tsai
/
ImageSharp
mirror of https://github.com/SixLabors/ImageSharp
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
Browse Source

Vectorized AverageFilter

pull/1630/head
TechPizza 5 years ago
parent
78b6d78058
commit
c16af90f79
1 changed files with 120 additions and 0 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 120
      src/ImageSharp/Formats/Png/Filters/AverageFilter.cs

120
src/ImageSharp/Formats/Png/Filters/AverageFilter.cs
View File

@ -5,6 +5,11 @@ using System;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
#if SUPPORTS_RUNTIME_INTRINSICS
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.X86;
#endif
namespace SixLabors.ImageSharp.Formats.Png.Filters
{
/// <summary>
@ -79,6 +84,89 @@ namespace SixLabors.ImageSharp.Formats.Png.Filters
sum += Numerics.Abs(unchecked((sbyte)res));
}
#if SUPPORTS_RUNTIME_INTRINSICS
if (Avx2.IsSupported)
{
Vector256<int> sumAccumulator = Vector256<int>.Zero;
for (int xLeft = x - bytesPerPixel; x + Vector256<byte>.Count <= scanline.Length; xLeft += Vector256<byte>.Count)
{
Vector256<byte> scan = Unsafe.As<byte, Vector256<byte>>(ref Unsafe.Add(ref scanBaseRef, x));
Vector256<byte> left = Unsafe.As<byte, Vector256<byte>>(ref Unsafe.Add(ref scanBaseRef, xLeft));
Vector256<byte> above = Unsafe.As<byte, Vector256<byte>>(ref Unsafe.Add(ref prevBaseRef, x));
Vector256<byte> res = Avx2.Subtract(scan, Average(left, above));
Unsafe.As<byte, Vector256<byte>>(ref Unsafe.Add(ref resultBaseRef, x + 1)) = res; // +1 to skip filter type
x += Vector256<byte>.Count;
Vector256<sbyte> absRes = Avx2.Abs(res.AsSByte()).AsSByte();
Vector256<short> loRes16 = Avx2.UnpackLow(absRes, Vector256<sbyte>.Zero).AsInt16();
Vector256<short> hiRes16 = Avx2.UnpackHigh(absRes, Vector256<sbyte>.Zero).AsInt16();
Vector256<int> loRes32 = Avx2.UnpackLow(loRes16, Vector256<short>.Zero).AsInt32();
Vector256<int> hiRes32 = Avx2.UnpackHigh(loRes16, Vector256<short>.Zero).AsInt32();
sumAccumulator = Avx2.Add(sumAccumulator, loRes32);
sumAccumulator = Avx2.Add(sumAccumulator, hiRes32);
loRes32 = Avx2.UnpackLow(hiRes16, Vector256<short>.Zero).AsInt32();
hiRes32 = Avx2.UnpackHigh(hiRes16, Vector256<short>.Zero).AsInt32();
sumAccumulator = Avx2.Add(sumAccumulator, loRes32);
sumAccumulator = Avx2.Add(sumAccumulator, hiRes32);
}
for (int i = 0; i < Vector256<int>.Count; i++)
{
sum += sumAccumulator.GetElement(i);
}
}
else if (Sse2.IsSupported)
{
var allBitsSet = Vector128.Create((sbyte)-1);
Vector128<int> sumAccumulator = Vector128<int>.Zero;
for (int xLeft = x - bytesPerPixel; x + Vector128<byte>.Count <= scanline.Length; xLeft += Vector128<byte>.Count)
{
Vector128<byte> scan = Unsafe.As<byte, Vector128<byte>>(ref Unsafe.Add(ref scanBaseRef, x));
Vector128<byte> left = Unsafe.As<byte, Vector128<byte>>(ref Unsafe.Add(ref scanBaseRef, xLeft));
Vector128<byte> above = Unsafe.As<byte, Vector128<byte>>(ref Unsafe.Add(ref prevBaseRef, x));
Vector128<byte> res = Sse2.Subtract(scan, Average(left, above));
Unsafe.As<byte, Vector128<byte>>(ref Unsafe.Add(ref resultBaseRef, x + 1)) = res; // +1 to skip filter type
