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using System;
using UnityEngine.Rendering;
using System.Collections.Generic;
using System.Runtime.InteropServices;
namespace UnityEngine.Experimental.Rendering.HDPipeline
{
[GenerateHLSL]
public struct DensityVolumeData
{
public Vector3 scattering; // [0, 1], prefer sRGB
public float extinction; // [0, 1], prefer sRGB
public Vector3 textureTiling;
public int textureIndex; //
public Vector3 textureScroll;
public static DensityVolumeData GetNeutralValues()
{
DensityVolumeData data;
data.scattering = Vector3.zero;
data.extinction = 0;
data.textureIndex = -1;
data.textureTiling = Vector3.one;
data.textureScroll = Vector3.zero;
return data;
}
} // struct VolumeProperties
public class VolumeRenderingUtils
{
public static float MeanFreePathFromExtinction(float extinction)
{
return 1.0f / extinction;
}
public static float ExtinctionFromMeanFreePath(float meanFreePath)
{
return 1.0f / meanFreePath;
}
public static Vector3 AbsorptionFromExtinctionAndScattering(float extinction, Vector3 scattering)
{
return new Vector3(extinction, extinction, extinction) - scattering;
}
public static Vector3 ScatteringFromExtinctionAndAlbedo(float extinction, Vector3 albedo)
{
return extinction * albedo;
}
public static Vector3 AlbedoFromMeanFreePathAndScattering(float meanFreePath, Vector3 scattering)
{
return meanFreePath * scattering;
}
}
public struct DensityVolumeList
{
public List<OrientedBBox> bounds;
public List<DensityVolumeData> density;
}
public class VolumetricLightingSystem
{
public enum VolumetricLightingPreset
{
Off,
Normal,
Ultra,
Count
} // enum VolumetricLightingPreset
public struct VBufferParameters
{
public Vector4 resolution;
public Vector2 sliceCount;
public Vector4 uvScaleAndLimit; // Necessary to work with sub-allocation (resource aliasing) in the RTHandle system
public Vector4 depthEncodingParams;
public Vector4 depthDecodingParams;
public VBufferParameters(Vector3Int viewportResolution, Vector3Int bufferResolution, Vector2 depthRange, float depthDistributionUniformity)
{
int w = viewportResolution.x;
int h = viewportResolution.y;
int d = viewportResolution.z;
// The depth is fixed for now.
Vector2 uvScale = new Vector2((float)w / (float)bufferResolution.x,
(float)h / (float)bufferResolution.y);
// vp_scale = vp_dim / tex_dim.
// clamp to (vp_dim - 0.5) / tex_dim = vp_scale - 0.5 * (1 / tex_dim) =
// vp_scale - 0.5 * (vp_scale / vp_dim) = vp_scale * (1 - 0.5 / vp_dim).
Vector2 uvLimit = new Vector2((w - 0.5f) / (float)bufferResolution.x,
(h - 0.5f) / (float)bufferResolution.y);
resolution = new Vector4(w, h, 1.0f / w, 1.0f / h);
sliceCount = new Vector2(d, 1.0f / d);
uvScaleAndLimit = new Vector4(uvScale.x, uvScale.y, uvLimit.x, uvLimit.y);
float n = depthRange.x;
float f = depthRange.y;
float c = 2 - 2 * depthDistributionUniformity; // remap [0, 1] -> [2, 0]
depthEncodingParams = ComputeLogarithmicDepthEncodingParams(n, f, c);
depthDecodingParams = ComputeLogarithmicDepthDecodingParams(n, f, c);
}
} // struct Parameters
public VolumetricLightingPreset preset { get { return (VolumetricLightingPreset)Math.Min(ShaderConfig.s_VolumetricLightingPreset, (int)VolumetricLightingPreset.Count); } }
static ComputeShader m_VolumeVoxelizationCS = null;
static ComputeShader m_VolumetricLightingCS = null;
List<OrientedBBox> m_VisibleVolumeBounds = null;
List<DensityVolumeData> m_VisibleVolumeData = null;
public const int k_MaxVisibleVolumeCount = 512;
// Static keyword is required here else we get a "DestroyBuffer can only be called from the main thread"
static ComputeBuffer s_VisibleVolumeBoundsBuffer = null;
static ComputeBuffer s_VisibleVolumeDataBuffer = null;
// These two buffers do not depend on the frameID and are therefore shared by all views.
