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Implement improved sorting algorithm #4

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115 changes: 115 additions & 0 deletions Assets/PixelSorter.compute
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
#pragma kernel CS_VisualizeSpans
#pragma kernel CS_RGBtoSortValue
#pragma kernel CS_PixelSort
#pragma kernel CS_PixelSort2
#pragma kernel CS_Composite

half _LowThreshold, _HighThreshold;
Expand All @@ -25,6 +26,7 @@ Texture2D<half4> _ColorTex;
RWTexture2D<half4> _SortedBuffer;
RWTexture2D<half> _HSLBuffer;
RWTexture2D<half> _SpanBuffer;
Texture2D<half> _SpanBufferRO;

RWTexture2D<half4> _ClearBuffer;

Expand Down Expand Up @@ -304,6 +306,119 @@ void CS_PixelSort(uint3 id : SV_DISPATCHTHREADID) {
}
}

groupshared half gs_PixelSortCache2[2048];
groupshared uint gs_PixelSortIndices2[2048];

void compareAndSwap2(uint2 idx)
{
half c1 = gs_PixelSortCache2[idx.x];
half c2 = gs_PixelSortCache2[idx.y];

bool result = _ReverseSorting ? c1 > c2 : c1 < c2;

if (result)
{
half temp = gs_PixelSortCache2[idx.x];
gs_PixelSortCache2[idx.x] = gs_PixelSortCache2[idx.y];
gs_PixelSortCache2[idx.y] = temp;

uint tempIndex = gs_PixelSortIndices2[idx.x];
gs_PixelSortIndices2[idx.x] = gs_PixelSortIndices2[idx.y];
gs_PixelSortIndices2[idx.y] = tempIndex;
}
}

void flip2(uint h, uint t, uint spanLength)
{
uint q = ((2 * t) / h) * h;
uint half_h = h / 2;
uint2 indices = q + uint2(t % half_h, h - (t % half_h) - 1);

if (indices.y < spanLength)
compareAndSwap2(indices);
}

void disperse2(uint h, uint t, uint spanLength)
{
uint q = ((2 * t) / h) * h;
uint half_h = h / 2;
uint2 indices = q + uint2(t % half_h, (t % half_h) + half_h);

if (indices.y < spanLength)
compareAndSwap2(indices);
}

[numthreads(1024, 1, 1)]
void CS_PixelSort2(uint3 gid : SV_GroupID, uint tid : SV_GroupIndex)
{
const uint spanLength = _SpanBufferRO[gid.xy];

if (spanLength < 1)
return;

const uint2 direction = _HorizontalSorting ? uint2(1, 0) : uint2(0, 1);

const uint2 idx1 = gid.xy + 2 * tid * direction;
const uint2 idx2 = gid.xy + (2 * tid + 1) * direction;

if (2 * tid < spanLength)
{
gs_PixelSortCache2[2 * tid] = _HSLBuffer[idx1];
if (2 * tid + 1 < spanLength)
{
gs_PixelSortCache2[2 * tid + 1] = _HSLBuffer[idx2];
}
else
{
gs_PixelSortCache2[2 * tid + 1] = _ReverseSorting ? 1.0f : 0.0f;
}
}
else
{
gs_PixelSortCache2[2 * tid] = _ReverseSorting ? 1.0f : 0.0f;
}
gs_PixelSortIndices2[2 * tid] = 2 * tid;
gs_PixelSortIndices2[2 * tid + 1] = 2 * tid + 1;

uint n = 2048;
while (n / 2 >= spanLength && n / 2 >= 4)
{
n /= 2;
}

GroupMemoryBarrierWithGroupSync();
flip2(2, tid, spanLength);

[unroll(10)]
for (uint h = 4, cnt = 1; h <= n; h *= 2, cnt += 1)
{
GroupMemoryBarrierWithGroupSync();
flip2(h, tid, spanLength);

[unroll(cnt)]
for (uint hh = h / 2; hh > 1; hh /= 2)
{
GroupMemoryBarrierWithGroupSync();
disperse2(hh, tid, spanLength);
}
}
GroupMemoryBarrierWithGroupSync();

if (2 * tid < spanLength)
{
const uint2 idxSorted1 = gid.xy + gs_PixelSortIndices2[2 * tid] * direction;

