Ryujinx/src/Ryujinx.Graphics.Texture/BC6Decoder.cs
TSRBerry 2989c163a8
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820 lines
32 KiB
C#

using Ryujinx.Graphics.Texture.Utils;
using System;
using System.Runtime.InteropServices;
namespace Ryujinx.Graphics.Texture
{
static class BC6Decoder
{
private const int HalfOne = 0x3C00;
public static void Decode(Span<byte> output, ReadOnlySpan<byte> data, int width, int height, bool signed)
{
ReadOnlySpan<Block> blocks = MemoryMarshal.Cast<byte, Block>(data);
Span<ulong> output64 = MemoryMarshal.Cast<byte, ulong>(output);
int wInBlocks = (width + 3) / 4;
int hInBlocks = (height + 3) / 4;
for (int y = 0; y < hInBlocks; y++)
{
int y2 = y * 4;
int bh = Math.Min(4, height - y2);
for (int x = 0; x < wInBlocks; x++)
{
int x2 = x * 4;
int bw = Math.Min(4, width - x2);
DecodeBlock(blocks[y * wInBlocks + x], output64[(y2 * width + x2)..], bw, bh, width, signed);
}
}
}
private static void DecodeBlock(Block block, Span<ulong> output, int w, int h, int width, bool signed)
{
int mode = (int)(block.Low & 3);
if ((mode & 2) != 0)
{
mode = (int)(block.Low & 0x1f);
}
Span<RgbaColor32> endPoints = stackalloc RgbaColor32[4];
int subsetCount = DecodeEndPoints(ref block, endPoints, mode, signed);
if (subsetCount == 0)
{
// Mode is invalid, the spec mandates that hardware fills the block with
// a opaque black color.
for (int ty = 0; ty < h; ty++)
{
int baseOffs = ty * width;
for (int tx = 0; tx < w; tx++)
{
output[baseOffs + tx] = (ulong)HalfOne << 48;
}
}
return;
}
int partition;
int indexBitCount;
ulong indices;
if (subsetCount > 1)
{
partition = (int)((block.High >> 13) & 0x1F);
indexBitCount = 3;
int fixUpIndex = BC67Tables.FixUpIndices[subsetCount - 1][partition][1] * 3;
ulong lowMask = (ulong.MaxValue >> (65 - fixUpIndex)) << 3;
ulong highMask = ulong.MaxValue << (fixUpIndex + 3);
indices = ((block.High >> 16) & highMask) | ((block.High >> 17) & lowMask) | ((block.High >> 18) & 3);
}
else
{
partition = 0;
indexBitCount = 4;
indices = (block.High & ~0xFUL) | ((block.High >> 1) & 7);
}
ulong indexMask = (1UL << indexBitCount) - 1;
for (int ty = 0; ty < h; ty++)
{
int baseOffs = ty * width;
for (int tx = 0; tx < w; tx++)
{
int offs = baseOffs + tx;
int index = (int)(indices & indexMask);
int endPointBase = BC67Tables.PartitionTable[subsetCount - 1][partition][ty * 4 + tx] << 1;
RgbaColor32 color1 = endPoints[endPointBase];
RgbaColor32 color2 = endPoints[endPointBase + 1];
RgbaColor32 color = BC67Utils.Interpolate(color1, color2, index, indexBitCount);
