// Advances ent up to dist towards the target cell. Returns the distance
// traveled.
func (e *Entity) DoAdvance(dist float32, x, y int) float32 {
if dist <= 0 {
e.sprite.sp.Command("stop")
return 0
}
e.sprite.sp.Command("move")
source := mathgl.Vec2{float32(e.X), float32(e.Y)}
target := mathgl.Vec2{float32(x), float32(y)}
var seg mathgl.Vec2
seg.Assign(&target)
seg.Subtract(&source)
e.TurnToFace(x, y)
var traveled float32
if seg.Length() > dist {
seg.Scale(dist / seg.Length())
traveled = dist
} else {
traveled = seg.Length()
}
seg.Add(&source)
e.X = float64(seg.X)
e.Y = float64(seg.Y)
return dist - traveled
}
