From eac46ad7ceca5e35b396a8b80bfc38dc6ef1a4fe Mon Sep 17 00:00:00 2001 From: GPUCode Date: Tue, 6 Jun 2023 23:10:06 +0300 Subject: video_core: Add BCn decoding support --- externals/bc_decoder/bc_decoder.cpp | 1522 +++++++++++++++++++++++++++++++++++ externals/bc_decoder/bc_decoder.h | 43 + 2 files changed, 1565 insertions(+) create mode 100644 externals/bc_decoder/bc_decoder.cpp create mode 100644 externals/bc_decoder/bc_decoder.h (limited to 'externals/bc_decoder') diff --git a/externals/bc_decoder/bc_decoder.cpp b/externals/bc_decoder/bc_decoder.cpp new file mode 100644 index 000000000..536c44f34 --- /dev/null +++ b/externals/bc_decoder/bc_decoder.cpp @@ -0,0 +1,1522 @@ +// SPDX-License-Identifier: MPL-2.0 +// Copyright © 2022 Skyline Team and Contributors (https://github.com/skyline-emu/) +// Copyright 2019 The SwiftShader Authors. All Rights Reserved. + +// This BCn Decoder is directly derivative of Swiftshader's BCn Decoder found at: https://github.com/google/swiftshader/blob/d070309f7d154d6764cbd514b1a5c8bfcef61d06/src/Device/BC_Decoder.cpp +// This file does not follow the Skyline code conventions but has certain Skyline specific code +// There are a lot of implicit and narrowing conversions in this file due to this (Warnings are disabled as a result) + +#include +#include +#include +#include + +namespace { + constexpr int BlockWidth = 4; + constexpr int BlockHeight = 4; + + struct BC_color { + void decode(uint8_t *dst, size_t x, size_t y, size_t dstW, size_t dstH, size_t dstPitch, size_t dstBpp, bool hasAlphaChannel, bool hasSeparateAlpha) const { + Color c[4]; + c[0].extract565(c0); + c[1].extract565(c1); + if (hasSeparateAlpha || (c0 > c1)) { + c[2] = ((c[0] * 2) + c[1]) / 3; + c[3] = ((c[1] * 2) + c[0]) / 3; + } else { + c[2] = (c[0] + c[1]) >> 1; + if (hasAlphaChannel) { + c[3].clearAlpha(); + } + } + + for (int j = 0; j < BlockHeight && (y + j) < dstH; j++) { + size_t dstOffset = j * dstPitch; + size_t idxOffset = j * BlockHeight; + for (size_t i = 0; i < BlockWidth && (x + i) < dstW; i++, idxOffset++, dstOffset += dstBpp) { + *reinterpret_cast(dst + dstOffset) = c[getIdx(idxOffset)].pack8888(); + } + } + } + + private: + struct Color { + Color() { + c[0] = c[1] = c[2] = 0; + c[3] = 0xFF000000; + } + + void extract565(const unsigned int c565) { + c[0] = ((c565 & 0x0000001F) << 3) | ((c565 & 0x0000001C) >> 2); + c[1] = ((c565 & 0x000007E0) >> 3) | ((c565 & 0x00000600) >> 9); + c[2] = ((c565 & 0x0000F800) >> 8) | ((c565 & 0x0000E000) >> 13); + } + + unsigned int pack8888() const { + return ((c[0] & 0xFF) << 16) | ((c[1] & 0xFF) << 8) | (c[2] & 0xFF) | c[3]; + } + + void clearAlpha() { + c[3] = 0; + } + + Color operator*(int factor) const { + Color res; + for (int i = 0; i < 4; ++i) { + res.c[i] = c[i] * factor; + } + return res; + } + + Color operator/(int factor) const { + Color res; + for (int i = 0; i < 4; ++i) { + res.c[i] = c[i] / factor; + } + return res; + } + + Color operator>>(int shift) const { + Color res; + for (int i = 0; i < 4; ++i) { + res.c[i] = c[i] >> shift; + } + return res; + } + + Color operator+(Color const &obj) const { + Color res; + for (int i = 0; i < 4; ++i) { + res.c[i] = c[i] + obj.c[i]; + } + return res; + } + + private: + int c[4]; + }; + + size_t getIdx(int i) const { + size_t offset = i << 1; // 2 bytes per index + return (idx & (0x3 << offset)) >> offset; + } + + unsigned short c0; + unsigned short c1; + unsigned int idx; + }; + static_assert(sizeof(BC_color) == 8, "BC_color must be 8 bytes"); + + struct BC_channel { + void decode(uint8_t *dst, size_t x, size_t y, size_t dstW, size_t dstH, size_t dstPitch, size_t dstBpp, size_t channel, bool isSigned) const { + int c[8] = {0}; + + if (isSigned) { + c[0] = static_cast(data & 0xFF); + c[1] = static_cast((data & 0xFF00) >> 8); + } else { + c[0] = static_cast(data & 0xFF); + c[1] = static_cast((data & 0xFF00) >> 8); + } + + if (c[0] > c[1]) { + for (int i = 2; i < 8; ++i) { + c[i] = ((8 - i) * c[0] + (i - 1) * c[1]) / 7; + } + } else { + for (int i = 2; i < 6; ++i) { + c[i] = ((6 - i) * c[0] + (i - 1) * c[1]) / 5; + } + c[6] = isSigned ? -128 : 0; + c[7] = isSigned ? 127 : 255; + } + + for (size_t j = 0; j < BlockHeight && (y + j) < dstH; j++) { + for (size_t i = 0; i < BlockWidth && (x + i) < dstW; i++) { + dst[channel + (i * dstBpp) + (j * dstPitch)] = static_cast(c[getIdx((j * BlockHeight) + i)]); + } + } + } + + private: + uint8_t getIdx(int i) const { + int offset = i * 3 + 16; + return static_cast((data & (0x7ull << offset)) >> offset); + } + + uint64_t data; + }; + static_assert(sizeof(BC_channel) == 8, "BC_channel must be 8 bytes"); + + struct BC_alpha { + void decode(uint8_t *dst, size_t x, size_t y, size_t dstW, size_t dstH, size_t dstPitch, size_t dstBpp) const { + dst += 3; // Write only to alpha (channel 3) + for (size_t j = 0; j < BlockHeight && (y + j) < dstH; j++, dst += dstPitch) { + uint8_t *dstRow = dst; + for (size_t i = 0; i < BlockWidth && (x + i) < dstW; i++, dstRow += dstBpp) { + *dstRow = getAlpha(j * BlockHeight + i); + } + } + } + + private: + uint8_t getAlpha(int i) const { + int offset = i << 2; + int alpha = (data & (0xFull << offset)) >> offset; + return static_cast(alpha | (alpha << 4)); + } + + uint64_t data; + }; + static_assert(sizeof(BC_alpha) == 8, "BC_alpha must be 8 bytes"); + + namespace BC6H { + static constexpr int MaxPartitions = 64; + + // @fmt:off + + static constexpr uint8_t PartitionTable2[MaxPartitions][16] = { + { 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1 }, + { 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1 }, + { 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1 }, + { 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1 }, + { 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1 }, + { 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1 }, + { 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1 }, + { 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1 }, + { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1 }, + { 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 }, + { 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1 }, + { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1 }, + { 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 }, + { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1 }, + { 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 }, + { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1 }, + { 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1, 1 }, + { 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0 }, + { 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0 }, + { 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0 }, + { 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0 }, + { 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0 }, + { 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0 }, + { 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1 }, + { 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0 }, + { 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0 }, + { 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0 }, + { 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0 }, + { 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0 }, + { 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0 }, + { 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0 }, + { 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0 }, + { 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1 }, + { 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1 }, + { 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0 }, + { 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0 }, + { 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0 }, + { 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0 }, + { 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1 }, + { 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1 }, + { 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0 }, + { 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0 }, + { 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0 }, + { 0, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 0, 0 }, + { 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0 }, + { 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1 }, + { 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1 }, + { 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0 }, + { 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0 }, + { 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0 }, + { 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0 }, + { 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0 }, + { 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1 }, + { 0, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1 }, + { 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0 }, + { 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0 }, + { 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1 }, + { 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1 }, + { 0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1 }, + { 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1 }, + { 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1 }, + { 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0 }, + { 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0 }, + { 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1 }, + }; + + static constexpr uint8_t AnchorTable2[MaxPartitions] = { + 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, + 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, + 0xf, 0x2, 0x8, 0x2, 0x2, 0x8, 0x8, 0xf, + 0x2, 0x8, 0x2, 0x2, 0x8, 0x8, 0x2, 0x2, + 0xf, 0xf, 0x6, 0x8, 0x2, 0x8, 0xf, 0xf, + 0x2, 0x8, 0x2, 0x2, 0x2, 0xf, 0xf, 0x6, + 0x6, 0x2, 0x6, 0x8, 0xf, 0xf, 0x2, 0x2, + 0xf, 0xf, 0xf, 0xf, 0xf, 0x2, 0x2, 0xf, + }; + + // @fmt:on + + // 1.0f in half-precision floating point format + static constexpr uint16_t halfFloat1 = 0x3C00; + union Color { + struct RGBA { + uint16_t r = 0; + uint16_t g = 0; + uint16_t b = 0; + uint16_t a = halfFloat1; + + RGBA(uint16_t r, uint16_t g, uint16_t b) + : r(r), g(g), b(b) { + } + + RGBA &operator=(const RGBA &other) { + this->r = other.r; + this->g = other.g; + this->b = other.b; + this->a = halfFloat1; + + return *this; + } + }; + + Color(uint16_t r, uint16_t g, uint16_t b) + : rgba(r, g, b) { + } + + Color(int r, int g, int b) + : rgba((uint16_t) r, (uint16_t) g, (uint16_t) b) { + } + + Color() {} + + Color(const Color &other) { + this->rgba = other.rgba; + } + + Color &operator=(const Color &other) { + this->rgba = other.rgba; + + return *this; + } + + RGBA rgba; + uint16_t channel[4]; + }; + static_assert(sizeof(Color) == 8, "BC6h::Color must be 8 bytes long"); + + inline int32_t extendSign(int32_t val, size_t size) { + // Suppose we have a 2-bit integer being stored in 4 bit variable: + // x = 0b00AB + // + // In order to sign extend x, we need to turn the 0s into A's: + // x_extend = 0bAAAB + // + // We can do that by flipping A in x then subtracting 0b0010 from x. + // Suppose A is 1: + // x = 0b001B + // x_flip = 0b000B + // x_minus = 0b111B + // Since A is flipped to 0, subtracting the mask sets it and all the bits above it to 1. + // And if A is 0: + // x = 0b000B + // x_flip = 0b001B + // x_minus = 0b000B + // We unset the bit we flipped, and touch no other bit + uint16_t mask = 1u << (size - 1); + return (val ^ mask) - mask; + } + + static int constexpr RGBfChannels = 3; + struct RGBf { + uint16_t channel[RGBfChannels]; + size_t size[RGBfChannels]; + bool isSigned; + + RGBf() { + static_assert(RGBfChannels == 3, "RGBf must have exactly 3 channels"); + static_assert(sizeof(channel) / sizeof(channel[0]) == RGBfChannels, "RGBf must have exactly 3 channels"); + static_assert(sizeof(channel) / sizeof(channel[0]) == sizeof(size) / sizeof(size[0]), "RGBf requires equally sized arrays for channels and channel sizes"); + + for (int i = 0; i < RGBfChannels; i++) { + channel[i] = 0; + size[i] = 0; + } + + isSigned = false; + } + + void extendSign() { + for (int i = 0; i < RGBfChannels; i++) { + channel[i] = BC6H::extendSign(channel[i], size[i]); + } + } + + // Assuming this is the delta, take the base-endpoint and transform this into + // a proper endpoint. + // + // The final computed endpoint is truncated to the base-endpoint's size; + void resolveDelta(RGBf base) { + for (int i = 0; i < RGBfChannels; i++) { + size[i] = base.size[i]; + channel[i] = (base.channel[i] + channel[i]) & ((1 << base.size[i]) - 1); + } + + // Per the spec: + // "For signed formats, the results of the delta calculation must be sign + // extended as well." + if (isSigned) { + extendSign(); + } + } + + void unquantize() { + if (isSigned) { + unquantizeSigned(); + } else { + unquantizeUnsigned(); + } + } + + void unquantizeUnsigned() { + for (int i = 0; i < RGBfChannels; i++) { + if (size[i] >= 15 || channel[i] == 0) { + continue; + } else if (channel[i] == ((1u << size[i]) - 1)) { + channel[i] = 0xFFFFu; + } else { + // Need 32 bits to avoid overflow + uint32_t tmp = channel[i]; + channel[i] = (uint16_t) (((tmp << 16) + 0x8000) >> size[i]); + } + size[i] = 16; + } + } + + void unquantizeSigned() { + for (int i = 0; i < RGBfChannels; i++) { + if (size[i] >= 16 || channel[i] == 0) { + continue; + } + + int16_t value = (int16_t)channel[i]; + int32_t result = value; + bool signBit = value < 0; + if (signBit) { + value = -value; + } + + if (value >= ((1 << (size[i] - 