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
31 // brightest. The brightest is LIGHT_SUN.
33 // Light is stored as 4 bits, thus 15 is the maximum.
34 // This brightness is reserved for sunlight
37 inline u8 diminish_light(u8 light)
41 if(light >= LIGHT_MAX)
47 inline u8 diminish_light(u8 light, u8 distance)
51 return light - distance;
54 inline u8 undiminish_light(u8 light)
56 // We don't know if light should undiminish from this particular 0.
57 // Thus, keep it at 0.
60 if(light == LIGHT_MAX)
66 extern u8 light_decode_table[LIGHT_MAX+1];
68 // 0 <= light <= LIGHT_SUN
69 // 0 <= return value <= 255
70 inline u8 decode_light(u8 light)
75 return light_decode_table[light];
78 // 0.0 <= light <= 1.0
79 // 0.0 <= return value <= 1.0
80 inline float decode_light_f(float light_f)
82 s32 i = (u32)(light_f * LIGHT_MAX + 0.5);
85 return (float)light_decode_table[0] / 255.0;
87 return (float)light_decode_table[LIGHT_MAX] / 255.0;
89 float v1 = (float)light_decode_table[i-1] / 255.0;
90 float v2 = (float)light_decode_table[i] / 255.0;
91 float f0 = (float)i - 0.5;
92 float f = light_f * LIGHT_MAX - f0;
93 return f * v2 + (1.0 - f) * v1;
96 // 0 <= daylight_factor <= 1000
97 // 0 <= lightday, lightnight <= LIGHT_SUN
98 // 0 <= return value <= LIGHT_SUN
99 inline u8 blend_light(u32 daylight_factor, u8 lightday, u8 lightnight)
102 u32 l = ((daylight_factor * lightday + (c-daylight_factor) * lightnight))/c;
108 // 0.0 <= daylight_factor <= 1.0
109 // 0 <= lightday, lightnight <= LIGHT_SUN
110 // 0 <= return value <= 255
111 inline u8 blend_light_f1(float daylight_factor, u8 lightday, u8 lightnight)
113 u8 l = ((daylight_factor * decode_light(lightday) +
114 (1.0-daylight_factor) * decode_light(lightnight)));