cocos-creator-template/assets/chunks/builtin/functionalities/shadow-map.chunk

// used for replacing cc-shadow-map-base.chunk
#include <builtin/uniforms/cc-shadow>
#if CC_SUPPORT_CASCADED_SHADOW_MAP
  #include <builtin/uniforms/cc-csm>
#endif
#include <common/common-define>
#include <common/math/coordinates>

#pragma define SHADOWMAP_FORMAT_RGBA8 1
#pragma define SHADOWMAP_FORMAT_FLOAT 0

#pragma define CC_DIR_LIGHT_SHADOW_NONE 0
#pragma define CC_DIR_LIGHT_SHADOW_UNIFORM 1
#pragma define CC_DIR_LIGHT_SHADOW_CASCADED 2
#pragma define CC_DIR_LIGHT_SHADOW_VARIANCE 3

#pragma define CC_SHADOW_NONE 0
#pragma define CC_SHADOW_PLANAR 1
#pragma define CC_SHADOW_MAP 2

float CCGetLinearDepth(vec3 worldPos, float viewSpaceBias) {
	vec4 viewPos = cc_matLightView * vec4(worldPos.xyz, 1.0);
  viewPos.z += viewSpaceBias;
	return GetLinearDepthFromViewSpace(viewPos.xyz, cc_shadowNFLSInfo.x, cc_shadowNFLSInfo.y);
}

float CCGetLinearDepth(vec3 worldPos) {
	return CCGetLinearDepth(worldPos, 0.0);
}

#if CC_RECEIVE_SHADOW
  #include <builtin/uniforms/cc-global>
  #include <builtin/uniforms/cc-shadow-map>

  #include <common/data/packing>
  #include <common/shadow/native-pcf>


  //////////////////////////////////////////////////////////Helper Functions
  bool GetShadowNDCPos(out vec3 shadowNDCPos, vec4 shadowPosWithDepthBias)
  {
  	shadowNDCPos = shadowPosWithDepthBias.xyz / shadowPosWithDepthBias.w * 0.5 + 0.5;
  	if (shadowNDCPos.x < 0.0 || shadowNDCPos.x > 1.0 ||
  		shadowNDCPos.y < 0.0 || shadowNDCPos.y > 1.0 ||
  		shadowNDCPos.z < 0.0 || shadowNDCPos.z > 1.0) {
  		return false;
  	}
  	CC_HANDLE_NDC_SAMPLE_FLIP(shadowNDCPos.xy, cc_cameraPos.w);
  	return true;
  }

  vec4 ApplyShadowDepthBias_FaceNormal(vec4 shadowPos, vec3 worldNormal, float normalBias, vec3 matViewDir0, vec3 matViewDir1, vec3 matViewDir2, vec2 projScaleXY)
  {
    vec4 newShadowPos = shadowPos;
    if (normalBias > EPSILON_LOWP)
    {
      vec3 viewNormal = vec3(dot(matViewDir0, worldNormal), dot(matViewDir1, worldNormal), dot(matViewDir2, worldNormal));
      if (viewNormal.z < 0.1)
        newShadowPos.xy += viewNormal.xy * projScaleXY * normalBias * clamp(viewNormal.z, 0.001, 0.1);
    }
    return newShadowPos;
  }

  vec4 ApplyShadowDepthBias_FaceNormal(vec4 shadowPos, vec3 worldNormal, float normalBias, mat4 matLightView, vec2 projScaleXY)
  {
  	vec4 newShadowPos = shadowPos;
  	if (normalBias > EPSILON_LOWP)
  	{
  		vec4 viewNormal = matLightView * vec4(worldNormal, 0.0);
  		if (viewNormal.z < 0.1)
  			newShadowPos.xy += viewNormal.xy * projScaleXY * normalBias * clamp(viewNormal.z, 0.001, 0.1);
  	}
  	return newShadowPos;
  }

  float GetViewSpaceDepthFromNDCDepth_Orthgraphic(float NDCDepth, float projScaleZ, float projBiasZ)
  {
  	return (NDCDepth - projBiasZ) / projScaleZ;
  }
  float GetViewSpaceDepthFromNDCDepth_Perspective(float NDCDepth, float homogenousDividW, float invProjScaleZ, float invProjBiasZ)
  {
  	return NDCDepth * invProjScaleZ + homogenousDividW * invProjBiasZ;
  }

