using System; using UnityEngine.Rendering; namespace UnityEngine.Experimental.Rendering.HDPipeline { [GenerateHLSL] public struct VolumeProperties { public Vector3 scattering; // [0, 1], prefer sRGB public float extinction; // [0, 1], prefer sRGB public static VolumeProperties GetNeutralVolumeProperties() { VolumeProperties properties = new VolumeProperties(); properties.scattering = Vector3.zero; properties.extinction = 0; return properties; } } // struct VolumeProperties [Serializable] public class VolumeParameters { public Bounds bounds; // Position and dimensions in meters public Color albedo; // Single scattering albedo [0, 1] public float meanFreePath; // In meters [1, inf]. Should be chromatic - this is an optimization! public VolumeParameters() { bounds = new Bounds(Vector3.zero, Vector3.positiveInfinity); albedo = new Color(0.5f, 0.5f, 0.5f); meanFreePath = 10.0f; } public bool IsVolumeUnbounded() { return bounds.size.x == float.PositiveInfinity && bounds.size.y == float.PositiveInfinity && bounds.size.z == float.PositiveInfinity; } public Vector3 GetAbsorptionCoefficient() { float extinction = GetExtinctionCoefficient(); Vector3 scattering = GetScatteringCoefficient(); return Vector3.Max(new Vector3(extinction, extinction, extinction) - scattering, Vector3.zero); } public Vector3 GetScatteringCoefficient() { float extinction = GetExtinctionCoefficient(); return new Vector3(albedo.r * extinction, albedo.g * extinction, albedo.b * extinction); } public float GetExtinctionCoefficient() { return 1.0f / meanFreePath; } public void Constrain() { bounds.size = Vector3.Max(bounds.size, Vector3.zero); albedo.r = Mathf.Clamp01(albedo.r); albedo.g = Mathf.Clamp01(albedo.g); albedo.b = Mathf.Clamp01(albedo.b); meanFreePath = Mathf.Max(meanFreePath, 1.0f); } public VolumeProperties GetProperties() { VolumeProperties properties = new VolumeProperties(); properties.scattering = GetScatteringCoefficient(); properties.extinction = GetExtinctionCoefficient(); return properties; } } // class VolumeParameters public partial class HDRenderPipeline : RenderPipeline { public enum VolumetricLightingPreset { Off, Normal, Ultra, Count }; VolumetricLightingPreset m_VolumetricLightingPreset { get { return (VolumetricLightingPreset)Math.Min(ShaderConfig.s_VolumetricLightingPreset, (int)VolumetricLightingPreset.Count); } } ComputeShader m_VolumetricLightingCS { get { return m_Asset.renderPipelineResources.volumetricLightingCS; } } float m_VBufferNearPlane = 0.5f; // Distance in meters; dynamic modifications not handled by reprojection float m_VBufferFarPlane = 64.0f; // Distance in meters; dynamic modifications not handled by reprojection const int k_VBufferCount = 3; // 0 and 1 - history (prev) and feedback (next), 2 - integral (curr) RenderTexture[] m_VBufferLighting = null; RenderTargetIdentifier[] m_VBufferLightingRT = null; int m_ViewCount = 0; int[] m_ViewIdArray = new int[8]; int ViewOffsetFromViewId(int viewId) { int viewOffset = -1; Debug.Assert(m_ViewCount == 0 || m_ViewIdArray != null); for (int i = 0; i < m_ViewCount; i++) { if (m_ViewIdArray[i] == viewId) { viewOffset = i; } } return viewOffset; } public 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; } } public static int ComputeVBufferSliceCount(VolumetricLightingPreset preset) { switch (preset) { case VolumetricLightingPreset.Normal: return 128; case