godot/thirdparty/basis_universal/basisu_global_selector_palette_helpers.cpp

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// basiu_global_selector_palette_helpers.cpp
// Copyright (C) 2019 Binomial LLC. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "basisu_global_selector_palette_helpers.h"
namespace basisu
{
uint64_t etc1_global_selector_codebook_find_best_entry(const basist::etc1_global_selector_codebook &codebook,
uint32_t num_src_pixel_blocks, const pixel_block *pSrc_pixel_blocks, const etc_block *pBlock_endpoints,
uint32_t &palette_index, basist::etc1_global_palette_entry_modifier &palette_modifier,
bool perceptual, uint32_t max_pal_entries, uint32_t max_modifiers)
{
uint64_t best_err = UINT64_MAX;
uint32_t best_pal_index = 0;
basist::etc1_global_palette_entry_modifier best_pal_modifier;
if (!max_pal_entries)
max_pal_entries = codebook.size();
if (!max_modifiers)
max_modifiers = basist::etc1_global_palette_entry_modifier::cTotalValues;
for (uint32_t pal_index = 0; pal_index < max_pal_entries; pal_index++)
{
for (uint32_t mod_index = 0; mod_index < max_modifiers; mod_index++)
{
const basist::etc1_global_palette_entry_modifier pal_modifier(mod_index);
const basist::etc1_selector_palette_entry pal_entry(codebook.get_entry(pal_index, pal_modifier));
uint64_t trial_err = 0;
for (uint32_t block_index = 0; block_index < num_src_pixel_blocks; block_index++)
{
etc_block trial_block(pBlock_endpoints[block_index]);
for (uint32_t y = 0; y < 4; y++)
for (uint32_t x = 0; x < 4; x++)
trial_block.set_selector(x, y, pal_entry(x, y));
trial_err += trial_block.evaluate_etc1_error(reinterpret_cast<const basisu::color_rgba *>(pSrc_pixel_blocks[block_index].get_ptr()), perceptual);
if (trial_err >= best_err)
break;
}
if (trial_err < best_err)
{
best_err = trial_err;
best_pal_index = pal_index;
best_pal_modifier = pal_modifier;
}
} // mod_index
} // pal_index
palette_index = best_pal_index;
palette_modifier = best_pal_modifier;
return best_err;
}
} // namespace basisu