Nested Scenes

Example of a scene rendered to a texture, which is shown in another scene.

Inception style. Since both the outer and inner scenes are lit, this may look a bit weird. The faces of the outer cube are like “screens” on which the subscene is displayed.

The sub-scene is rendered to a texture, and that texture is used for the surface of the cube in the outer scene.

import numpy as np
import imageio.v3 as iio
from wgpu.gui.auto import WgpuCanvas, run
import pygfx as gfx
import pylinalg as la


# First create the subscene, that reders into a texture

texture1 = gfx.Texture(dim=2, size=(200, 200, 1), format="rgba8unorm")

renderer1 = gfx.renderers.WgpuRenderer(texture1)
scene1 = gfx.Scene()

background1 = gfx.Background(None, gfx.BackgroundMaterial((0, 0.5, 0, 1)))
scene1.add(background1)

im = iio.imread("imageio:bricks.jpg").astype(np.float32) / 255
tex = gfx.Texture(im, dim=2)
geometry1 = gfx.box_geometry(200, 200, 200)
material1 = gfx.MeshPhongMaterial(map=tex, color=(1, 1, 0, 1.0))
cube1 = gfx.Mesh(geometry1, material1)
scene1.add(cube1)

camera1 = gfx.PerspectiveCamera(70, 16 / 9)
camera1.show_object(scene1)

scene1.add(gfx.AmbientLight(), camera1.add(gfx.DirectionalLight()))


# Then create the actual scene, in the visible canvas

canvas = WgpuCanvas()  # for gallery scraper, bc we have 2 renderers
renderer2 = gfx.renderers.WgpuRenderer(canvas)
scene2 = gfx.Scene()

geometry2 = gfx.box_geometry(200, 200, 200)
material2 = gfx.MeshPhongMaterial(map=texture1)
cube2 = gfx.Mesh(geometry2, material2)
scene2.add(cube2)

camera2 = gfx.PerspectiveCamera(70, 16 / 9)
camera2.local.z = 400

scene2.add(gfx.AmbientLight(), camera2.add(gfx.DirectionalLight()))


def animate():
    rot = la.quat_from_euler((0.005, 0.01), order="xy")
    cube1.local.rotation = la.quat_mul(rot, cube1.local.rotation)
    cube2.local.rotation = la.quat_mul(rot, cube2.local.rotation)

    renderer1.render(scene1, camera1)
    renderer2.render(scene2, camera2)

    renderer2.request_draw()


if __name__ == "__main__":
    renderer2.request_draw(animate)
    run()