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68 lines
1.6 KiB
C
68 lines
1.6 KiB
C
// Luanti
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// SPDX-License-Identifier: LGPL-2.1-or-later
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// Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
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#pragma once
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#include <cassert>
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#include "config.h"
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#include "irrlichttypes.h"
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/*
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Lower level lighting stuff
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*/
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// This directly sets the range of light.
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// Actually this is not the real maximum, and this is not the brightest, the
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// brightest is LIGHT_SUN.
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// If changed, this constant as defined in builtin/game/constants.lua must
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// also be changed.
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#define LIGHT_MAX 14
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// Light is stored as 4 bits, thus 15 is the maximum.
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// This brightness is reserved for sunlight
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#define LIGHT_SUN 15
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#if IS_CLIENT_BUILD
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/**
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* \internal
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*
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* \warning DO NOT USE this directly; it is here simply so that decode_light()
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* can be inlined.
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*
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* Array size is #LIGHTMAX+1
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*
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* The array is a lookup table to convert the internal representation of light
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* (brightness) to the display brightness.
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*
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*/
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extern const u8 *light_decode_table;
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// 0 <= light <= LIGHT_SUN
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// 0 <= return value <= 255
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inline u8 decode_light(u8 light)
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{
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// assert(light <= LIGHT_SUN);
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if (light > LIGHT_SUN)
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light = LIGHT_SUN;
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return light_decode_table[light];
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}
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// 0.0 <= light <= 1.0
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// 0.0 <= return value <= 1.0
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float decode_light_f(float light_f);
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void set_light_table(float gamma);
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#endif
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// 0 <= daylight_factor <= 1000
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// 0 <= lightday, lightnight <= LIGHT_SUN
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// 0 <= return value <= LIGHT_SUN
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inline u8 blend_light(u32 daylight_factor, u8 lightday, u8 lightnight)
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{
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u32 c = 1000;
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u32 l = ((daylight_factor * lightday + (c - daylight_factor) * lightnight)) / c;
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if (l > LIGHT_SUN)
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l = LIGHT_SUN;
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return l;
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}
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