output[offs] =
(ulong)FinishUnquantize(color.R, signed) |
((ulong)FinishUnquantize(color.G, signed) << 16) |
((ulong)FinishUnquantize(color.B, signed) << 32) |
((ulong)HalfOne << 48);
indices >>= indexBitCount;
}
}
}
private static int DecodeEndPoints(ref Block block, Span<RgbaColor32> endPoints, int mode, bool signed)
{
ulong low = block.Low;
ulong high = block.High;
int r0 = 0, g0 = 0, b0 = 0, r1 = 0, g1 = 0, b1 = 0, r2 = 0, g2 = 0, b2 = 0, r3 = 0, g3 = 0, b3 = 0;
int subsetCount;
switch (mode)
{
case 0:
r0 = (int)(low >> 5) & 0x3FF;
g0 = (int)(low >> 15) & 0x3FF;
b0 = (int)(low >> 25) & 0x3FF;
if (signed)
{
r0 = SignExtend(r0, 10);
g0 = SignExtend(g0, 10);
b0 = SignExtend(b0, 10);
}
r1 = r0 + SignExtend((int)(low >> 35), 5);
g1 = g0 + SignExtend((int)(low >> 45), 5);
b1 = b0 + SignExtend((int)(low >> 55), 5);
r2 = r0 + SignExtend((int)(high >> 1), 5);
g2 = g0 + SignExtend((int)(((low << 2) & 0x10) | ((low >> 41) & 0xF)), 5);
b2 = b0 + SignExtend((int)(((low << 1) & 0x10) | ((high << 3) & 0x08) | (low >> 61)), 5);
r3 = r0 + SignExtend((int)(high >> 7), 5);
g3 = g0 + SignExtend((int)(((low >> 36) & 0x10) | ((low >> 51) & 0xF)), 5);
b3 = b0 + SignExtend((int)(
((low) & 0x10) |
((high >> 9) & 0x08) |
((high >> 4) & 0x04) |
((low >> 59) & 0x02) |
((low >> 50) & 0x01)), 5);
r0 = Unquantize(r0, 10, signed);
g0 = Unquantize(g0, 10, signed);
b0 = Unquantize(b0, 10, signed);
r1 = Unquantize(r1 & 0x3FF, 10, signed);
g1 = Unquantize(g1 & 0x3FF, 10, signed);
b1 = Unquantize(b1 & 0x3FF, 10, signed);
r2 = Unquantize(r2 & 0x3FF, 10, signed);
g2 = Unquantize(g2 & 0x3FF, 10, signed);
b2 = Unquantize(b2 & 0x3FF, 10, signed);
r3 = Unquantize(r3 & 0x3FF, 10, signed);
g3 = Unquantize(g3 & 0x3FF, 10, signed);
b3 = Unquantize(b3 & 0x3FF, 10, signed);
subsetCount = 2;
break;
case 1:
r0 = (int)(low >> 5) & 0x7F;
g0 = (int)(low >> 15) & 0x7F;
b0 = (int)(low >> 25) & 0x7F;
if (signed)
{
r0 = SignExtend(r0, 7);
g0 = SignExtend(g0, 7);
b0 = SignExtend(b0, 7);
}
r1 = r0 + SignExtend((int)(low >> 35), 6);
g1 = g0 + SignExtend((int)(low >> 45), 6);
b1 = b0 + SignExtend((int)(low >> 55), 6);
r2 = r0 + SignExtend((int)(high >> 1), 6);
g2 = g0 + SignExtend((int)(((low << 3) & 0x20) | ((low >> 20) & 0x10) | ((low >> 41) & 0x0F)), 6);
b2 = b0 + SignExtend((int)(
((low >> 17) & 0x20) |
((low >> 10) & 0x10) |
((high << 3) & 0x08) |
(low >> 61)), 6);
r3 = r0 + SignExtend((int)(high >> 7), 6);
g3 = g0 + SignExtend((int)(((low << 1) & 0x30) | ((low >> 51) & 0xF)), 6);
