func drawacceleration(entity *physics.Entity, drawable *gdk.Drawable, gc *gdk.GC) {
startx := utils.RoundInt(entity.Position.X)
starty := utils.RoundInt(entity.Position.Y)
endx := utils.RoundInt(entity.Position.X + entity.Acceleration.X)
endy := utils.RoundInt(entity.Position.Y + entity.Acceleration.Y)
drawable.DrawLine(gc, centerx(startx), centery(starty), centerx(endx), centery(endy))
}