3 Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as published by
7 the Free Software Foundation; either version 2.1 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public License along
16 with this program; if not, write to the Free Software Foundation, Inc.,
17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
23 #include "irrlichttypes.h"
26 Lower level lighting stuff
29 // This directly sets the range of light.
30 // Actually this is not the real maximum, and this is not the brightest, the
31 // brightest is LIGHT_SUN.
32 // If changed, this constant as defined in builtin/game/constants.lua must
35 // Light is stored as 4 bits, thus 15 is the maximum.
36 // This brightness is reserved for sunlight
39 inline u8 diminish_light(u8 light)
43 if (light >= LIGHT_MAX)
49 inline u8 diminish_light(u8 light, u8 distance)
51 if (distance >= light)
53 return light - distance;
56 inline u8 undiminish_light(u8 light)
58 // We don't know if light should undiminish from this particular 0.
59 // Thus, keep it at 0.
62 if (light == LIGHT_MAX)
73 * \warning DO NOT USE this directly; it is here simply so that decode_light()
76 * Array size is #LIGHTMAX+1
78 * The array is a lookup table to convert the internal representation of light
79 * (brightness) to the display brightness.
82 extern const u8 *light_decode_table;
84 // 0 <= light <= LIGHT_SUN
85 // 0 <= return value <= 255
86 inline u8 decode_light(u8 light)
88 if (light > LIGHT_MAX)
91 return light_decode_table[light];
94 // 0.0 <= light <= 1.0
95 // 0.0 <= return value <= 1.0
96 inline float decode_light_f(float light_f)
98 s32 i = (u32)(light_f * LIGHT_MAX + 0.5);
101 return (float)light_decode_table[0] / 255.0;
103 return (float)light_decode_table[LIGHT_MAX] / 255.0;
105 float v1 = (float)light_decode_table[i - 1] / 255.0;
106 float v2 = (float)light_decode_table[i] / 255.0;
107 float f0 = (float)i - 0.5;
108 float f = light_f * LIGHT_MAX - f0;
109 return f * v2 + (1.0 - f) * v1;
112 void set_light_table(float gamma);
114 #endif // ifndef SERVER
116 // 0 <= daylight_factor <= 1000
117 // 0 <= lightday, lightnight <= LIGHT_SUN
118 // 0 <= return value <= LIGHT_SUN
119 inline u8 blend_light(u32 daylight_factor, u8 lightday, u8 lightnight)
122 u32 l = ((daylight_factor * lightday + (c - daylight_factor) * lightnight)) / c;