1)) - 1)) { + result = 0x7FFF; + } else { + // Need 32 bits to avoid overflow + int32_t tmp = value; + result = (((tmp << 15) + 0x4000) >> (size[i] - 1)); + } + + if (signBit) { + result = -result; + } + + channel[i] = (uint16_t) result; + size[i] = 16; + } + } + }; + + struct Data { + uint64_t low64; + uint64_t high64; + + Data() = default; + + Data(uint64_t low64, uint64_t high64) + : low64(low64), high64(high64) { + } + + // Consumes the lowest N bits from from low64 and high64 where N is: + // abs(MSB - LSB) + // MSB and LSB come from the block description of the BC6h spec and specify + // the location of the bits in the returned bitstring. + // + // If MSB < LSB, then the bits are reversed. Otherwise, the bitstring is read and + // shifted without further modification. + // + uint32_t consumeBits(uint32_t MSB, uint32_t LSB) { + bool reversed = MSB < LSB; + if (reversed) { + std::swap(MSB, LSB); + } + assert(MSB - LSB + 1 < sizeof(uint32_t) * 8); + + uint32_t numBits = MSB - LSB + 1; + uint32_t mask = (1 << numBits) - 1; + // Read the low N bits + uint32_t bits = (low64 & mask); + + low64 >>= numBits; + // Put the low N bits of high64 into the high 64-N bits of low64 + low64 |= (high64 & mask) << (sizeof(high64) * 8 - numBits); + high64 >>= numBits; + + if (reversed) { + uint32_t tmp = 0; + for (uint32_t numSwaps = 0; numSwaps < numBits; numSwaps++) { + tmp <<= 1; + tmp |= (bits & 1); + bits >>= 1; + } + + bits = tmp; + } + + return bits << LSB; + } + }; + + struct IndexInfo { + uint64_t value; + int numBits; + }; + +// Interpolates between two endpoints, then does a final unquantization step + Color interpolate(RGBf e0, RGBf e1, const IndexInfo &index, bool isSigned) { + static constexpr uint32_t weights3[] = {0, 9, 18, 27, 37, 46, 55, 64}; + static constexpr uint32_t weights4[] = {0, 4, 9, 13, 17, 21, 26, 30, + 34, 38, 43, 47, 51, 55, 60, 64}; + static constexpr uint32_t const *weightsN[] = { + nullptr, nullptr, nullptr, weights3, weights4 + }; + auto weights = weightsN[index.numBits]; + assert(weights != nullptr); + Color color; + uint32_t e0Weight = 64 - weights[index.value]; + uint32_t e1Weight = weights[index.value]; + + for (int i = 0; i < RGBfChannels; i++) { + int32_t e0Channel = e0.channel[i]; + int32_t e1Channel = e1.channel[i]; + + if (isSigned) { + e0Channel = extendSign(e0Channel, 16); + e1Channel = extendSign(e1Channel, 16); + } + + int32_t e0Value = e0Channel * e0Weight; + int32_t e1Value = e1Channel * e1Weight; + + uint32_t tmp = ((e0Value + e1Value + 32) >> 6); + + // Need to unquantize value to limit it to the legal range of half-precision + // floats. We do this by scaling by 31/32 or 31/64 depending on if the value + // is signed or unsigned. + if (isSigned) { + tmp = ((tmp & 0x80000000) != 0) ? (((~tmp + 1) * 31) >> 5) | 0x8000 : (tmp * 31) >> 5; + // Don't return -0.0f, just normalize it to 0.0f. + if (tmp == 0x8000) + tmp = 0; + } else { + tmp = (tmp * 31) >> 6; + } + + color.channel[i] = (uint16_t) tmp; + } + + return color; + } + + enum DataType { + // Endpoints + EP0 = 0, + EP1 = 1, + EP2 = 2, + EP3 = 3, + Mode, + Partition, + End, + }; + + enum Channel { + R = 0, + G = 1, + B = 2, + None, + }; + + struct DeltaBits { + size_t channel[3]; + + constexpr DeltaBits() + : channel{0, 0, 0} { + } + + constexpr DeltaBits(size_t r, size_t g, size_t b) + : channel{r, g, b} { + } + }; + + struct ModeDesc { + int number; + bool hasDelta; + int partitionCount; + int endpointBits; + DeltaBits deltaBits; + + constexpr ModeDesc() + : number(-1), hasDelta(false), partitionCount(0), endpointBits(0) { + } + + constexpr ModeDesc(int number, bool hasDelta, int partitionCount, int endpointBits, DeltaBits deltaBits) + : number(number), hasDelta(hasDelta), partitionCount(partitionCount), endpointBits(endpointBits), deltaBits(deltaBits) { + } + }; + + struct BlockDesc { + DataType type; + Channel channel; + int MSB; + int LSB; + ModeDesc modeDesc; + + constexpr BlockDesc() + : type(End), channel(None), MSB(0), LSB(0), modeDesc() { + } + + constexpr BlockDesc(const DataType type, Channel channel, int MSB, int LSB, ModeDesc modeDesc) + : type(type), channel(channel), MSB(MSB), LSB(LSB), modeDesc(modeDesc) { + } + + constexpr BlockDesc(DataType type, Channel channel, int MSB, int LSB) + : type(type), channel(channel), MSB(MSB), LSB(LSB), modeDesc() { + } + }; + +// Turns a legal mode into an index into the BlockDesc table. +// Illegal or reserved modes return -1. + static int modeToIndex(uint8_t mode) { + if (mode <= 3) { + return mode; + } else if ((mode & 0x2) != 0) { + if (mode <= 18) { +// Turns 6 into 4, 7 into 5, 10 into 6, etc. + return (mode / 2) + 1 + (mode & 0x1); + } else if (mode == 22 || mode == 26 || mode == 30) { +// Turns 22 into 11, 26 into 12, etc. + return mode / 4 + 6; + } + } + + return -1; + } + +// Returns a description of the bitfields for each mode from the LSB +// to the MSB before the index data starts. +// +// The numbers come from the BC6h block description. Each BlockDesc in the +// {Type, Channel, MSB, LSB} +// * Type describes which endpoint this is, or if this is a mode, a partition +// number, or the end of the block description. +// * Channel describes one of the 3 color channels within an endpoint +// * MSB and LSB specificy: +// * The size of the bitfield being read +// * The position of the bitfield within the variable it is being read to +// * If the bitfield is stored in reverse bit order +// If MSB < LSB then the bitfield is stored in reverse order. The size of +// the bitfield is abs(MSB-LSB+1). And the position of the bitfield within +// the variable is min(LSB, MSB). +// +// Invalid or reserved modes return an empty list. + static constexpr int NumBlocks = 14; +// The largest number of descriptions within a block. + static constexpr int MaxBlockDescIndex = 26; + static constexpr BlockDesc blockDescs[NumBlocks][MaxBlockDescIndex] = { +// @fmt:off +// Mode 0, Index 0 +{ +{ Mode, None, 1, 0, { 0, true, 2, 10, { 5, 5, 5 } } }, +{ EP2, G, 4, 4 }, { EP2, B, 4, 4 }, { EP3, B, 4, 4 }, +{ EP0, R, 9, 0 }, { EP0, G, 9, 0 }, { EP0, B, 9, 0 }, +{ EP1, R, 4, 0 }, { EP3, G, 4, 4 }, { EP2, G, 3, 0 }, +{ EP1, G, 4, 0 }, { EP3, B, 0, 0 }, { EP3, G, 3, 0 }, +{ EP1, B, 4, 0 }, { EP3, B, 1, 1 }, { EP2, B, 3, 0 }, +{ EP2, R, 4, 0 }, { EP3, B, 2, 2 }, { EP3, R, 4, 0 }, +{ EP3, B, 3, 3 }, +{ Partition, None, 4, 0 }, +{ End, None, 0, 0}, +}, +// Mode 1, Index 1 +{ +{ Mode, None, 1, 0, { 1, true, 2, 7, { 6, 6, 6 } } }, +{ EP2, G, 5, 5 }, { EP3, G, 5, 4 }, { EP0, R, 6, 0 }, +{ EP3, B, 1, 0 }, { EP2, B, 4, 4 }, { EP0, G, 6, 0 }, +{ EP2, B, 5, 5 }, { EP3, B, 2, 2 }, { EP2, G, 4, 4 }, +{ EP0, B, 6, 0 }, { EP3, B, 3, 3 }, { EP3, B, 5, 5 }, +{ EP3, B, 4, 4 }, { EP1, R, 5, 0 }, { EP2, G, 3, 0 }, +{ EP1, G, 5, 0 }, { EP3, G, 3, 0 }, { EP1, B, 5, 0 }, +{ EP2, B, 3, 0 }, { EP2, R, 5, 0 }, { EP3, R, 5, 0 }, +{ Partition, None, 4, 0 }, +{ End, None, 0, 0}, +}, +// Mode 2, Index 2 +{ +{ Mode, None, 4, 0, { 2, true, 2, 11, { 5, 4, 4 } } }, +{ EP0, R, 9, 0 }, { EP0, G, 9, 0 }, { EP0, B, 9, 0 }, +{ EP1, R, 4, 0 }, { EP0, R, 10, 10 }, { EP2, G, 3, 0 }, +{ EP1, G, 3, 0 }, { EP0, G, 10, 10 }, { EP3, B, 0, 0 }, +{ EP3, G, 3, 0 }, { EP1, B, 3, 0 }, { EP0, B, 10, 10 }, +{ EP3, B, 1, 1 }, { EP2, B, 3, 0 }, { EP2, R, 4, 0 }, +{ EP3, B, 2, 2 }, { EP3, R, 4, 0 }, { EP3, B, 3, 3 }, +{ Partition, None, 4, 0 }, +{ End, None, 0, 0}, +}, +// Mode 3, Index 3 +{ +{ Mode, None, 4, 0, { 3, false, 1, 10, { 0, 0, 0 } } }, +{ EP0, R, 9, 0 }, { EP0, G, 9, 0 }, { EP0, B, 9, 0 }, +{ EP1, R, 9, 0 }, { EP1, G, 9, 0 }, { EP1, B, 9, 0 }, +{ End, None, 0, 0}, +}, +// Mode 6, Index 4 +{ +{ Mode, None, 4, 0, { 6, true, 2, 11, { 4, 5, 4 } } }, // 1 1 +{ EP0, R, 9, 0 }, { EP0, G, 9, 0 }, { EP0, B, 9, 0 }, +{ EP1, R, 3, 0 }, { EP0, R, 10, 10 }, { EP3, G, 4, 4 }, +{ EP2, G, 3, 0 }, { EP1, G, 4, 0 }, { EP0, G, 10, 10 }, +{ EP3, G, 3, 0 }, { EP1, B, 3, 0 }, { EP0, B, 10, 10 }, +{ EP3, B, 1, 1 }, { EP2, B, 3, 0 }, { EP2, R, 3, 0 }, +{ EP3, B, 0, 0 }, { EP3, B, 2, 2 }, { EP3, R, 3, 0 }, // 18 19 +{ EP2, G, 4, 4 }, { EP3, B, 3, 3 }, // 2 21 +{ Partition, None, 4, 0 }, +{ End, None, 0, 0}, +}, +// Mode 7, Index 5 +{ +{ Mode, None, 4, 0, { 7, true, 1, 11, { 9, 9, 9 } } }, +{ EP0, R, 9, 0 }, { EP0, G, 9, 0 }, { EP0, B, 9, 0 }, +{ EP1, R, 8, 0 }, { EP0, R, 10, 10 }, { EP1, G, 8, 0 }, +{ EP0, G, 10, 10 }, { EP1, B, 8, 0 }, { EP0, B, 10, 10 }, +{ End, None, 0, 0}, +}, +// Mode 10, Index 6 +{ +{ Mode, None, 4, 0, { 10, true, 2, 11, { 4, 4, 5 } } }, +{ EP0, R, 9, 0 }, { EP0, G, 9, 0 }, { EP0, B, 9, 0 }, +{ EP1, R, 3, 0 }, { EP0, R, 10, 10 }, { EP2, B, 4, 4 }, +{ EP2, G, 3, 0 }, { EP1, G, 3, 0 }, { EP0, G, 10, 10 }, +{ EP3, B, 0, 0 }, { EP3, G, 3, 0 }, { EP1, B, 4, 0 }, +{ EP0, B, 10, 10 }, { EP2, B, 3, 0 }, { EP2, R, 3, 0 }, +{ EP3, B, 1, 1 }, { EP3, B, 2, 2 }, { EP3, R, 3, 0 }, +{ EP3, B, 4, 4 }, { EP3, B, 3, 3 }, +{ Partition, None, 4, 0 }, +{ End, None, 0, 0}, +}, +// Mode 11, Index 7 +{ +{ Mode, None, 4, 0, { 11, true, 1, 12, { 8, 8, 8 } } }, +{ EP0, R, 9, 0 }, { EP0, G, 9, 0 }, { EP0, B, 9, 0 }, +{ EP1, R, 7, 0 }, { EP0, R, 10, 11 }, { EP1, G, 7, 0 }, +{ EP0, G, 10, 11 }, { EP1, B, 7, 0 }, { EP0, B, 10, 11 }, +{ End, None, 0, 0}, +}, +// Mode 14, Index 8 +{ +{ Mode, None, 4, 0, { 14, true, 2, 9, { 5, 5, 5 } } }, +{ EP0, R, 8, 0 }, { EP2, B, 4, 4 }, { EP0, G, 8, 0 }, +{ EP2, G, 4, 4 }, { EP0, B, 8, 0 }, { EP3, B, 4, 4 }, +{ EP1, R, 4, 0 }, { EP3, G, 4, 4 }, { EP2, G, 3, 0 }, +{ EP1, G, 4, 0 }, { EP3, B, 0, 0 }, { EP3, G, 3, 0 }, +{ EP1, B, 4, 0 }, { EP3, B, 1, 1 }, { EP2, B, 3, 0 }, +{ EP2, R, 4, 0 }, { EP3, B, 2, 2 }, { EP3, R, 4, 0 }, +{ EP3, B, 3, 3 }, +{ Partition, None, 4, 0 }, +{ End, None, 0, 0}, +}, +// Mode 15, Index 9 +{ +{ Mode, None, 4, 0, { 15, true, 1, 16, { 4, 4, 4 } } }, +{ EP0, R, 9, 0 }, { EP0, G, 9, 0 }, { EP0, B, 9, 0 }, +{ EP1, R, 3, 0 }, { EP0, R, 10, 15 }, { EP1, G, 3, 0 }, +{ EP0, G, 10, 15 }, { EP1, B, 3, 0 }, { EP0, B, 10, 15 }, +{ End, None, 0, 0}, +}, +// Mode 18, Index 10 +{ +{ Mode, None, 4, 0, { 18, true, 2, 8, { 6, 5, 5 } } }, +{ EP0, R, 7, 0 }, { EP3, G, 4, 4 }, { EP2, B, 4, 4 }, +{ EP0, G, 7, 0 }, { EP3, B, 2, 2 }, { EP2, G, 4, 4 }, +{ EP0, B, 7, 0 }, { EP3, B, 3, 3 }, { EP3, B, 4, 4 }, +{ EP1, R, 5, 0 }, { EP2, G, 3, 0 }, { EP1, G, 4, 0 }, +{ EP3, B, 0, 0 }, { EP3, G, 3, 0 }, { EP1, B, 4, 0 }, +{ EP3, B, 1, 1 }, { EP2, B, 3, 0 }, { EP2, R, 5, 0 }, +{ EP3, R, 5, 0 }, +{ Partition, None, 4, 0 }, +{ End, None, 0, 0}, +}, +// Mode 22, Index 11 +{ +{ Mode, None, 4, 0, { 22, true, 2, 8, { 5, 6, 5 } } }, +{ EP0, R, 7, 0 }, { EP3, B, 0, 0 }, { EP2, B, 4, 4 }, +{ EP0, G, 7, 0 }, { EP2, G, 5, 5 }, { EP2, G, 4, 4 }, +{ EP0, B, 7, 0 }, { EP3, G, 5, 5 }, { EP3, B, 4, 4 }, +{ EP1, R, 4, 0 }, { EP3, G, 4, 4 }, { EP2, G, 3, 0 }, +{ EP1, G, 5, 0 }, { EP3, G, 3, 0 }, { EP1, B, 4, 0 }, +{ EP3, B, 1, 1 }, { EP2, B, 3, 0 }, { EP2, R, 4, 0 }, +{ EP3, B, 2, 2 }, { EP3, R, 4, 0 }, { EP3, B, 3, 3 }, +{ Partition, None, 4, 0 }, +{ End, None, 0, 0}, +}, +// Mode 26, Index 12 +{ +{ Mode, None, 4, 0, { 26, true, 2, 8, { 5, 5, 6 } } }, +{ EP0, R, 7, 0 }, { EP3, B, 1, 1 }, { EP2, B, 4, 4 }, +{ EP0, G, 7, 0 }, { EP2, B, 5, 5 }, { EP2, G, 4, 4 }, +{ EP0, B, 7, 0 }, { EP3, B, 5, 5 }, { EP3, B, 4, 4 }, +{ EP1, R, 4, 0 }, { EP3, G, 4, 4 }, { EP2, G, 3, 0 }, +{ EP1, G, 4, 0 }, { EP3, B, 0, 0 }, { EP3, G, 3, 0 }, +{ EP1, B, 5, 0 }, { EP2, B, 3, 0 }, { EP2, R, 4, 0 }, +{ EP3, B, 2, 2 }, { EP3, R, 4, 0 }, { EP3, B, 3, 3 }, +{ Partition, None, 4, 0 }, +{ End, None, 0, 0}, +}, +// Mode 30, Index 13 +{ +{ Mode, None, 4, 0, { 30, false, 2, 6, { 0, 0, 0 } } }, +{ EP0, R, 5, 0 }, { EP3, G, 4, 4 }, { EP3, B, 0, 0 }, +{ EP3, B, 1, 1 }, { EP2, B, 4, 4 }, { EP0, G, 5, 0 }, +{ EP2, G, 5, 5 }, { EP2, B, 5, 5 }, { EP3, B, 2, 2 }, +{ EP2, G, 4, 4 }, { EP0, B, 5, 0 }, { EP3, G, 5, 5 }, +{ EP3, B, 3, 3 }, { EP3, B, 5, 5 }, { EP3, B, 4, 4 }, +{ EP1, R, 5, 0 }, { EP2, G, 3, 0 }, { EP1, G, 5, 0 }, +{ EP3, G, 3, 0 }, { EP1, B, 5, 0 }, { EP2, B, 3, 0 }, +{ EP2, R, 5, 0 }, { EP3, R, 5, 0 }, +{ Partition, None, 4, 0 }, +{ End, None, 0, 0}, +} +// @fmt:on + }; + + struct Block { + uint64_t low64; + uint64_t high64; + + void decode(uint8_t *dst, size_t dstX, size_t dstY, size_t dstWidth, size_t dstHeight, size_t dstPitch, size_t dstBpp, bool isSigned) const { + uint8_t mode = 0; + Data data(low64, high64); + assert(dstBpp == sizeof(Color)); + + if ((data.low64 & 0x2) == 0) { + mode = data.consumeBits(1, 0); + } else { + mode = data.consumeBits(4, 0); + } + + int blockIndex = modeToIndex(mode); + // Handle illegal or reserved mode + if (blockIndex == -1) { + for (int y = 0; y < 4 && y + dstY < dstHeight; y++) { + for (int x = 0; x < 4 && x + dstX < dstWidth; x++) { + auto out = reinterpret_cast(dst + sizeof(Color) * x + dstPitch * y); + out->rgba = {0, 0, 0}; + } + } + return; + } + const BlockDesc *blockDesc = blockDescs[blockIndex]; + + RGBf e[4]; + e[0].isSigned = e[1].isSigned = e[2].isSigned = e[3].isSigned = isSigned; + + int partition = 0; + ModeDesc modeDesc; + for (int index = 0; blockDesc[index].type != End; index++) { + const BlockDesc desc = blockDesc[index]; + + switch (desc.type) { + case Mode: + modeDesc = desc.modeDesc; + assert(modeDesc.number == mode); + + e[0].size[0] = e[0].size[1] = e[0].size[2] = modeDesc.endpointBits; + for (int i = 0; i < RGBfChannels; i++) { + if (modeDesc.hasDelta) { + e[1].size[i] = e[2].size[i] = e[3].size[i] = modeDesc.deltaBits.channel[i]; + } else { + e[1].size[i] = e[2].size[i] = e[3].size[i] = modeDesc.endpointBits; + } + } + break; + case