  vec4 ApplyShadowDepthBias_Perspective(vec4 shadowPos, float viewspaceDepthBias)
  {
  	// Recover the coord in view space: cc_matLightInvProj * shadowPos
  	vec3 viewSpacePos;
  	viewSpacePos.xy = shadowPos.xy * cc_shadowProjInfo.zw;
  	viewSpacePos.z = GetViewSpaceDepthFromNDCDepth_Perspective(shadowPos.z, shadowPos.w, cc_shadowInvProjDepthInfo.x, cc_shadowInvProjDepthInfo.y);

  	// Apply bias
  	viewSpacePos.xyz += cc_shadowProjDepthInfo.z * normalize(viewSpacePos.xyz) * viewspaceDepthBias;

  	// Reconstuct clipspace: cc_matLightProj * viewSpacePos
  	vec4 clipSpacePos;
  	clipSpacePos.xy = viewSpacePos.xy * cc_shadowProjInfo.xy;
  	clipSpacePos.zw = viewSpacePos.z * cc_shadowProjDepthInfo.xz + vec2(cc_shadowProjDepthInfo.y, 0.0);

  	// enabled linear depth?
  	#if CC_SHADOWMAP_USE_LINEAR_DEPTH
  		clipSpacePos.z = GetLinearDepthFromViewSpace(viewSpacePos.xyz, cc_shadowNFLSInfo.x, cc_shadowNFLSInfo.y);
  		clipSpacePos.z = (clipSpacePos.z * 2.0 - 1.0) * clipSpacePos.w;
  	#endif

  	return clipSpacePos;
  }

  // (projScaleZ, projBiasZ) = cc_shadowProjDepthInfo.xy
  vec4 ApplyShadowDepthBias_Orthographic(vec4 shadowPos, float viewspaceDepthBias, float projScaleZ, float projBiasZ)
  {
  	float coeffA = projScaleZ;
  	float coeffB = projBiasZ;

  	// Recover the Z distance in view space:
  	float viewSpacePos_z = GetViewSpaceDepthFromNDCDepth_Orthgraphic(shadowPos.z, projScaleZ, projBiasZ);

  	// Apply bias
  	viewSpacePos_z += viewspaceDepthBias;

  	// Reconstuct clipspace
  	vec4 result = shadowPos;
  	result.z = viewSpacePos_z * coeffA + coeffB;
  	return result;
  }

  vec4 ApplyShadowDepthBias_PerspectiveLinearDepth(vec4 shadowPos, float viewspaceDepthBias, vec3 worldPos)
  {
    // reverse operation for GetShadowNDCPos
    shadowPos.z = CCGetLinearDepth(worldPos, viewspaceDepthBias) * 2.0 - 1.0;
    shadowPos.z *= shadowPos.w;
    return shadowPos;
  }

  //////////////////////////////////////////////////////////Directional Light Shadow
  float CCGetDirLightShadowFactorHard (vec4 shadowPosWithDepthBias) {
	  vec3 shadowNDCPos;
	  if (!GetShadowNDCPos(shadowNDCPos, shadowPosWithDepthBias)) {
		  return 1.0;
	  }
    return NativePCFShadowFactorHard(shadowNDCPos, cc_shadowMap, cc_shadowWHPBInfo.xy);
  }

  float CCGetDirLightShadowFactorSoft (vec4 shadowPosWithDepthBias) {
	  vec3 shadowNDCPos;
	  if (!GetShadowNDCPos(shadowNDCPos, shadowPosWithDepthBias)) {
		  return 1.0;
	  }
    return NativePCFShadowFactorSoft(shadowNDCPos, cc_shadowMap, cc_shadowWHPBInfo.xy);
  }

  float CCGetDirLightShadowFactorSoft3X (vec4 shadowPosWithDepthBias) {
	  vec3 shadowNDCPos;
	  if (!GetShadowNDCPos(shadowNDCPos, shadowPosWithDepthBias)) {
		  return 1.0;
	  }
    return NativePCFShadowFactorSoft3X(shadowNDCPos, cc_shadowMap, cc_shadowWHPBInfo.xy);
  }

  float CCGetDirLightShadowFactorSoft5X (vec4 shadowPosWithDepthBias) {
	  vec3 shadowNDCPos;
	  if (!GetShadowNDCPos(shadowNDCPos, shadowPosWithDepthBias)) {
		  return 1.0;
	  }
    return NativePCFShadowFactorSoft5X(shadowNDCPos, cc_shadowMap, cc_shadowWHPBInfo.xy);
  }


