mirror of
https://github.com/minetest/minetest.git
synced 2024-11-27 10:03:45 +01:00
126 lines
3.0 KiB
C
126 lines
3.0 KiB
C
/*
|
|
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;
|
|
}
|