cocos-creator-template/assets/chunks/lighting-models/data-structures/lighting-intermediate-data.chunk

struct LightingIntermediateData
{
  vec3 N, H, L, V; // normalized
  float distToLight, distToLightSqr; // (pos->light)^2
  float distToCamera, distToCameraSqr; // pos->camera
  float angleAttenuation, distAttenuation;

  float NoL, NoV, NoH, VoH;
  float NoLSat, NoVSat, NoHSat;//, VoHSat; // clamped to 0-1
  float NoVAbsSat, VoHAbsSat; // abs and clamped to 1

  HIGHP_VALUE_STRUCT_DEFINE(vec3, worldPosition);

  // for advanced material
  vec3 T, B;

  // material data
  float specularParam; // roughness or specular power
  // todo: add F0 & F90
  float ior, layerOpacity;

#if CC_SURFACES_LIGHTING_ANISOTROPIC
  float anisotropyShape;
#endif

#if CC_SURFACES_LIGHTING_TRANSMIT_DIFFUSE
  vec4 shadowPosAndDepth; //xy: shadowmap uv, z: camera depth from pixel LVP, w: camera depth from shadowmap, (z == w && z > 999998.0) means disable get distance from shadowmap
  vec4 transmitDiffuseParams; //zw: min/max DepthWS for shadowmap,  x: transmit irradiance apply shadow, y: additional transmit mask, for shadowmap uncovered area
#endif
#if CC_SURFACES_LIGHTING_TRANSMIT_SPECULAR || CC_SURFACES_LIGHTING_TRANSMIT_DIFFUSE
  vec4 transmitScatteringParams; // xy: extinction coef for out/in-scattering, z: in-scattering coef, w: transmit distance(water depth, leaf thickness)
  vec3 outScatteringColor, inScatteringColor;
#endif
#if CC_SURFACES_LIGHTING_TT
  vec3 baseColorTT;
  float ttIntensity, ttScatterCoef;
#endif
};

// add overrided functions for difference shading-models in <surfaces/module-functions/>
void CCSurfacesLightingGetIntermediateData_PerPixel(inout LightingIntermediateData data, vec3 worldNormal, vec3 worldPos, vec3 worldTangent, vec3 worldBinormal
#if CC_SURFACES_LIGHTING_ANISOTROPIC
    , float anisotropyShape
#endif
)
{
  // N V
  data.N = worldNormal;

  data.V = cc_cameraPos.xyz - worldPos;
  data.distToCameraSqr = dot(data.V, data.V);
  data.distToCamera = sqrt(data.distToCameraSqr);
  data.V /= data.distToCamera;

  data.angleAttenuation = data.distAttenuation = 1.0;

  data.NoV = dot(data.N, data.V);
  data.NoVSat = max(data.NoV, 0.0);
  data.NoVAbsSat = max(abs(data.NoV), 0.0);

  HIGHP_VALUE_TO_STRUCT_DEFINED(worldPos, data.worldPosition);
  data.T = worldTangent;
  data.B = worldBinormal;

#if CC_SURFACES_LIGHTING_ANISOTROPIC
  data.anisotropyShape = anisotropyShape;
#endif
#if CC_SURFACES_LIGHTING_TRANSMIT_SPECULAR || CC_SURFACES_LIGHTING_TRANSMIT_DIFFUSE
  data.outScatteringColor = vec3(1.0);
  data.inScatteringColor = vec3(0.0);
  data.transmitScatteringParams = vec4(0.0);
#endif
#if CC_SURFACES_LIGHTING_TRANSMIT_DIFFUSE
  data.shadowPosAndDepth = vec4(0.0, 0.0, SURFACES_MAX_TRANSMIT_DEPTH_VALUE, SURFACES_MAX_TRANSMIT_DEPTH_VALUE);
#endif
#if CC_SURFACES_LIGHTING_TT
  data.baseColorTT = vec3(0.0);
  data.ttIntensity = data.ttScatterCoef = 0.0;
#endif
}

void CCSurfacesLightingGetIntermediateData_PerLight(inout LightingIntermediateData data, vec3 lightDirWithDist)
{
  // L H
  data.L = lightDirWithDist;
  data.distToLightSqr = dot(data.L, data.L);
  data.distToLight = sqrt(data.distToLightSqr);

  data.L /= data.distToLight;

  data.H = normalize(data.L + data.V);

  // dot
  data.NoL = dot(data.N, data.L);
  data.NoH = dot(data.N, data.H);
  data.VoH = dot(data.V, data.H);

  data.NoLSat = max(data.NoL, 0.0);
  data.NoHSat = max(data.NoH, 0.0);
  // data.VoHSat = max(data.VoH, 0.0);

  data.VoHAbsSat = max(abs(data.VoH), 0.0);
}