func (sprite *Sprite) BoundingBoxEx(x, y, rot, hscale, vscale float64) *rect.Rect {
var tx1, ty1, tx2, ty2 float64
var sint, cost float64
rect := new(rect.Rect)
tx1 = -sprite.HotX * hscale
ty1 = -sprite.HotY * vscale
tx2 = (sprite.W - sprite.HotX) * hscale
ty2 = (sprite.H - sprite.HotY) * vscale
if rot != 0.0 {
cost = math.Cos(rot)
sint = math.Sin(rot)
rect.Encapsulate(tx1*cost-ty1*sint+x, tx1*sint+ty1*cost+y)
rect.Encapsulate(tx2*cost-ty1*sint+x, tx2*sint+ty1*cost+y)
rect.Encapsulate(tx2*cost-ty2*sint+x, tx2*sint+ty2*cost+y)
rect.Encapsulate(tx1*cost-ty2*sint+x, tx1*sint+ty2*cost+y)
} else {
rect.Encapsulate(tx1+x, ty1+y)
rect.Encapsulate(tx2+x, ty1+y)
rect.Encapsulate(tx2+x, ty2+y)
rect.Encapsulate(tx1+x, ty2+y)
}
return rect
}
func (ps ParticleSystem) BoundingBox(rect *rect.Rect) *rect.Rect {
rect.SetRect(ps.boundingBox)
return rect
}