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quicktex/src/BC4/BC4Decoder.cpp

46 lines
1.7 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/>.
*/
#include "BC4Decoder.h"
#include <assert.h> // for assert
#include <array> // for array
#include "../Color.h" // for Color
#include "../ColorBlock.h" // for ColorBlock
#include "../blocks.h" // for BC4Block
#include "../ndebug.h" // for ndebug
void rgbcx::BC4Decoder::DecodeBlock(Color4x4 dest, BC4Block *const block, size_t channel) const noexcept(ndebug) {
auto l = block->GetLowAlpha();
auto h = block->GetHighAlpha();
auto values = BC4Block::GetValues(l, h);
auto selectors = block->UnpackSelectors();
for (unsigned y = 0; y < 4; y++) {
for (unsigned x = 0; x < 4; x++) {
const auto selector = selectors[y][x];
assert(selector < 8);
dest[y][x][channel] = values[selector];
}
}
}