b3 = b0 + SignExtend((int)(
((low >> 28) & 0x20) |
((low >> 30) & 0x10) |
((low >> 29) & 0x08) |
((low >> 21) & 0x04) |
((low >> 12) & 0x03)), 6);
r0 = Unquantize(r0, 7, signed);
g0 = Unquantize(g0, 7, signed);
b0 = Unquantize(b0, 7, signed);
r1 = Unquantize(r1 & 0x7F, 7, signed);
g1 = Unquantize(g1 & 0x7F, 7, signed);
b1 = Unquantize(b1 & 0x7F, 7, signed);
r2 = Unquantize(r2 & 0x7F, 7, signed);
g2 = Unquantize(g2 & 0x7F, 7, signed);
b2 = Unquantize(b2 & 0x7F, 7, signed);
r3 = Unquantize(r3 & 0x7F, 7, signed);
g3 = Unquantize(g3 & 0x7F, 7, signed);
b3 = Unquantize(b3 & 0x7F, 7, signed);
subsetCount = 2;
break;
case 2:
r0 = (int)(((low >> 30) & 0x400) | ((low >> 5) & 0x3FF));
g0 = (int)(((low >> 39) & 0x400) | ((low >> 15) & 0x3FF));
b0 = (int)(((low >> 49) & 0x400) | ((low >> 25) & 0x3FF));
if (signed)
{
r0 = SignExtend(r0, 11);
g0 = SignExtend(g0, 11);
b0 = SignExtend(b0, 11);
}
r1 = r0 + SignExtend((int)(low >> 35), 5);
g1 = g0 + SignExtend((int)(low >> 45), 4);
b1 = b0 + SignExtend((int)(low >> 55), 4);
r2 = r0 + SignExtend((int)(high >> 1), 5);
g2 = g0 + SignExtend((int)(low >> 41), 4);
b2 = b0 + SignExtend((int)(((high << 3) & 8) | (low >> 61)), 4);
r3 = r0 + SignExtend((int)(high >> 7), 5);
g3 = g0 + SignExtend((int)(low >> 51), 4);
b3 = b0 + SignExtend((int)(
((high >> 9) & 8) |
((high >> 4) & 4) |
((low >> 59) & 2) |
((low >> 50) & 1)), 4);
r0 = Unquantize(r0, 11, signed);
g0 = Unquantize(g0, 11, signed);
b0 = Unquantize(b0, 11, signed);
r1 = Unquantize(r1 & 0x7FF, 11, signed);
g1 = Unquantize(g1 & 0x7FF, 11, signed);
b1 = Unquantize(b1 & 0x7FF, 11, signed);
r2 = Unquantize(r2 & 0x7FF, 11, signed);
g2 = Unquantize(g2 & 0x7FF, 11, signed);
b2 = Unquantize(b2 & 0x7FF, 11, signed);
r3 = Unquantize(r3 & 0x7FF, 11, signed);
g3 = Unquantize(g3 & 0x7FF, 11, signed);
b3 = Unquantize(b3 & 0x7FF, 11, signed);
subsetCount = 2;
break;
case 3:
r0 = (int)(low >> 5) & 0x3FF;
g0 = (int)(low >> 15) & 0x3FF;
b0 = (int)(low >> 25) & 0x3FF;
r1 = (int)(low >> 35) & 0x3FF;
g1 = (int)(low >> 45) & 0x3FF;
b1 = (int)(((high << 9) & 0x200) | (low >> 55));
if (signed)
{
r0 = SignExtend(r0, 10);
g0 = SignExtend(g0, 10);
b0 = SignExtend(b0, 10);
r1 = SignExtend(r1, 10);
g1 = SignExtend(g1, 10);
b1 = SignExtend(b1, 10);
}
r0 = Unquantize(r0, 10, signed);
g0 = Unquantize(g0, 10, signed);
b0 = Unquantize(b0, 10, signed);
r1 = Unquantize(r1, 10, signed);
g1 = Unquantize(g1, 10, signed);
b1 = Unquantize(b1, 10, signed);
subsetCount = 1;
break;
case 6:
