BansheeEngine/Data/Raw/Engine/Includes/ReflectionCubemapSampling.bslinc

Technique : base("ReflectionCubemapSampling") =
{
	Language = "HLSL11";

	Pass =
	{
		Common = 
		{
			TextureCube gSkyCubemapTex;
			SamplerState gSkyCubemapSamp;

			cbuffer ReflectionParams
			{
				int gSkyNumMips;
			}	
			
			float3 getSkyReflection(float3 dir, float roughness)
			{
				float mipLevel = mapRoughnessToMipLevel(roughness, gSkyNumMips);
				float3 reflection = gSkyCubemapTex.SampleLevel(gSkyCubemapSamp, dir, mipLevel);

				return reflection;
			}
			
			float3 getSphereReflectionContribution(float normalizedDistance)
			{			
				// If closer than 60% to the probe radius, then full contribution is used.
				// For the other 40% we smoothstep and return contribution lower than 1 so other
				// reflection probes can be blended.			
			
				// smoothstep from 1 to 0.6:
				//   float t = clamp((x - edge0) / (edge1 - edge0), 0.0, 1.0);
				//   return t * t * (3.0 - 2.0 * t);
				float t = saturate(2.5 - 2.5 * normalizedDistance);
				return t * t * (3.0 - 2.0 * t);
			}
			
			float3 getLookupForSphereProxy(float3 originWS, float3 dirWS, float3 centerWS, float radius)
			{
				float radius2 = radius * radius;
				float3 originLS = originWS - centerWS;
				
				float a = dot(originLS, dirWS);
				float dist2 = a * a - dot(originLS, originLS) + radius2;

				float3 lookupDir = dirWS;
				
				[flatten]
				if(dist2 >= 0)
				{
					float farDist = sqrt(dist2) - a;
					lookupDir = originLS + farDist * dirWS;
				}
				
				return lookupDir;
			}
			
			float3 getDistBoxToPoint(float3 point, float3 extents)
			{
				float3 d = max(max(-extents - point, 0), point - extents);
				return length(d);
			}
			
			float3 getLookupForBoxProxy(float3 originWS, float3 dirWS, float3 centerWS, float3 extents, float4x4 invBoxTransform, float transitionDistance, out float contribution)
			{
				// Transform origin and direction into box local space, where it is united sized and axis aligned
				float3 originLS = mul(invBoxTransform, float4(originWS, 1)).xyz;
				float3 dirLS = mul(invBoxTransform, float4(dirWS, 0)).xyz;
				
				// Get distance from 3 min planes and 3 max planes of the unit AABB
				//  float3 unitVec = float3(1.0f, 1.0f, 1.0f);
				//  float3 intersectsMax = (unitVec - originLS) / dirLS;
				//  float3 intersectsMin = (-unitVec - originLS) / dirLS;
				
				float3 invDirLS = rcp(dirLS);
				float3 intersectsMax = invDirLS - originLS * invDirLS;
				float3 intersectsMin = -invDirLS - originLS * invDirLS;
				
				// Find nearest positive (along ray direction) intersection
				float3 positiveIntersections = max(intersectsMax, intersectsMin);
				float intersectDist = min(positiveIntersections.x, min(positiveIntersections.y, positiveIntersections.z));
				
				float3 intersectPositionWS = originWS + intersectDist * dirWS;
				float3 lookupDir = intersectPositionWS - centerWS;
				
				// Calculate contribution
				//// Shrink the box so fade out happens within box extents
				float3 reducedExtents = extents - float3(transitionDistance, transitionDistance, transitionDistance);
				float distToBox = getDistBoxToPoint(originLS * reducedExtents, reducedExtents);
				
				float normalizedDistance = distToBox / transitionDistance;
				
				// If closer than 70% to the probe radius, then full contribution is used.
				// For the other 30% we smoothstep and return contribution lower than 1 so other
				// reflection probes can be blended.			
			
				// smoothstep from 1 to 0.7:
				//   float t = clamp((x - edge0) / (edge1 - edge0), 0.0, 1.0);
				//   return t * t * (3.0 - 2.0 * t);
				
				float t = saturate(3.3333 - 3.3333 * normalizedDistance);
				return t * t * (3.0 - 2.0 * t);
				
				return lookupDir;
			}
		};
	};
};

Technique : base("ReflectionCubemapSampling") =
{
	Language = "GLSL";

	Pass =
	{
		Common = 
		{
		
		};
	};
};