VolumetricLightingPreset.Ultra: return 256; case VolumetricLightingPreset.Off: return 0; default: Debug.Assert(false, "Encountered an unexpected VolumetricLightingPreset."); return 0; } } // Since a single voxel corresponds to a tile (e.g. 8x8) of pixels, // the VBuffer can potentially extend past the boundaries of the viewport. // The function returns the fraction of the {width, height} of the VBuffer visible on screen. Vector2 ComputeVBufferResolutionAndScale(float screenWidth, float screenHeight, ref int w, ref int h, ref int d) { int t = ComputeVBufferTileSize(m_VolumetricLightingPreset); // Ceil(ScreenSize / TileSize). w = ((int)screenWidth + t - 1) / t; h = ((int)screenHeight + t - 1) / t; d = ComputeVBufferSliceCount(m_VolumetricLightingPreset); return new Vector2(screenWidth / (w * t), screenHeight / (h * t)); } void ResizeVBuffer(int viewId, int screenWidth, int screenHeight) { int viewOffset = ViewOffsetFromViewId(viewId); if (viewOffset >= 0) { // Found, check resolution. int w = 0, h = 0, d = 0; ComputeVBufferResolutionAndScale(screenWidth, screenHeight, ref w, ref h, ref d); Debug.Assert(m_VBufferLighting != null); Debug.Assert(m_VBufferLighting.Length >= (viewOffset + 1) * k_VBufferCount); Debug.Assert(m_VBufferLighting[viewOffset * k_VBufferCount] != null); if (w == m_VBufferLighting[viewOffset * k_VBufferCount].width && h == m_VBufferLighting[viewOffset * k_VBufferCount].height && d == m_VBufferLighting[viewOffset * k_VBufferCount].volumeDepth) { // Everything matches, nothing to do here. return; } } // Otherwise, we have to recreate the VBuffer. CreateVBuffer(viewId, screenWidth, screenHeight); } void CreateVBuffer(int viewId, int screenWidth, int screenHeight) { // Clean up first. DestroyVBuffer(viewId); int viewOffset = ViewOffsetFromViewId(viewId); if (viewOffset < 0) { // Not found. Push back. viewOffset = m_ViewCount++; Debug.Assert(viewOffset < 8); m_ViewIdArray[viewOffset] = viewId; if (m_VBufferLighting == null) { // Lazy initialize. m_VBufferLighting = new RenderTexture[k_VBufferCount]; m_VBufferLightingRT = new RenderTargetIdentifier[k_VBufferCount]; } else if (m_VBufferLighting.Length < m_ViewCount * k_VBufferCount) { // Grow by reallocation and copy. RenderTexture[] newArray = new RenderTexture[m_ViewCount * k_VBufferCount]; RenderTargetIdentifier[] newArrayRT = new RenderTargetIdentifier[m_ViewCount * k_VBufferCount]; for (int i = 0, n = m_VBufferLighting.Length; i < n; i++) { newArray[i] = m_VBufferLighting[i]; newArrayRT[i] = m_VBufferLightingRT[i]; } // Reassign and release memory. m_VBufferLighting = newArray; m_VBufferLightingRT = newArrayRT; } } Debug.Assert(m_VBufferLighting != null); int w = 0, h = 0, d = 0; ComputeVBufferResolutionAndScale(screenWidth, screenHeight, ref w, ref h, ref d); for (int i = viewOffset * k_VBufferCount, n = viewOffset * k_VBufferCount + k_VBufferCount; i < n; i++) { m_VBufferLighting[i] = new RenderTexture(w, h, 0, RenderTextureFormat.ARGBHalf, RenderTextureReadWrite.Linear); m_VBufferLighting[i].filterMode = FilterMode.Trilinear; // Custom m_VBufferLighting[i].dimension = TextureDimension.Tex3D; // TODO: request the thick 3D tiling layout m_VBufferLighting[i].volumeDepth = d; m_VBufferLighting[i].enableRandomWrite = true; m_VBufferLighting[i].Create(); m_VBufferLightingRT[i] = new RenderTargetIdentifier(m_VBufferLighting[i]); } } void