[셰이더 프로그래밍 입문] 5.디퓨즈/스페큘러 매핑

5.디퓨즈/스페큘러 매핑

• 난반사광 = 빛의 색상X난반사광의 양X디퓨즈맵의 값

• 정반사광 = 빛의 색상X정반사광의 양X스페큘러맵의 값

• 스페큘러맵은 각 픽셀의 정반사광을 조절하는 것이 목적

▶렌더몽키 코드 

- 버텍스 셰이더

float4x4 gWorldMatrix;
float4x4 gViewMatrix;
float4x4 gProjectionMatrix;
 
float4 gWorldLightPosition;
float4 gWorldCameraPosition;
 
struct VS_INPUT
{
   float4 mPosition:POSITION;
   float3 mNormal:NORMAL;
   float2 mUV:TEXCOORD0;
};
 
struct VS_OUTPUT
{
   float4 mPosition:POSITION;
   float2 mUV:TEXCOORD0;
   float3 mDiffuse:TEXCOORD1;
   float3 mViewDir:TEXCOORD2;
   float3 mReflection:TEXCOORD3;
};
 
 
VS_OUTPUT vs_main(VS_INPUT Input)
{
   VS_OUTPUT Output;
   
   Output.mPosition=mul(Input.mPosition,gWorldMatrix);
   
   float3 lightDir=Output.mPosition.xyz-gWorldLightPosition.xyz;
   lightDir=normalize(lightDir);
   
   float3 viewDir=normalize(Output.mPosition.xyz-gWorldCameraPosition.xyz);
   Output.mViewDir=viewDir;
   
   Output.mPosition=mul(Output.mPosition,gViewMatrix);
   Output.mPosition=mul(Output.mPosition,gProjectionMatrix);
   
   float3 worldNormal=mul(Input.mNormal,(float3x3)gWorldMatrix);
   worldNormal=normalize(worldNormal);
   
   Output.mDiffuse=dot(-lightDir,worldNormal);
   Output.mReflection=reflect(lightDir,worldNormal);
   
   Output.mUV=Input.mUV;
   
   return Output;
}

- 픽셀 셰이더

sampler2D DiffuseSampler;
sampler2D SpecularSampler;
 
float3 gLightColor;
 
struct PS_INPUT
{
   float2 mUV:TEXCOORD0;
   float3 mDiffuse:TEXCOORD1;
   float3 mViewDir:TEXCOORD2;
   float3 mReflection:TEXCOORD3;
};
 
float4 ps_main(PS_INPUT Input):COLOR
{
   float4 albedo=tex2D(DiffuseSampler,Input.mUV);
   float3 diffuse=gLightColor*albedo.rgb*saturate(Input.mDiffuse);
   
   float3 reflection=normalize(Input.mReflection);
   float3 viewdir=normalize(Input.mViewDir);
   float3 specular=0;
   
   if(diffuse.x>0)
   {
      specular=saturate(dot(reflection,-viewdir));
      specular=pow(specular,10.0f);
      
      float4 specularIntensity=tex2D(SpecularSampler,Input.mUV);
      specular*=specularIntensity.rgb*gLightColor;
   }
   float3 ambient=float3(0.1f,0.1f,0.1f)*albedo.rgb;
   
   return float4(diffuse+ambient+specular,1);
}

- 결과

난반사광과 정반사광에 텍스처를 적용한 디퓨즈/스페큘러 매핑입니다.