RTHandleSystem.RTHandle m_DensityBufferHandle;
RTHandleSystem.RTHandle m_LightingBufferHandle;
// Do we support volumetric or not?
bool m_supportVolumetric = false;
public void Build(HDRenderPipelineAsset asset)
{
m_supportVolumetric = asset.renderPipelineSettings.supportVolumetric;
if (!m_supportVolumetric)
return;
m_VolumeVoxelizationCS = asset.renderPipelineResources.volumeVoxelizationCS;
m_VolumetricLightingCS = asset.renderPipelineResources.volumetricLightingCS;
CreateBuffers();
}
// RTHandleSystem API expects a function which computes the resolution. We define it here.
Vector2Int ComputeVBufferResolutionXY(Vector2Int screenSize)
{
Vector3Int resolution = ComputeVBufferResolution(preset, screenSize.x, screenSize.y);
return new Vector2Int(resolution.x, resolution.y);
}
// RTHandleSystem API expects a function which computes the resolution. We define it here.
Vector2Int ComputeHistoryVBufferResolutionXY(Vector2Int screenSize)
{
Vector2Int resolution = ComputeVBufferResolutionXY(screenSize);
// Since the buffers owned by the VolumetricLightingSystem may have different lifetimes compared
// to those owned by the HDCamera, we need to make sure that the buffer resolution is the same
// (in order to share the UV scale and the UV limit).
if (m_LightingBufferHandle != null)
{
resolution.x = Math.Max(resolution.x, m_LightingBufferHandle.rt.width);
resolution.y = Math.Max(resolution.y, m_LightingBufferHandle.rt.height);
}
return resolution;
}
// BufferedRTHandleSystem API expects an allocator function. We define it here.
RTHandleSystem.RTHandle HistoryBufferAllocatorFunction(string viewName, int frameIndex, RTHandleSystem rtHandleSystem)
{
frameIndex &= 1;
int d = ComputeVBufferSliceCount(preset);
return rtHandleSystem.Alloc(scaleFunc: ComputeHistoryVBufferResolutionXY,
slices: d,
dimension: TextureDimension.Tex3D,
colorFormat: RenderTextureFormat.ARGBHalf,
sRGB: false,
enableRandomWrite: true,
enableMSAA: false,
/* useDynamicScale: true, // <- TODO */
name: string.Format("{0}_VBufferHistory{1}", viewName, frameIndex)
);
}
void CreateBuffers()
{
Debug.Assert(m_VolumetricLightingCS != null);
m_VisibleVolumeBounds = new List<OrientedBBox>();
m_VisibleVolumeData = new List<DensityVolumeData>();
s_VisibleVolumeBoundsBuffer = new ComputeBuffer(k_MaxVisibleVolumeCount, Marshal.SizeOf(typeof(OrientedBBox)));
s_VisibleVolumeDataBuffer = new ComputeBuffer(k_MaxVisibleVolumeCount, Marshal.SizeOf(typeof(DensityVolumeData)));
int d = ComputeVBufferSliceCount(preset);
m_DensityBufferHandle = RTHandles.Alloc(scaleFunc: ComputeVBufferResolutionXY,
slices: d,
dimension: TextureDimension.Tex3D,
colorFormat: RenderTextureFormat.ARGBHalf,
sRGB: false,
enableRandomWrite: true,
enableMSAA: false,
/* useDynamicScale: true, // <- TODO */
name: "VBufferDensity");
m_LightingBufferHandle = RTHandles.Alloc(scaleFunc: ComputeVBufferResolutionXY,
slices: d,
dimension: TextureDimension.Tex3D,
colorFormat: RenderTextureFormat.ARGBHalf,
sRGB: false,
enableRandomWrite: true,
enableMSAA: false,
/* useDynamicScale: true, // <- TODO */
name: "VBufferIntegral");
}
// For the initial allocation, no suballocation happens (the texture is full size).
