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100 lines
2.9 KiB
100 lines
2.9 KiB
#include "utils/palette_blending.hpp" |
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#include <array> |
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#include <cstdint> |
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#include <limits> |
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#include <SDL.h> |
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#include "utils/palette_kd_tree.hpp" |
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namespace devilution { |
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// This array is read from a lot on every frame. |
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// We do not use `std::array` here to improve debug build performance. |
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// In a debug build, `std::array` accesses are function calls. |
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uint8_t paletteTransparencyLookup[256][256]; |
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#if DEVILUTIONX_PALETTE_TRANSPARENCY_BLACK_16_LUT |
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uint16_t paletteTransparencyLookupBlack16[65536]; |
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#endif |
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namespace { |
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PaletteKdTree CurrentPaletteKdTree; |
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using RGB = std::array<uint8_t, 3>; |
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RGB BlendColors(const SDL_Color &a, const SDL_Color &b) |
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{ |
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return RGB { |
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static_cast<uint8_t>((static_cast<int>(a.r) + static_cast<int>(b.r)) / 2), |
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static_cast<uint8_t>((static_cast<int>(a.g) + static_cast<int>(b.g)) / 2), |
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static_cast<uint8_t>((static_cast<int>(a.b) + static_cast<int>(b.b)) / 2), |
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}; |
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} |
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#if DEVILUTIONX_PALETTE_TRANSPARENCY_BLACK_16_LUT |
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void SetPaletteTransparencyLookupBlack16(unsigned i, unsigned j) |
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{ |
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paletteTransparencyLookupBlack16[i | (j << 8U)] = paletteTransparencyLookup[0][i] | (paletteTransparencyLookup[0][j] << 8U); |
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} |
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#endif |
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} // namespace |
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void GenerateBlendedLookupTable(const SDL_Color *palette, int skipFrom, int skipTo) |
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{ |
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CurrentPaletteKdTree = PaletteKdTree { palette, skipFrom, skipTo }; |
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for (unsigned i = 0; i < 256; i++) { |
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paletteTransparencyLookup[i][i] = i; |
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unsigned j = 0; |
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for (; j < i; j++) { |
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paletteTransparencyLookup[i][j] = paletteTransparencyLookup[j][i]; |
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} |
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++j; |
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for (; j < 256; j++) { |
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paletteTransparencyLookup[i][j] = CurrentPaletteKdTree.findNearestNeighbor(BlendColors(palette[i], palette[j])); |
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} |
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} |
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#if DEVILUTIONX_PALETTE_TRANSPARENCY_BLACK_16_LUT |
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for (unsigned i = 0; i < 256; ++i) { |
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SetPaletteTransparencyLookupBlack16(i, i); |
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for (unsigned j = 0; j < i; ++j) { |
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SetPaletteTransparencyLookupBlack16(i, j); |
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SetPaletteTransparencyLookupBlack16(j, i); |
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} |
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} |
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#endif |
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} |
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void UpdateBlendedLookupTableSingleColor(const SDL_Color *palette, unsigned i) |
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{ |
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for (unsigned j = 0; j < 256; j++) { |
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if (i == j) { // No need to calculate transparency between 2 identical colors |
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paletteTransparencyLookup[i][j] = j; |
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continue; |
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} |
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const uint8_t best = CurrentPaletteKdTree.findNearestNeighbor(BlendColors(palette[i], palette[j])); |
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paletteTransparencyLookup[i][j] = paletteTransparencyLookup[j][i] = best; |
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} |
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#if DEVILUTIONX_PALETTE_TRANSPARENCY_BLACK_16_LUT |
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UpdateTransparencyLookupBlack16(i, i); |
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#endif |
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} |
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#if DEVILUTIONX_PALETTE_TRANSPARENCY_BLACK_16_LUT |
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void UpdateTransparencyLookupBlack16(unsigned from, unsigned to) |
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{ |
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for (unsigned i = from; i <= to; i++) { |
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for (unsigned j = 0; j < 256; j++) { |
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SetPaletteTransparencyLookupBlack16(i, j); |
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SetPaletteTransparencyLookupBlack16(j, i); |
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} |
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} |
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} |
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#endif |
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} // namespace devilution
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