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))
}
func drawposition(entity *physics.Entity, drawable *gdk.Drawable, gc *gdk.GC) {
radius := math.Sqrt(entity.Mass)
startx := utils.RoundInt(centerfloatx(entity.Position.X) - (radius / 2))
starty := utils.RoundInt(centerfloaty(entity.Position.Y) - (radius / 2))
// Draw at least 1 pixel for position
if radius < 1 {
radius = 1
}
drawable.DrawArc(gc, true, startx, starty, int(utils.Round(radius)), int(radius), 0, 360*64)
}