  //////////////////////////////////////////////////////////Spot Light Shadow
  float CCGetSpotLightShadowFactorHard (vec4 shadowPosWithDepthBias, vec3 worldPos) {
	  vec3 shadowNDCPos;
	  if (!GetShadowNDCPos(shadowNDCPos, shadowPosWithDepthBias)) {
		  return 1.0;
	  }
    return NativePCFShadowFactorHard(shadowNDCPos, cc_spotShadowMap, cc_shadowWHPBInfo.xy);
  }

  float CCGetSpotLightShadowFactorSoft (vec4 shadowPosWithDepthBias, vec3 worldPos) {
	  vec3 shadowNDCPos;
	  if (!GetShadowNDCPos(shadowNDCPos, shadowPosWithDepthBias)) {
		  return 1.0;
	  }
    return NativePCFShadowFactorSoft(shadowNDCPos, cc_spotShadowMap, cc_shadowWHPBInfo.xy);
  }

  float CCGetSpotLightShadowFactorSoft3X (vec4 shadowPosWithDepthBias, vec3 worldPos) {
	  vec3 shadowNDCPos;
	  if (!GetShadowNDCPos(shadowNDCPos, shadowPosWithDepthBias)) {
		  return 1.0;
	  }
    return NativePCFShadowFactorSoft3X(shadowNDCPos, cc_spotShadowMap, cc_shadowWHPBInfo.xy);
  }

  float CCGetSpotLightShadowFactorSoft5X (vec4 shadowPosWithDepthBias, vec3 worldPos) {
	  vec3 shadowNDCPos;
	  if (!GetShadowNDCPos(shadowNDCPos, shadowPosWithDepthBias)) {
		  return 1.0;
	  }
    return NativePCFShadowFactorSoft5X(shadowNDCPos, cc_spotShadowMap, cc_shadowWHPBInfo.xy);
  }


  //////////////////////////////////////////////////////////Main Functions
  float CCSpotShadowFactorBase(out vec4 shadowPosWithDepthBias, vec4 shadowPos, vec3 worldPos, vec2 shadowBias)
  {
    float pcf = cc_shadowWHPBInfo.z;
    vec4 pos = vec4(1.0);
    #if CC_SHADOWMAP_USE_LINEAR_DEPTH
      pos = ApplyShadowDepthBias_PerspectiveLinearDepth(shadowPos, shadowBias.x, worldPos);
    #else
      pos = ApplyShadowDepthBias_Perspective(shadowPos, shadowBias.x);
    #endif

    float realtimeShadow = 1.0;
    if (pcf > 2.9) {
      realtimeShadow = CCGetSpotLightShadowFactorSoft5X(pos, worldPos);
    }else if (pcf > 1.9) {
      realtimeShadow = CCGetSpotLightShadowFactorSoft3X(pos, worldPos);
    }else if (pcf > 0.9) {
      realtimeShadow = CCGetSpotLightShadowFactorSoft(pos, worldPos);
    }else {
      realtimeShadow = CCGetSpotLightShadowFactorHard(pos, worldPos);
    }

    shadowPosWithDepthBias = pos;
    return mix(realtimeShadow, 1.0, cc_shadowNFLSInfo.w);
  }

  float CCShadowFactorBase(out vec4 shadowPosWithDepthBias, vec4 shadowPos, vec3 N, vec2 shadowBias)
  {
    vec4 pos = ApplyShadowDepthBias_FaceNormal(shadowPos, N, shadowBias.y, cc_matLightView, cc_shadowProjInfo.xy);
    pos = ApplyShadowDepthBias_Orthographic(pos, shadowBias.x, cc_shadowProjDepthInfo.x, cc_shadowProjDepthInfo.y);

