Distance fog

Add distance-based fog to fade objects into a background color.

This example demonstrates viser.SceneApi.configure_fog(), which applies linear fog to the scene. Objects between near and far will gradually blend into the fog color, giving a sense of depth.

Source: examples/01_scene/10_fog.py

Code

import time

import numpy as np
import viser


def main() -> None:
    server = viser.ViserServer()

    # Ground grid.
    server.scene.add_grid(
        "/grid",
        width=40.0,
        height=40.0,
        cell_size=1.0,
        position=(0.0, 0.0, -1.0),
    )

    # A row of boxes receding into the distance.
    for i in range(12):
        server.scene.add_box(
            f"/boxes/{i}",
            color=(60, 120, 200),
            position=(3.0 + i * -2.0, 3.0 + i * -2.0, 0.0),
        )

    # Point cloud spread along the depth axis.
    rng = np.random.default_rng(0)
    num_points = 2000
    server.scene.add_point_cloud(
        "/points",
        points=rng.uniform((-5, 0, -2), (5, 35, 2), size=(num_points, 3)).astype(
            np.float32
        ),
        colors=rng.integers(80, 255, size=(num_points, 3), dtype=np.uint8),
        point_size=0.06,
        position=(-8.0, 0.0, 0.0),
    )

    # Gaussian splats scattered into the distance.
    num_splats = 500
    server.scene.add_gaussian_splats(
        "/splats",
        centers=rng.uniform((-4, 2, -1), (4, 35, 2), size=(num_splats, 3)).astype(
            np.float32
        ),
        covariances=np.tile(0.01 * np.eye(3, dtype=np.float32), (num_splats, 1, 1)),
        rgbs=rng.uniform(0.3, 1.0, size=(num_splats, 3)).astype(np.float32),
        opacities=rng.uniform(0.6, 1.0, size=(num_splats, 1)).astype(np.float32),
        position=(8.0, 0.0, 0.0),
    )

    # Configure fog.
    server.scene.configure_fog(near=3.0, far=20.0, color=(255, 255, 255))

    # GUI controls.
    with server.gui.add_folder("Fog"):
        gui_enabled = server.gui.add_checkbox("Enabled", initial_value=True)
        gui_near = server.gui.add_slider(
            "Near", min=0.0, max=50.0, step=0.5, initial_value=3.0
        )
        gui_far = server.gui.add_slider(
            "Far", min=1.0, max=50.0, step=0.5, initial_value=20.0
        )
        gui_color = server.gui.add_rgb("Color", initial_value=(255, 255, 255))

    def update_fog(_) -> None:
        server.scene.configure_fog(
            gui_near.value,
            gui_far.value,
            color=gui_color.value,
            enabled=gui_enabled.value,
        )

    gui_enabled.on_update(update_fog)
    gui_near.on_update(update_fog)
    gui_far.on_update(update_fog)
    gui_color.on_update(update_fog)

    while True:
        time.sleep(10.0)


if __name__ == "__main__":
    main()