forked from suyu/suyu
126 lines
4.2 KiB
C++
126 lines
4.2 KiB
C++
// Copyright 2018 yuzu Emulator Project
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#pragma once
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#include <bit>
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#include "common/common_types.h"
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namespace Tegra::Texture::ASTC {
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enum class IntegerEncoding { JustBits, Quint, Trit };
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struct IntegerEncodedValue {
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constexpr IntegerEncodedValue() = default;
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constexpr IntegerEncodedValue(IntegerEncoding encoding_, u32 num_bits_)
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: encoding{encoding_}, num_bits{num_bits_} {}
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constexpr bool MatchesEncoding(const IntegerEncodedValue& other) const {
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return encoding == other.encoding && num_bits == other.num_bits;
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}
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// Returns the number of bits required to encode num_vals values.
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u32 GetBitLength(u32 num_vals) const {
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u32 total_bits = num_bits * num_vals;
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if (encoding == IntegerEncoding::Trit) {
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total_bits += (num_vals * 8 + 4) / 5;
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} else if (encoding == IntegerEncoding::Quint) {
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total_bits += (num_vals * 7 + 2) / 3;
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}
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return total_bits;
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}
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IntegerEncoding encoding{};
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u32 num_bits = 0;
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u32 bit_value = 0;
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union {
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u32 quint_value = 0;
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u32 trit_value;
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};
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};
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// Returns a new instance of this struct that corresponds to the
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// can take no more than mav_value values
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constexpr IntegerEncodedValue CreateEncoding(u32 mav_value) {
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while (mav_value > 0) {
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u32 check = mav_value + 1;
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// Is mav_value a power of two?
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if (!(check & (check - 1))) {
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return IntegerEncodedValue(IntegerEncoding::JustBits, std::popcount(mav_value));
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}
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// Is mav_value of the type 3*2^n - 1?
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if ((check % 3 == 0) && !((check / 3) & ((check / 3) - 1))) {
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return IntegerEncodedValue(IntegerEncoding::Trit, std::popcount(check / 3 - 1));
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}
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// Is mav_value of the type 5*2^n - 1?
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if ((check % 5 == 0) && !((check / 5) & ((check / 5) - 1))) {
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return IntegerEncodedValue(IntegerEncoding::Quint, std::popcount(check / 5 - 1));
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}
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// Apparently it can't be represented with a bounded integer sequence...
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// just iterate.
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mav_value--;
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}
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return IntegerEncodedValue(IntegerEncoding::JustBits, 0);
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}
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constexpr std::array<IntegerEncodedValue, 256> MakeEncodedValues() {
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std::array<IntegerEncodedValue, 256> encodings{};
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for (std::size_t i = 0; i < encodings.size(); ++i) {
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encodings[i] = CreateEncoding(static_cast<u32>(i));
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}
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return encodings;
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}
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constexpr std::array<IntegerEncodedValue, 256> ASTC_ENCODINGS_VALUES = MakeEncodedValues();
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// Replicates low num_bits such that [(to_bit - 1):(to_bit - 1 - from_bit)]
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// is the same as [(num_bits - 1):0] and repeats all the way down.
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template <typename IntType>
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constexpr IntType Replicate(IntType val, u32 num_bits, u32 to_bit) {
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if (num_bits == 0 || to_bit == 0) {
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return 0;
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}
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const IntType v = val & static_cast<IntType>((1 << num_bits) - 1);
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IntType res = v;
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u32 reslen = num_bits;
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while (reslen < to_bit) {
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u32 comp = 0;
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if (num_bits > to_bit - reslen) {
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u32 newshift = to_bit - reslen;
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comp = num_bits - newshift;
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num_bits = newshift;
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}
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res = static_cast<IntType>(res << num_bits);
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res = static_cast<IntType>(res | (v >> comp));
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reslen += num_bits;
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}
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return res;
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}
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constexpr std::size_t NumReplicateEntries(u32 num_bits) {
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return std::size_t(1) << num_bits;
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}
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template <typename IntType, u32 num_bits, u32 to_bit>
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constexpr auto MakeReplicateTable() {
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std::array<IntType, NumReplicateEntries(num_bits)> table{};
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for (IntType value = 0; value < static_cast<IntType>(std::size(table)); ++value) {
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table[value] = Replicate(value, num_bits, to_bit);
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}
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return table;
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}
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constexpr auto REPLICATE_6_BIT_TO_8_TABLE = MakeReplicateTable<u32, 6, 8>();
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constexpr auto REPLICATE_7_BIT_TO_8_TABLE = MakeReplicateTable<u32, 7, 8>();
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constexpr auto REPLICATE_8_BIT_TO_8_TABLE = MakeReplicateTable<u32, 8, 8>();
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void Decompress(std::span<const uint8_t> data, uint32_t width, uint32_t height, uint32_t depth,
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uint32_t block_width, uint32_t block_height, std::span<uint8_t> output);
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} // namespace Tegra::Texture::ASTC
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