diff options
Diffstat (limited to 'Ryujinx.Graphics.Texture/BC6Decoder.cs')
| -rw-r--r-- | Ryujinx.Graphics.Texture/BC6Decoder.cs | 819 |
1 files changed, 819 insertions, 0 deletions
diff --git a/Ryujinx.Graphics.Texture/BC6Decoder.cs b/Ryujinx.Graphics.Texture/BC6Decoder.cs new file mode 100644 index 00000000..819bf022 --- /dev/null +++ b/Ryujinx.Graphics.Texture/BC6Decoder.cs @@ -0,0 +1,819 @@ +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.Slice(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; + } + } +} |