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Ryujinx/Ryujinx.Graphics.Texture/BCnDecoder.cs
gdkchan 42c75dbb8f
Add support for BC1/2/3 decompression (for 3D textures) (#2987)
* Add support for BC1/2/3 decompression (for 3D textures)

* Optimize and clean up

* Unsafe not needed here

* Fix alpha value interpolation when a0 <= a1
2022-01-22 19:23:00 +01:00

808 lines
No EOL
32 KiB
C#

using Ryujinx.Common;
using System;
using System.Buffers.Binary;
using System.Runtime.InteropServices;
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.X86;
namespace Ryujinx.Graphics.Texture
{
public static class BCnDecoder
{
private const int BlockWidth = 4;
private const int BlockHeight = 4;
public static byte[] DecodeBC1(ReadOnlySpan<byte> data, int width, int height, int depth, int levels, int layers)
{
int size = 0;
for (int l = 0; l < levels; l++)
{
size += Math.Max(1, width >> l) * Math.Max(1, height >> l) * Math.Max(1, depth >> l) * layers * 4;
}
byte[] output = new byte[size];
Span<byte> tile = stackalloc byte[BlockWidth * BlockHeight * 4];
Span<uint> tileAsUint = MemoryMarshal.Cast<byte, uint>(tile);
Span<uint> outputAsUint = MemoryMarshal.Cast<byte, uint>(output);
Span<Vector128<byte>> tileAsVector128 = MemoryMarshal.Cast<byte, Vector128<byte>>(tile);
Span<Vector128<byte>> outputLine0 = default;
Span<Vector128<byte>> outputLine1 = default;
Span<Vector128<byte>> outputLine2 = default;
Span<Vector128<byte>> outputLine3 = default;
int imageBaseOOffs = 0;
for (int l = 0; l < levels; l++)
{
int w = BitUtils.DivRoundUp(width, BlockWidth);
int h = BitUtils.DivRoundUp(height, BlockHeight);
for (int l2 = 0; l2 < layers; l2++)
{
for (int z = 0; z < depth; z++)
{
for (int y = 0; y < h; y++)
{
int baseY = y * BlockHeight;
int copyHeight = Math.Min(BlockHeight, height - baseY);
int lineBaseOOffs = imageBaseOOffs + baseY * width;
if (copyHeight == 4)
{
outputLine0 = MemoryMarshal.Cast<uint, Vector128<byte>>(outputAsUint.Slice(lineBaseOOffs));
outputLine1 = MemoryMarshal.Cast<uint, Vector128<byte>>(outputAsUint.Slice(lineBaseOOffs + width));
outputLine2 = MemoryMarshal.Cast<uint, Vector128<byte>>(outputAsUint.Slice(lineBaseOOffs + width * 2));
outputLine3 = MemoryMarshal.Cast<uint, Vector128<byte>>(outputAsUint.Slice(lineBaseOOffs + width * 3));
}
for (int x = 0; x < w; x++)
{
int baseX = x * BlockWidth;
int copyWidth = Math.Min(BlockWidth, width - baseX);
BC1DecodeTileRgb(tile, data);
if ((copyWidth | copyHeight) == 4)
{
outputLine0[x] = tileAsVector128[0];
outputLine1[x] = tileAsVector128[1];
outputLine2[x] = tileAsVector128[2];
outputLine3[x] = tileAsVector128[3];
}
else
{
int pixelBaseOOffs = lineBaseOOffs + baseX;
for (int tY = 0; tY < copyHeight; tY++)
{
tileAsUint.Slice(tY * 4, copyWidth).CopyTo(outputAsUint.Slice(pixelBaseOOffs + width * tY, copyWidth));
}
}
data = data.Slice(8);
}
}
imageBaseOOffs += width * height;
}
}
width = Math.Max(1, width >> 1);
height = Math.Max(1, height >> 1);
depth = Math.Max(1, depth >> 1);
}
return output;
}