x += Vector128<byte>.Count;
Vector128<sbyte> absRes;
if (Ssse3.IsSupported)
{
absRes = Ssse3.Abs(res.AsSByte()).AsSByte();
}
else
{
Vector128<sbyte> mask = Sse2.CompareGreaterThan(res.AsSByte(), Vector128<sbyte>.Zero);
mask = Sse2.Xor(mask, allBitsSet);
absRes = Sse2.Xor(Sse2.Add(res.AsSByte(), mask), mask);
}
Vector128<short> loRes16 = Sse2.UnpackLow(absRes, Vector128<sbyte>.Zero).AsInt16();
Vector128<short> hiRes16 = Sse2.UnpackHigh(absRes, Vector128<sbyte>.Zero).AsInt16();
Vector128<int> loRes32 = Sse2.UnpackLow(loRes16, Vector128<short>.Zero).AsInt32();
Vector128<int> hiRes32 = Sse2.UnpackHigh(loRes16, Vector128<short>.Zero).AsInt32();
sumAccumulator = Sse2.Add(sumAccumulator, loRes32);
sumAccumulator = Sse2.Add(sumAccumulator, hiRes32);
loRes32 = Sse2.UnpackLow(hiRes16, Vector128<short>.Zero).AsInt32();
hiRes32 = Sse2.UnpackHigh(hiRes16, Vector128<short>.Zero).AsInt32();
sumAccumulator = Sse2.Add(sumAccumulator, loRes32);
sumAccumulator = Sse2.Add(sumAccumulator, hiRes32);
}
for (int i = 0; i < Vector128<int>.Count; i++)
{
sum += sumAccumulator.GetElement(i);
}
}
#endif
for (int xLeft = x - bytesPerPixel; x < scanline.Length; ++xLeft /* Note: ++x happens in the body to avoid one add operation */)
{
byte scan = Unsafe.Add(ref scanBaseRef, x);
@ -101,5 +189,37 @@ namespace SixLabors.ImageSharp.Formats.Png.Filters
/// <returns>The <see cref="int"/></returns>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static int Average(byte left, byte above) => (left + above) >> 1;
#if SUPPORTS_RUNTIME_INTRINSICS
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static Vector128<byte> Average(Vector128<byte> left, Vector128<byte> above)
{
Vector128<ushort> loLeft16 = Sse2.UnpackLow(left, Vector128<byte>.Zero).AsUInt16();
Vector128<ushort> hiLeft16 = Sse2.UnpackHigh(left, Vector128<byte>.Zero).AsUInt16();
Vector128<ushort> loAbove16 = Sse2.UnpackLow(above, Vector128<byte>.Zero).AsUInt16();
Vector128<ushort> hiAbove16 = Sse2.UnpackHigh(above, Vector128<byte>.Zero).AsUInt16();
Vector128<ushort> div1 = Sse2.ShiftRightLogical(Sse2.Add(loLeft16, loAbove16), 1);
Vector128<ushort> div2 = Sse2.ShiftRightLogical(Sse2.Add(hiLeft16, hiAbove16), 1);
return Sse2.PackUnsignedSaturate(div1.AsInt16(), div2.AsInt16());
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static Vector256<byte> Average(Vector256<byte> left, Vector256<byte> above)
{
Vector256<ushort> loLeft16 = Avx2.UnpackLow(left, Vector256<byte>.Zero).AsUInt16();
Vector256<ushort> hiLeft16 = Avx2.UnpackHigh(left, Vector256<byte>.Zero).AsUInt16();
Vector256<ushort> loAbove16 = Avx2.UnpackLow(above, Vector256<byte>.Zero).AsUInt16();
Vector256<ushort> hiAbove16 = Avx2.UnpackHigh(above, Vector256<byte>.Zero).AsUInt16();
Vector256<ushort> div1 = Avx2.ShiftRightLogical(Avx2.Add(loLeft16, loAbove16), 1);
Vector256<ushort> div2 = Avx2.ShiftRightLogical(Avx2.Add(hiLeft16, hiAbove16), 1);
return Avx2.PackUnsignedSaturate(div1.AsInt16(), div2.AsInt16());
}
#endif
}
}

Write Preview
Loading…
Cancel
Save