    float realtimeShadow = 1.0;
    #if CC_DIR_SHADOW_PCF_TYPE == CC_SHADOW_PCF_SOFT_5X
      realtimeShadow = CCGetDirLightShadowFactorSoft5X(pos);
    #endif
    #if CC_DIR_SHADOW_PCF_TYPE == CC_SHADOW_PCF_SOFT_3X
      realtimeShadow =  CCGetDirLightShadowFactorSoft3X(pos);
    #endif
    #if CC_DIR_SHADOW_PCF_TYPE == CC_SHADOW_PCF_SOFT
      realtimeShadow = CCGetDirLightShadowFactorSoft(pos);
    #endif
    #if CC_DIR_SHADOW_PCF_TYPE == CC_SHADOW_PCF_HARD
      realtimeShadow = CCGetDirLightShadowFactorHard(pos);
    #endif

    shadowPosWithDepthBias = pos;
    return mix(realtimeShadow, 1.0, cc_shadowNFLSInfo.w);
  }

  #if CC_SUPPORT_CASCADED_SHADOW_MAP
    bool CCGetCSMLevelWithTransition(out highp float ratio, vec3 clipPos) {
      highp float maxRange = 1.0 - cc_csmSplitsInfo.x;
      highp float minRange = cc_csmSplitsInfo.x;
      highp float thresholdInvert = 1.0 / cc_csmSplitsInfo.x;
      ratio = 0.0;
      if (clipPos.x <= minRange) {
        ratio = clipPos.x * thresholdInvert;
        return true;
      }
      if (clipPos.x >= maxRange) {
        ratio = 1.0 - (clipPos.x - maxRange) * thresholdInvert;
        return true;
      }
      if (clipPos.y <= minRange) {
        ratio = clipPos.y  * thresholdInvert;
        return true;
      }
      if (clipPos.y >= maxRange) {
        ratio = 1.0 - (clipPos.y - maxRange) * thresholdInvert;
        return true;
      }
      return false;
    }

    bool CCHasCSMLevel(int level, vec3 worldPos) {
      highp float layerThreshold = cc_csmViewDir0[0].w;
      bool hasLevel = false;
      for (int i = 0; i < NUMCASCADES; i++) {
        if (i == level) {
          vec4 shadowPos = cc_matCSMViewProj[i] * vec4(worldPos.xyz, 1.0);
          vec3 clipPos = shadowPos.xyz / shadowPos.w * 0.5 + 0.5;
          if (clipPos.x >= layerThreshold && clipPos.x <= (1.0 - layerThreshold) &&
              clipPos.y >= layerThreshold && clipPos.y <= (1.0 - layerThreshold) &&
              clipPos.z >= 0.0 && clipPos.z <= 1.0) {
            hasLevel = true;
          }
        }
      }
      return hasLevel;
    }

    void CCGetCSMLevel(out vec4 csmPos, out vec4 shadowProjDepthInfo, out vec4 shadowProjInfo, out vec3 shadowViewDir0, out vec3 shadowViewDir1, out vec3 shadowViewDir2, vec3 worldPos, int level) {
      highp float layerThreshold = cc_csmViewDir0[0].w;
      for (int i = 0; i < NUMCASCADES; i++) {
        vec4 shadowPos = cc_matCSMViewProj[i] * vec4(worldPos.xyz, 1.0);
        vec3 clipPos = shadowPos.xyz / shadowPos.w * 0.5 + 0.5;
        if (clipPos.x >= layerThreshold && clipPos.x <= (1.0 - layerThreshold) &&
            clipPos.y >= layerThreshold && clipPos.y <= (1.0 - layerThreshold) &&
            clipPos.z >= 0.0 && clipPos.z <= 1.0 && i == level) {
          csmPos = cc_matCSMViewProj[i] * vec4(worldPos.xyz, 1.0);
          csmPos.xy = csmPos.xy * cc_csmAtlas[i].xy + cc_csmAtlas[i].zw;
          shadowProjDepthInfo = cc_csmProjDepthInfo[i];
          shadowProjInfo = cc_csmProjInfo[i];
          shadowViewDir0 = cc_csmViewDir0[i].xyz;
          shadowViewDir1 = cc_csmViewDir1[i].xyz;
          shadowViewDir2 = cc_csmViewDir2[i].xyz;
        }
      }
    }