public static byte[] DecodeBC2(ReadOnlySpan<byte> data, int width, int height, int depth, int levels, int layers)
{
int size = 0;
for (int l = 0; l < levels; l++)
{
size += Math.Max(1, width >> l) * Math.Max(1, height >> l) * Math.Max(1, depth >> l) * layers * 4;
}
byte[] output = new byte[size];
Span<byte> tile = stackalloc byte[BlockWidth * BlockHeight * 4];
Span<uint> tileAsUint = MemoryMarshal.Cast<byte, uint>(tile);
Span<uint> outputAsUint = MemoryMarshal.Cast<byte, uint>(output);
Span<Vector128<byte>> tileAsVector128 = MemoryMarshal.Cast<byte, Vector128<byte>>(tile);
Span<Vector128<byte>> outputLine0 = default;
Span<Vector128<byte>> outputLine1 = default;
Span<Vector128<byte>> outputLine2 = default;
Span<Vector128<byte>> outputLine3 = default;
int imageBaseOOffs = 0;
for (int l = 0; l < levels; l++)
{
int w = BitUtils.DivRoundUp(width, BlockWidth);
int h = BitUtils.DivRoundUp(height, BlockHeight);
for (int l2 = 0; l2 < layers; l2++)
{
for (int z = 0; z < depth; z++)
{
for (int y = 0; y < h; y++)
{
int baseY = y * BlockHeight;
int copyHeight = Math.Min(BlockHeight, height - baseY);
int lineBaseOOffs = imageBaseOOffs + baseY * width;
if (copyHeight == 4)
{
outputLine0 = MemoryMarshal.Cast<uint, Vector128<byte>>(outputAsUint.Slice(lineBaseOOffs));
outputLine1 = MemoryMarshal.Cast<uint, Vector128<byte>>(outputAsUint.Slice(lineBaseOOffs + width));
outputLine2 = MemoryMarshal.Cast<uint, Vector128<byte>>(outputAsUint.Slice(lineBaseOOffs + width * 2));
outputLine3 = MemoryMarshal.Cast<uint, Vector128<byte>>(outputAsUint.Slice(lineBaseOOffs + width * 3));
}
for (int x = 0; x < w; x++)
{
int baseX = x * BlockWidth;
int copyWidth = Math.Min(BlockWidth, width - baseX);
BC23DecodeTileRgb(tile, data.Slice(8));
ulong block = BinaryPrimitives.ReadUInt64LittleEndian(data);
for (int i = 3; i < BlockWidth * BlockHeight * 4; i += 4, block >>= 4)
{
tile[i] = (byte)((block & 0xf) | (block << 4));
}
if ((copyWidth | copyHeight) == 4)
{
outputLine0[x] = tileAsVector128[0];
outputLine1[x] = tileAsVector128[1];
outputLine2[x] = tileAsVector128[2];
outputLine3[x] = tileAsVector128[3];
}
else
{
int pixelBaseOOffs = lineBaseOOffs + baseX;
for (int tY = 0; tY < copyHeight; tY++)
{
tileAsUint.Slice(tY * 4, copyWidth).CopyTo(outputAsUint.Slice(pixelBaseOOffs + width * tY, copyWidth));
}
}
data = data.Slice(16);
}
}
imageBaseOOffs += width * height;
}
}
width = Math.Max(1, width >> 1);
height = Math.Max(1, height >> 1);
depth = Math.Max(1, depth >> 1);
}
return output;
}
public static byte[] DecodeBC3(ReadOnlySpan<byte> data, int width, int height, int depth, int levels, int layers)
{
int size = 0;
for (int l = 0; l < levels; l++)
{
size += Math.Max(1, width >> l) * Math.Max(1, height >> l) * Math.Max(1, depth >> l) * layers * 4;
}
byte[] output = new byte[size];
Span<byte> tile = stackalloc byte[BlockWidth * BlockHeight * 4];
Span<byte> rPal = stackalloc byte[8];
Span<uint> tileAsUint = MemoryMarshal.Cast<byte, uint>(tile);
Span<uint> outputAsUint = MemoryMarshal.Cast<byte, uint>(output);
