// 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
}
func (e *Entity) TurnToFace(x, y int) {
target := mathgl.Vec2{float32(x), float32(y)}
source := mathgl.Vec2{float32(e.X), float32(e.Y)}
var seg mathgl.Vec2
seg.Assign(&target)
seg.Subtract(&source)
target_facing := facing(seg)
f_diff := target_facing - e.sprite.sp.StateFacing()
if f_diff != 0 {
f_diff = (f_diff + 6) % 6
if f_diff > 3 {
f_diff -= 6
}
for f_diff < 0 {
e.sprite.sp.Command("turn_left")
f_diff++
}
for f_diff > 0 {
e.sprite.sp.Command("turn_right")
f_diff--
}
}
}