DestroyVBuffer(int viewId) { int viewOffset = ViewOffsetFromViewId(viewId); if (viewOffset < 0) { // Not found. return; } int lastOffset = m_ViewCount - 1; Debug.Assert(lastOffset >= 0); if (m_VBufferLighting != null) { Debug.Assert(m_VBufferLighting.Length >= m_ViewCount * k_VBufferCount); for (int i = 0; i < k_VBufferCount; i++) { int viewBuffer = viewOffset * k_VBufferCount + i; int lastBuffer = lastOffset * k_VBufferCount + i; // Release the memory. if (m_VBufferLighting[viewBuffer] != null) { m_VBufferLighting[viewBuffer].Release(); } // Swap with the last element. m_VBufferLighting[viewBuffer] = m_VBufferLighting[lastBuffer]; m_VBufferLightingRT[viewBuffer] = m_VBufferLightingRT[lastBuffer]; } } // Swap with the last element and shrink the array. m_ViewIdArray[viewOffset] = m_ViewIdArray[lastOffset]; m_ViewCount--; } // Uses a logarithmic depth encoding. // Near plane: depth = 0; far plane: depth = 1. // x = n, y = log2(f/n), z = 1/n, w = 1/log2(f/n). public static Vector4 ComputeLogarithmicDepthEncodingParams(float nearPlane, float farPlane) { Vector4 depthParams = new Vector4(); float n = nearPlane; float f = farPlane; depthParams.x = n; depthParams.y = Mathf.Log(f / n, 2); depthParams.z = 1.0f / depthParams.x; depthParams.w = 1.0f / depthParams.y; return depthParams; } // Returns NULL if a global fog component does not exist, or is not enabled. public static HomogeneousFog GetGlobalFogComponent() { HomogeneousFog globalFogComponent = null; HomogeneousFog[] fogComponents = Object.FindObjectsOfType(typeof(HomogeneousFog)) as HomogeneousFog[]; foreach (HomogeneousFog fogComponent in fogComponents) { if (fogComponent.enabled && fogComponent.volumeParameters.IsVolumeUnbounded()) { globalFogComponent = fogComponent; break; } } return globalFogComponent; } RenderTargetIdentifier GetVBufferLightingHistory(int viewOffset) // From the previous frame { return m_VBufferLightingRT[viewOffset * k_VBufferCount + ((Time.renderedFrameCount + 0) & 1)]; // Does not work in the Scene view } RenderTargetIdentifier GetVBufferLightingFeedback(int viewOffset) // For the next frame { return m_VBufferLightingRT[viewOffset * k_VBufferCount + ((Time.renderedFrameCount + 1) & 1)]; // Does not work in the Scene view } RenderTargetIdentifier GetVBufferLightingIntegral(int viewOffset) // Of the current frame { return m_VBufferLightingRT[viewOffset * k_VBufferCount + 2]; } public void SetVolumetricLightingData(HDCamera camera, CommandBuffer cmd) { HomogeneousFog globalFogComponent = GetGlobalFogComponent(); // TODO: may want to cache these results somewhere. VolumeProperties globalFogProperties = (globalFogComponent != null) ? globalFogComponent.volumeParameters.GetProperties() : VolumeProperties.GetNeutralVolumeProperties(); cmd.SetGlobalVector(HDShaderIDs._GlobalFog_Scattering, globalFogProperties.scattering); cmd.SetGlobalFloat( HDShaderIDs._GlobalFog_Extinction, globalFogProperties.extinction); int w = 0, h = 0, d = 0; Vector2 scale = ComputeVBufferResolutionAndScale(camera.screenSize.x, camera.screenSize.y, ref w, ref h, ref d); int viewId = camera.camera.GetInstanceID(); int viewOffset = ViewOffsetFromViewId(viewId); cmd.SetGlobalVector( HDShaderIDs._VBufferResolution, new Vector4(w, h, 1.0f / w, 1.0f / h)); cmd.SetGlobalVector( HDShaderIDs._VBufferScaleAndSliceCount, new Vector4(scale.x, scale.y, d, 1.0f / d)); cmd.SetGlobalVector( HDShaderIDs._VBufferDepthEncodingParams, ComputeLogarithmicDepthEncodingParams(m_VBufferNearPlane, m_VBufferFarPlane)); cmd.SetGlobalTexture(HDShaderIDs._VBufferLighting, GetVBufferLightingIntegral(viewOffset)); } // 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 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; } void VolumetricLightingPass(HDCamera camera, CommandBuffer cmd) { if (m_VolumetricLightingPreset == VolumetricLightingPreset.Off) return; using (new ProfilingSample(cmd, "Volumetric Lighting")) { int viewId = camera.camera.GetInstanceID(); // Warning: different views can use the same camera int viewOffset = ViewOffsetFromViewId(viewId); if (GetGlobalFogComponent() == null) { // Clear the render target instead of running the shader. // CoreUtils.SetRenderTarget(cmd, GetVBufferLightingIntegral(viewOffset), ClearFlag.Color, CoreUtils.clearColorAllBlack); // return; // Clearing 3D textures does not seem to work! // Use the workaround by running the full shader with no volume. } bool enableClustered = m_FrameSettings.lightLoopSettings.enableTileAndCluster; bool enableReprojection = Application.isPlaying && camera.camera.cameraType == CameraType.Game; int kernel; if (enableReprojection) { // Only available in the Play Mode because all the frame counters in the Edit Mode are broken. kernel = m_VolumetricLightingCS.FindKernel(enableClustered ? "VolumetricLightingClusteredReproj" : "VolumetricLightingAllLightsReproj"); } else { kernel = m_VolumetricLightingCS.FindKernel(enableClustered ? "VolumetricLightingClustered" : "VolumetricLightingAllLights"); } int w = 0, h = 0, d = 0; Vector2 scale = ComputeVBufferResolutionAndScale(camera.screenSize.x, camera.screenSize.y, ref w, ref h, ref d); float vFoV = camera.camera.fieldOfView * Mathf.Deg2Rad; // Compose the matrix which allows us to compute the world space view direction. // Compute it using the scaled resolution to account for the visible area of the VBuffer. Vector4 scaledRes = new Vector4(w * scale.x, h * scale.y, 1.0f / (w * scale.x), 1.0f / (h * scale.y)); Matrix4x4 transform = HDUtils.ComputePixelCoordToWorldSpaceViewDirectionMatrix(vFoV, scaledRes, camera.viewMatrix, false); camera.SetupComputeShader(m_VolumetricLightingCS, cmd); 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 rfc = Time.renderedFrameCount; int sampleIndex = rfc % 7; Vector4 offset = new Vector4(xySeq[sampleIndex].x, xySeq[sampleIndex].y, zSeq[sampleIndex], rfc); // TODO: set 'm_VolumetricLightingPreset'. cmd.SetComputeVectorParam( m_VolumetricLightingCS, HDShaderIDs._VBufferSampleOffset, offset); cmd.SetComputeMatrixParam( m_VolumetricLightingCS, HDShaderIDs._VBufferCoordToViewDirWS, transform); cmd.SetComputeTextureParam(m_VolumetricLightingCS, kernel, HDShaderIDs._VBufferLightingHistory, GetVBufferLightingHistory(viewOffset)); // Read cmd.SetComputeTextureParam(m_VolumetricLightingCS, kernel, HDShaderIDs._VBufferLightingFeedback, GetVBufferLightingFeedback(viewOffset)); // Write cmd.SetComputeTextureParam(m_VolumetricLightingCS, kernel, HDShaderIDs._VBufferLightingIntegral, GetVBufferLightingIntegral(viewOffset)); // Write // The shader defines GROUP_SIZE_1D = 16. cmd.DispatchCompute(m_VolumetricLightingCS, kernel, (w + 15) / 16, (h + 15) / 16, 1); } } } // class HDRenderPipeline } // namespace UnityEngine.Experimental.Rendering.HDPipeline