Span<Vector128<byte>> tileAsVector128 = MemoryMarshal.Cast<byte, Vector128<byte>>(tile);
Span<Vector128<byte>> outputLine0 = default;
Span<Vector128<byte>> outputLine1 = default;
Span<Vector128<byte>> outputLine2 = default;
Span<Vector128<byte>> outputLine3 = default;
int imageBaseOOffs = 0;
for (int l = 0; l < levels; l++)
{
int w = BitUtils.DivRoundUp(width, BlockWidth);
int h = BitUtils.DivRoundUp(height, BlockHeight);
for (int l2 = 0; l2 < layers; l2++)
{
for (int z = 0; z < depth; z++)
{
for (int y = 0; y < h; y++)
{
int baseY = y * BlockHeight;
int copyHeight = Math.Min(BlockHeight, height - baseY);
int lineBaseOOffs = imageBaseOOffs + baseY * width;
if (copyHeight == 4)
{
outputLine0 = MemoryMarshal.Cast<uint, Vector128<byte>>(outputAsUint.Slice(lineBaseOOffs));
outputLine1 = MemoryMarshal.Cast<uint, Vector128<byte>>(outputAsUint.Slice(lineBaseOOffs + width));
outputLine2 = MemoryMarshal.Cast<uint, Vector128<byte>>(outputAsUint.Slice(lineBaseOOffs + width * 2));
outputLine3 = MemoryMarshal.Cast<uint, Vector128<byte>>(outputAsUint.Slice(lineBaseOOffs + width * 3));
}
for (int x = 0; x < w; x++)
{
int baseX = x * BlockWidth;
int copyWidth = Math.Min(BlockWidth, width - baseX);
BC23DecodeTileRgb(tile, data.Slice(8));
ulong block = BinaryPrimitives.ReadUInt64LittleEndian(data);
rPal[0] = (byte)block;
rPal[1] = (byte)(block >> 8);
BCnLerpAlphaUnorm(rPal);
BCnDecodeTileAlphaRgba(tile, rPal, block >> 16);
if ((copyWidth | copyHeight) == 4)
{
outputLine0[x] = tileAsVector128[0];
outputLine1[x] = tileAsVector128[1];
outputLine2[x] = tileAsVector128[2];
outputLine3[x] = tileAsVector128[3];
}
else
{
int pixelBaseOOffs = lineBaseOOffs + baseX;
for (int tY = 0; tY < copyHeight; tY++)
{
tileAsUint.Slice(tY * 4, copyWidth).CopyTo(outputAsUint.Slice(pixelBaseOOffs + width * tY, copyWidth));
}
}
data = data.Slice(16);
}
}
imageBaseOOffs += width * height;
}
}
width = Math.Max(1, width >> 1);
height = Math.Max(1, height >> 1);
depth = Math.Max(1, depth >> 1);
}
return output;
}
public static byte[] DecodeBC4(ReadOnlySpan<byte> data, int width, int height, int depth, int levels, int layers, bool signed)
{
int size = 0;
for (int l = 0; l < levels; l++)
{
size += Math.Max(1, width >> l) * Math.Max(1, height >> l) * Math.Max(1, depth >> l) * layers;
}
byte[] output = new byte[size];
Span<byte> outputSpan = new Span<byte>(output);
ReadOnlySpan<ulong> data64 = MemoryMarshal.Cast<byte, ulong>(data);
Span<byte> tile = stackalloc byte[BlockWidth * BlockHeight];
Span<byte> rPal = stackalloc byte[8];
Span<uint> tileAsUint = MemoryMarshal.Cast<byte, uint>(tile);
Span<uint> outputLine0 = default;
Span<uint> outputLine1 = default;
Span<uint> outputLine2 = default;
Span<uint> outputLine3 = default;
int imageBaseOOffs = 0;
for (int l = 0; l < levels; l++)
{
int w = BitUtils.DivRoundUp(width, BlockWidth);
int h = BitUtils.DivRoundUp(height, BlockHeight);
for (int l2 = 0; l2 < layers; l2++)
{
for (int z = 0; z < depth; z++)
{
for (int y = 0; y < h; y++)
{
int baseY = y * BlockHeight;