r0 = (int)(((low >> 29) & 0x400) | ((low >> 5) & 0x3FF));
g0 = (int)(((low >> 40) & 0x400) | ((low >> 15) & 0x3FF));
b0 = (int)(((low >> 49) & 0x400) | ((low >> 25) & 0x3FF));
if (signed)
{
r0 = SignExtend(r0, 11);
g0 = SignExtend(g0, 11);
b0 = SignExtend(b0, 11);
}
r1 = r0 + SignExtend((int)(low >> 35), 4);
g1 = g0 + SignExtend((int)(low >> 45), 5);
b1 = b0 + SignExtend((int)(low >> 55), 4);
r2 = r0 + SignExtend((int)(high >> 1), 4);
g2 = g0 + SignExtend((int)(((high >> 7) & 0x10) | ((low >> 41) & 0x0F)), 5);
b2 = b0 + SignExtend((int)(((high << 3) & 0x08) | ((low >> 61))), 4);
r3 = r0 + SignExtend((int)(high >> 7), 4);
g3 = g0 + SignExtend((int)(((low >> 36) & 0x10) | ((low >> 51) & 0x0F)), 5);
b3 = b0 + SignExtend((int)(
((high >> 9) & 8) |
((high >> 4) & 4) |
((low >> 59) & 2) |
((high >> 5) & 1)), 4);
r0 = Unquantize(r0, 11, signed);
g0 = Unquantize(g0, 11, signed);
b0 = Unquantize(b0, 11, signed);
r1 = Unquantize(r1 & 0x7FF, 11, signed);
g1 = Unquantize(g1 & 0x7FF, 11, signed);
b1 = Unquantize(b1 & 0x7FF, 11, signed);
r2 = Unquantize(r2 & 0x7FF, 11, signed);
g2 = Unquantize(g2 & 0x7FF, 11, signed);
b2 = Unquantize(b2 & 0x7FF, 11, signed);
r3 = Unquantize(r3 & 0x7FF, 11, signed);
g3 = Unquantize(g3 & 0x7FF, 11, signed);
b3 = Unquantize(b3 & 0x7FF, 11, signed);
subsetCount = 2;
break;
case 7:
r0 = (int)(((low >> 34) & 0x400) | ((low >> 5) & 0x3FF));
g0 = (int)(((low >> 44) & 0x400) | ((low >> 15) & 0x3FF));
b0 = (int)(((high << 10) & 0x400) | ((low >> 25) & 0x3FF));
if (signed)
{
r0 = SignExtend(r0, 11);
g0 = SignExtend(g0, 11);
b0 = SignExtend(b0, 11);
}
r1 = (r0 + SignExtend((int)(low >> 35), 9)) & 0x7FF;
g1 = (g0 + SignExtend((int)(low >> 45), 9)) & 0x7FF;
b1 = (b0 + SignExtend((int)(low >> 55), 9)) & 0x7FF;
r0 = Unquantize(r0, 11, signed);
g0 = Unquantize(g0, 11, signed);
b0 = Unquantize(b0, 11, signed);
r1 = Unquantize(r1, 11, signed);
g1 = Unquantize(g1, 11, signed);
b1 = Unquantize(b1, 11, signed);
subsetCount = 1;
break;
case 10:
r0 = (int)(((low >> 29) & 0x400) | ((low >> 5) & 0x3FF));
g0 = (int)(((low >> 39) & 0x400) | ((low >> 15) & 0x3FF));
b0 = (int)(((low >> 50) & 0x400) | ((low >> 25) & 0x3FF));
if (signed)
{
r0 = SignExtend(r0, 11);
g0 = SignExtend(g0, 11);
b0 = SignExtend(b0, 11);
}
r1 = r0 + SignExtend((int)(low >> 35), 4);
g1 = g0 + SignExtend((int)(low >> 45), 4);
b1 = b0 + SignExtend((int)(low >> 55), 5);
r2 = r0 + SignExtend((int)(high >> 1), 4);
g2 = g0 + SignExtend((int)(low >> 41), 4);