VBufferParameters ComputeVBufferParameters(HDCamera hdCamera, bool isInitialAllocation)
{
Vector3Int viewportResolution = ComputeVBufferResolution(preset, hdCamera.camera.pixelWidth, hdCamera.camera.pixelHeight);
Vector3Int bufferResolution; // Could be higher due to sub-allocation (resource aliasing) in the RTHandle system
if (isInitialAllocation)
{
bufferResolution = viewportResolution;
}
else
{
// All V-Buffers of the current frame should have the same size (you have to double-buffer history, of course).
bufferResolution = new Vector3Int(m_LightingBufferHandle.rt.width, m_LightingBufferHandle.rt.height, m_LightingBufferHandle.rt.volumeDepth);
}
var controller = VolumeManager.instance.stack.GetComponent<VolumetricLightingController>();
// We must not allow the V-Buffer to extend outside of the camera's frustum.
float n = hdCamera.camera.nearClipPlane;
float f = hdCamera.camera.farClipPlane;
Vector2 vBufferDepthRange = controller.depthRange.value;
vBufferDepthRange.y = Mathf.Clamp(vBufferDepthRange.y, n, f); // far
vBufferDepthRange.x = Mathf.Clamp(vBufferDepthRange.x, n, vBufferDepthRange.y); // near
float vBufferDepthDistributionUniformity = controller.depthDistributionUniformity.value;
return new VBufferParameters(viewportResolution, bufferResolution, vBufferDepthRange, vBufferDepthDistributionUniformity);
}
public void InitializePerCameraData(HDCamera hdCamera)
{
// Note: Here we can't test framesettings as they are not initialize yet
// TODO: Here we allocate history even for camera that may not use volumetric
if (!m_supportVolumetric)
return;
// Start with the same parameters for both frames. Then update them one by one every frame.
var parameters = ComputeVBufferParameters(hdCamera, true);
hdCamera.vBufferParams = new VBufferParameters[2];
hdCamera.vBufferParams[0] = parameters;
hdCamera.vBufferParams[1] = parameters;
if (hdCamera.camera.cameraType == CameraType.Game ||
hdCamera.camera.cameraType == CameraType.SceneView)
{
// We don't need reprojection for other view types, such as reflection and preview.
hdCamera.AllocHistoryFrameRT((int)HDCameraFrameHistoryType.VolumetricLighting, HistoryBufferAllocatorFunction);
}
}
// This function relies on being called once per camera per frame.
// The results are undefined otherwise.
public void UpdatePerCameraData(HDCamera hdCamera)
{
if (!hdCamera.frameSettings.enableVolumetric)
return;
var parameters = ComputeVBufferParameters(hdCamera, false);
// Double-buffer. I assume the cost of copying is negligible (don't want to use the frame index).
hdCamera.vBufferParams[1] = hdCamera.vBufferParams[0];
hdCamera.vBufferParams[0] = parameters;
// Note: resizing of history buffer is automatic (handled by the BufferedRTHandleSystem).
}
void DestroyBuffers()
{
if (m_DensityBufferHandle != null)
RTHandles.Release(m_DensityBufferHandle);
if (m_LightingBufferHandle != null)
RTHandles.Release(m_LightingBufferHandle);
CoreUtils.SafeRelease(s_VisibleVolumeBoundsBuffer);
CoreUtils.SafeRelease(s_VisibleVolumeDataBuffer);
m_VisibleVolumeBounds = null;
m_VisibleVolumeData = null;
}
public void Cleanup()
{
// Note: No need to test for support volumetric here, we do saferelease and null assignation
DestroyBuffers();
m_VolumeVoxelizationCS = null;
m_VolumetricLightingCS = null;
}
static int ComputeVBufferTileSize(VolumetricLightingPreset preset)
{
switch (preset)
{
case VolumetricLightingPreset.Normal:
return 8;
case VolumetricLightingPreset.Ultra:
return 4;
case VolumetricLightingPreset.Off:
return 0;
default:
Debug.Assert(false, "Encountered an unexpected VolumetricLightingPreset.");
return 0;
}
}
static int ComputeVBufferSliceCount(VolumetricLightingPreset preset)
{
switch (preset)
{
case VolumetricLightingPreset.Normal:
return 64;
case VolumetricLightingPreset.Ultra:
return 128;
case VolumetricLightingPreset.Off:
return 0;
default:
Debug.Assert(false, "Encountered an unexpected VolumetricLightingPreset.");
return 0;
}
}
static Vector3Int ComputeVBufferResolution(VolumetricLightingPreset preset,
int screenWidth, int screenHeight)
{
int t = ComputeVBufferTileSize(preset);
// ceil(ScreenSize / TileSize).