Partition: + partition |= data.consumeBits(desc.MSB, desc.LSB); + break; + case EP0: + case EP1: + case EP2: + case EP3: + e[desc.type].channel[desc.channel] |= data.consumeBits(desc.MSB, desc.LSB); + break; + default: + assert(false); + return; + } + } + + // Sign extension + if (isSigned) { + for (int ep = 0; ep < modeDesc.partitionCount * 2; ep++) { + e[ep].extendSign(); + } + } else if (modeDesc.hasDelta) { + // Don't sign-extend the base endpoint in an unsigned format. + for (int ep = 1; ep < modeDesc.partitionCount * 2; ep++) { + e[ep].extendSign(); + } + } + + // Turn the deltas into endpoints + if (modeDesc.hasDelta) { + for (int ep = 1; ep < modeDesc.partitionCount * 2; ep++) { + e[ep].resolveDelta(e[0]); + } + } + + for (int ep = 0; ep < modeDesc.partitionCount * 2; ep++) { + e[ep].unquantize(); + } + + // Get the indices, calculate final colors, and output + for (int y = 0; y < 4; y++) { + for (int x = 0; x < 4; x++) { + int pixelNum = x + y * 4; + IndexInfo idx; + bool isAnchor = false; + int firstEndpoint = 0; + // Bc6H can have either 1 or 2 petitions depending on the mode. + // The number of petitions affects the number of indices with implicit + // leading 0 bits and the number of bits per index. + if (modeDesc.partitionCount == 1) { + idx.numBits = 4; + // There's an implicit leading 0 bit for the first idx + isAnchor = (pixelNum == 0); + } else { + idx.numBits = 3; + // There are 2 indices with implicit leading 0-bits. + isAnchor = ((pixelNum == 0) || (pixelNum == AnchorTable2[partition])); + firstEndpoint = PartitionTable2[partition][pixelNum] * 2; + } + + idx.value = data.consumeBits(idx.numBits - isAnchor - 1, 0); + + // Don't exit the loop early, we need to consume these index bits regardless if + // we actually output them or not. + if ((y + dstY >= dstHeight) || (x + dstX >= dstWidth)) { + continue; + } + + Color color = interpolate(e[firstEndpoint], e[firstEndpoint + 1], idx, isSigned); + auto out = reinterpret_cast(dst + dstBpp * x + dstPitch * y); + *out = color; + } + } + } + }; + + } // namespace BC6H + + namespace BC7 { +// https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_texture_compression_bptc.txt +// https://docs.microsoft.com/en-us/windows/win32/direct3d11/bc7-format + + struct Bitfield { + int offset; + int count; + + constexpr Bitfield Then(const int bits) { return {offset + count, bits}; } + + constexpr bool operator==(const Bitfield &rhs) { + return offset == rhs.offset && count == rhs.count; + } + }; + + struct Mode { + const int IDX; // Mode index + const int NS; // Number of subsets in each partition + const int PB; // Partition bits + const int RB; // Rotation bits + const int ISB; // Index selection bits + const int CB; // Color bits + const int AB; // Alpha bits + const int EPB; // Endpoint P-bits + const int SPB; // Shared P-bits + const int IB; // Primary index bits per element + const int IBC; // Primary index bits total + const int IB2; // Secondary index bits per element + + constexpr int NumColors() const { return NS * 2; } + + constexpr Bitfield Partition() const { return {IDX + 1, PB}; } + + constexpr Bitfield Rotation() const { return Partition().Then(RB); } + + constexpr Bitfield IndexSelection() const { return Rotation().Then(ISB); } + + constexpr Bitfield Red(int idx) const { + return IndexSelection().Then(CB * idx).Then(CB); + } + + constexpr Bitfield Green(int idx) const { + return Red(NumColors() - 1).Then(CB * idx).Then(CB); + } + + constexpr Bitfield Blue(int idx) const { + return Green(NumColors() - 1).Then(CB * idx).Then(CB); + } + + constexpr Bitfield Alpha(int idx) const { + return Blue(NumColors() - 1).Then(AB * idx).Then(AB); + } + + constexpr Bitfield EndpointPBit(int idx) const { + return Alpha(NumColors() - 1).Then(EPB * idx).Then(EPB); + } + + constexpr Bitfield SharedPBit0() const { + return EndpointPBit(NumColors() - 1).Then(SPB); + } + + constexpr Bitfield SharedPBit1() const { + return SharedPBit0().Then(SPB); + } + + constexpr Bitfield PrimaryIndex(int offset, int count) const { + return SharedPBit1().Then(offset).Then(count); + } + + constexpr Bitfield SecondaryIndex(int offset, int count) const { + return SharedPBit1().Then(IBC + offset).Then(count); + } + }; + + static constexpr Mode Modes[] = { + // IDX NS PB RB ISB CB AB EPB SPB IB IBC, IB2 + /**/ {0x0, 0x3, 0x4, 0x0, 0x0, 0x4, 0x0, 0x1, 0x0, 0x3, 0x2d, 0x0}, +/**/ {0x1, 0x2, 0x6, 0x0, 0x0, 0x6, 0x0, 0x0, 0x1, 0x3, 0x2e, 0x0}, +/**/ {0x2, 0x3, 0x6, 0x0, 0x0, 0x5, 0x0, 0x0, 0x0, 0x2, 0x1d, 0x0}, +/**/ {0x3, 0x2, 0x6, 0x0, 0x0, 0x7, 0x0, 0x1, 0x0, 0x2, 0x1e, 0x0}, +/**/ {0x4, 0x1, 0x0, 0x2, 0x1, 0x5, 0x6, 0x0, 0x0, 0x2, 0x1f, 0x3}, +/**/ {0x5, 0x1, 0x0, 0x2, 0x0, 0x7, 0x8, 0x0, 0x0, 0x2, 0x1f, 0x2}, +/**/ {0x6, 0x1, 0x0, 0x0, 0x0, 0x7, 0x7, 0x1, 0x0, 0x4, 0x3f, 0x0}, +/**/ {0x7, 0x2, 0x6, 0x0, 0x0, 0x5, 0x5, 0x1, 0x0, 0x2, 0x1e, 0x0}, +/**/ {-1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x00, 0x0}, + }; + + static constexpr int MaxPartitions = 64; + static constexpr int MaxSubsets = 3; + + static constexpr uint8_t PartitionTable2[MaxPartitions][16] = { + {0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1}, + {0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1}, + {0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1}, + {0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1}, + {0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1}, + {0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1}, + {0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1}, + {0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1}, + {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1}, + {0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, + {0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1}, + {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1}, + {0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, + {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1}, + {0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, + {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1}, + {0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1, 