b2 = b0 + SignExtend((int)(((low >> 36) & 0x10) | ((high << 3) & 8) | (low >> 61)), 5);
r3 = r0 + SignExtend((int)(high >> 7), 4);
g3 = g0 + SignExtend((int)(low >> 51), 4);
b3 = b0 + SignExtend((int)(
((high >> 7) & 0x10) |
((high >> 9) & 0x08) |
((high >> 4) & 0x06) |
((low >> 50) & 0x01)), 5);
r0 = Unquantize(r0, 11, signed);
g0 = Unquantize(g0, 11, signed);
b0 = Unquantize(b0, 11, signed);
r1 = Unquantize(r1 & 0x7FF, 11, signed);
g1 = Unquantize(g1 & 0x7FF, 11, signed);
b1 = Unquantize(b1 & 0x7FF, 11, signed);
r2 = Unquantize(r2 & 0x7FF, 11, signed);
g2 = Unquantize(g2 & 0x7FF, 11, signed);
b2 = Unquantize(b2 & 0x7FF, 11, signed);
r3 = Unquantize(r3 & 0x7FF, 11, signed);
g3 = Unquantize(g3 & 0x7FF, 11, signed);
b3 = Unquantize(b3 & 0x7FF, 11, signed);
subsetCount = 2;
break;
case 11:
r0 = (int)(((low >> 32) & 0x800) | ((low >> 34) & 0x400) | ((low >> 5) & 0x3FF));
g0 = (int)(((low >> 42) & 0x800) | ((low >> 44) & 0x400) | ((low >> 15) & 0x3FF));
b0 = (int)(((low >> 52) & 0x800) | ((high << 10) & 0x400) | ((low >> 25) & 0x3FF));
if (signed)
{
r0 = SignExtend(r0, 12);
g0 = SignExtend(g0, 12);
b0 = SignExtend(b0, 12);
}
r1 = (r0 + SignExtend((int)(low >> 35), 8)) & 0xFFF;
g1 = (g0 + SignExtend((int)(low >> 45), 8)) & 0xFFF;
b1 = (b0 + SignExtend((int)(low >> 55), 8)) & 0xFFF;
r0 = Unquantize(r0, 12, signed);
g0 = Unquantize(g0, 12, signed);
b0 = Unquantize(b0, 12, signed);
r1 = Unquantize(r1, 12, signed);
g1 = Unquantize(g1, 12, signed);
b1 = Unquantize(b1, 12, signed);
subsetCount = 1;
break;
case 14:
r0 = (int)(low >> 5) & 0x1FF;
g0 = (int)(low >> 15) & 0x1FF;
b0 = (int)(low >> 25) & 0x1FF;
if (signed)
{
r0 = SignExtend(r0, 9);
g0 = SignExtend(g0, 9);
b0 = SignExtend(b0, 9);
}
r1 = r0 + SignExtend((int)(low >> 35), 5);
g1 = g0 + SignExtend((int)(low >> 45), 5);
b1 = b0 + SignExtend((int)(low >> 55), 5);
r2 = r0 + SignExtend((int)(high >> 1), 5);
g2 = g0 + SignExtend((int)(((low >> 20) & 0x10) | ((low >> 41) & 0xF)), 5);
b2 = b0 + SignExtend((int)(((low >> 10) & 0x10) | ((high << 3) & 8) | (low >> 61)), 5);
r3 = r0 + SignExtend((int)(high >> 7), 5);
g3 = g0 + SignExtend((int)(((low >> 36) & 0x10) | ((low >> 51) & 0xF)), 5);
b3 = b0 + SignExtend((int)(
((low >> 30) & 0x10) |
((high >> 9) & 0x08) |
((high >> 4) & 0x04) |
((low >> 59) & 0x02) |
((low >> 50) & 0x01)), 5);
r0 = Unquantize(r0, 9, signed);
g0 = Unquantize(g0, 9, signed);
b0 = Unquantize(b0, 9, signed);
r1 = Unquantize(r1 & 0x1FF, 9, signed);
g1 = Unquantize(g1 & 0x1FF, 9, signed);
b1 = Unquantize(b1 & 0x1FF, 9, signed);
