void PushVolumetricLightingGlobalParams(HDCamera hdCamera, CommandBuffer cmd, int frameIndex)
{
if (!Fog.IsVolumetricLightingEnabled(hdCamera))
{
cmd.SetGlobalTexture(HDShaderIDs._VBufferLighting, HDUtils.clearTexture3D);
return;
}
// Get the interpolated anisotropy value.
var fog = VolumeManager.instance.stack.GetComponent <Fog>();
SetPreconvolvedAmbientLightProbe(cmd, fog.globalLightProbeDimmer.value, fog.anisotropy.value);
var currFrameParams = hdCamera.vBufferParams[0];
var prevFrameParams = hdCamera.vBufferParams[1];
// The lighting & density buffers are shared by all cameras.
// The history & feedback buffers are specific to the camera.
// These 2 types of buffers can have different sizes.
// Additionally, history buffers can have different sizes, since they are not resized at the same time
// (every frame, we swap the buffers, and resize the feedback buffer but not the history buffer).
// The viewport size is the same for all of these buffers.
// All of these buffers may have sub-native-resolution viewports.
// The 3rd dimension (number of slices) is the same for all of these buffers.
Vector2Int sharedBufferSize = new Vector2Int(m_LightingBufferHandle.rt.width, m_LightingBufferHandle.rt.height);
Debug.Assert(m_LightingBufferHandle.rt.width == m_DensityBufferHandle.rt.width);
Debug.Assert(m_LightingBufferHandle.rt.height == m_DensityBufferHandle.rt.height);
Vector2Int historyBufferSize = Vector2Int.zero;
if (hdCamera.IsVolumetricReprojectionEnabled())
{
var historyRT = hdCamera.GetPreviousFrameRT((int)HDCameraFrameHistoryType.VolumetricLighting);
historyBufferSize = new Vector2Int(historyRT.rt.width, historyRT.rt.height);
}
var cvp = currFrameParams.viewportSize;
var pvp = prevFrameParams.viewportSize;
// Adjust slices for XR rendering: VBuffer is shared for all single-pass views
int sliceCount = cvp.z / hdCamera.viewCount;
cmd.SetGlobalVector(HDShaderIDs._VBufferViewportSize, new Vector4(cvp.x, cvp.y, 1.0f / cvp.x, 1.0f / cvp.y));
cmd.SetGlobalInt(HDShaderIDs._VBufferSliceCount, sliceCount);
cmd.SetGlobalFloat(HDShaderIDs._VBufferRcpSliceCount, 1.0f / sliceCount);
cmd.SetGlobalVector(HDShaderIDs._VBufferSharedUvScaleAndLimit, currFrameParams.ComputeUvScaleAndLimit(sharedBufferSize));
cmd.SetGlobalVector(HDShaderIDs._VBufferDistanceEncodingParams, currFrameParams.depthEncodingParams);
cmd.SetGlobalVector(HDShaderIDs._VBufferDistanceDecodingParams, currFrameParams.depthDecodingParams);
cmd.SetGlobalFloat(HDShaderIDs._VBufferLastSliceDist, currFrameParams.ComputeLastSliceDistance(sliceCount));
cmd.SetGlobalFloat(HDShaderIDs._VBufferRcpInstancedViewCount, 1.0f / hdCamera.viewCount);
cmd.SetGlobalVector(HDShaderIDs._VBufferPrevViewportSize, new Vector4(pvp.x, pvp.y, 1.0f / pvp.x, 1.0f / pvp.y));
cmd.SetGlobalVector(HDShaderIDs._VBufferHistoryPrevUvScaleAndLimit, prevFrameParams.ComputeUvScaleAndLimit(historyBufferSize));
cmd.SetGlobalVector(HDShaderIDs._VBufferPrevDepthEncodingParams, prevFrameParams.depthEncodingParams);
cmd.SetGlobalVector(HDShaderIDs._VBufferPrevDepthDecodingParams, prevFrameParams.depthDecodingParams);
cmd.SetGlobalTexture(HDShaderIDs._VBufferLighting, m_LightingBufferHandle);
}
// Must be called AFTER UpdateVolumetricBufferParams.
static internal void ResizeVolumetricHistoryBuffers(HDCamera hdCamera, int frameIndex)
{
if (!hdCamera.IsVolumetricReprojectionEnabled())
{
return;
}
Debug.Assert(hdCamera.vBufferParams != null);
Debug.Assert(hdCamera.vBufferParams.Length == 2);
Debug.Assert(hdCamera.volumetricHistoryBuffers != null);
var currIdx = (frameIndex + 0) & 1;
var prevIdx = (frameIndex + 1) & 1;
var currentParams = hdCamera.vBufferParams[currIdx];
// Render texture contents can become "lost" on certain events, like loading a new level,
// system going to a screensaver mode, in and out of fullscreen and so on.
// https://docs.unity3d.com/ScriptReference/RenderTexture.html
if (hdCamera.volumetricHistoryBuffers[0] == null || hdCamera.volumetricHistoryBuffers[1] == null)
{
DestroyVolumetricHistoryBuffers(hdCamera);
CreateVolumetricHistoryBuffers(hdCamera, hdCamera.vBufferParams.Length); // Basically, assume it's 2
}
string[] names = new string[2] {
"VBufferHistory0", "VBufferHistory1"
};
// We only resize the feedback buffer (#0), not the history buffer (#1).
// We must NOT resize the buffer from the previous frame (#1), as that would invalidate its contents.
ResizeVolumetricBuffer(ref hdCamera.volumetricHistoryBuffers[currIdx], names[currIdx], currentParams.viewportSize.x,
currentParams.viewportSize.y,
currentParams.viewportSize.z);
}