func (g *Geometry) buildRotateZ() func(angle float64) *Geometry {
// rotate geometry around world z-axis
var m1 math3d.Matrix4
return func(angle float64) *Geometry {
if m1 == nil {
m1 = math3d.NewMatrix4()
}
m1.MakeRotationZ(angle)
g.ApplyMatrix(m1)
return g
}
}