r2 = Unquantize(r2 & 0x1FF, 9, signed);
g2 = Unquantize(g2 & 0x1FF, 9, signed);
b2 = Unquantize(b2 & 0x1FF, 9, signed);
r3 = Unquantize(r3 & 0x1FF, 9, signed);
g3 = Unquantize(g3 & 0x1FF, 9, signed);
b3 = Unquantize(b3 & 0x1FF, 9, signed);
subsetCount = 2;
break;
case 15:
r0 = (BitReverse6((int)(low >> 39) & 0x3F) << 10) | ((int)(low >> 5) & 0x3FF);
g0 = (BitReverse6((int)(low >> 49) & 0x3F) << 10) | ((int)(low >> 15) & 0x3FF);
b0 = ((BitReverse6((int)(low >> 59)) | (int)(high & 1)) << 10) | ((int)(low >> 25) & 0x3FF);
if (signed)
{
r0 = SignExtend(r0, 16);
g0 = SignExtend(g0, 16);
b0 = SignExtend(b0, 16);
}
r1 = (r0 + SignExtend((int)(low >> 35), 4)) & 0xFFFF;
g1 = (g0 + SignExtend((int)(low >> 45), 4)) & 0xFFFF;
b1 = (b0 + SignExtend((int)(low >> 55), 4)) & 0xFFFF;
subsetCount = 1;
break;
case 18:
r0 = (int)(low >> 5) & 0xFF;
g0 = (int)(low >> 15) & 0xFF;
b0 = (int)(low >> 25) & 0xFF;
if (signed)
{
r0 = SignExtend(r0, 8);
g0 = SignExtend(g0, 8);
b0 = SignExtend(b0, 8);
}
r1 = r0 + SignExtend((int)(low >> 35), 6);
g1 = g0 + SignExtend((int)(low >> 45), 5);
b1 = b0 + SignExtend((int)(low >> 55), 5);
r2 = r0 + SignExtend((int)(high >> 1), 6);
g2 = g0 + SignExtend((int)(((low >> 20) & 0x10) | ((low >> 41) & 0xF)), 5);
b2 = b0 + SignExtend((int)(((low >> 10) & 0x10) | ((high << 3) & 8) | (low >> 61)), 5);
r3 = r0 + SignExtend((int)(high >> 7), 6);
g3 = g0 + SignExtend((int)(((low >> 9) & 0x10) | ((low >> 51) & 0xF)), 5);
b3 = b0 + SignExtend((int)(
((low >> 30) & 0x18) |
((low >> 21) & 0x04) |
((low >> 59) & 0x02) |
((low >> 50) & 0x01)), 5);
r0 = Unquantize(r0, 8, signed);
g0 = Unquantize(g0, 8, signed);
b0 = Unquantize(b0, 8, signed);
r1 = Unquantize(r1 & 0xFF, 8, signed);
g1 = Unquantize(g1 & 0xFF, 8, signed);
b1 = Unquantize(b1 & 0xFF, 8, signed);
r2 = Unquantize(r2 & 0xFF, 8, signed);
g2 = Unquantize(g2 & 0xFF, 8, signed);
b2 = Unquantize(b2 & 0xFF, 8, signed);
r3 = Unquantize(r3 & 0xFF, 8, signed);
g3 = Unquantize(g3 & 0xFF, 8, signed);
b3 = Unquantize(b3 & 0xFF, 8, signed);
subsetCount = 2;
break;
case 22:
r0 = (int)(low >> 5) & 0xFF;
g0 = (int)(low >> 15) & 0xFF;
b0 = (int)(low >> 25) & 0xFF;
if (signed)
{
r0 = SignExtend(r0, 8);
g0 = SignExtend(g0, 8);
b0 = SignExtend(b0, 8);
}
r1 = r0 + SignExtend((int)(low >> 35), 5);
g1 = g0 + SignExtend((int)(low >> 45), 6);
b1 = b0 + SignExtend((int)(low >> 55), 5);
r2 = r0 + SignExtend((int)(high >> 1), 5);
g2 = g0 + SignExtend((int)(((low >> 18) & 0x20) | ((low >> 20) & 0x10) | ((low >> 41) & 0xF)), 6);
