mirror of https://bitbucket.org/CPMADevs/cnq3
66 lines
2.0 KiB
HLSL
66 lines
2.0 KiB
HLSL
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/*
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===========================================================================
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Copyright (C) 2024 Gian 'myT' Schellenbaum
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This file is part of Challenge Quake 3 (CNQ3).
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Challenge Quake 3 is free software; you can redistribute it
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and/or modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the License,
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or (at your option) any later version.
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Challenge Quake 3 is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with Challenge Quake 3. If not, see <https://www.gnu.org/licenses/>.
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===========================================================================
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*/
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// volumetric lighting: point light shadow volume
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#include "common.hlsli"
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#include "scene_view.h.hlsli"
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cbuffer RootConstants
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{
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float3 lightPosition;
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float extinctionWorldScale;
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float shadowWorldScale;
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uint shadowTextureIndex;
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}
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[numthreads(4, 4, 4)]
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void cs(uint3 id : SV_DispatchThreadID)
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{
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RWTexture3D<float> shadowTexture = ResourceDescriptorHeap[shadowTextureIndex];
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uint3 shadowSize = GetTextureSize(shadowTexture);
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if(any(id >= shadowSize))
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{
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return;
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}
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SceneView scene = GetSceneView();
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float3 voxelPosition = AABoxIndexToWorldSpace(id, lightPosition, shadowSize, shadowWorldScale);
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float dist = distance(voxelPosition, lightPosition);
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float stepDist = extinctionWorldScale;
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uint stepCount = uint(dist / stepDist);
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float3 step = normalize(lightPosition - voxelPosition) * stepDist;
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ExtinctionCascade cascade = scene.GetExtinctionCascade(stepDist);
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float transmittance = 1.0;
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float3 extinctionPositionWS = voxelPosition;
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for(uint i = 0; i < stepCount; i++)
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{
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float extinction = cascade.ExtinctionAt(extinctionPositionWS);
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float trans = Transmittance(stepDist, extinction);
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transmittance *= saturate(trans);
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extinctionPositionWS += step;
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}
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shadowTexture[id] = transmittance;
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}
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