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125 行
4.4 KiB

using System;
using UnityEngine.Rendering;
namespace UnityEngine.Experimental.Rendering.HDPipeline
{
public partial class LTCAreaLight
{
static LTCAreaLight s_Instance;
public static LTCAreaLight instance
{
get
{
if (s_Instance == null)
s_Instance = new LTCAreaLight();
return s_Instance;
}
}
int m_refCounting;
// For area lighting - We pack all texture inside a texture array to reduce the number of resource required
Texture2DArray m_LtcData; // 0: m_LtcGGXMatrix - RGBA, 2: m_LtcDisneyDiffuseMatrix - RGBA, 3: m_LtcMultiGGXFresnelDisneyDiffuse - RGB, A unused
const int k_LtcLUTMatrixDim = 3; // size of the matrix (3x3)
const int k_LtcLUTResolution = 64;
LTCAreaLight()
{
m_refCounting = 0;
}
// Load LUT with one scalar in alpha of a tex2D
void LoadLUT(Texture2DArray tex, int arrayElement, TextureFormat format, float[] LUTScalar)
{
const int count = k_LtcLUTResolution * k_LtcLUTResolution;
Color[] pixels = new Color[count];
for (int i = 0; i < count; i++)
{
pixels[i] = new Color(0, 0, 0, LUTScalar[i]);
}
tex.SetPixels(pixels, arrayElement);
}
// Load LUT with 3x3 matrix in RGBA of a tex2D (some part are zero)
void LoadLUT(Texture2DArray tex, int arrayElement, TextureFormat format, double[,] LUTTransformInv)
{
const int count = k_LtcLUTResolution * k_LtcLUTResolution;
Color[] pixels = new Color[count];
for (int i = 0; i < count; i++)
{
// Both GGX and Disney Diffuse BRDFs have zero values in columns 1, 3, 5, 7.
// Column 8 contains only ones.
pixels[i] = new Color((float)LUTTransformInv[i, 0],
(float)LUTTransformInv[i, 2],
(float)LUTTransformInv[i, 4],
(float)LUTTransformInv[i, 6]);
}
tex.SetPixels(pixels, arrayElement);
}
// Special-case function for 'm_LtcMultiGGXFresnelDisneyDiffuse'.
void LoadLUT(Texture2DArray tex, int arrayElement, TextureFormat format, float[] LtcGGXMagnitudeData, float[] LtcGGXFresnelData, float[] LtcDisneyDiffuseMagnitudeData)
{
const int count = k_LtcLUTResolution * k_LtcLUTResolution;
Color[] pixels = new Color[count];
for (int i = 0; i < count; i++)
{
// We store the result of the subtraction as a run-time optimization.
// See the footnote 2 of "LTC Fresnel Approximation" by Stephen Hill.
pixels[i] = new Color(LtcGGXMagnitudeData[i] - LtcGGXFresnelData[i], LtcGGXFresnelData[i], LtcDisneyDiffuseMagnitudeData[i], 1);
}
tex.SetPixels(pixels, arrayElement);
}
public void Build()
{
Debug.Assert(m_refCounting >= 0);
if (m_refCounting == 0)
{
m_LtcData = new Texture2DArray(k_LtcLUTResolution, k_LtcLUTResolution, 3, TextureFormat.RGBAHalf, false /*mipmap*/, true /* linear */)
{
hideFlags = HideFlags.HideAndDontSave,
wrapMode = TextureWrapMode.Clamp,
filterMode = FilterMode.Bilinear,
name = CoreUtils.GetTextureAutoName(k_LtcLUTResolution, k_LtcLUTResolution, TextureFormat.RGBAHalf, depth: 3, dim: TextureDimension.Tex2DArray, name: "LTC_LUT")
};
LoadLUT(m_LtcData, 0, TextureFormat.RGBAHalf, s_LtcGGXMatrixData);
LoadLUT(m_LtcData, 1, TextureFormat.RGBAHalf, s_LtcDisneyDiffuseMatrixData);
// TODO: switch to RGBA64 when it becomes available.
LoadLUT(m_LtcData, 2, TextureFormat.RGBAHalf, s_LtcGGXMagnitudeData, s_LtcGGXFresnelData, s_LtcDisneyDiffuseMagnitudeData);
m_LtcData.Apply();
}
m_refCounting++;
}
public void Cleanup()
{
m_refCounting--;
if (m_refCounting == 0)
{
CoreUtils.Destroy(m_LtcData);
}
Debug.Assert(m_refCounting >= 0);
}
public void Bind()
{
Shader.SetGlobalTexture("_LtcData", m_LtcData);
}
}
}