new: extract rendering intrinsics (K) and extrinsics (T) set by Open3D

[yxlao]

Introducing ct.render.get_render_K_T(), allowing for the extraction of camera intrinsic (K) and extrinsic (T) matrices from Open3D visualizations. This allows obtaining the camera parameters such that it can be applied to render new geometries.

Example Usage:

import open3d as o3d
import numpy as np
import camtools as ct

# Load or create geometries
geometry_a = o3d.geometry.TriangleMesh.create_sphere()
geometry_b = o3d.geometry.TriangleMesh.create_box()

# Extract the default camera parameters from the first visualization
K, T = ct.get_render_K_T([geometry_a])

# Apply the same parameters to render another geometry
ct.render.render_geometries([geometry_b], K=K, T=T)