set.seed(123)
test_that("3D sprites work", {
  open3d()
  # Warning:  these tests depend on order of evaluation
  # of the x, y, z arguments in sprites3d. 
  particles3d( rnorm(100), rnorm(100), rnorm(100), color = rainbow(100) )
  # is the same as
  sprites3d( rnorm(100), rnorm(100), rnorm(100), color = rainbow(100),
             lit = FALSE, alpha = .2,
             textype = "alpha", texture = system.file("textures/particle.png", package = "rgl") )
  sprites3d( rnorm(10) + 6, rnorm(10), rnorm(10), shape = shade3d(tetrahedron3d(), col = "red") )
  expect_known_scene("r3d")
})