ScriptableRenderPipeline/Assets/ScriptableRenderLoop/fptl/ReflectionTemplate.hlsl

#ifndef __REFLECTIONTEMPLATE_H__
#define __REFLECTIONTEMPLATE_H__

#include "UnityCG.cginc"
#include "UnityStandardBRDF.cginc"
#include "UnityStandardUtils.cginc"
#include "UnityPBSLighting.cginc"


UNITY_DECLARE_TEXCUBEARRAY(_reflCubeTextures);

half3 Unity_GlossyEnvironment (UNITY_ARGS_TEXCUBEARRAY(tex), int sliceIndex, half4 hdr, Unity_GlossyEnvironmentData glossIn);

half3 distanceFromAABB(half3 p, half3 aabbMin, half3 aabbMax)
{
	return max(max(p - aabbMax, aabbMin - p), half3(0.0, 0.0, 0.0));
}


float3 ExecuteReflectionList(uint start, uint numReflProbes, float3 vP, float3 vNw, float3 Vworld, float smoothness)
{
	float3 worldNormalRefl = reflect(-Vworld, vNw);

	float3 vspaceRefl = mul((float3x3) g_mWorldToView, worldNormalRefl).xyz;

	float percRoughness = SmoothnessToPerceptualRoughness(smoothness);

	UnityLight light;
	light.color = 0;
	light.dir = 0;
	
	float3 ints = 0;

	uint l=0;

	// we need this outer loop for when we cannot assume a wavefront is 64 wide
	// since in this case we cannot assume the lights will remain sorted by type
	// during processing in lightlist_cs.hlsl
#if !defined(XBONE) && !defined(PLAYSTATION4)
	while(l<numReflProbes)
#endif
	{
		uint uIndex = l<numReflProbes ? FetchIndex(start, l) : 0;
		uint uLgtType = l<numReflProbes ? g_vLightData[uIndex].uLightType : 0;
		
		// specialized loop for sphere lights
		while(l<numReflProbes && uLgtType==(uint) BOX_LIGHT)
		{
			SFiniteLightData lgtDat = g_vLightData[uIndex];	
			float3 vLp = lgtDat.vLpos.xyz;
			float3 vecToSurfPos  = vP - vLp;		// vector from reflection volume to surface position in camera space
			float3 posInReflVolumeSpace = float3( dot(vecToSurfPos, lgtDat.vLaxisX), dot(vecToSurfPos, lgtDat.vLaxisY), dot(vecToSurfPos, lgtDat.vLaxisZ) );


			float blendDistance = lgtDat.fProbeBlendDistance;//unity_SpecCube1_ProbePosition.w; // will be set to blend distance for this probe

			float3 sampleDir;
			if((lgtDat.flags&IS_BOX_PROJECTED)!=0)
			{
				// For box projection, use expanded bounds as they are rendered; otherwise
				// box projection artifacts when outside of the box.
				//float4 boxMin = unity_SpecCube0_BoxMin - float4(blendDistance,blendDistance,blendDistance,0);
				//float4 boxMax = unity_SpecCube0_BoxMax + float4(blendDistance,blendDistance,blendDistance,0);
				//sampleDir = BoxProjectedCubemapDirection (worldNormalRefl, worldPos, unity_SpecCube0_ProbePosition, boxMin, boxMax);

				float4 vBoxOuterDistance = float4( lgtDat.vBoxInnerDist + float3(blendDistance, blendDistance, blendDistance), 0.0 );
#if 0
				// if rotation is NOT supported
				sampleDir = BoxProjectedCubemapDirection(worldNormalRefl, posInReflVolumeSpace, float4(lgtDat.vLocalCubeCapturePoint, 1.0), -vBoxOuterDistance, vBoxOuterDistance);
#else
				float3 volumeSpaceRefl = float3( dot(vspaceRefl, lgtDat.vLaxisX), dot(vspaceRefl, lgtDat.vLaxisY), dot(vspaceRefl, lgtDat.vLaxisZ) );
				float3 vPR = BoxProjectedCubemapDirection(volumeSpaceRefl, posInReflVolumeSpace, float4(lgtDat.vLocalCubeCapturePoint, 1.0), -vBoxOuterDistance, vBoxOuterDistance);	// Volume space corrected reflection vector
				sampleDir = mul( (float3x3) g_mViewToWorld, vPR.x*lgtDat.vLaxisX + vPR.y*lgtDat.vLaxisY + vPR.z*lgtDat.vLaxisZ );
#endif
			}
			else
				sampleDir = worldNormalRefl;

