cocos-creator-template/assets/chunks/builtin/functionalities/fog.chunk

#pragma define-meta CC_USE_FOG range([0, 4])
#pragma define CC_FOG_LINEAR 0
#pragma define CC_FOG_EXP 1
#pragma define CC_FOG_EXP_SQUARED 2
#pragma define CC_FOG_LAYERED 3
#pragma define CC_FOG_NONE 4

#include <builtin/uniforms/cc-global>
#if CC_USE_FOG != CC_FOG_NONE
  #include <common/effect/fog>
#endif

// Fog helper functions
void CC_TRANSFER_FOG_BASE(vec4 pos, out float factor)
{
#if CC_USE_FOG == CC_FOG_LINEAR
	factor = LinearFog(pos, cc_cameraPos.xyz, cc_fogBase.x, cc_fogBase.y);
#elif CC_USE_FOG == CC_FOG_EXP
	factor = ExpFog(pos, cc_cameraPos.xyz, cc_fogBase.x, cc_fogBase.z, cc_fogAdd.z);
#elif CC_USE_FOG == CC_FOG_EXP_SQUARED
	factor = ExpSquaredFog(pos, cc_cameraPos.xyz, cc_fogBase.x, cc_fogBase.z, cc_fogAdd.z);
#elif CC_USE_FOG == CC_FOG_LAYERED
	factor = LayeredFog(pos, cc_cameraPos.xyz, cc_fogAdd.x, cc_fogAdd.y, cc_fogAdd.z);
#else
	factor = 1.0;
#endif
}

void CC_APPLY_FOG_BASE(inout vec4 color, float factor) {
	color = vec4(mix(cc_fogColor.rgb, color.rgb, factor), color.a);
}