int w = (screenWidth + (t - 1)) / t;
int h = (screenHeight + (t - 1)) / t;
int d = ComputeVBufferSliceCount(preset);
return new Vector3Int(w, h, d);
}
// See EncodeLogarithmicDepthGeneralized().
static Vector4 ComputeLogarithmicDepthEncodingParams(float nearPlane, float farPlane, float c)
{
Vector4 depthParams = new Vector4();
float n = nearPlane;
float f = farPlane;
c = Mathf.Max(c, 0.001f); // Avoid NaNs
depthParams.y = 1.0f / Mathf.Log(c * (f - n) + 1, 2);
depthParams.x = Mathf.Log(c, 2) * depthParams.y;
depthParams.z = n - 1.0f / c; // Same
depthParams.w = 0.0f;
return depthParams;
}
// See DecodeLogarithmicDepthGeneralized().
static Vector4 ComputeLogarithmicDepthDecodingParams(float nearPlane, float farPlane, float c)
{
Vector4 depthParams = new Vector4();
float n = nearPlane;
float f = farPlane;
c = Mathf.Max(c, 0.001f); // Avoid NaNs
depthParams.x = 1.0f / c;
depthParams.y = Mathf.Log(c * (f - n) + 1, 2);
depthParams.z = n - 1.0f / c; // Same
depthParams.w = 0.0f;
return depthParams;
}
void SetPreconvolvedAmbientLightProbe(CommandBuffer cmd, float anisotropy)
{
SphericalHarmonicsL2 probeSH = SphericalHarmonicMath.UndoCosineRescaling(RenderSettings.ambientProbe);
ZonalHarmonicsL2 phaseZH = ZonalHarmonicsL2.GetCornetteShanksPhaseFunction(anisotropy);
SphericalHarmonicsL2 finalSH = SphericalHarmonicMath.PremultiplyCoefficients(SphericalHarmonicMath.Convolve(probeSH, phaseZH));
cmd.SetGlobalVectorArray(HDShaderIDs._AmbientProbeCoeffs, SphericalHarmonicMath.PackCoefficients(finalSH));
}
float CornetteShanksPhasePartConstant(float anisotropy)
{
float g = anisotropy;
return (1.0f / (4.0f * Mathf.PI)) * 1.5f * (1.0f - g * g) / (2.0f + g * g);
}
public void PushGlobalParams(HDCamera hdCamera, CommandBuffer cmd, uint frameIndex)
{
if (!hdCamera.frameSettings.enableVolumetric)
return;
var visualEnvironment = VolumeManager.instance.stack.GetComponent<VisualEnvironment>();
// VisualEnvironment sets global fog parameters: _GlobalAnisotropy, _GlobalScattering, _GlobalExtinction.
if (visualEnvironment.fogType != FogType.Volumetric)
{
// Set the neutral black texture.
cmd.SetGlobalTexture(HDShaderIDs._VBufferLighting, CoreUtils.blackVolumeTexture);
return;
}
// Get the interpolated anisotropy value.