int copyHeight = Math.Min(BlockHeight, height - baseY);
int lineBaseOOffs = imageBaseOOffs + baseY * width;
if (copyHeight == 4)
{
outputLine0 = MemoryMarshal.Cast<byte, uint>(outputSpan.Slice(lineBaseOOffs));
outputLine1 = MemoryMarshal.Cast<byte, uint>(outputSpan.Slice(lineBaseOOffs + width));
outputLine2 = MemoryMarshal.Cast<byte, uint>(outputSpan.Slice(lineBaseOOffs + width * 2));
outputLine3 = MemoryMarshal.Cast<byte, uint>(outputSpan.Slice(lineBaseOOffs + width * 3));
}
for (int x = 0; x < w; x++)
{
int baseX = x * BlockWidth;
int copyWidth = Math.Min(BlockWidth, width - baseX);
ulong block = data64[0];
rPal[0] = (byte)block;
rPal[1] = (byte)(block >> 8);
if (signed)
{
BCnLerpAlphaSnorm(rPal);
}
else
{
BCnLerpAlphaUnorm(rPal);
}
BCnDecodeTileAlpha(tile, rPal, block >> 16);
if ((copyWidth | copyHeight) == 4)
{
outputLine0[x] = tileAsUint[0];
outputLine1[x] = tileAsUint[1];
outputLine2[x] = tileAsUint[2];
outputLine3[x] = tileAsUint[3];
}
else
{
int pixelBaseOOffs = lineBaseOOffs + baseX;
for (int tY = 0; tY < copyHeight; tY++)
{
tile.Slice(tY * 4, copyWidth).CopyTo(outputSpan.Slice(pixelBaseOOffs + width * tY, copyWidth));
}
}
data64 = data64.Slice(1);
}
}
imageBaseOOffs += width * height;
}
}
width = Math.Max(1, width >> 1);
height = Math.Max(1, height >> 1);
depth = Math.Max(1, depth >> 1);
}
return output;
}
public static byte[] DecodeBC5(ReadOnlySpan<byte> data, int width, int height, int depth, int levels, int layers, bool signed)
{
int size = 0;
for (int l = 0; l < levels; l++)
{
size += Math.Max(1, width >> l) * Math.Max(1, height >> l) * Math.Max(1, depth >> l) * layers * 2;
}
byte[] output = new byte[size];
ReadOnlySpan<ulong> data64 = MemoryMarshal.Cast<byte, ulong>(data);
Span<byte> rTile = stackalloc byte[BlockWidth * BlockHeight * 2];
Span<byte> gTile = stackalloc byte[BlockWidth * BlockHeight * 2];
Span<byte> rPal = stackalloc byte[8];
Span<byte> gPal = stackalloc byte[8];
Span<ushort> outputAsUshort = MemoryMarshal.Cast<byte, ushort>(output);
Span<uint> rTileAsUint = MemoryMarshal.Cast<byte, uint>(rTile);
Span<uint> gTileAsUint = MemoryMarshal.Cast<byte, uint>(gTile);
Span<ulong> outputLine0 = default;
Span<ulong> outputLine1 = default;
Span<ulong> outputLine2 = default;
Span<ulong> outputLine3 = default;
int imageBaseOOffs = 0;
for (int l = 0; l < levels; l++)
{
int w = BitUtils.DivRoundUp(width, BlockWidth);
int h = BitUtils.DivRoundUp(height, BlockHeight);
for (int l2 = 0; l2 < layers; l2++)
{
for (int z = 0; z < depth; z++)
{
for (int y = 0; y < h; y++)
{
int baseY = y * BlockHeight;
int copyHeight = Math.Min(BlockHeight, height - baseY);
int lineBaseOOffs = imageBaseOOffs + baseY * width;
if (copyHeight == 4)
{
outputLine0 = MemoryMarshal.Cast<ushort, ulong>(outputAsUshort.Slice(lineBaseOOffs));
outputLine1 = MemoryMarshal.Cast<ushort, ulong>(outputAsUshort.Slice(lineBaseOOffs + width));
outputLine2 = MemoryMarshal.Cast<ushort, ulong>(outputAsUshort.Slice(lineBaseOOffs + width * 2));