    int CCGetCSMLevel(out bool isTransitionArea, out highp float transitionRatio, out vec4 csmPos, out vec4 shadowProjDepthInfo, out vec4 shadowProjInfo, out vec3 shadowViewDir0, out vec3 shadowViewDir1, out vec3 shadowViewDir2, vec3 worldPos)
    {
      int level = -1;
      highp float layerThreshold = cc_csmViewDir0[0].w;
      for (int i = 0; i < NUMCASCADES; i++) {
        vec4 shadowPos = cc_matCSMViewProj[i] * vec4(worldPos.xyz, 1.0);
        vec3 clipPos = shadowPos.xyz / shadowPos.w * 0.5 + 0.5;
        if (clipPos.x >= layerThreshold && clipPos.x <= (1.0 - layerThreshold) &&
            clipPos.y >= layerThreshold && clipPos.y <= (1.0 - layerThreshold) &&
            clipPos.z >= 0.0 && clipPos.z <= 1.0 && level < 0) {
          #if CC_CASCADED_LAYERS_TRANSITION
            isTransitionArea = CCGetCSMLevelWithTransition(transitionRatio, clipPos);
          #endif
          csmPos = cc_matCSMViewProj[i] * vec4(worldPos.xyz, 1.0);
          csmPos.xy = csmPos.xy * cc_csmAtlas[i].xy + cc_csmAtlas[i].zw;
          shadowProjDepthInfo = cc_csmProjDepthInfo[i];
          shadowProjInfo = cc_csmProjInfo[i];
          shadowViewDir0 = cc_csmViewDir0[i].xyz;
          shadowViewDir1 = cc_csmViewDir1[i].xyz;
          shadowViewDir2 = cc_csmViewDir2[i].xyz;
          level = i;
        }
      }
      return level;
    }

    int CCGetCSMLevel(out vec4 csmPos, out vec4 shadowProjDepthInfo, out vec4 shadowProjInfo, out vec3 shadowViewDir0, out vec3 shadowViewDir1, out vec3 shadowViewDir2, vec3 worldPos)
    {
      bool isTransitionArea = false;
      highp float transitionRatio = 0.0;
      return CCGetCSMLevel(isTransitionArea, transitionRatio, csmPos, shadowProjDepthInfo, shadowProjInfo, shadowViewDir0, shadowViewDir1, shadowViewDir2, worldPos);
    }

    // output csmPos is non-biased position that can be used for sampling shadow map after homogeneous divid
    float CCCSMFactorBase(out vec4 csmPos, out vec4 csmPosWithBias, vec3 worldPos, vec3 N, vec2 shadowBias)
    {
      bool isTransitionArea = false;
      highp float ratio = 0.0;
      csmPos = vec4(1.0);
      vec4 shadowProjDepthInfo, shadowProjInfo;
      vec3 shadowViewDir0, shadowViewDir1, shadowViewDir2;
      int level = -1;
      #if CC_CASCADED_LAYERS_TRANSITION
        level = CCGetCSMLevel(isTransitionArea, ratio, csmPos, shadowProjDepthInfo, shadowProjInfo, shadowViewDir0, shadowViewDir1, shadowViewDir2, worldPos);
      #else
        level = CCGetCSMLevel(csmPos, shadowProjDepthInfo, shadowProjInfo, shadowViewDir0, shadowViewDir1, shadowViewDir2, worldPos);
      #endif
      if (level < 0) { return 1.0; }

      vec4 pos = ApplyShadowDepthBias_FaceNormal(csmPos, N, shadowBias.y, shadowViewDir0, shadowViewDir1, shadowViewDir2, shadowProjInfo.xy);
      pos = ApplyShadowDepthBias_Orthographic(pos, shadowBias.x, shadowProjDepthInfo.x, shadowProjDepthInfo.y);
      csmPosWithBias = pos;

      float realtimeShadow = 1.0;
      #if CC_DIR_SHADOW_PCF_TYPE == CC_SHADOW_PCF_SOFT_5X
        realtimeShadow = CCGetDirLightShadowFactorSoft5X(pos);
      #endif
      #if CC_DIR_SHADOW_PCF_TYPE == CC_SHADOW_PCF_SOFT_3X
        realtimeShadow = CCGetDirLightShadowFactorSoft3X(pos);
      #endif
      #if CC_DIR_SHADOW_PCF_TYPE == CC_SHADOW_PCF_SOFT
        realtimeShadow = CCGetDirLightShadowFactorSoft(pos);
      #endif
      #if CC_DIR_SHADOW_PCF_TYPE == CC_SHADOW_PCF_HARD
        realtimeShadow = CCGetDirLightShadowFactorHard(pos);
      #endif