var fog = VolumeManager.instance.stack.GetComponent<VolumetricFog>();
SetPreconvolvedAmbientLightProbe(cmd, fog.anisotropy);
var currFrameParams = hdCamera.vBufferParams[0];
var prevFrameParams = hdCamera.vBufferParams[1];
cmd.SetGlobalVector( HDShaderIDs._VBufferResolution, currFrameParams.resolution);
cmd.SetGlobalVector( HDShaderIDs._VBufferSliceCount, currFrameParams.sliceCount);
cmd.SetGlobalVector( HDShaderIDs._VBufferUvScaleAndLimit, currFrameParams.uvScaleAndLimit);
cmd.SetGlobalVector( HDShaderIDs._VBufferDepthEncodingParams, currFrameParams.depthEncodingParams);
cmd.SetGlobalVector( HDShaderIDs._VBufferDepthDecodingParams, currFrameParams.depthDecodingParams);
cmd.SetGlobalVector( HDShaderIDs._VBufferPrevResolution, prevFrameParams.resolution);
cmd.SetGlobalVector( HDShaderIDs._VBufferPrevSliceCount, prevFrameParams.sliceCount);
cmd.SetGlobalVector( HDShaderIDs._VBufferPrevUvScaleAndLimit, prevFrameParams.uvScaleAndLimit);
cmd.SetGlobalVector( HDShaderIDs._VBufferPrevDepthEncodingParams, prevFrameParams.depthEncodingParams);
cmd.SetGlobalVector( HDShaderIDs._VBufferPrevDepthDecodingParams, prevFrameParams.depthDecodingParams);
cmd.SetGlobalTexture(HDShaderIDs._VBufferLighting, m_LightingBufferHandle);
}
public DensityVolumeList PrepareVisibleDensityVolumeList(HDCamera hdCamera, CommandBuffer cmd)
{
DensityVolumeList densityVolumes = new DensityVolumeList();
if (!hdCamera.frameSettings.enableVolumetric)
return densityVolumes;
var visualEnvironment = VolumeManager.instance.stack.GetComponent<VisualEnvironment>();
if (visualEnvironment.fogType != FogType.Volumetric)
return densityVolumes;
using (new ProfilingSample(cmd, "Prepare Visible Density Volume List"))
{
Vector3 camPosition = hdCamera.camera.transform.position;
Vector3 camOffset = Vector3.zero; // World-origin-relative
if (ShaderConfig.s_CameraRelativeRendering != 0)
{
camOffset = camPosition; // Camera-relative
}
m_VisibleVolumeBounds.Clear();
m_VisibleVolumeData.Clear();
// Collect all visible finite volume data, and upload it to the GPU.
DensityVolume[] volumes = DensityVolumeManager.manager.PrepareDensityVolumeData(cmd);
for (int i = 0; i < Math.Min(volumes.Length, k_MaxVisibleVolumeCount); i++)
{
DensityVolume volume = volumes[i];
// TODO: cache these?
var obb = OrientedBBox.Create(volume.transform);
// Handle camera-relative rendering.
obb.center -= camOffset;
// Frustum cull on the CPU for now. TODO: do it on the GPU.
// TODO: account for custom near and far planes of the V-Buffer's frustum.
// It's typically much shorter (along the Z axis) than the camera's frustum.
if (GeometryUtils.Overlap(obb, hdCamera.frustum, 6, 8))
{
// TODO: cache these?
var data = volume.parameters.GetData();
m_VisibleVolumeBounds.Add(obb);
m_VisibleVolumeData.Add(data);
}
}
s_VisibleVolumeBoundsBuffer.SetData(m_VisibleVolumeBounds);
s_VisibleVolumeDataBuffer.SetData(m_VisibleVolumeData);
// Fill the struct with pointers in order to share the data with the light loop.
densityVolumes.bounds = m_VisibleVolumeBounds;
densityVolumes.density = m_VisibleVolumeData;
return densityVolumes;
}
}
public void VolumeVoxelizationPass(HDCamera hdCamera, CommandBuffer cmd, uint frameIndex, DensityVolumeList densityVolumes)
{
if (!hdCamera.frameSettings.enableVolumetric)
return;
var visualEnvironment = VolumeManager.instance.stack.GetComponent<VisualEnvironment>();
if (visualEnvironment.fogType != FogType.Volumetric)
return;
using (new ProfilingSample(cmd, "Volume Voxelization"))
{
int numVisibleVolumes = m_VisibleVolumeBounds.Count;
if (numVisibleVolumes == 0)
{
// Clear the render target instead of running the shader.
// Note: the clear must take the global fog into account!
// CoreUtils.SetRenderTarget(cmd, vBuffer.GetDensityBuffer(), ClearFlag.Color, CoreUtils.clearColorAllBlack);
// return;
// Clearing 3D textures does not seem to work!
// Use the workaround by running the full shader with 0 density
}
bool enableClustered = hdCamera.frameSettings.lightLoopSettings.enableTileAndCluster;
int kernel = m_VolumeVoxelizationCS.FindKernel(enableClustered ? "VolumeVoxelizationClustered"
: "VolumeVoxelizationBruteforce");
var frameParams = hdCamera.vBufferParams[0];
Vector4 resolution = frameParams.resolution;
float vFoV = hdCamera.camera.fieldOfView * Mathf.Deg2Rad;
// Compose the matrix which allows us to compute the world space view direction.
