minetest.git - modified minetest for gpcfs purposes

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Diffstat (limited to 'src/util/sha1.h')

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/* Minetest Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com> This program is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #include "light.h" #include <math.h> #include "util/numeric.h" #ifndef SERVER // Length of LIGHT_MAX+1 means LIGHT_MAX is the last value. // LIGHT_SUN is read as LIGHT_MAX from here. u8 light_LUT[LIGHT_MAX+1]; // the const ref to light_LUT is what is actually used in the code. const u8 *light_decode_table = light_LUT; /** Initialize or update the light value tables using the specified \p gamma. * If \p gamma == 1.0 then the light table is linear. Typically values for * gamma range between 1.8 and 2.2. * * @note The value for gamma will be restricted to the range 1.1 <= gamma <= 3.0. * * @note This function is not, currently, a simple linear to gamma encoding * because adjustments are made so that a gamma of 1.8 gives the same * results as those hardcoded for use by the server. */ void set_light_table(float gamma) { static const float brightness_step = 255.0f / (LIGHT_MAX + 1); // this table is pure arbitrary values, made so that // at gamma 2.2 the game looks not too dark at light=1, // and mostly linear for the rest of the scale. // we could try to inverse the gamma power function, but this // is simpler and quicker. static const int adjustments[LIGHT_MAX + 1] = { -67, -91, -125, -115, -104, -85, -70, -63, -56, -49, -42, -35, -28, -22, 0 }; gamma = rangelim(gamma, 1.0, 3.0); float brightness = brightness_step; for (size_t i = 0; i < LIGHT_MAX; i++) { light_LUT[i] = (u8)(255 * powf(brightness / 255.0f, 1.0 / gamma)); light_LUT[i] = rangelim(light_LUT[i] + adjustments[i], 0, 255); if (i > 1 && light_LUT[i] < light_LUT[i - 1]) light_LUT[i] = light_LUT[i - 1] + 1; brightness += brightness_step; } light_LUT[LIGHT_MAX] = 255; } #endif


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