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fdbb27a796
... after finding out what an inefficient and poorly working method the Build backend uses for downconverting true color textures.
97 lines
No EOL
3.3 KiB
C++
97 lines
No EOL
3.3 KiB
C++
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/*
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** imagehelpers.cpp
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** Utilities for image conversion - mostly 8 bit paletted baggage
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**
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**---------------------------------------------------------------------------
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** Copyright 2004-2007 Randy Heit
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** Copyright 2006-2018 Christoph Oelckers
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** All rights reserved.
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**
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** Redistribution and use in source and binary forms, with or without
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** modification, are permitted provided that the following conditions
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** are met:
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**
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** 1. Redistributions of source code must retain the above copyright
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** notice, this list of conditions and the following disclaimer.
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** 2. Redistributions in binary form must reproduce the above copyright
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** notice, this list of conditions and the following disclaimer in the
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** documentation and/or other materials provided with the distribution.
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** 3. The name of the author may not be used to endorse or promote products
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** derived from this software without specific prior written permission.
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**
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** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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**---------------------------------------------------------------------------
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**
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**
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*/
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#include "imagehelpers.h"
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namespace ImageHelpers
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{
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uint8_t GrayMap[256];
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PalEntry BaseColors[256];
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PalEntry BasePalette[256]; // same as above, but with a being a proper alpha channel.
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int WhiteIndex, BlackIndex;
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ColorTable256k RGB256k;
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int BestColor(int r, int g, int b, int first, int num)
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{
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const PalEntry* pal = BaseColors;
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int bestcolor = first;
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int bestdist = 257 * 257 + 257 * 257 + 257 * 257;
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for (int color = first; color < num; color++)
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{
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if (pal[color].a > 0) continue; // marks a fullbright color which we should not pick here
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int x = r - pal[color].r;
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int y = g - pal[color].g;
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int z = b - pal[color].b;
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int dist = x * x + y * y + z * z;
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if (dist < bestdist)
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{
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if (dist == 0)
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return color;
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bestdist = dist;
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bestcolor = color;
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}
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}
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return bestcolor;
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}
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void SetPalette(const PalEntry* colors)
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{
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for (int i = 0; i < 255; i++)
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{
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BasePalette[i] = BaseColors[i] = colors[i];
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BasePalette[i].a = 255;
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}
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BasePalette[255] = BaseColors[255] = 0; // 255 is always translucent black - whatever color the original data has here
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// Find white and black from the original palette so that they can be
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// used to make an educated guess of the translucency % for a
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// translucency map.
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WhiteIndex = BestColor(255, 255, 255);
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BlackIndex = BestColor(0, 0, 0);
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// create the RGB666 lookup table
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for (int r = 0; r < 64; r++)
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for (int g = 0; g < 64; g++)
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for (int b = 0; b < 64; b++)
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RGB256k.RGB[r][g][b] = BestColor((r<<2)|(r>>4), (g<<2)|(g>>4), (b<<2)|(b>>4));
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}
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} |