3 changed files with 80 additions and 138 deletions
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#pragma once |
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#include <cstddef> |
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#include <cstdint> |
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#include <vector> |
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namespace devilution { |
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inline void AppendCl2TransparentRun(unsigned width, std::vector<uint8_t> &out) |
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{ |
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while (width >= 0x7F) { |
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out.push_back(0x7F); |
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width -= 0x7F; |
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} |
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if (width == 0) |
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return; |
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out.push_back(width); |
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} |
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inline void AppendCl2FillRun(uint8_t color, unsigned width, std::vector<uint8_t> &out) |
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{ |
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while (width >= 0x3F) { |
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out.push_back(0x80); |
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out.push_back(color); |
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width -= 0x3F; |
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} |
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if (width == 0) |
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return; |
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out.push_back(0xBF - width); |
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out.push_back(color); |
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} |
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inline void AppendCl2PixelsRun(const uint8_t *src, unsigned width, std::vector<uint8_t> &out) |
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{ |
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while (width >= 0x41) { |
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out.push_back(0xBF); |
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for (size_t i = 0; i < 0x41; ++i) |
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out.push_back(src[i]); |
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width -= 0x41; |
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src += 0x41; |
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} |
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if (width == 0) |
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return; |
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out.push_back(256 - width); |
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for (size_t i = 0; i < width; ++i) |
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out.push_back(src[i]); |
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} |
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inline void AppendCl2PixelsOrFillRun(const uint8_t *src, unsigned length, std::vector<uint8_t> &out) |
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{ |
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const uint8_t *begin = src; |
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const uint8_t *prevColorBegin = src; |
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unsigned prevColorRunLength = 1; |
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uint8_t prevColor = *src++; |
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while (--length > 0) { |
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const uint8_t color = *src; |
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if (prevColor == color) { |
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++prevColorRunLength; |
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} else { |
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// A tunable parameter that decides at which minimum length we encode a fill run.
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// 3 appears to be optimal for most of our data (much better than 2, rarely very slightly worse than 4).
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constexpr unsigned MinFillRunLength = 3; |
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if (prevColorRunLength >= MinFillRunLength) { |
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AppendCl2PixelsRun(begin, prevColorBegin - begin, out); |
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AppendCl2FillRun(prevColor, prevColorRunLength, out); |
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begin = src; |
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} |
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prevColorBegin = src; |
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prevColorRunLength = 1; |
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prevColor = color; |
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} |
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++src; |
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} |
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AppendCl2PixelsRun(begin, prevColorBegin - begin, out); |
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AppendCl2FillRun(prevColor, prevColorRunLength, out); |
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} |
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} // namespace devilution
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