b2 = b0 + SignExtend((int)(((low >> 10) & 0x10) | ((high << 3) & 0x08) | (low >> 61)), 5);
r3 = r0 + SignExtend((int)(high >> 7), 5);
g3 = g0 + SignExtend((int)(((low >> 28) & 0x20) | ((low >> 36) & 0x10) | ((low >> 51) & 0x0F)), 6);
b3 = b0 + SignExtend((int)(
((low >> 30) & 0x10) |
((high >> 9) & 0x08) |
((high >> 4) & 0x04) |
((low >> 59) & 0x02) |
((low >> 13) & 0x01)), 5);
r0 = Unquantize(r0, 8, signed);
g0 = Unquantize(g0, 8, signed);
b0 = Unquantize(b0, 8, signed);
r1 = Unquantize(r1 & 0xFF, 8, signed);
g1 = Unquantize(g1 & 0xFF, 8, signed);
b1 = Unquantize(b1 & 0xFF, 8, signed);
r2 = Unquantize(r2 & 0xFF, 8, signed);
g2 = Unquantize(g2 & 0xFF, 8, signed);
b2 = Unquantize(b2 & 0xFF, 8, signed);
r3 = Unquantize(r3 & 0xFF, 8, signed);
g3 = Unquantize(g3 & 0xFF, 8, signed);
b3 = Unquantize(b3 & 0xFF, 8, signed);
subsetCount = 2;
break;
case 26:
r0 = (int)(low >> 5) & 0xFF;
g0 = (int)(low >> 15) & 0xFF;
b0 = (int)(low >> 25) & 0xFF;
if (signed)
{
r0 = SignExtend(r0, 8);
g0 = SignExtend(g0, 8);
b0 = SignExtend(b0, 8);
}
r1 = r0 + SignExtend((int)(low >> 35), 5);
g1 = g0 + SignExtend((int)(low >> 45), 5);
b1 = b0 + SignExtend((int)(low >> 55), 6);
r2 = r0 + SignExtend((int)(high >> 1), 5);
g2 = g0 + SignExtend((int)(((low >> 20) & 0x10) | ((low >> 41) & 0xF)), 5);
b2 = b0 + SignExtend((int)(
((low >> 18) & 0x20) |
((low >> 10) & 0x10) |
((high << 3) & 0x08) |
(low >> 61)), 6);
r3 = r0 + SignExtend((int)(high >> 7), 5);
g3 = g0 + SignExtend((int)(((low >> 36) & 0x10) | ((low >> 51) & 0xF)), 5);
b3 = b0 + SignExtend((int)(
((low >> 28) & 0x20) |
((low >> 30) & 0x10) |
((high >> 9) & 0x08) |
((high >> 4) & 0x04) |
((low >> 12) & 0x02) |
((low >> 50) & 0x01)), 6);
r0 = Unquantize(r0, 8, signed);
g0 = Unquantize(g0, 8, signed);
b0 = Unquantize(b0, 8, signed);
r1 = Unquantize(r1 & 0xFF, 8, signed);
g1 = Unquantize(g1 & 0xFF, 8, signed);
b1 = Unquantize(b1 & 0xFF, 8, signed);
r2 = Unquantize(r2 & 0xFF, 8, signed);
g2 = Unquantize(g2 & 0xFF, 8, signed);
b2 = Unquantize(b2 & 0xFF, 8, signed);
r3 = Unquantize(r3 & 0xFF, 8, signed);
g3 = Unquantize(g3 & 0xFF, 8, signed);
b3 = Unquantize(b3 & 0xFF, 8, signed);
subsetCount = 2;
break;
case 30:
r0 = (int)(low >> 5) & 0x3F;
g0 = (int)(low >> 15) & 0x3F;
b0 = (int)(low >> 25) & 0x3F;
r1 = (int)(low >> 35) & 0x3F;
g1 = (int)(low >> 45) & 0x3F;
b1 = (int)(low >> 55) & 0x3F;
r2 = (int)(high >> 1) & 0x3F;
g2 = (int)(((low >> 16) & 0x20) | ((low >> 20) & 0x10) | ((low >> 41) & 0xF));
