Library/PackageCache/com.unity.postprocessing@2.1.6/PostProcessing/Runtime/Monitors/HistogramMonitor.cs

   1 using System;
   2
   3 namespace UnityEngine.Rendering.PostProcessing
   4 {
   5     /// <summary>
   6     /// This class holds settings for the Histogram monitor.
   7     /// </summary>
   8     [Serializable]
   9     public sealed class HistogramMonitor : Monitor
  10     {
  11         /// <summary>
  12         /// Displayable channels.
  13         /// </summary>
  14         public enum Channel
  15         {
  16             /// <summary>
  17             /// The red channel.
  18             /// </summary>
  19             Red,
  20
  21             /// <summary>
  22             /// The green channel.
  23             /// </summary>
  24             Green,
  25
  26             /// <summary>
  27             /// The blue channel.
  28             /// </summary>
  29             Blue,
  30
  31             /// <summary>
  32             /// The master (luminance) channel.
  33             /// </summary>
  34             Master
  35         }
  36
  37         /// <summary>
  38         /// The width of the rendered histogram.
  39         /// </summary>
  40         public int width = 512;
  41
  42         /// <summary>
  43         /// The height of the rendered histogram.
  44         /// </summary>
  45         public int height = 256;
  46
  47         /// <summary>
  48         /// The channel to render.
  49         /// </summary>
  50         public Channel channel = Channel.Master;
  51
  52         ComputeBuffer m_Data;
  53         const int k_NumBins = 256;
  54         const int k_ThreadGroupSizeX = 16;
  55         const int k_ThreadGroupSizeY = 16;
  56
  57         internal override void OnDisable()
  58         {
  59             base.OnDisable();
  60
  61             if (m_Data != null)
  62                 m_Data.Release();
  63
  64             m_Data = null;
  65         }
  66
  67         internal override bool NeedsHalfRes()
  68         {
  69             return true;
  70         }
  71
  72         internal override bool ShaderResourcesAvailable(PostProcessRenderContext context)
  73         {
  74             return context.resources.computeShaders.gammaHistogram;
  75         }
  76
  77         internal override void Render(PostProcessRenderContext context)
  78         {
  79             CheckOutput(width, height);
  80
  81             if (m_Data == null)
  82                 m_Data = new ComputeBuffer(k_NumBins, sizeof(uint));
  83
  84             var compute = context.resources.computeShaders.gammaHistogram;
  85             var cmd = context.command;
  86             cmd.BeginSample("GammaHistogram");
  87
  88             // Clear the buffer on every frame as we use it to accumulate values on every frame
  89             int kernel = compute.FindKernel("KHistogramClear");
  90             cmd.SetComputeBufferParam(compute, kernel, "_HistogramBuffer", m_Data);
  91             cmd.DispatchCompute(compute, kernel, Mathf.CeilToInt(k_NumBins / (float)k_ThreadGroupSizeX), 1, 1);
  92
  93             // Gather all pixels and fill in our histogram
  94             kernel = compute.FindKernel("KHistogramGather");
  95             var parameters = new Vector4(
  96                 context.width / 2,
  97                 context.height / 2,
  98                 RuntimeUtilities.isLinearColorSpace ? 1 : 0,
  99                 (int)channel
 100             );
 101
 102             cmd.SetComputeVectorParam(compute, "_Params", parameters);
 103             cmd.SetComputeTextureParam(compute, kernel, "_Source", ShaderIDs.HalfResFinalCopy);
 104             cmd.SetComputeBufferParam(compute, kernel, "_HistogramBuffer", m_Data);
 105             cmd.DispatchCompute(compute, kernel,
 106                 Mathf.CeilToInt(parameters.x / k_ThreadGroupSizeX),
 107                 Mathf.CeilToInt(parameters.y / k_ThreadGroupSizeY),
 108                 1
 109             );
 110
 111             // Generate the histogram texture
 112             var sheet = context.propertySheets.Get(context.resources.shaders.gammaHistogram);
 113             sheet.properties.SetVector(ShaderIDs.Params, new Vector4(width, height, 0f, 0f));
 114             sheet.properties.SetBuffer(ShaderIDs.HistogramBuffer, m_Data);
 115             cmd.BlitFullscreenTriangle(BuiltinRenderTextureType.None, output, sheet, 0);
 116
 117             cmd.EndSample("GammaHistogram");
 118         }
 119     }
 120 }