Optimize updateFastFaceRow processing by removing some TileSpec copy (#5678)

[oweals/minetest.git] / src / light.h

diff --git a/src/light.h b/src/light.h
index 218af348e1a21419add94aecc622cd9051a4c50d..30a647581485aac11a6c37c8e11482e7b2a844f4 100644 (file)
--- a/src/light.h
+++ b/src/light.h
@@ -1,6 +1,6 @@
 /*
-Minetest-c55
-Copyright (C) 2010 celeron55, Perttu Ahola <celeron55@gmail.com>
+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
@@ -21,24 +21,16 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #define LIGHT_HEADER
 
 #include "irrlichttypes.h"
-#include "debug.h"
-
-/*
-       Day/night cache:
-       Meshes are cached for different day-to-night transition values
-*/
-
-/*#define DAYNIGHT_CACHE_COUNT 3
-// First one is day, last one is night.
-extern u32 daynight_cache_ratios[DAYNIGHT_CACHE_COUNT];*/
 
 /*
        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.
+// 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
@@ -46,56 +38,91 @@ extern u32 daynight_cache_ratios[DAYNIGHT_CACHE_COUNT];*/
 
 inline u8 diminish_light(u8 light)
 {
-       if(light == 0)
+       if (light == 0)
                return 0;
-       if(light >= LIGHT_MAX)
+       if (light >= LIGHT_MAX)
                return LIGHT_MAX - 1;
-               
+
        return light - 1;
 }
 
 inline u8 diminish_light(u8 light, u8 distance)
 {
-       if(distance >= light)
+       if (distance >= light)
                return 0;
-       return  light - distance;
+       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)
+       if (light == 0)
                return 0;
-       if(light == LIGHT_MAX)
+       if (light == LIGHT_MAX)
                return light;
-       
+
        return light + 1;
 }
 
-extern u8 light_decode_table[LIGHT_MAX+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)
+       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)
+       u32 l = ((daylight_factor * lightday + (c - daylight_factor) * lightnight)) / c;
+       if (l > LIGHT_SUN)
                l = LIGHT_SUN;
        return l;
 }
 
 #endif
-