      #if CC_CASCADED_LAYERS_TRANSITION
        vec4 nextCSMPos = vec4(1.0);
        vec4 nextShadowProjDepthInfo, nextShadowProjInfo;
        vec3 nextShadowViewDir0, nextShadowViewDir1, nextShadowViewDir2;
        float nextRealtimeShadow = 1.0;
        CCGetCSMLevel(nextCSMPos, nextShadowProjDepthInfo, nextShadowProjInfo, nextShadowViewDir0, nextShadowViewDir1, nextShadowViewDir2, worldPos, level + 1);
        bool hasNextLevel = CCHasCSMLevel(level + 1, worldPos);
        if (hasNextLevel && isTransitionArea) {
          vec4 nexPos = ApplyShadowDepthBias_FaceNormal(nextCSMPos, N, shadowBias.y, nextShadowViewDir0, nextShadowViewDir1, nextShadowViewDir2, nextShadowProjInfo.xy);
          nexPos = ApplyShadowDepthBias_Orthographic(nexPos, shadowBias.x, nextShadowProjDepthInfo.x, nextShadowProjDepthInfo.y);

          #if CC_DIR_SHADOW_PCF_TYPE == CC_SHADOW_PCF_SOFT_5X
            nextRealtimeShadow = CCGetDirLightShadowFactorSoft5X(nexPos);
          #endif
          #if CC_DIR_SHADOW_PCF_TYPE == CC_SHADOW_PCF_SOFT_3X
            nextRealtimeShadow = CCGetDirLightShadowFactorSoft3X(nexPos);
          #endif
          #if CC_DIR_SHADOW_PCF_TYPE == CC_SHADOW_PCF_SOFT
            nextRealtimeShadow = CCGetDirLightShadowFactorSoft(nexPos);
          #endif
          #if CC_DIR_SHADOW_PCF_TYPE == CC_SHADOW_PCF_HARD
            nextRealtimeShadow = CCGetDirLightShadowFactorHard(nexPos);
          #endif

          return mix(mix(nextRealtimeShadow, realtimeShadow, ratio), 1.0, cc_shadowNFLSInfo.w);
        }
        return mix(realtimeShadow, 1.0, cc_shadowNFLSInfo.w);
      #else
        return mix(realtimeShadow, 1.0, cc_shadowNFLSInfo.w);
      #endif
    }
  #else
    int CCGetCSMLevel(out vec4 csmPos, out vec4 shadowProjDepthInfo, out vec4 shadowProjInfo, out vec3 shadowViewDir0, out vec3 shadowViewDir1, out vec3 shadowViewDir2, vec3 worldPos) {
      return -1;
    }

    float CCCSMFactorBase(out vec4 csmPos, out vec4 csmPosWithBias, vec3 worldPos, vec3 N, vec2 shadowBias) {
      csmPos = cc_matLightViewProj * vec4(worldPos, 1.0);
      return CCShadowFactorBase(csmPosWithBias, csmPos, N, shadowBias);
    }
  #endif

  // compatible version
  float CCShadowFactorBase(vec4 shadowPos, vec3 N, vec2 shadowBias) {
    vec4 shadowPosWithDepthBias;
    return CCShadowFactorBase(shadowPosWithDepthBias, shadowPos, N, shadowBias);
  }

  float CCCSMFactorBase(vec3 worldPos, vec3 N, vec2 shadowBias) {
    vec4 csmPos, csmPosWithBias;
    return CCCSMFactorBase(csmPos, csmPosWithBias, worldPos, N, shadowBias);
  }

  float CCSpotShadowFactorBase(vec4 shadowPos, vec3 worldPos, vec2 shadowBias)
  {
    vec4 shadowPosWithDepthBias;
    return CCSpotShadowFactorBase(shadowPosWithDepthBias, shadowPos, worldPos, shadowBias);
  }
#endif