77 lines
3.2 KiB
C
77 lines
3.2 KiB
C
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// File: rg_etc1.h - Fast, high quality ETC1 block packer/unpacker - Rich Geldreich <richgel99@gmail.com>
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// Please see ZLIB license at the end of this file.
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#pragma once
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namespace rg_etc1
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{
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// Unpacks an 8-byte ETC1 compressed block to a block of 4x4 32bpp RGBA pixels.
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// Returns false if the block is invalid. Invalid blocks will still be unpacked with clamping.
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// This function is thread safe, and does not dynamically allocate any memory.
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// If preserve_alpha is true, the alpha channel of the destination pixels will not be overwritten. Otherwise, alpha will be set to 255.
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bool unpack_etc1_block(const void *pETC1_block, unsigned int* pDst_pixels_rgba, bool preserve_alpha = false);
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// Quality setting = the higher the quality, the slower.
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// To pack large textures, it is highly recommended to call pack_etc1_block() in parallel, on different blocks, from multiple threads (particularly when using cHighQuality).
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enum etc1_quality
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{
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cLowQuality,
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cMediumQuality,
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cHighQuality,
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};
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struct etc1_pack_params
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{
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etc1_quality m_quality;
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bool m_dithering;
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inline etc1_pack_params()
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{
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clear();
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}
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void clear()
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{
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m_quality = cHighQuality;
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m_dithering = false;
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}
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};
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// Important: pack_etc1_block_init() must be called before calling pack_etc1_block().
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void pack_etc1_block_init();
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// Packs a 4x4 block of 32bpp RGBA pixels to an 8-byte ETC1 block.
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// 32-bit RGBA pixels must always be arranged as (R,G,B,A) (R first, A last) in memory, independent of platform endianness. A should always be 255.
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// Returns squared error of result.
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// This function is thread safe, and does not dynamically allocate any memory.
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// pack_etc1_block() does not currently support "perceptual" colorspace metrics - it primarily optimizes for RGB RMSE.
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unsigned int pack_etc1_block(void* pETC1_block, const unsigned int* pSrc_pixels_rgba, etc1_pack_params& pack_params);
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} // namespace rg_etc1
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//------------------------------------------------------------------------------
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//
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// rg_etc1 uses the ZLIB license:
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// http://opensource.org/licenses/Zlib
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//
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// Copyright (c) 2012 Rich Geldreich
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//
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// This software is provided 'as-is', without any express or implied
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// warranty. In no event will the authors be held liable for any damages
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// arising from the use of this software.
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//
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// Permission is granted to anyone to use this software for any purpose,
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// including commercial applications, and to alter it and redistribute it
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// freely, subject to the following restrictions:
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//
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// 1. The origin of this software must not be misrepresented; you must not
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// claim that you wrote the original software. If you use this software
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// in a product, an acknowledgment in the product documentation would be
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// appreciated but is not required.
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//
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// 2. Altered source versions must be plainly marked as such, and must not be
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// misrepresented as being the original software.
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//
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// 3. This notice may not be removed or altered from any source distribution.
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//
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//------------------------------------------------------------------------------
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