Matrix4x4 transform = HDUtils.ComputePixelCoordToWorldSpaceViewDirectionMatrix(vFoV, resolution, hdCamera.viewMatrix, false);
Texture3D volumeAtlas = DensityVolumeManager.manager.volumeAtlas.volumeAtlas;
Vector2 volumeAtlasDimensions = new Vector2(0.0f, 0.0f);
if (volumeAtlas != null)
{
volumeAtlasDimensions.x = volumeAtlas.width / volumeAtlas.depth; // 1 / number of textures
volumeAtlasDimensions.y = 1.0f / volumeAtlas.width;
}
cmd.SetComputeTextureParam(m_VolumeVoxelizationCS, kernel, HDShaderIDs._VBufferDensity, m_DensityBufferHandle);
cmd.SetComputeBufferParam( m_VolumeVoxelizationCS, kernel, HDShaderIDs._VolumeBounds, s_VisibleVolumeBoundsBuffer);
cmd.SetComputeBufferParam( m_VolumeVoxelizationCS, kernel, HDShaderIDs._VolumeData, s_VisibleVolumeDataBuffer);
cmd.SetComputeTextureParam(m_VolumeVoxelizationCS, kernel, HDShaderIDs._VolumeMaskAtlas, volumeAtlas);
// TODO: set the constant buffer data only once.
cmd.SetComputeMatrixParam( m_VolumeVoxelizationCS, HDShaderIDs._VBufferCoordToViewDirWS, transform);
cmd.SetComputeIntParam( m_VolumeVoxelizationCS, HDShaderIDs._NumVisibleDensityVolumes, numVisibleVolumes);
cmd.SetComputeVectorParam(m_VolumeVoxelizationCS, HDShaderIDs._VolumeMaskDimensions, volumeAtlasDimensions);
int w = (int)resolution.x;
int h = (int)resolution.y;
// The shader defines GROUP_SIZE_1D = 8.
cmd.DispatchCompute(m_VolumeVoxelizationCS, kernel, (w + 7) / 8, (h + 7) / 8, 1);
}
}
// Ref: https://en.wikipedia.org/wiki/Close-packing_of_equal_spheres
// The returned {x, y} coordinates (and all spheres) are all within the (-0.5, 0.5)^2 range.
// The pattern has been rotated by 15 degrees to maximize the resolution along X and Y:
// https://www.desmos.com/calculator/kcpfvltz7c
static Vector2[] GetHexagonalClosePackedSpheres7()
{
Vector2[] coords = new Vector2[7];
float r = 0.17054068870105443882f;
float d = 2 * r;
float s = r * Mathf.Sqrt(3);
// Try to keep the weighted average as close to the center (0.5) as possible.
// (7)(5) ( )( ) ( )( ) ( )( ) ( )( ) ( )(o) ( )(x) (o)(x) (x)(x)
// (2)(1)(3) ( )(o)( ) (o)(x)( ) (x)(x)(o) (x)(x)(x) (x)(x)(x) (x)(x)(x) (x)(x)(x) (x)(x)(x)
// (4)(6) ( )( ) ( )( ) ( )( ) (o)( ) (x)( ) (x)(o) (x)(x) (x)(x)
coords[0] = new Vector2( 0, 0);
coords[1] = new Vector2(-d, 0);
coords[2] = new Vector2( d, 0);
coords[3] = new Vector2(-r, -s);
coords[4] = new Vector2( r, s);
coords[5] = new Vector2( r, -s);
coords[6] = new Vector2(-r, s);
// Rotate the sampling pattern by 15 degrees.
const float cos15 = 0.96592582628906828675f;
const float sin15 = 0.25881904510252076235f;
for (int i = 0; i < 7; i++)
{
Vector2 coord = coords[i];
coords[i].x = coord.x * cos15 - coord.y * sin15;
coords[i].y = coord.x * sin15 + coord.y * cos15;
}
return coords;
}
public void VolumetricLightingPass(HDCamera hdCamera, CommandBuffer cmd, uint frameIndex)
{
if (!hdCamera.frameSettings.enableVolumetric)
return;
var visualEnvironment = VolumeManager.instance.stack.GetComponent<VisualEnvironment>();
if (visualEnvironment.fogType != FogType.Volumetric)
return;
using (new ProfilingSample(cmd, "Volumetric Lighting"))
{
// Only available in the Play Mode because all the frame counters in the Edit Mode are broken.
