[devicenull]

Why not try this, instead of the two subtractions

#define SHOTGUN_X2 64 

Then use

            vec2[0]-=SHOTGUN_X2;

Instead of

            vec2[0]-=SHOTGUN_AIMING; // Repeated substraction is faster then multiplication !
            vec2[0]-=SHOTGUN_AIMING; // Repeated substraction is faster then multiplication ! 

The way I see that, one subtraction would be faster then two.. right?