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Additionally, changing Ortho light calculations to use View.ViewForward instead of world position to camera position + correcting the distance as a result, leading to more accurate light ray angles and distance for ortho views. Non-Reflection passes only. #jira UE-191798, FORT-641623 #rb Andrew.Lauritzen, Krzysztof.Narkowicz, Jason.Nadro [CL 30014700 by jon cain in ue5-main branch]
75 lines
2.6 KiB
Plaintext
75 lines
2.6 KiB
Plaintext
// Copyright Epic Games, Inc. All Rights Reserved.
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/*=============================================================================
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LightFunction.usf: Pixel shader for computing a light function.
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=============================================================================*/
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#include "Common.ush"
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#include "/Engine/Generated/Material.ush"
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#include "LightFunctionCommon.ush"
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#include "DynamicLightingCommon.ush"
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// used like this: mul(float4(SvPosition.xyz, 1), SvPositionToLight);
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float4x4 SvPositionToLight;
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/** Fade distance in x, disabled brightness in y, output for preview shadows mask in z, hair strands in w */
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float4 LightFunctionParameters2;
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Texture2D HairOnlyDepthTexture;
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void Main(
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// in float4 ScreenPosition : TEXCOORD0, // Not used and not output in VS
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in float4 SvPosition : SV_Position, // after all interpolators
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out float4 OutColor : SV_Target0
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)
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{
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ResolvedView = ResolveView();
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float2 ScreenUV = SvPositionToBufferUV(SvPosition);
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// make SvPosition appear to be rasterized with the depth from the depth buffer
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SvPosition.z = LookupDeviceZ(ScreenUV);
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#if HAIR_STRANDS_SUPPORTED
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BRANCH
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if (LightFunctionParameters2.w > 0)
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{
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SvPosition.z = Texture2DSampleLevel(HairOnlyDepthTexture, SceneTexturesStruct_SceneDepthTextureSampler, ScreenUV, 0).r;
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}
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#endif
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float3 LightVector;
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{
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float4 Hom = mul(float4(SvPosition.xyz, 1), SvPositionToLight);
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LightVector = Hom.xyz / Hom.w;
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}
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float3 TranslatedWorldPosition = SvPositionToTranslatedWorld(SvPosition);
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// Calculate radial view distance for stable fading
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float ViewDistance = GetDistanceToCameraFromViewVector(PrimaryView.TranslatedWorldCameraOrigin - TranslatedWorldPosition);
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float GreyScale;
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{
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float3 Color = GetLightFunctionColor(LightVector, TranslatedWorldPosition);
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GreyScale = dot(Color, .3333f);
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}
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float DistanceFadeAlpha = saturate((LightFunctionParameters2.x - ViewDistance) / (LightFunctionParameters2.x * .2f));
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// Fade to disabled based on LightFunctionFadeDistance
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GreyScale = lerp(LightFunctionParameters2.y, GreyScale, DistanceFadeAlpha);
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// Fade to disabled based on ShadowFadeFraction
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GreyScale = lerp(LightFunctionParameters2.y, GreyScale, LightFunctionParameters.y);
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#if FORWARD_SHADING
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float LightInfluenceMask = GetLightInfluenceMask(TranslatedWorldPosition);
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GreyScale = lerp(1, GreyScale, LightInfluenceMask);
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OutColor = EncodeLightAttenuation(GreyScale);
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#else
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float EncodedLightAttenuation = EncodeLightAttenuation(GreyScale);
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// Light function shadows write to the blue channel.
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OutColor = lerp(float4(1, 1, EncodedLightAttenuation.xx), EncodedLightAttenuation.xxxx, LightFunctionParameters2.z);
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#endif
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}
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