Note
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Transparency 1
Example showing transparency using three overlapping planes. Press space to toggle the order of the planes. Press 1-7 to select the blend mode.

from wgpu.gui.auto import WgpuCanvas, run
import pygfx as gfx
canvas = WgpuCanvas()
renderer = gfx.renderers.WgpuRenderer(canvas)
scene = gfx.Scene()
background = gfx.Background.from_color("#000")
geometry = gfx.plane_geometry(50, 50)
plane1 = gfx.Mesh(geometry, gfx.MeshBasicMaterial(color=(1, 0, 0, 0.4)))
plane2 = gfx.Mesh(geometry, gfx.MeshBasicMaterial(color=(0, 1, 0, 0.4)))
plane3 = gfx.Mesh(geometry, gfx.MeshBasicMaterial(color=(0, 0, 1, 0.4)))
plane1.local.position = (-10, -10, 1)
plane2.local.position = (0, 0, 2)
plane3.local.position = (10, 10, 3)
scene.add(background, plane1, plane2, plane3)
camera = gfx.OrthographicCamera(100, 100)
scene_overlay = gfx.Scene()
blend_mode_text = gfx.Text(
gfx.TextGeometry(f"Blend mode: {renderer.blend_mode}", anchor="bottom-left"),
gfx.TextMaterial(outline_thickness=0.3),
)
scene_overlay.add(blend_mode_text)
screen_camera = gfx.ScreenCoordsCamera()
@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, # 0
"opaque", # 1
"ordered1", # 2
"ordered2", # 3
"weighted", # 4
"weighted_depth", # 5
"weighted_plus", # 6
"additive", # 7
]
mode = m[int(event.key)]
renderer.blend_mode = mode
print("Selecting blend_mode", mode)
blend_mode_text.geometry.set_text(f"Blend mode: {mode}")
def animate():
renderer.render(scene, camera, flush=False)
renderer.render(scene_overlay, screen_camera, flush=True)
if __name__ == "__main__":
print(__doc__)
canvas.request_draw(animate)
run()
Total running time of the script: (0 minutes 0.271 seconds)