Switch the license to be LGPLv2/later, with small parts still remaining as GPLv2...

[minetest.git] / src / light.h

diff --git a/src/light.h b/src/light.h
index c1af7fa62dcee09929b013a3cc2da3d21e9ca52f..8c397e1d4d28e6ac8bcc11283675311707e8abbd 100644 (file)
--- a/src/light.h
+++ b/src/light.h
@@ -3,16 +3,16 @@ Minetest-c55
 Copyright (C) 2010 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 General Public License as published by
-the Free Software Foundation; either version 2 of the License, or
+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 General Public License for more details.
+GNU Lesser General Public License for more details.
 
-You should have received a copy of the GNU General Public License along
+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.
 */
@@ -75,16 +75,27 @@ inline u8 undiminish_light(u8 light)
 
 extern u8 light_decode_table[LIGHT_MAX+1];
 
+// 0 <= light <= LIGHT_SUN
+// 0 <= return value <= 255
 inline u8 decode_light(u8 light)
 {
-       if(light == LIGHT_SUN)
-               return light_decode_table[LIGHT_MAX];
-       
        if(light > LIGHT_MAX)
                light = LIGHT_MAX;
        
        return light_decode_table[light];
 }
 
+// 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;
+}
+
 #endif