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quicktex/src/BlockView.h

115 lines
3.8 KiB
C++

/* Python-rgbcx Texture Compression Library
Copyright (C) 2021 Andrew Cassidy <drewcassidy@me.com>
Partially derived from rgbcx.h written by Richard Geldreich <richgel99@gmail.com>
and licenced under the public domain
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <array>
#include <cassert>
#include <cstdint>
#include <cstdio>
#include <vector>
#include "Color.h"
#include "ndebug.h"
namespace rgbcx {
template <typename S, size_t N> class RowView {
public:
RowView(S *start, int pixel_stride = 1) : start(start), pixel_stride(pixel_stride) {}
constexpr S &operator[](size_t index) noexcept(ndebug) {
assert(index < N);
return start[index * pixel_stride];
}
constexpr const S &operator[](size_t index) const noexcept(ndebug) {
assert(index < N);
return start[index * pixel_stride];
}
constexpr int size() noexcept { return N; }
S *const start;
const int pixel_stride;
};
template <typename S, size_t M, size_t N> class BlockView {
public:
using Row = RowView<S, N>;
BlockView(S *start, int row_stride = N, int pixel_stride = 1) : start(start), row_stride(row_stride), pixel_stride(pixel_stride) {}
constexpr Row operator[](unsigned index) noexcept(ndebug) {
assert(index < M);
return RowView<S, N>(&start[row_stride * (int)index], pixel_stride);
}
constexpr int width() noexcept { return N; }
constexpr int height() noexcept { return M; }
constexpr int size() noexcept { return N * M; }
constexpr S &get(unsigned x, unsigned y) noexcept(ndebug) {
assert(x < N);
assert(y < M);
return start[(row_stride * (int)y) + (pixel_stride * (int)x)];
}
constexpr S get(unsigned x, unsigned y) const noexcept(ndebug) {
assert(x < N);
assert(y < M);
return start[(row_stride * (int)y) + (pixel_stride * (int)x)];
}
constexpr void set(unsigned x, unsigned y, S value) noexcept(ndebug) {
assert(x < N);
assert(y < M);
start[(row_stride * (int)y) + (pixel_stride * (int)x)] = value;
}
constexpr std::array<S, M * N> flatten() noexcept {
std::array<S, M * N> result;
for (int x = 0; x < N; x++) {
for (int y = 0; y < M; y++) { result[x + (N * y)] = start[(row_stride * y) + (pixel_stride * x)]; }
}
return result;
}
S *const start;
const int row_stride;
const int pixel_stride;
};
template <size_t M, size_t N> class ColorBlockView : public BlockView<Color, M, N> {
public:
using Base = BlockView<Color, M, N>;
using ChannelView = BlockView<uint8_t, M, N>;
ColorBlockView(Color *start, int row_stride = N, int pixel_stride = 1) : Base(start, row_stride, pixel_stride) {}
constexpr ChannelView GetChannel(uint8_t index) noexcept(ndebug) {
assert(index < 4U);
auto channelStart = reinterpret_cast<uint8_t *>(Base::start) + index;
return ChannelView(channelStart, Base::row_stride * 4, Base::pixel_stride * 4);
}
void SetRGB(unsigned x, unsigned y, Color value) noexcept(ndebug) { Base::get(x, y).SetRGB(value); }
};
using Color4x4 = ColorBlockView<4, 4>;
} // namespace rgbcx