1}, + {0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0}, + {0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0}, + {0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0}, + {0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0}, + {0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0}, + {0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0}, + {0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1}, + {0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0}, + {0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0}, + {0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0}, + {0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0}, + {0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0}, + {0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0}, + {0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0}, + {0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0}, + {0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1}, + {0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1}, + {0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0}, + {0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0}, + {0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0}, + {0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0}, + {0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1}, + {0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1}, + {0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0}, + {0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0}, + {0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0}, + {0, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 0, 0}, + {0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0}, + {0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1}, + {0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1}, + {0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0}, + {0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0}, + {0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0}, + {0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0}, + {0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0}, + {0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1}, + {0, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1}, + {0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0}, + {0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0}, + {0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1}, + {0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1}, + {0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1}, + {0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1}, + {0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1}, + {0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0}, + {0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0}, + {0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1}, + }; + + static constexpr uint8_t PartitionTable3[MaxPartitions][16] = { + {0, 0, 1, 1, 0, 0, 1, 1, 0, 2, 2, 1, 2, 2, 2, 2}, + {0, 0, 0, 1, 0, 0, 1, 1, 2, 2, 1, 1, 2, 2, 2, 1}, + {0, 0, 0, 0, 2, 0, 0, 1, 2, 2, 1, 1, 2, 2, 1, 1}, + {0, 2, 2, 2, 0, 0, 2, 2, 0, 0, 1, 1, 0, 1, 1, 1}, + {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 1, 1, 2, 2}, + {0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 2, 2, 0, 0, 2, 2}, + {0, 0, 2, 2, 0, 0, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1}, + {0, 0, 1, 1, 0, 0, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1}, + {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2}, + {0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2}, + {0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2}, + {0, 0, 1, 2, 0, 0, 1, 2, 0, 0, 1, 2, 0, 0, 1, 2}, + {0, 1, 1, 2, 0, 1, 1, 2, 0, 1, 1, 2, 0, 1, 1, 2}, + {0, 1, 2, 2, 0, 1, 2, 2, 0, 1, 2, 2, 0, 1, 2, 2}, + {0, 0, 1, 1, 0, 1, 1, 2, 1, 1, 2, 2, 1, 2, 2, 2}, + {0, 0, 1, 1, 2, 0, 0, 1, 2, 2, 0, 0, 2, 2, 2, 0}, + {0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 2, 1, 1, 2, 2}, + {0, 1, 1, 1, 0, 0, 1, 1, 2, 0, 0, 1, 2, 2, 0, 0}, + {0, 0, 0, 0, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2}, + {0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 2, 2, 1, 1, 1, 1}, + {0, 1, 1, 1, 0, 1, 1, 1, 0, 2, 2, 2, 0, 2, 2, 2}, + {0, 0, 0, 1, 0, 0, 0, 1, 2, 2, 2, 1, 2, 2, 2, 1}, + {0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 2, 2, 0, 1, 2, 2}, + {0, 0, 0, 0, 1, 1, 0, 0, 2, 2, 1, 0, 2, 2, 1, 0}, + {0, 1, 2, 2, 0, 1, 2, 2, 0, 0, 1, 1, 0, 0, 0, 0}, + {0, 0, 1, 2, 0, 0, 1, 2, 1, 1, 2, 2, 2, 2, 2, 2}, + {0, 1, 1, 0, 1, 2, 2, 1, 1, 2, 2, 1, 0, 1, 1, 0}, + {0, 0, 0, 0, 0, 1, 1, 0, 1, 2, 2, 1, 1, 2, 2, 1}, + {0, 0, 2, 2, 1, 1, 0, 2, 1, 1, 0, 2, 0, 0, 2, 2}, + {0, 1, 1, 0, 0, 1, 1, 0, 2, 0, 0, 2, 2, 2, 2, 2}, + {0, 0, 1, 1, 0, 1, 2, 2, 0, 1, 2, 2, 0, 0, 1, 1}, + {0, 0, 0, 0, 2, 0, 0, 0, 2, 2, 1, 1, 2, 2, 2, 1}, + {0, 0, 0, 0, 0, 0, 0, 2, 1, 1, 2, 2, 1, 2, 2, 2}, + {0, 2, 2, 2, 0, 0, 2, 2, 0, 0, 1, 2, 0, 0, 1, 1}, + {0, 0, 1, 1, 0, 0, 1, 2, 0, 0, 2, 2, 0, 2, 2, 2}, + {0, 1, 2, 0, 0, 1, 2, 0, 0, 1, 2, 0, 0, 1, 2, 0}, + {0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 0, 0, 0, 0}, + {0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0}, + {0, 1, 2, 0, 2, 0, 1, 2, 1, 2, 0, 1, 0, 1, 2, 0}, + {0, 0, 1, 1, 2, 2, 0, 0, 1, 1, 2, 2, 0, 0, 1, 1}, + {0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 0, 0, 0, 0, 1, 1}, + {0, 1, 0, 1, 0, 1, 0, 1, 2, 2, 2, 2, 2, 2, 2, 2}, + {0, 0, 0, 0, 0, 0, 0, 0, 2, 1, 2, 1, 2, 1, 2, 1}, + {0, 0, 2, 2, 1, 1, 2, 2, 0, 0, 2, 2, 1, 1, 2, 2}, + {0, 0, 2, 2, 0, 0, 1, 1, 0, 0, 2, 2, 0, 0, 1, 1}, + {0, 2, 2, 0, 1, 2, 2, 1, 0, 2, 2, 0, 1, 2, 2, 1}, + {0, 1, 0, 1, 2, 2, 2, 2, 2, 2, 2, 2, 0, 1, 0, 1}, + {0, 0, 0, 0, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1}, + {0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 2, 2, 2, 2}, + {0, 2, 2, 2, 0, 1, 1, 1, 0, 2, 2, 2, 0, 1, 1, 1}, + {0, 0, 0, 2, 1, 1, 1, 2, 0, 0, 0, 2, 1, 1, 1, 2}, + {0, 0, 0, 0, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2}, + {0, 2, 2, 2, 0, 1, 1, 1, 0, 1, 1, 1, 0, 2, 2, 2}, + {0, 0, 0, 2, 1, 1, 1, 2, 1, 1, 1, 2, 0, 0, 0, 2}, + {0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 2, 2, 2, 2}, + {0, 0, 0, 0, 0, 0, 0, 0, 2, 1, 1, 2, 2, 1, 1, 2}, + {0, 1, 1, 0, 0, 1, 1, 0, 2, 2, 2, 2, 2, 2, 2, 2}, + {0, 0, 2, 2, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 2, 2}, + {0, 0, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 0, 0, 2, 2}, + {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 1, 1, 2}, + {0, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 1}, + {0, 2, 2, 2, 1, 2, 2, 2, 0, 2, 2, 2, 1, 2, 2, 2}, + {0, 1, 0, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2}, + {0, 1, 1, 1, 2, 0, 1, 1, 2, 2, 0, 1, 2, 2, 2, 0}, + }; + + static constexpr uint8_t AnchorTable2[MaxPartitions] = { +// @fmt:off +0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, +0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, +0xf, 0x2, 0x8, 0x2, 0x2, 0x8, 0x8, 0xf, +0x2, 0x8, 0x2, 0x2, 0x8, 0x8, 0x2, 0x2, +0xf, 0xf, 0x6, 0x8, 0x2, 0x8, 0xf, 0xf, +0x2, 0x8, 0x2, 0x2, 0x2, 0xf, 0xf, 0x6, +0x6, 0x2, 0x6, 0x8, 0xf, 0xf, 0x2, 0x2, +0xf, 0xf, 0xf, 0xf, 0xf, 0x2, 0x2, 0xf, +// @fmt:on + }; + + static constexpr uint8_t AnchorTable3a[MaxPartitions] = { +// @fmt:off +0x3, 0x3, 0xf, 0xf, 0x8, 0x3, 0xf, 0xf, +0x8, 0x8, 0x6, 0x6, 0x6, 0x5, 0x3, 0x3, +0x3, 0x3, 0x8, 0xf, 0x3, 0x3, 0x6, 0xa, +0x5, 