_SortedBuffer[idx1] = _ColorBuffer[idxSorted1];

if (2 * tid + 1 < spanLength)
{
const uint2 idxSorted2 = gid.xy + gs_PixelSortIndices2[2 * tid + 1] * direction;

_SortedBuffer[idx2] = _ColorBuffer[idxSorted2];
}
}
}

[numthreads(8, 8, 1)]
void CS_Composite(uint3 id : SV_DISPATCHTHREADID) {
if (_Mask[id.xy] == 1) {
Expand Down
29 changes: 21 additions & 8 deletions Assets/PixelSorter.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,7 @@ public class PixelSorter : MonoBehaviour {

public bool visualizeSpans = false;

[Range(0, 1080)]
[Range(0, 2048)]
public int maxSpanLength = 1080;

[Range(0, 512)]
Expand All @@ -60,10 +60,13 @@ public enum SortMode {

public bool reverseSorting = false;

public bool improvedSorting = false;

private float animatedLowThreshold = 0.5f;
private float animatedHighThreshold = 0.5f;

private int createMaskPass, testSelectionSortPass, testBitonicSortPass, testCustomSortPass, clearBufferPass, indentifySpansPass, visualizeSpansPass, rgbToHslPass, pixelSortPass, compositePass;
private int createMaskPass, testSelectionSortPass, testBitonicSortPass, testCustomSortPass;
private int clearBufferPass, indentifySpansPass, visualizeSpansPass, rgbToHslPass, pixelSortPass, pixelSort2Pass, compositePass;

private RenderTexture maskTex, spanTex, colorTex, hslTex, sortedTex;

Expand Down Expand Up @@ -103,6 +106,7 @@ void OnEnable() {
visualizeSpansPass = pixelSorter.FindKernel("CS_VisualizeSpans");
rgbToHslPass = pixelSorter.FindKernel("CS_RGBtoSortValue");
pixelSortPass = pixelSorter.FindKernel("CS_PixelSort");
pixelSort2Pass = pixelSorter.FindKernel("CS_PixelSort2");
compositePass = pixelSorter.FindKernel("CS_Composite");

/*
Expand Down Expand Up @@ -198,12 +202,21 @@ private void OnRenderImage(RenderTexture source, RenderTexture destination) {

pixelSorter.Dispatch(rgbToHslPass, Mathf.CeilToInt(Screen.width / 8.0f), Mathf.CeilToInt(Screen.height / 8.0f), 1);

pixelSorter.SetTexture(pixelSortPass, "_HSLBuffer", hslTex);
pixelSorter.SetTexture(pixelSortPass, "_ColorBuffer", colorTex);
pixelSorter.SetTexture(pixelSortPass, "_SortedBuffer", sortedTex);
pixelSorter.SetTexture(pixelSortPass, "_SpanBuffer", spanTex);

pixelSorter.Dispatch(pixelSortPass, Screen.width, Screen.height, 1);
if (improvedSorting) {
pixelSorter.SetTexture(pixelSort2Pass, "_HSLBuffer", hslTex);
pixelSorter.SetTexture(pixelSort2Pass, "_ColorBuffer", colorTex);
pixelSorter.SetTexture(pixelSort2Pass, "_SortedBuffer", sortedTex);
pixelSorter.SetTexture(pixelSort2Pass, "_SpanBufferRO", spanTex);

pixelSorter.Dispatch(pixelSort2Pass, Screen.width, Screen.height, 1);
} else {
pixelSorter.SetTexture(pixelSortPass, "_HSLBuffer", hslTex);
pixelSorter.SetTexture(pixelSortPass, "_ColorBuffer", colorTex);
pixelSorter.SetTexture(pixelSortPass, "_SortedBuffer", sortedTex);
pixelSorter.SetTexture(pixelSortPass, "_SpanBuffer", spanTex);

pixelSorter.Dispatch(pixelSortPass, Screen.width, Screen.height, 1);
}

pixelSorter.SetTexture(compositePass, "_Mask", maskTex);
pixelSorter.SetTexture(compositePass, "_ColorBuffer", colorTex);
Expand Down