Bloom Effect Demo

This example shows a bloom rendering effect.

Note

To run this example, you need a model from the source repo’s example folder. If you are running this example from a local copy of the code (dev install) no further actions are needed. Otherwise, you may have to replace the path below to point to the location of the model.

import os
from pathlib import Path

try:
    # modify this line if your model is located elsewhere
    model_dir = Path(__file__).parents[1] / "data"
except NameError:
    # compatibility with sphinx-gallery
    model_dir = Path(os.getcwd()).parent / "data"

Once the path is set correctly, you can use the model as follows:

import imageio.v3 as iio
from rendercanvas.auto import RenderCanvas, loop
import pygfx as gfx

from wgpu.utils.imgui import ImguiRenderer, Stats
from imgui_bundle import imgui

# Init
canvas = RenderCanvas(
    size=(1280, 720), title="bloom_effect", update_mode="fastest", vsync=False
)
renderer = gfx.renderers.WgpuRenderer(canvas)
scene = gfx.Scene()

# Read cube image and turn it into a 3D image (a 4d array)
env_img = iio.imread("imageio:meadow_cube.jpg")
cube_size = env_img.shape[1]
env_img.shape = 6, cube_size, cube_size, env_img.shape[-1]

# Create environment map
env_tex = gfx.Texture(
    env_img, dim=2, size=(cube_size, cube_size, 6), generate_mipmaps=True
)

# Apply env map to skybox
background = gfx.Background.from_color((0.0, 0.0, 0.0, 1))
scene.add(background)

# Load meshes, and apply env map
# Note that this lights the helmet already
gltf_path = model_dir / "phoenix_bird.glb"

gltf = gfx.load_gltf(gltf_path)
# gfx.print_scene_graph(gltf.scene) # Uncomment to see the tree structure


def add_env_map(obj, env_map):
    if isinstance(obj, gfx.Mesh) and isinstance(obj.material, gfx.MeshStandardMaterial):
        obj.material.env_map = env_map


gltf.scene.traverse(lambda obj: add_env_map(obj, env_tex))

scene.add(gltf.scene)

# Add extra light more or less where the sun seems to be in the skybox
light = gfx.SpotLight(color="#444")
light.local.position = (-500, 1000, -1000)
scene.add(light)

# Create bloom effect pass using the new API
bloom_pass = gfx.renderers.wgpu.PhysicalBasedBloomPass(
    bloom_strength=0.4,
    max_mip_levels=6,
    filter_radius=0.005,
    use_karis_average=False,
)

# Add bloom pass to renderer's effect passes
renderer.effect_passes = [bloom_pass]

action_clip = gltf.animations[0]

animation_mixer = gfx.AnimationMixer()
action = animation_mixer.clip_action(action_clip)
action.play()

# Create camera and controller
camera = gfx.PerspectiveCamera(45, 16 / 9)
camera.show_object(gltf.scene)
controller = gfx.OrbitController(camera, register_events=renderer)

clock = gfx.Clock()

gui_renderer = ImguiRenderer(renderer.device, canvas)


def draw_imgui():
    imgui.set_next_window_size((400, 0), imgui.Cond_.always)
    imgui.set_next_window_pos((0, 0), imgui.Cond_.always)
    imgui.begin("Bloom Settings")

    changed, value = imgui.checkbox("bloom", bloom_pass.enabled)
    if changed:
        bloom_pass.enabled = value

    changed, value = imgui.slider_float(
        "Bloom Strength", bloom_pass.bloom_strength, 0.0, 3.0
    )
    if changed:
        bloom_pass.bloom_strength = value

    changed, value = imgui.slider_int(
        "Max Mipmap Levels", bloom_pass.max_mip_levels, 1, 10
    )
    if changed:
        bloom_pass.max_mip_levels = value

    changed, value = imgui.slider_float(
        "Filter Radius", bloom_pass.filter_radius, 0.0, 0.01
    )
    if changed:
        bloom_pass.filter_radius = value

    changed, value = imgui.checkbox("Use Karis Average", bloom_pass.use_karis_average)
    if changed:
        bloom_pass.use_karis_average = value

    imgui.end()


gui_renderer.set_gui(draw_imgui)
stats = Stats(renderer.device, canvas, align="right")


def animate():
    dt = clock.get_delta()

    animation_mixer.update(dt)
    with stats:
        renderer.render(scene, camera)
        gui_renderer.render()
    canvas.request_draw()


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

Interactive example

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