MatCap

  • MatCap(Material Capture)
    • SEM(Spherical Environment Mapping) / Lit Sphere
  • 환경을 텍스쳐에 맵핑하고, 뷰스페이스 노말로 색을 얻어온다.
  • 케릭터에 사용할때는 Diffuse용/Reflect용 맵캡을 이용하도록 하자
// vert
float4x4 MATRIX_IT_MV = UNITY_MATRIX_IT_MV;
float3 binormalOS = cross(IN.normalOS, IN.tangentOS.xyz) * IN.tangentOS.w * unity_WorldTransformParams.w;
float3x3 TBN_os = float3x3(IN.tangentOS.xyz, binormalOS, IN.normalOS);

OUT.TtoV0 = mul(TBN_os, MATRIX_IT_MV[0].xyz);
OUT.TtoV1 = mul(TBN_os, MATRIX_IT_MV[1].xyz);

// frag
half2 normalVS;
normalVS.x = dot(IN.tan0, normalTS);
normalVS.y = dot(IN.tan1, normalTS);
half2 uv_Matcap = normalVS * 0.5 + 0.5;

half3 matcapTex = SAMPLE_TEXTURE2D(_MatcapTex, sampler_MatcapTex, uv_Matcap).rgb;

// vert
half4x4 MATRIX_IT_MV = UNITY_MATRIX_IT_MV;

half2 normalVS;
normalVS.x = dot(MATRIX_IT_MV[0].xyz, IN.normalOS);
normalVS.y = dot(MATRIX_IT_MV[1].xyz, IN.normalOS);
OUT.uv_Matcap = normalVS * 0.5 + 0.5;

// vert
half3 normalWS = TransformObjectToWorldNormal(IN.normalOS);
half3 normalVS = normalize(TransformWorldToView(normalWS));

// 좀 더 디테일한 버전
half3 normalVS = normalize(mul(UNITY_MATRIX_IT_MV, IN.normal));
half3 positionVS = UnityObjectToViewPos(IN.positionOS);
half3 r = reflect(positionVS, normalVS);
half m = 2.0 * sqrt(r.x * r.x + r.y * r.y + (r.z + 1) * (r.z + 1));
OUT.uv_Matcap = r.xy / m + 0.5;

// 회전
half s;
half c;
sincos(_RotateRadian, s, c);
half2x2 rot = {
	c, -s,
	s, c
};
normalVS = mul(rot, normalVS);

번외

OUT.uv_Matcap = normalWS.xy * 0.5 + 0.5;

Ref