Method Set

CollisionB2ShapePolygon.go:142–260

(vertices []B2Vec2, count int)

}

func (poly *B2PolygonShape) Set(vertices []B2Vec2, count int) {
	B2Assert(3 <= count && count <= B2_maxPolygonVertices)
	if count < 3 {
		poly.SetAsBox(1.0, 1.0)
		return
	}

	n := MinInt(count, B2_maxPolygonVertices)

	// Perform welding and copy vertices into local buffer.
	ps := make([]B2Vec2, B2_maxPolygonVertices)
	tempCount := 0

	for i := 0; i < n; i++ {
		v := vertices[i]

		unique := true
		for j := 0; j < tempCount; j++ {
			if B2Vec2DistanceSquared(v, ps[j]) < ((0.5 * B2_linearSlop) * (0.5 * B2_linearSlop)) {
				unique = false
				break
			}
		}

		if unique {
			ps[tempCount] = v
			tempCount++
		}
	}

	n = tempCount
	if n < 3 {
		// Polygon is degenerate.
		B2Assert(false)
		poly.SetAsBox(1.0, 1.0)
		return
	}

	// Create the convex hull using the Gift wrapping algorithm
	// http://en.wikipedia.org/wiki/Gift_wrapping_algorithm

	// Find the right most point on the hull
	i0 := 0
	x0 := ps[0].X
	for i := 1; i < n; i++ {
		x := ps[i].X
		if x > x0 || (x == x0 && ps[i].Y < ps[i0].Y) {
			i0 = i
			x0 = x
		}
	}

	hull := make([]int, B2_maxPolygonVertices)
	m := 0
	ih := i0

	for {
		B2Assert(m < B2_maxPolygonVertices)