outputLine3 = MemoryMarshal.Cast<ushort, ulong>(outputAsUshort.Slice(lineBaseOOffs + width * 3));
}
for (int x = 0; x < w; x++)
{
int baseX = x * BlockWidth;
int copyWidth = Math.Min(BlockWidth, width - baseX);
ulong blockL = data64[0];
ulong blockH = data64[1];
rPal[0] = (byte)blockL;
rPal[1] = (byte)(blockL >> 8);
gPal[0] = (byte)blockH;
gPal[1] = (byte)(blockH >> 8);
if (signed)
{
BCnLerpAlphaSnorm(rPal);
BCnLerpAlphaSnorm(gPal);
}
else
{
BCnLerpAlphaUnorm(rPal);
BCnLerpAlphaUnorm(gPal);
}
BCnDecodeTileAlpha(rTile, rPal, blockL >> 16);
BCnDecodeTileAlpha(gTile, gPal, blockH >> 16);
if ((copyWidth | copyHeight) == 4)
{
outputLine0[x] = InterleaveBytes(rTileAsUint[0], gTileAsUint[0]);
outputLine1[x] = InterleaveBytes(rTileAsUint[1], gTileAsUint[1]);
outputLine2[x] = InterleaveBytes(rTileAsUint[2], gTileAsUint[2]);
outputLine3[x] = InterleaveBytes(rTileAsUint[3], gTileAsUint[3]);
}
else
{
int pixelBaseOOffs = lineBaseOOffs + baseX;
for (int tY = 0; tY < copyHeight; tY++)
{
int line = pixelBaseOOffs + width * tY;
for (int tX = 0; tX < copyWidth; tX++)
{
int texel = tY * BlockWidth + tX;
outputAsUshort[line + tX] = (ushort)(rTile[texel] | (gTile[texel] << 8));
}
}
}
data64 = data64.Slice(2);
}
}
imageBaseOOffs += width * height;
}
}
width = Math.Max(1, width >> 1);
height = Math.Max(1, height >> 1);
depth = Math.Max(1, depth >> 1);
}
return output;
}
private static ulong InterleaveBytes(uint left, uint right)
{
return InterleaveBytesWithZeros(left) | (InterleaveBytesWithZeros(right) << 8);
}
private static ulong InterleaveBytesWithZeros(uint value)
{
ulong output = value;
output = (output ^ (output << 16)) & 0xffff0000ffffUL;
output = (output ^ (output << 8)) & 0xff00ff00ff00ffUL;
return output;
}
private static void BCnLerpAlphaUnorm(Span<byte> alpha)
{
byte a0 = alpha[0];
byte a1 = alpha[1];
if (a0 > a1)
{
alpha[2] = (byte)((6 * a0 + 1 * a1) / 7);
alpha[3] = (byte)((5 * a0 + 2 * a1) / 7);
alpha[4] = (byte)((4 * a0 + 3 * a1) / 7);
alpha[5] = (byte)((3 * a0 + 4 * a1) / 7);
alpha[6] = (byte)((2 * a0 + 5 * a1) / 7);
alpha[7] = (byte)((1 * a0 + 6 * a1) / 7);
}
else
{
alpha[2] = (byte)((4 * a0 + 1 * a1) / 5);
alpha[3] = (byte)((3 * a0 + 2 * a1) / 5);
alpha[4] = (byte)((2 * a0 + 3 * a1) / 5);
alpha[5] = (byte)((1 * a0 + 4 * a1) / 5);
alpha[6] = 0;
alpha[7] = 0xff;
}
}
private static void BCnLerpAlphaSnorm(Span<byte> alpha)
{
sbyte a0 = (sbyte)alpha[0];
sbyte a1 = (sbyte)alpha[1];
if (a0 > a1)
{
alpha[2] = (byte)((6 * a0 + 1 * a1) / 7);
alpha[3] = (byte)((5 * a0 + 2 * a1) / 7);
alpha[4] = (byte)((4 * a0 + 3 * a1) / 7);
alpha[5] = (byte)((3 * a0 + 4 * a1) / 7);
alpha[6] = (byte)((2 * a0 + 5 * a1) / 7);
alpha[7] = (byte)((1 * a0 + 6 * a1) / 7);
}
else
{
alpha[2] = (byte)((4 * a0 + 1 * a1) / 5);
alpha[3] = (byte)((3 * a0 + 2 * a1) / 5);
alpha[4] = (byte)((2 * a0 + 3 * a1) / 5);
alpha[5] = (byte)((1 * a0 + 4 * a1) / 5);
alpha[6] = 0x80;
alpha[7] = 0x7f;
}
}
private unsafe static void BCnDecodeTileAlpha(Span<byte> output, Span<byte> rPal, ulong rI)
{
if (Avx2.IsSupported)
{