bool enableClustered = hdCamera.frameSettings.lightLoopSettings.enableTileAndCluster;
bool enableReprojection = Application.isPlaying && hdCamera.camera.cameraType == CameraType.Game;
int kernel;
if (enableReprojection)
{
kernel = m_VolumetricLightingCS.FindKernel(enableClustered ? "VolumetricLightingClusteredReproj"
: "VolumetricLightingBruteforceReproj");
}
else
{
kernel = m_VolumetricLightingCS.FindKernel(enableClustered ? "VolumetricLightingClustered"
: "VolumetricLightingBruteforce");
}
var frameParams = hdCamera.vBufferParams[0];
Vector4 resolution = frameParams.resolution;
float vFoV = hdCamera.camera.fieldOfView * Mathf.Deg2Rad;
// Compose the matrix which allows us to compute the world space view direction.
Matrix4x4 transform = HDUtils.ComputePixelCoordToWorldSpaceViewDirectionMatrix(vFoV, resolution, hdCamera.viewMatrix, false);
Vector2[] xySeq = GetHexagonalClosePackedSpheres7();
// This is a sequence of 7 equidistant numbers from 1/14 to 13/14.
// Each of them is the centroid of the interval of length 2/14.
// They've been rearranged in a sequence of pairs {small, large}, s.t. (small + large) = 1.
// That way, the running average position is close to 0.5.
// | 6 | 2 | 4 | 1 | 5 | 3 | 7 |
// | | | | o | | | |
// | | o | | x | | | |
// | | x | | x | | o | |
// | | x | o | x | | x | |
// | | x | x | x | o | x | |
// | o | x | x | x | x | x | |
// | x | x | x | x | x | x | o |
// | x | x | x | x | x | x | x |
float[] zSeq = {7.0f/14.0f, 3.0f/14.0f, 11.0f/14.0f, 5.0f/14.0f, 9.0f/14.0f, 1.0f/14.0f, 13.0f/14.0f};
int sampleIndex = (int)frameIndex % 7;
// TODO: should we somehow reorder offsets in Z based on the offset in XY? S.t. the samples more evenly cover the domain.
// Currently, we assume that they are completely uncorrelated, but maybe we should correlate them somehow.
Vector4 offset = new Vector4(xySeq[sampleIndex].x, xySeq[sampleIndex].y, zSeq[sampleIndex], frameIndex);
// Get the interpolated anisotropy value.
var fog = VolumeManager.instance.stack.GetComponent<VolumetricFog>();
// TODO: set 'm_VolumetricLightingPreset'.
// TODO: set the constant buffer data only once.
cmd.SetComputeMatrixParam( m_VolumetricLightingCS, HDShaderIDs._VBufferCoordToViewDirWS, transform);
cmd.SetComputeVectorParam( m_VolumetricLightingCS, HDShaderIDs._VBufferSampleOffset, offset);
cmd.SetComputeFloatParam( m_VolumetricLightingCS, HDShaderIDs._CornetteShanksConstant, CornetteShanksPhasePartConstant(fog.anisotropy));
cmd.SetComputeTextureParam(m_VolumetricLightingCS, kernel, HDShaderIDs._VBufferDensity, m_DensityBufferHandle); // Read
cmd.SetComputeTextureParam(m_VolumetricLightingCS, kernel, HDShaderIDs._VBufferLightingIntegral, m_LightingBufferHandle); // Write
if (enableReprojection)
{
cmd.SetComputeTextureParam(m_VolumetricLightingCS, kernel, HDShaderIDs._VBufferLightingHistory, hdCamera.GetPreviousFrameRT((int)HDCameraFrameHistoryType.VolumetricLighting)); // Read
cmd.SetComputeTextureParam(m_VolumetricLightingCS, kernel, HDShaderIDs._VBufferLightingFeedback, hdCamera.GetCurrentFrameRT((int)HDCameraFrameHistoryType.VolumetricLighting)); // Write
}
int w = (int)resolution.x;
int h = (int)resolution.y;
// The shader defines GROUP_SIZE_1D = 8.
cmd.DispatchCompute(m_VolumetricLightingCS, kernel, (w + 7) / 8, (h + 7) / 8, 1);
}
}
} // class VolumetricLightingModule
} // namespace UnityEngine.Experimental.Rendering.HDPipeline