Initial files

src/light.h

@@ -0,0 +1,54 @@
+#ifndef LIGHT_HEADER
+#define LIGHT_HEADER
+
+#include "common_irrlicht.h"
+
+// This directly sets the range of light
+#define LIGHT_MAX 14
+// 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;
+}
+
+extern u8 light_decode_table[LIGHT_MAX+1];
+
+inline u8 decode_light(u8 light)
+{
+	if(light == LIGHT_SUN)
+		return light_decode_table[LIGHT_MAX];
+	
+	if(light > LIGHT_MAX)
+		throw;
+	
+	return light_decode_table[light];
+}
+
+#endif
+