Camera Views¶

Use camera view structures to represent pinhole cameras in a 3D scene. Given camera locations, orientations, and field of view (intrinsics + extrinsics), Polyscope will draw a camera frame on the scene. Images quantities can be associated with the cameras and displayed on the camera frame. You can even align the interactive viewport with a selected camera.

Add an Image Quantity!

Camera views structures on their own are not so interesting; they are simplify displayed as a wireframe camera widget in the viewport.

Try adding an Image Quantitiy to the camera view. When image quantities are added to camera view structures, they gain the additional ability to be displayed in the camera’s frame.

Example:

import polyscope as ps
import numpy as np

ps.init()

# Create a camera view from parameters
intrinsics = ps.CameraIntrinsics(fov_vertical_deg=60, aspect=2)
extrinsics = ps.CameraExtrinsics(root=(2., 2., 2.), look_dir=(-1., -1.,-1.), up_dir=(0.,1.,0.))
params = ps.CameraParameters(intrinsics, extrinsics)
cam = ps.register_camera_view("cam", params)

# Set some options for the camera view
# these can also be set as keyword args in register_camera_view()
cam.set_widget_focal_length(0.75)          # size of displayed widget (relative value)
cam.set_widget_thickness(0.25)             # thickness of widget lines
cam.set_widget_color((0.25, 0.25, 0.25))   # color of widget lines


# Add an image to be displayed in the camera frame
w = 600
h = 300
cam.add_scalar_image_quantity("scalar_img", np.zeros((h, w)),
                              enabled=True, show_in_camera_billboard=True)

ps.show(3)

Registering a Camera View¶

Camera views are created from Camera Parameters.

Note that we do not specify an image resolution for the camera view. It can hold images of any resolution, as long as the aspect ratio is right.

register_camera_view(name, params, **kwargs)

Add a new camera view structure to Polyscope.

params is a Camera Parameters.

Additional optional keyword arguments:

enabled boolean, is the structure enabled initially
widget_focal_length float, size of displayed widget (relative value)
widget_thickness float, thickness of widget lines
widget_color float 3-tuple, color of widget lines

As with all structures, there is also get_camera_view("name"), has_camera_view("name"), and remove_camera_view("name").

Updating a Camera View¶

You can update the parameters associated with a camera view to move it within the scene after creation.

CameraView.update_camera_parameters(new_params)

Update camera parameters.

params is a Camera Parameters.

Options¶

See structure management for options common to all structures such as enabling/disabling, transforms, and transparency.

Parameter	Meaning	Getter	Setter	Persistent?
focal length	size of rendered widget	`get_widget_focal_length()`	`set_widget_focal_length(newVal, relative=true)`	yes
thickness	rendered widget line thickness	`get_widget_thickness()`	`set_widget_thickness(newVal)`	yes
color	widget color	`get_widget_color()`	`set_widget_color(newVal)`	yes