added ScaleTo() to alter vertices postion located on sphere (7b6a0f1d) · Commits · bsmrgo / geometry

icosahedron/icosahedron.go

+10 −0

Original line number	Diff line number	Diff line
		@@ -174,3 +174,13 @@ func Subdivide(icoIn Icosahedron) (Icosahedron, error) {

		return &icoOut, nil
		}

		// ScaleTo aligns the vertices on a sphere with radius r.
		func (i *Icosahedron) ScaleTo(r float32) error {
		for ni, vi := range i.Vertices() {
		d := vi.Len()
		s := r / d
		i.vs[ni] = vi.Mul(s)
		}
		return nil
		}

+54 −0

Original line number	Diff line number	Diff line
		@@ -34,3 +34,57 @@ func TestIcosahedronSubdivide(t *testing.T) {
		t.Logf("Icosahedron: subdivision %d, %d vertices, %d faces", ico.Level(), cv, cf)
		}
		}

		func abs(x float32) float32 {
		if x < 0 {
		return -x
		}
		return x
		}

		func TestIcosahedronVarious(t *testing.T) {
		ico, err := Create()
		if err != nil {
		t.Errorf("Create() failed with error: %v", err)
		}
		var ds [numberOfVertices]float32
		for i, v := range ico.Vertices() {
		ds[i] = v.Len()
		}
		for i, d := range ds {
		t.Logf("v[%d].Len() = %f", i, d)
		}
		log := false
		for _, r0 := range []float32{
		1.0,
		2.0,
		3.0,
		50.0,
		123.0,
		123.4,
		1234567.0,
		1234567.8,
		1234567.89,
		1234567.891,
		1234567.89123456789,
		//12345678.0,
		//12345678.9,
		//123456789,
		} {
		if err := ico.ScaleTo(r0); err != nil {
		t.Errorf("ScaleTo(%f) failed with error: %v", r0, err)
		}
		for i, v := range ico.Vertices() {
		ds[i] = v.Len()
		dx := abs(ds[i] - r0)
		if dx > 0.000001 {
		t.Errorf("ds[%d] = %f, expected %f (diff: %f)", i, ds[i], r0, dx)
		}
		}
		if log {
		for i, d := range ds {
		t.Logf("%f: v[%d].Len() = %f", r0, i, d)
		}
		}
		}
		}