fix integer overflow (fixes #414)

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

diff --git a/src/light.h b/src/light.h
index 8c397e1d4d28e6ac8bcc11283675311707e8abbd..f1c458ad8bc42bfdadb4386995cfae9ec8980e78 100644 (file)
--- a/src/light.h
+++ b/src/light.h
@@ -20,7 +20,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #ifndef LIGHT_HEADER
 #define LIGHT_HEADER
 
-#include "common_irrlicht.h"
+#include "irrlichttypes.h"
 #include "debug.h"
 
 /*
@@ -85,6 +85,24 @@ inline u8 decode_light(u8 light)
        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;
+}
+
 // 0 <= daylight_factor <= 1000
 // 0 <= lightday, lightnight <= LIGHT_SUN
 // 0 <= return value <= LIGHT_SUN
@@ -97,5 +115,15 @@ inline u8 blend_light(u32 daylight_factor, u8 lightday, u8 lightnight)
        return l;
 }
 
+// 0.0 <= daylight_factor <= 1.0
+// 0 <= lightday, lightnight <= LIGHT_SUN
+// 0 <= return value <= 255
+inline u8 blend_light_f1(float daylight_factor, u8 lightday, u8 lightnight)
+{
+       u8 l = ((daylight_factor * decode_light(lightday) +
+                       (1.0-daylight_factor) * decode_light(lightnight)));
+       return l;
+}
+
 #endif