Span<Vector128<byte>> outputAsVector128 = MemoryMarshal.Cast<byte, Vector128<byte>>(output);
Vector128<uint> shifts = Vector128.Create(0u, 3u, 6u, 9u);
Vector128<uint> masks = Vector128.Create(7u);
Vector128<byte> vClut;
fixed (byte* pRPal = rPal)
{
vClut = Sse2.LoadScalarVector128((ulong*)pRPal).AsByte();
}
Vector128<uint> indices0 = Vector128.Create((uint)rI);
Vector128<uint> indices1 = Vector128.Create((uint)(rI >> 24));
Vector128<uint> indices00 = Avx2.ShiftRightLogicalVariable(indices0, shifts);
Vector128<uint> indices10 = Avx2.ShiftRightLogicalVariable(indices1, shifts);
Vector128<uint> indices01 = Sse2.ShiftRightLogical(indices00, 12);
Vector128<uint> indices11 = Sse2.ShiftRightLogical(indices10, 12);
indices00 = Sse2.And(indices00, masks);
indices10 = Sse2.And(indices10, masks);
indices01 = Sse2.And(indices01, masks);
indices11 = Sse2.And(indices11, masks);
Vector128<ushort> indicesW0 = Sse41.PackUnsignedSaturate(indices00.AsInt32(), indices01.AsInt32());
Vector128<ushort> indicesW1 = Sse41.PackUnsignedSaturate(indices10.AsInt32(), indices11.AsInt32());
Vector128<byte> indices = Sse2.PackUnsignedSaturate(indicesW0.AsInt16(), indicesW1.AsInt16());
outputAsVector128[0] = Ssse3.Shuffle(vClut, indices);
}
else
{
for (int i = 0; i < BlockWidth * BlockHeight; i++, rI >>= 3)
{
output[i] = rPal[(int)(rI & 7)];
}
}
}
private unsafe static void BCnDecodeTileAlphaRgba(Span<byte> output, Span<byte> rPal, ulong rI)
{
if (Avx2.IsSupported)
{
Span<Vector256<uint>> outputAsVector256 = MemoryMarshal.Cast<byte, Vector256<uint>>(output);
Vector256<uint> shifts = Vector256.Create(0u, 3u, 6u, 9u, 12u, 15u, 18u, 21u);
Vector128<uint> vClut128;
fixed (byte* pRPal = rPal)
{
vClut128 = Sse2.LoadScalarVector128((ulong*)pRPal).AsUInt32();
}
Vector256<uint> vClut = Avx2.ConvertToVector256Int32(vClut128.AsByte()).AsUInt32();
vClut = Avx2.ShiftLeftLogical(vClut, 24);
Vector256<uint> indices0 = Vector256.Create((uint)rI);
Vector256<uint> indices1 = Vector256.Create((uint)(rI >> 24));
indices0 = Avx2.ShiftRightLogicalVariable(indices0, shifts);
indices1 = Avx2.ShiftRightLogicalVariable(indices1, shifts);
outputAsVector256[0] = Avx2.Or(outputAsVector256[0], Avx2.PermuteVar8x32(vClut, indices0));
outputAsVector256[1] = Avx2.Or(outputAsVector256[1], Avx2.PermuteVar8x32(vClut, indices1));
}
else
{
for (int i = 3; i < BlockWidth * BlockHeight * 4; i += 4, rI >>= 3)
{
output[i] = rPal[(int)(rI & 7)];
}
}
}
private unsafe static void BC1DecodeTileRgb(Span<byte> output, ReadOnlySpan<byte> input)
{
Span<uint> clut = stackalloc uint[4];
uint c0c1 = BinaryPrimitives.ReadUInt32LittleEndian(input);
uint c0 = (ushort)c0c1;
uint c1 = (ushort)(c0c1 >> 16);
clut[0] = ConvertRgb565ToRgb888(c0) | 0xff000000;
clut[1] = ConvertRgb565ToRgb888(c1) | 0xff000000;
clut[2] = BC1LerpRgb2(clut[0], clut[1], c0, c1);
clut[3] = BC1LerpRgb3(clut[0], clut[1], c0, c1);
BCnDecodeTileRgb(clut, output, input);
}
private unsafe static void BC23DecodeTileRgb(Span<byte> output, ReadOnlySpan<byte> input)
{
Span<uint> clut = stackalloc uint[4];
