PBR Instanced Rendering

This example shows how to use PBR rendering with instanced meshes.

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

# Init
canvas = WgpuCanvas(size=(640, 480), title="gfx_pbr")
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(None, gfx.BackgroundSkyboxMaterial(map=env_tex))
scene.add(background)

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

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

m = gltf.scene.children[0]

m.material.env_map = env_tex

instanced_mesh = gfx.InstancedMesh(m.geometry, m.material, 100)

instanced_mesh.local.matrix = m.local.matrix

# Set matrices. Note that these are sub-transforms of the mesh's own matrix.
for y in range(10):
    for x in range(10):
        m_t = la.mat_from_translation((y * 2, x * 2, 0))
        m_r = la.mat_from_euler((np.pi / 5 * x, np.pi / 5 * y, 0))
        m = m_t @ m_r
        instanced_mesh.set_matrix_at(x + y * 10, m)


scene.add(instanced_mesh)

# 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 camera and controller
camera = gfx.PerspectiveCamera(45, 640 / 480)
camera.local.position = (15, 15, 15)
camera.show_pos((10, 0, 10))
controller = gfx.OrbitController(camera, register_events=renderer)


if __name__ == "__main__":
    renderer.request_draw(lambda: renderer.render(scene, camera))
    run()