0x8, 0x8, 0x6, 0x8, 0x5, 0xf, 0xf, +0x8, 0xf, 0x3, 0x5, 0x6, 0xa, 0x8, 0xf, +0xf, 0x3, 0xf, 0x5, 0xf, 0xf, 0xf, 0xf, +0x3, 0xf, 0x5, 0x5, 0x5, 0x8, 0x5, 0xa, +0x5, 0xa, 0x8, 0xd, 0xf, 0xc, 0x3, 0x3, +// @fmt:on + }; + + static constexpr uint8_t AnchorTable3b[MaxPartitions] = { +// @fmt:off +0xf, 0x8, 0x8, 0x3, 0xf, 0xf, 0x3, 0x8, +0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, 0x8, +0xf, 0x8, 0xf, 0x3, 0xf, 0x8, 0xf, 0x8, +0x3, 0xf, 0x6, 0xa, 0xf, 0xf, 0xa, 0x8, +0xf, 0x3, 0xf, 0xa, 0xa, 0x8, 0x9, 0xa, +0x6, 0xf, 0x8, 0xf, 0x3, 0x6, 0x6, 0x8, +0xf, 0x3, 0xf, 0xf, 0xf, 0xf, 0xf, 0xf, +0xf, 0xf, 0xf, 0xf, 0x3, 0xf, 0xf, 0x8, +// @fmt:on + }; + + struct Color { + struct RGB { + RGB() = default; + + RGB(uint8_t r, uint8_t g, uint8_t b) + : b(b), g(g), r(r) {} + + RGB(int r, int g, int b) + : b(static_cast(b)), g(static_cast(g)), r(static_cast(r)) {} + + RGB operator<<(int shift) const { return {r << shift, g << shift, b << shift}; } + + RGB operator>>(int shift) const { return {r >> shift, g >> shift, b >> shift}; } + + RGB operator|(int bits) const { return {r | bits, g | bits, b | bits}; } + + RGB operator|(const RGB &rhs) const { return {r | rhs.r, g | rhs.g, b | rhs.b}; } + + RGB operator+(const RGB &rhs) const { return {r + rhs.r, g + rhs.g, b + rhs.b}; } + + uint8_t b; + uint8_t g; + uint8_t r; + }; + + RGB rgb; + uint8_t a; + }; + + static_assert(sizeof(Color) == 4, "Color size must be 4 bytes"); + + struct Block { + constexpr uint64_t Get(const Bitfield &bf) const { + uint64_t mask = (1ULL << bf.count) - 1; + if (bf.offset + bf.count <= 64) { + return (low >> bf.offset) & mask; + } + if (bf.offset >= 64) { + return (high >> (bf.offset - 64)) & mask; + } + return ((low >> bf.offset) | (high << (64 - bf.offset))) & mask; + } + + const Mode &mode() const { + if ((low & 0b00000001) != 0) { + return Modes[0]; + } + if ((low & 0b00000010) != 0) { + return Modes[1]; + } + if ((low & 0b00000100) != 0) { + return Modes[2]; + } + if ((low & 0b00001000) != 0) { + return Modes[3]; + } + if ((low & 0b00010000) != 0) { + return Modes[4]; + } + if ((low & 0b00100000) != 0) { + return Modes[5]; + } + if ((low & 0b01000000) != 0) { + return Modes[6]; + } + if ((low & 0b10000000) != 0) { + return Modes[7]; + } + return Modes[8]; // Invalid mode + } + + struct IndexInfo { + uint64_t value; + int numBits; + }; + + uint8_t interpolate(uint8_t e0, uint8_t e1, const IndexInfo &index) const { + static constexpr uint16_t weights2[] = {0, 21, 43, 64}; + static constexpr uint16_t weights3[] = {0, 9, 18, 27, 37, 46, 55, 64}; + static constexpr uint16_t weights4[] = {0, 4, 9, 13, 17, 21, 26, 30, + 34, 38, 43, 47, 51, 55, 60, 64}; + static constexpr uint16_t const *weightsN[] = { + nullptr, nullptr, weights2, weights3, weights4 + }; + auto weights = weightsN[index.numBits]; + assert(weights != nullptr); + return (uint8_t) (((64 - weights[index.value]) * uint16_t(e0) + weights[index.value] * uint16_t(e1) + 32) >> 6); + } + + void decode(uint8_t *dst, size_t dstX, size_t dstY, size_t dstWidth, size_t dstHeight, size_t dstPitch) const { + auto const &mode = this->mode(); + + if (mode.IDX < 0) // Invalid mode: + { + for (size_t y = 0; y < 4 && y + dstY < dstHeight; y++) { + for (size_t x = 0; x < 4 && x + dstX < dstWidth; x++) { + auto out = reinterpret_cast(dst + sizeof(Color) * x + dstPitch * y); + out->rgb = {0, 0, 0}; + out->a = 0; + } + } + return; + } + + using Endpoint = std::array; + std::array subsets; + + for (size_t i = 0; i < mode.NS; i++) { + auto &subset = subsets[i]; + subset[0].rgb.r = Get(mode.Red(i * 2 + 0)); + subset[0].rgb.g = Get(mode.Green(i * 2 + 0)); + subset[0].rgb.b = Get(mode.Blue(i * 2 + 0)); + subset[0].a = (mode.AB > 0) ? Get(mode.Alpha(i * 2 + 0)) : 255; + + subset[1].rgb.r = Get(mode.Red(i * 2 + 1)); + subset[1].rgb.g = Get(mode.Green(i * 2 + 1)); + subset[1].rgb.b = Get(mode.Blue(i * 2 + 1)); + subset[1].a = (mode.AB > 0) ? Get(mode.Alpha(i * 2 + 1)) : 255; + } + + if (mode.SPB > 0) { + auto pbit0 = Get(mode.SharedPBit0()); + auto pbit1 = Get(mode.SharedPBit1()); + subsets[0][0].rgb = (subsets[0][0].rgb << 1) | pbit0; + subsets[0][1].rgb = (subsets[0][1].rgb << 1) | pbit0; + subsets[1][0].rgb = (subsets[1][0].rgb << 1) | pbit1; + subsets[1][1].rgb = (subsets[1][1].rgb << 1) | pbit1; + } + + if (mode.EPB > 0) { + for (size_t i = 0; i < mode.NS; i++) { + auto &subset = subsets[i]; + auto pbit0 = Get(mode.EndpointPBit(i * 2 + 0)); + auto pbit1 = Get(mode.EndpointPBit(i * 2 + 1)); + subset[0].rgb = (subset[0].rgb << 1) | pbit0; + subset[1].rgb = (subset[1].rgb << 1) | pbit1; + if (mode.AB > 0) { + subset[0].a = (subset[0].a << 1) | pbit0; + subset[1].a = (subset[1].a << 1) | pbit1; + } + } + } + + auto const colorBits = mode.CB + mode.SPB + mode.EPB; + auto const alphaBits = mode.AB + mode.SPB + mode.EPB; + + for (size_t i = 0; i < mode.NS; i++) { + auto &subset = subsets[i]; + subset[0].rgb = subset[0].rgb << (8 - colorBits); + subset[1].rgb = subset[1].rgb << (8 - colorBits); + subset[0].rgb = subset[0].rgb | (subset[0].rgb >> colorBits); + subset[1].rgb = subset[1].rgb | (subset[1].rgb >> colorBits); + + if (mode.AB > 0) { + subset[0].a = subset[0].a << (8 - alphaBits); + subset[1].a = subset[1].a << (8 - alphaBits); + subset[0].a = subset[0].a | (subset[0].a >> alphaBits); + subset[1].a = subset[1].a | (subset[1].a >> alphaBits); + } + } + + int colorIndexBitOffset = 0; + int alphaIndexBitOffset = 0; + for (int y = 0; y < 4; y++) { + for (int x = 0; x < 4; x++) { + auto texelIdx = y * 4 + x; + auto partitionIdx = Get(mode.Partition()); + assert(partitionIdx < MaxPartitions); + auto subsetIdx = subsetIndex(mode, partitionIdx, texelIdx); + assert(subsetIdx < MaxSubsets); + auto const &subset = subsets[subsetIdx]; + + auto anchorIdx = anchorIndex(mode, partitionIdx, subsetIdx); + auto isAnchor = anchorIdx == texelIdx; + auto colorIdx = colorIndex(mode, isAnchor, colorIndexBitOffset); + auto alphaIdx = alphaIndex(mode, isAnchor, alphaIndexBitOffset); + + if (y + dstY >= dstHeight || x + dstX >= dstWidth) { + // Don't be tempted to skip early at the loops: + // The calls to colorIndex() and alphaIndex() adjust bit + // offsets that need to be carefully tracked. + continue; + } + + Color output; + // Note: We flip r and b channels past this point as the texture storage is BGR while the output is RGB + output.rgb.r = interpolate(subset[0].rgb.b, subset[1].rgb.b, colorIdx); + output.rgb.g = interpolate(subset[0].rgb.g, subset[1].rgb.g, colorIdx); + output.rgb.b = interpolate(subset[0].rgb.r, subset[1].rgb.r, colorIdx); + output.a = interpolate(subset[0].a, subset[1].a, alphaIdx); + + switch (Get(mode.Rotation())) { + default: + break; + case 1: + std::swap(output.a, output.rgb.b); + break; + case 2: + std::swap(output.a, output.rgb.g); + break; + case 3: + std::swap(output.a, output.rgb.r); + break; + } + + auto out = reinterpret_cast(dst + sizeof(Color) * x + dstPitch * y); + *out = output; + } + } + } + + int subsetIndex(const Mode &mode, int partitionIdx, int texelIndex) const { + switch (mode.NS) { + default: + return 0; + case 2: + return PartitionTable2[partitionIdx][texelIndex]; + case 3: + return PartitionTable3[partitionIdx][texelIndex]; + } + } + + int anchorIndex(const Mode &mode, int partitionIdx, int subsetIdx) const { + // ARB_texture_compression_bptc states: + // "In partition zero, the anchor index is always index zero. + // In other partitions, the anchor index is specified by tables + // Table.A2 and Table.A3."" + // Note: This is really confusing - I believe they meant subset instead + // of partition here. + switch (subsetIdx) { + default: + return 0; + case 1: + return mode.NS == 2 ? AnchorTable2[partitionIdx] : AnchorTable3a[partitionIdx]; + case 2: + return AnchorTable3b[partitionIdx]; + } + } + + IndexInfo colorIndex(const Mode &mode, bool isAnchor, + int &indexBitOffset) const { + // ARB_texture_compression_bptc states: + // "The index value for interpolating color comes from the secondary + // index for the texel if the format has an index selection bit and its + // value is one and from the primary index otherwise."" + auto idx = Get(mode.IndexSelection()); + assert(idx <= 1); + bool secondary = idx == 1; + auto numBits = secondary ? mode.IB2 : mode.IB; + auto numReadBits = numBits - (isAnchor ? 1 : 0); + auto index = + Get(secondary ? mode.SecondaryIndex(indexBitOffset, numReadBits) + : mode.PrimaryIndex(indexBitOffset, numReadBits)); + indexBitOffset += numReadBits; + return {index, numBits}; + } + + IndexInfo alphaIndex(const Mode &mode, bool isAnchor, + int &indexBitOffset) const { + // ARB_texture_compression_bptc states: + // "The alpha index comes from the secondary index if the block has a + // secondary index and the block either doesn't have an index selection + // bit or that bit is zero and the primary index otherwise." + auto idx = Get(mode.IndexSelection()); + assert(idx <= 1); + bool secondary = (mode.IB2 != 0) && (idx == 0); + auto numBits = secondary ? mode.IB2 : mode.IB; + auto numReadBits = numBits - (isAnchor ? 1 : 0); + auto index = + Get(secondary ? mode.SecondaryIndex(indexBitOffset, numReadBits) + : mode.PrimaryIndex(indexBitOffset, numReadBits)); + indexBitOffset += numReadBits; + return {index, numBits}; + } + + // Assumes little-endian + uint64_t low; + uint64_t high; + }; + + } // namespace BC7 +} // anonymous namespace + +namespace bcn { + constexpr size_t R8Bpp{1}; //!< The amount of bytes per pixel in R8 + constexpr size_t R8g8Bpp{2}; //!< The amount of bytes per pixel in R8G8 + constexpr size_t R8g8b8a8Bpp{4}; //!< The amount of bytes per pixel in R8G8B8A8 + constexpr size_t R16g16b16a16Bpp{8}; //!< The amount of bytes per pixel in R16G16B16 + + void DecodeBc1(const uint8_t *src, uint8_t *dst, size_t x, size_t y, size_t width, size_t height) { + const auto *color{reinterpret_cast(src)}; + size_t pitch{R8g8b8a8Bpp * width}; + color->decode(dst, x, y, width, height, pitch, R8g8b8a8Bpp, true, false); + } + + void DecodeBc2(const uint8_t *src, uint8_t *dst, size_t x, size_t y, size_t width, size_t height) { + const auto *alpha{reinterpret_cast(src)}; + const auto *color{reinterpret_cast(src + 8)}; + size_t pitch{R8g8b8a8Bpp * width}; + color->decode(dst, x, y, width, height, pitch, R8g8b8a8Bpp, false, true); + alpha->decode(dst, x, y, width, height, pitch, R8g8b8a8Bpp); + } + + void DecodeBc3(const uint8_t *src, uint8_t *dst, size_t x, size_t y, size_t width, size_t height) { + const auto *alpha{reinterpret_cast(src)}; + const auto *color{reinterpret_cast(src + 8)}; + size_t pitch{R8g8b8a8Bpp * width}; + color->decode(dst, x, y, width, height, pitch, R8g8b8a8Bpp, false, true); + alpha->decode(dst, x, y, width, height, pitch, R8g8b8a8Bpp, 3, false); + } + + void DecodeBc4(const uint8_t *src, uint8_t *dst, size_t x, size_t y, size_t width, size_t height, bool isSigned) { + const auto *red{reinterpret_cast(src)}; + size_t pitch{R8Bpp * width}; + red->decode(dst, x, y, width, height, pitch, R8Bpp, 0, isSigned); + } + + void DecodeBc5(const uint8_t *src, uint8_t *dst, size_t x, size_t y, size_t width, size_t height, bool isSigned) { + const auto *red{reinterpret_cast(src)}; + const auto *green{reinterpret_cast(src + 8)}; + size_t pitch{R8g8Bpp * width}; + red->decode(dst, x, y, width, height, pitch, R8g8Bpp, 0, isSigned); + green->decode(dst, x, y, width, height, pitch, R8g8Bpp, 1, isSigned); + } + + void DecodeBc6(const uint8_t *src, uint8_t *dst, size_t x, size_t y, size_t width, size_t height, bool isSigned) { + const auto *block{reinterpret_cast(src)}; + size_t pitch{R16g16b16a16Bpp * width}; + block->decode(dst, x, y, width, height, pitch, R16g16b16a16Bpp, isSigned); + } + + void DecodeBc7(const uint8_t *src, uint8_t *dst, size_t x, size_t y, size_t width, size_t height) { + const auto *block{reinterpret_cast(src)}; + size_t pitch{R8g8b8a8Bpp * width}; + block->decode(dst, x, y, width, height, pitch); + } +} diff --git a/externals/bc_decoder/bc_decoder.h b/externals/bc_decoder/bc_decoder.h new file mode 100644 index 000000000..4f0ead7d3 --- /dev/null +++ b/externals/bc_decoder/bc_decoder.h @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: MPL-2.0 +// Copyright © 2022 Skyline Team and Contributors (https://github.com/skyline-emu/) + +#pragma once + +#include + +namespace bcn { + /** + * @brief Decodes a BC1 encoded image to R8G8B8A8 + */ + void DecodeBc1(const uint8_t *src, uint8_t *dst, size_t x, size_t y, size_t width, size_t height); + + /** + * @brief Decodes a BC2 encoded image to R8G8B8A8 + */ + void DecodeBc2(const uint8_t *src, uint8_t *dst, size_t x, size_t y, size_t width, size_t height); + + /** + * @brief Decodes a BC3 encoded image to R8G8B8A8 + */ + void DecodeBc3(const uint8_t *src, uint8_t *dst, size_t x, size_t y, size_t width, size_t height); + + /** + * @brief Decodes a BC4 encoded image to R8 + */ + void DecodeBc4(const uint8_t *src, uint8_t *dst, size_t x, size_t y, size_t width, size_t height, bool isSigned); + + /** + * @brief Decodes a BC5 encoded image to R8G8 + */ + void DecodeBc5(const uint8_t *src, uint8_t *dst, size_t x, size_t y, size_t width, size_t height, bool isSigned); + + /** + * @brief Decodes a BC6 encoded image to R16G16B16A16 + */ + void DecodeBc6(const uint8_t *src, uint8_t *dst, size_t x, size_t y, size_t width, size_t height, bool isSigned); + + /** + * @brief Decodes a BC7 encoded image to R8G8B8A8 + */ + void DecodeBc7(const uint8_t *src, uint8_t *dst, size_t x, size_t y, size_t width, size_t height); +} -- cgit v1.2.3