uint c0c1 = BinaryPrimitives.ReadUInt32LittleEndian(input);
uint c0 = (ushort)c0c1;
uint c1 = (ushort)(c0c1 >> 16);
clut[0] = ConvertRgb565ToRgb888(c0);
clut[1] = ConvertRgb565ToRgb888(c1);
clut[2] = BC23LerpRgb2(clut[0], clut[1]);
clut[3] = BC23LerpRgb3(clut[0], clut[1]);
BCnDecodeTileRgb(clut, output, input);
}
private unsafe static void BCnDecodeTileRgb(Span<uint> clut, Span<byte> output, ReadOnlySpan<byte> input)
{
if (Avx2.IsSupported)
{
Span<Vector256<uint>> outputAsVector256 = MemoryMarshal.Cast<byte, Vector256<uint>>(output);
Vector256<uint> shifts0 = Vector256.Create(0u, 2u, 4u, 6u, 8u, 10u, 12u, 14u);
Vector256<uint> shifts1 = Vector256.Create(16u, 18u, 20u, 22u, 24u, 26u, 28u, 30u);
Vector256<uint> masks = Vector256.Create(3u);
Vector256<uint> vClut;
fixed (uint* pClut = &clut[0])
{
vClut = Sse2.LoadVector128(pClut).ToVector256Unsafe();
}
Vector256<uint> indices0;
fixed (byte* pInput = input)
{
indices0 = Avx2.BroadcastScalarToVector256((uint*)(pInput + 4));
}
Vector256<uint> indices1 = indices0;
indices0 = Avx2.ShiftRightLogicalVariable(indices0, shifts0);
indices1 = Avx2.ShiftRightLogicalVariable(indices1, shifts1);
indices0 = Avx2.And(indices0, masks);
indices1 = Avx2.And(indices1, masks);
outputAsVector256[0] = Avx2.PermuteVar8x32(vClut, indices0);
outputAsVector256[1] = Avx2.PermuteVar8x32(vClut, indices1);
}
else
{
Span<uint> outputAsUint = MemoryMarshal.Cast<byte, uint>(output);
uint indices = BinaryPrimitives.ReadUInt32LittleEndian(input.Slice(4));
for (int i = 0; i < BlockWidth * BlockHeight; i++, indices >>= 2)
{
outputAsUint[i] = clut[(int)(indices & 3)];
}
}
}
private static uint BC1LerpRgb2(uint color0, uint color1, uint c0, uint c1)
{
if (c0 > c1)
{
return BC23LerpRgb2(color0, color1) | 0xff000000;
}
uint carry = color0 & color1;
uint addHalve = ((color0 ^ color1) >> 1) & 0x7f7f7f;
return (addHalve + carry) | 0xff000000;
}
private static uint BC23LerpRgb2(uint color0, uint color1)
{
uint r0 = (byte)color0;
uint g0 = color0 & 0xff00;
uint b0 = color0 & 0xff0000;
uint r1 = (byte)color1;
uint g1 = color1 & 0xff00;
uint b1 = color1 & 0xff0000;
uint mixR = (2 * r0 + r1) / 3;
uint mixG = (2 * g0 + g1) / 3;
uint mixB = (2 * b0 + b1) / 3;
return mixR | (mixG & 0xff00) | (mixB & 0xff0000);
}
private static uint BC1LerpRgb3(uint color0, uint color1, uint c0, uint c1)
{
if (c0 > c1)
{
return BC23LerpRgb3(color0, color1) | 0xff000000;
}
return 0;
}
private static uint BC23LerpRgb3(uint color0, uint color1)
{
uint r0 = (byte)color0;
uint g0 = color0 & 0xff00;
uint b0 = color0 & 0xff0000;
uint r1 = (byte)color1;
uint g1 = color1 & 0xff00;
uint b1 = color1 & 0xff0000;
uint mixR = (2 * r1 + r0) / 3;
uint mixG = (2 * g1 + g0) / 3;
uint mixB = (2 * b1 + b0) / 3;
return mixR | (mixG & 0xff00) | (mixB & 0xff0000);
}
private static uint ConvertRgb565ToRgb888(uint value)
{
uint b = (value & 0x1f) << 19;
uint g = (value << 5) & 0xfc00;
uint r = (value >> 8) & 0xf8;
b |= b >> 5;
g |= g >> 6;
r |= r >> 5;
return r | (g & 0xff00) | (b & 0xff0000);
}
}
}