richgel999
55 lines
2.1 KiB
C++
55 lines
2.1 KiB
C++
// File: rg_etc1.h - Fast, high quality ETC1 block packer/unpacker - Rich Geldreich <richgel99@gmail.com>
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// This software is in the public domain. Please see license.txt.
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#pragma once
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namespace crnlib {
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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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} // namespace crnlib
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