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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.
- */
- #pragma once
- #include "irrlichttypes.h"
- /*
- Lower level lighting stuff
- */
- // This directly sets the range of light.
- // Actually this is not the real maximum, and this is not the brightest, the
- // brightest is LIGHT_SUN.
- // If changed, this constant as defined in builtin/game/constants.lua must
- // also be changed.
- #define LIGHT_MAX 14
- // Light is stored as 4 bits, thus 15 is the maximum.
- // This brightness is reserved for sunlight
- #define LIGHT_SUN 15
- inline u8 diminish_light(u8 light)
- {
- if (light == 0)
- return 0;
- if (light >= LIGHT_MAX)
- return LIGHT_MAX - 1;
- return light - 1;
- }
- inline u8 diminish_light(u8 light, u8 distance)
- {
- if (distance >= light)
- return 0;
- return light - distance;
- }
- inline u8 undiminish_light(u8 light)
- {
- // We don't know if light should undiminish from this particular 0.
- // Thus, keep it at 0.
- if (light == 0)
- return 0;
- if (light == LIGHT_MAX)
- return light;
- return light + 1;
- }
- #ifndef SERVER
- /**
- * \internal
- *
- * \warning DO NOT USE this directly; it is here simply so that decode_light()
- * can be inlined.
- *
- * Array size is #LIGHTMAX+1
- *
- * The array is a lookup table to convert the internal representation of light
- * (brightness) to the display brightness.
- *
- */
- extern const u8 *light_decode_table;
- // 0 <= light <= LIGHT_SUN
- // 0 <= return value <= 255
- inline u8 decode_light(u8 light)
- {
- if (light > LIGHT_MAX)
- light = LIGHT_MAX;
- return light_decode_table[light];
- }
- // 0.0 <= light <= 1.0
- // 0.0 <= return value <= 1.0
- inline float decode_light_f(float light_f)
- {
- s32 i = (u32)(light_f * LIGHT_MAX + 0.5);
- if (i <= 0)
- return (float)light_decode_table[0] / 255.0;
- if (i >= LIGHT_MAX)
- return (float)light_decode_table[LIGHT_MAX] / 255.0;
- float v1 = (float)light_decode_table[i - 1] / 255.0;
- float v2 = (float)light_decode_table[i] / 255.0;
- float f0 = (float)i - 0.5;
- float f = light_f * LIGHT_MAX - f0;
- return f * v2 + (1.0 - f) * v1;
- }
- void set_light_table(float gamma);
- #endif // ifndef SERVER
- // 0 <= daylight_factor <= 1000
- // 0 <= lightday, lightnight <= LIGHT_SUN
- // 0 <= return value <= LIGHT_SUN
- inline u8 blend_light(u32 daylight_factor, u8 lightday, u8 lightnight)
- {
- u32 c = 1000;
- u32 l = ((daylight_factor * lightday + (c - daylight_factor) * lightnight)) / c;
- if (l > LIGHT_SUN)
- l = LIGHT_SUN;
- return l;
- }
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