Transparency 2

Example showing transparency using three orthogonal planes. Press space to toggle the order of the planes. Press 1-6 to select the blend mode.

from wgpu.gui.auto import WgpuCanvas, run
import pygfx as gfx
import pylinalg as la

canvas = WgpuCanvas()
renderer = gfx.renderers.WgpuRenderer(canvas)
scene = gfx.Scene()

background = gfx.Background(None, gfx.BackgroundMaterial("#000"))

sphere = gfx.Mesh(gfx.sphere_geometry(10), gfx.MeshPhongMaterial())

geometry = gfx.plane_geometry(50, 50)
plane1 = gfx.Mesh(geometry, gfx.MeshBasicMaterial(color=(1, 0, 0, 0.3)))
plane2 = gfx.Mesh(geometry, gfx.MeshBasicMaterial(color=(0, 1, 0, 0.5)))
plane3 = gfx.Mesh(geometry, gfx.MeshBasicMaterial(color=(0, 0, 1, 0.7)))

plane1.local.rotation = la.quat_from_axis_angle((1, 0, 0), 1.571)
plane2.local.rotation = la.quat_from_axis_angle((0, 1, 0), 1.571)
plane3.local.rotation = la.quat_from_axis_angle((0, 0, 1), 1.571)

scene.add(background, plane1, plane2, plane3, sphere)

camera = gfx.PerspectiveCamera(70, 16 / 9)
camera.show_object(scene, view_dir=(-1, -2, -3))
controller = gfx.OrbitController(camera, register_events=renderer)

scene.add(camera.add(gfx.DirectionalLight()))


@renderer.add_event_handler("key_down")
def handle_event(event):
    if event.key == " ":
        print("Rotating scene element order")
        scene.add(scene.children[1])  # skip bg
        canvas.request_draw()
    elif event.key == ".":
        clr = "#fff" if background.material.color_bottom_left == "#000" else "#000"
        print(f"Changing background color to {clr}")
        background.material.set_colors(clr)
        canvas.request_draw()
    elif event.key in "0123456789":
        m = [
            None,
            "opaque",
            "ordered1",
            "ordered2",
            "weighted",
            "weighted_depth",
            "weighted_plus",
        ]
        mode = m[int(event.key)]
        renderer.blend_mode = mode
        print("Selecting blend_mode", mode)


def animate():
    renderer.render(scene, camera)
    canvas.request_draw()


if __name__ == "__main__":
    print(__doc__)
    canvas.request_draw(animate)
    run()