91 lines
2.4 KiB
C
91 lines
2.4 KiB
C
/*
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* libtilemcore - Graphing calculator emulation library
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*
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* Copyright (C) 2010 Benjamin Moody
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public License
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* as published by the Free Software Foundation; either version 2.1 of
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* the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see
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* <http://www.gnu.org/licenses/>.
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*/
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <stdio.h>
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#include <math.h>
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#include "tilem.h"
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dword* tilem_color_palette_new(int rlight, int glight, int blight,
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int rdark, int gdark, int bdark,
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double gamma)
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{
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dword* pal = tilem_new_atomic(dword, 256);
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double r0, g0, b0, dr, dg, db;
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double igamma = 1.0 / gamma;
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double s = (1.0 / 255.0);
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int r, g, b, i;
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r0 = pow(rlight * s, gamma);
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g0 = pow(glight * s, gamma);
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b0 = pow(blight * s, gamma);
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dr = (pow(rdark * s, gamma) - r0) * s;
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dg = (pow(gdark * s, gamma) - g0) * s;
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db = (pow(bdark * s, gamma) - b0) * s;
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pal[0] = (rlight << 16) | (glight << 8) | blight;
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for (i = 1; i < 255; i++) {
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r = pow(r0 + i * dr, igamma) * 255.0 + 0.5;
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if (r < 0) r = 0;
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if (r > 255) r = 255;
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g = pow(g0 + i * dg, igamma) * 255.0 + 0.5;
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if (g < 0) g = 0;
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if (g > 255) g = 255;
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b = pow(b0 + i * db, igamma) * 255.0 + 0.5;
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if (b < 0) b = 0;
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if (b > 255) b = 255;
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pal[i] = (r << 16) | (g << 8) | b;
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}
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pal[255] = (rdark << 16) | (gdark << 8) | bdark;
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return pal;
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}
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byte* tilem_color_palette_new_packed(int rlight, int glight, int blight,
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int rdark, int gdark, int bdark,
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double gamma)
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{
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dword* palette;
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byte* packed;
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int i;
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palette = tilem_color_palette_new(rlight, glight, blight,
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rdark, gdark, bdark, gamma);
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packed = tilem_new_atomic(byte, 256 * 3);
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for (i = 0; i < 256; i++) {
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packed[i * 3] = palette[i] >> 16;
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packed[i * 3 + 1] = palette[i] >> 8;
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packed[i * 3 + 2] = palette[i];
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}
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tilem_free(palette);
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return packed;
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}
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