63 lines
2.4 KiB
C#
63 lines
2.4 KiB
C#
namespace UnityEngine.Rendering.PostProcessing
|
|
{
|
|
internal sealed class LogHistogram
|
|
{
|
|
public const int rangeMin = -9; // ev
|
|
public const int rangeMax = 9; // ev
|
|
|
|
// Don't forget to update 'ExposureHistogram.hlsl' if you change these values !
|
|
const int k_Bins = 128;
|
|
|
|
public ComputeBuffer data { get; private set; }
|
|
|
|
public void Generate(PostProcessRenderContext context)
|
|
{
|
|
if (data == null)
|
|
data = new ComputeBuffer(k_Bins, sizeof(uint));
|
|
|
|
uint threadX, threadY, threadZ;
|
|
var scaleOffsetRes = GetHistogramScaleOffsetRes(context);
|
|
var compute = context.resources.computeShaders.exposureHistogram;
|
|
var cmd = context.command;
|
|
cmd.BeginSample("LogHistogram");
|
|
|
|
// Clear the buffer on every frame as we use it to accumulate luminance values on each frame
|
|
int kernel = compute.FindKernel("KEyeHistogramClear");
|
|
cmd.SetComputeBufferParam(compute, kernel, "_HistogramBuffer", data);
|
|
compute.GetKernelThreadGroupSizes(kernel, out threadX, out threadY, out threadZ);
|
|
cmd.DispatchCompute(compute, kernel, Mathf.CeilToInt(k_Bins / (float)threadX), 1, 1);
|
|
|
|
// Get a log histogram
|
|
kernel = compute.FindKernel("KEyeHistogram");
|
|
cmd.SetComputeBufferParam(compute, kernel, "_HistogramBuffer", data);
|
|
cmd.SetComputeTextureParam(compute, kernel, "_Source", context.source);
|
|
cmd.SetComputeVectorParam(compute, "_ScaleOffsetRes", scaleOffsetRes);
|
|
|
|
compute.GetKernelThreadGroupSizes(kernel, out threadX, out threadY, out threadZ);
|
|
cmd.DispatchCompute(compute, kernel,
|
|
Mathf.CeilToInt(scaleOffsetRes.z / 2f / threadX),
|
|
Mathf.CeilToInt(scaleOffsetRes.w / 2f / threadY),
|
|
1
|
|
);
|
|
|
|
cmd.EndSample("LogHistogram");
|
|
}
|
|
|
|
public Vector4 GetHistogramScaleOffsetRes(PostProcessRenderContext context)
|
|
{
|
|
float diff = rangeMax - rangeMin;
|
|
float scale = 1f / diff;
|
|
float offset = -rangeMin * scale;
|
|
return new Vector4(scale, offset, context.width, context.height);
|
|
}
|
|
|
|
public void Release()
|
|
{
|
|
if (data != null)
|
|
data.Release();
|
|
|
|
data = null;
|
|
}
|
|
}
|
|
}
|