TEXCOORD0;
};

struct VS_OUTPUT
{
float4 Position : POSITION0;
float2 Texcoord : TEXCOORD0;
float4 Color : COLOR0;
};

float4 PointLighting(float3 position, float3 normal
, float3 eyedir, float4 ambient
, float3 lightpos, float3 lightatt, float4 lightcolor)
{
float3 lightdir = normalize(position - lightpos);
float3 dis = distance(position, lightpos);
float disatt = saturate(1 / ( lightatt.x + lightatt.y * dis + lightatt.z * dis * dis ));
float angleatt = saturate(-lightdir * normal);
float3 reflectdir = normalize(reflect(lightdir, normal));
float specularatt = pow(saturate(reflectdir * eyedir), alpha);

return ambient + lightcolor * disatt * (angleatt + specularatt);
}

VS_OUTPUT vs_main( VS_INPUT Input )
{
VS_OUTPUT Output;

Output.Position = mul( Input.Position, matViewProjection );
Output.Texcoord = Input.Texcoord;
float3 eyedir = normalize(vViewPosition - Input.Position);
Output.Color = PointLighting(Input.Position, Input.Normal
, eyedir, Ambient_Color
, Light_Position, Light_Attenuation, Light_Color);

return( Output );

}