A Tetrahedral Mesh Emitter

In this example we make a tetrahedral mesh emitter by using a Discrete3DMesh class. Note that Py3DViewer is used to load a tetrahedra mesh, and each tetrahedra mesh has the unity volume emission.

import os
import time
import numpy as np
from matplotlib import pyplot as plt
from Py3DViewer import Tetmesh

from raysect.optical import World, translate, Point3D, Vector3D, rotate_basis
from raysect.core.math.function.float.function3d.interpolate import Discrete3DMesh
from raysect.optical.library import RoughTitanium
from raysect.optical.material import InhomogeneousVolumeEmitter
from raysect.optical.observer import PinholeCamera, RGBPipeline2D, RGBAdaptiveSampler2D
from raysect.primitive import Box

BASE_PATH = os.path.split(os.path.realpath(__file__))[0]


class UnityEmitter(InhomogeneousVolumeEmitter):

    def __init__(self, radiation_function):
        super().__init__()
        self.radiation_function = radiation_function

    def emission_function(self, point, direction, spectrum, world, ray, primitive, to_local, to_world):
        spectrum = ray.new_spectrum()
        spectrum.samples[:] = self.radiation_function(point.x, point.y, point.z)
        return spectrum


# Rabbit tetrahedra mesh emitter
mesh = Tetmesh(os.path.join(BASE_PATH, "../resources/stanford_bunny.mesh"))

try:
    tetra = Discrete3DMesh(mesh.vertices, mesh.polys, np.ones((mesh.num_polys)), False, 0)
except AttributeError:  # for backward compatibility with older versions of Py3DViewer
    tetra = Discrete3DMesh(mesh.vertices, mesh.tets, np.ones((mesh.num_tets)), False, 0)

# scene
world = World()
lower = Point3D(mesh.bbox[0, 0], mesh.bbox[0, 1], mesh.bbox[0, 2])
upper = Point3D(mesh.bbox[1, 0], mesh.bbox[1, 1], mesh.bbox[1, 2])
emitter = Box(lower, upper, material=UnityEmitter(tetra), parent=world)
floor = Box(Point3D(-100, -0.1, -100), Point3D(100, -0.01, 100), world, material=RoughTitanium(0.1))

# camera
camera_pos = Point3D(-0.015, 0.204, 0.25)
rgb_pipeline = RGBPipeline2D(display_update_time=5)
sampler = RGBAdaptiveSampler2D(rgb_pipeline, min_samples=100, fraction=0.2)
camera = PinholeCamera((512, 512), parent=world, transform=translate(camera_pos.x, camera_pos.y, camera_pos.z) * rotate_basis(camera_pos.vector_to(Point3D(0, 0.06, 0)), Vector3D(0, 1, 0)),
                       pipelines=[rgb_pipeline], frame_sampler=sampler)
camera.fov = 50
camera.spectral_bins = 1
camera.spectral_rays = 1
camera.pixel_samples = 200

# integration resolution
emitter.material.integrator.step = 0.0001

# start ray tracing
os.nice(15)
plt.ion()
timestamp = time.strftime("%Y-%m-%d_%H-%M-%S")
for p in range(1, 1000):
    print("Rendering pass {}...".format(p))
    camera.observe()
    rgb_pipeline.save("demo_volume_{}_pass_{}.png".format(timestamp, p))
    print()

# display final result
plt.ioff()
rgb_pipeline.display()
plt.show()