b2 = (int)(((low >> 17) & 0x20) | ((low >> 10) & 0x10) | ((high << 3) & 0x08) | (low >> 61));
r3 = (int)(high >> 7) & 0x3F;
g3 = (int)(((low >> 26) & 0x20) | ((low >> 7) & 0x10) | ((low >> 51) & 0xF));
b3 = (int)(
((low >> 28) & 0x20) |
((low >> 30) & 0x10) |
((low >> 29) & 0x08) |
((low >> 21) & 0x04) |
((low >> 12) & 0x03));
if (signed)
{
r0 = SignExtend(r0, 6);
g0 = SignExtend(g0, 6);
b0 = SignExtend(b0, 6);
r1 = SignExtend(r1, 6);
g1 = SignExtend(g1, 6);
b1 = SignExtend(b1, 6);
r2 = SignExtend(r2, 6);
g2 = SignExtend(g2, 6);
b2 = SignExtend(b2, 6);
r3 = SignExtend(r3, 6);
g3 = SignExtend(g3, 6);
b3 = SignExtend(b3, 6);
}
r0 = Unquantize(r0, 6, signed);
g0 = Unquantize(g0, 6, signed);
b0 = Unquantize(b0, 6, signed);
r1 = Unquantize(r1, 6, signed);
g1 = Unquantize(g1, 6, signed);
b1 = Unquantize(b1, 6, signed);
r2 = Unquantize(r2, 6, signed);
g2 = Unquantize(g2, 6, signed);
b2 = Unquantize(b2, 6, signed);
r3 = Unquantize(r3, 6, signed);
g3 = Unquantize(g3, 6, signed);
b3 = Unquantize(b3, 6, signed);
subsetCount = 2;
break;
default:
subsetCount = 0;
break;
}
if (subsetCount > 0)
{
endPoints[0] = new RgbaColor32(r0, g0, b0, HalfOne);
endPoints[1] = new RgbaColor32(r1, g1, b1, HalfOne);
if (subsetCount > 1)
{
endPoints[2] = new RgbaColor32(r2, g2, b2, HalfOne);
endPoints[3] = new RgbaColor32(r3, g3, b3, HalfOne);
}
}
return subsetCount;
}
private static int SignExtend(int value, int bits)
{
int shift = 32 - bits;
return (value << shift) >> shift;
}
private static int Unquantize(int value, int bits, bool signed)
{
if (signed)
{
if (bits >= 16)
{
return value;
}
else
{
bool sign = value < 0;
if (sign)
{
value = -value;
}
if (value == 0)
{
return value;
}
else if (value >= ((1 << (bits - 1)) - 1))
{
value = 0x7FFF;
}
else
{
value = ((value << 15) + 0x4000) >> (bits - 1);
}
if (sign)
{
value = -value;
}
}
}
else
{
if (bits >= 15 || value == 0)
{
return value;
}
else if (value == ((1 << bits) - 1))
{
return 0xFFFF;
}
else
{
return ((value << 16) + 0x8000) >> bits;
}
}
return value;
}
private static ushort FinishUnquantize(int value, bool signed)
{
if (signed)
{
value = value < 0 ? -((-value * 31) >> 5) : (value * 31) >> 5;
int sign = 0;
if (value < 0)
{
sign = 0x8000;
value = -value;
}
return (ushort)(sign | value);
}
else
{
return (ushort)((value * 31) >> 6);
}
}
private static int BitReverse6(int value)
{
value = ((value >> 1) & 0x55) | ((value << 1) & 0xaa);
value = ((value >> 2) & 0x33) | ((value << 2) & 0xcc);
value = ((value >> 4) & 0x0f) | ((value << 4) & 0xf0);
return value >> 2;
}
}
}