			Unity_GlossyEnvironmentData g;
			g.roughness = percRoughness;
			g.reflUVW		= sampleDir;

			half3 env0 = Unity_GlossyEnvironment(UNITY_PASS_TEXCUBEARRAY(_reflCubeTextures), lgtDat.iSliceIndex, float4(lgtDat.fLightIntensity, lgtDat.fDecodeExp, 0.0, 0.0), g);
			

			UnityIndirect ind;
			ind.diffuse = 0;
			ind.specular = env0;// * data.occlusion;

			//half3 rgb = UNITY_BRDF_PBS(0, data.specularColor, oneMinusReflectivity, data.smoothness, data.normalWorld, vWSpaceVDir, light, ind).rgb;
			half3 rgb = EvalIndirectSpecular(light, ind);

			// Calculate falloff value, so reflections on the edges of the Volume would gradually blend to previous reflection.
			// Also this ensures that pixels not located in the reflection Volume AABB won't
			// accidentally pick up reflections from this Volume.
			//half3 distance = distanceFromAABB(worldPos, unity_SpecCube0_BoxMin.xyz, unity_SpecCube0_BoxMax.xyz);
			half3 distance = distanceFromAABB(posInReflVolumeSpace, -lgtDat.vBoxInnerDist, lgtDat.vBoxInnerDist);
			half falloff = saturate(1.0 - length(distance)/blendDistance);

			ints = lerp(ints, rgb, falloff);
					
			// next probe
			++l; uIndex = l<numReflProbes ? FetchIndex(start, l) : 0;
			uLgtType = l<numReflProbes ? g_vLightData[uIndex].uLightType : 0;
		}

#if !defined(XBONE) && !defined(PLAYSTATION4)
		if(uLgtType!=BOX_LIGHT) ++l;
#endif
	}

	return ints;
}


half3 Unity_GlossyEnvironment (UNITY_ARGS_TEXCUBEARRAY(tex), int sliceIndex, half4 hdr, Unity_GlossyEnvironmentData glossIn)
{
#if UNITY_GLOSS_MATCHES_MARMOSET_TOOLBAG2 && (SHADER_TARGET >= 30)
	// TODO: remove pow, store cubemap mips differently
	half perceptualRoughness = pow(glossIn.roughness, 3.0/4.0);
#else
	half perceptualRoughness = glossIn.roughness;			// MM: switched to this
#endif
	//perceptualRoughness = sqrt(sqrt(2/(64.0+2)));		// spec power to the square root of real roughness

#if 0
	float m = perceptualRoughness*perceptualRoughness;				// m is the real roughness parameter
	const float fEps = 1.192092896e-07F;        // smallest such that 1.0+FLT_EPSILON != 1.0  (+1e-4h is NOT good here. is visibly very wrong)
	float n =  (2.0/max(fEps, m*m))-2.0;		// remap to spec power. See eq. 21 in --> https://dl.dropboxusercontent.com/u/55891920/papers/mm_brdf.pdf

	n /= 4;									    // remap from n_dot_h formulatino to n_dot_r. See section "Pre-convolved Cube Maps vs Path Tracers" --> https://s3.amazonaws.com/docs.knaldtech.com/knald/1.0.0/lys_power_drops.html

	perceptualRoughness = pow( 2/(n+2), 0.25);			// remap back to square root of real roughness
#else
	// MM: came up with a surprisingly close approximation to what the #if 0'ed out code above does.
	perceptualRoughness = perceptualRoughness*(1.7 - 0.7*perceptualRoughness);
#endif



	half mip = perceptualRoughness * UNITY_SPECCUBE_LOD_STEPS;
	half4 rgbm = UNITY_SAMPLE_TEXCUBEARRAY_LOD(tex, float4(glossIn.reflUVW.xyz, sliceIndex), mip);

	//return rgbm.xyz;
	return DecodeHDR_NoLinearSupportInSM2 (rgbm, hdr);
}




#endif