From 224db7a9a2adf80e5bbc1265da725c8d356ff691 Mon Sep 17 00:00:00 2001
From: SamTov <tovey.samuel@gmail.com>
Date: Sun, 8 Oct 2023 13:17:57 +0200
Subject: [PATCH 01/13] updates

---
 examples/rendering.py          | 69 ++++++++++++++++++++++++++++++++++
 znvis/visualizer/visualizer.py |  2 +-
 2 files changed, 70 insertions(+), 1 deletion(-)
 create mode 100644 examples/rendering.py

diff --git a/examples/rendering.py b/examples/rendering.py
new file mode 100644
index 0000000..5b2f88b
--- /dev/null
+++ b/examples/rendering.py
@@ -0,0 +1,69 @@
+import open3d as o3d
+import mitsuba as mi
+
+
+def render_mesh(mesh, mesh_center):
+    scene = mi.load_dict({
+        'type': 'scene',
+        'integrator': {
+            'type': 'path'
+        },
+        'light': {
+            'type': 'constant',
+            'radiance': {
+                'type': 'rgb',
+                'value': 1.0
+            }
+            # NOTE: For better results comment out the constant emitter above
+            # and uncomment out the lines below changing the filename to an HDRI
+            # envmap you have.
+            # 'type': 'envmap',
+            # 'filename': '/home/renes/Downloads/solitude_interior_4k.exr'
+        },
+        'sensor': {
+            'type':
+                'perspective',
+            'focal_length':
+                '50mm',
+            'to_world':
+                mi.ScalarTransform4f.look_at(origin=[0, 0, 5],
+                                             target=mesh_center,
+                                             up=[0, 1, 0]),
+            'thefilm': {
+                'type': 'hdrfilm',
+                'width': 1024,
+                'height': 768,
+            },
+            'thesampler': {
+                'type': 'multijitter',
+                'sample_count': 64,
+            },
+        },
+        'themesh': mesh,
+    })
+
+    img = mi.render(scene, spp=256)
+    return img
+
+
+# Default to LLVM variant which should be available on all
+# platforms. If you have a system with a CUDA device then comment out LLVM
+# variant and uncomment cuda variant
+mi.set_variant('llvm_ad_rgb')
+# mi.set_variant('cuda_ad_rgb')
+
+
+mesh = o3d.t.geometry.TriangleMesh.create_sphere(radius=1.0)
+mesh.compute_vertex_normals()
+mesh_center = mesh.get_axis_aligned_bounding_box().get_center()
+
+
+# mesh.material.set_default_properties()
+print('Render mesh with material converted to Mitsuba principled BSDF')
+# mi_mesh = mesh.to_mitsuba('sphere')
+# img = render_mesh(mi_mesh, mesh_center.numpy())
+# mi.Bitmap(img).write('test.exr')
+
+
+# Render with Open3D
+o3d.visualization.draw(mesh)
\ No newline at end of file
diff --git a/znvis/visualizer/visualizer.py b/znvis/visualizer/visualizer.py
index ea347fa..d6032aa 100644
--- a/znvis/visualizer/visualizer.py
+++ b/znvis/visualizer/visualizer.py
@@ -394,7 +394,7 @@ def save_callable():
                     mesh += item.mesh_list[self.counter]
 
             o3d.io.write_triangle_mesh(
-                (self.obj_folder / f"export_mesh_{self.counter}.obj").as_posix(), mesh
+                (self.obj_folder / f"export_mesh_{self.counter}.ply").as_posix(), mesh
             )
             self.save_thread_finished = True
 

From d3cb1f4e77f8b2f844e8646b6055e61c59c8ddfc Mon Sep 17 00:00:00 2001
From: SamTov <tovey.samuel@gmail.com>
Date: Sun, 8 Oct 2023 22:56:37 +0200
Subject: [PATCH 02/13] Add mitsuba rendering.

---
 examples/rendering.py          |  69 --------------
 examples/simple_spheres.py     |  14 +--
 znvis/__init__.py              |   2 +
 znvis/material/material.py     |   4 +
 znvis/rendering/__init__.py    |  25 +++++
 znvis/rendering/mitsuba.py     | 165 +++++++++++++++++++++++++++++++++
 znvis/visualizer/visualizer.py |  49 ++++++++--
 7 files changed, 246 insertions(+), 82 deletions(-)
 delete mode 100644 examples/rendering.py
 create mode 100644 znvis/rendering/__init__.py
 create mode 100644 znvis/rendering/mitsuba.py

diff --git a/examples/rendering.py b/examples/rendering.py
deleted file mode 100644
index 5b2f88b..0000000
--- a/examples/rendering.py
+++ /dev/null
@@ -1,69 +0,0 @@
-import open3d as o3d
-import mitsuba as mi
-
-
-def render_mesh(mesh, mesh_center):
-    scene = mi.load_dict({
-        'type': 'scene',
-        'integrator': {
-            'type': 'path'
-        },
-        'light': {
-            'type': 'constant',
-            'radiance': {
-                'type': 'rgb',
-                'value': 1.0
-            }
-            # NOTE: For better results comment out the constant emitter above
-            # and uncomment out the lines below changing the filename to an HDRI
-            # envmap you have.
-            # 'type': 'envmap',
-            # 'filename': '/home/renes/Downloads/solitude_interior_4k.exr'
-        },
-        'sensor': {
-            'type':
-                'perspective',
-            'focal_length':
-                '50mm',
-            'to_world':
-                mi.ScalarTransform4f.look_at(origin=[0, 0, 5],
-                                             target=mesh_center,
-                                             up=[0, 1, 0]),
-            'thefilm': {
-                'type': 'hdrfilm',
-                'width': 1024,
-                'height': 768,
-            },
-            'thesampler': {
-                'type': 'multijitter',
-                'sample_count': 64,
-            },
-        },
-        'themesh': mesh,
-    })
-
-    img = mi.render(scene, spp=256)
-    return img
-
-
-# Default to LLVM variant which should be available on all
-# platforms. If you have a system with a CUDA device then comment out LLVM
-# variant and uncomment cuda variant
-mi.set_variant('llvm_ad_rgb')
-# mi.set_variant('cuda_ad_rgb')
-
-
-mesh = o3d.t.geometry.TriangleMesh.create_sphere(radius=1.0)
-mesh.compute_vertex_normals()
-mesh_center = mesh.get_axis_aligned_bounding_box().get_center()
-
-
-# mesh.material.set_default_properties()
-print('Render mesh with material converted to Mitsuba principled BSDF')
-# mi_mesh = mesh.to_mitsuba('sphere')
-# img = render_mesh(mi_mesh, mesh_center.numpy())
-# mi.Bitmap(img).write('test.exr')
-
-
-# Render with Open3D
-o3d.visualization.draw(mesh)
\ No newline at end of file
diff --git a/examples/simple_spheres.py b/examples/simple_spheres.py
index 4a55279..b19df00 100644
--- a/examples/simple_spheres.py
+++ b/examples/simple_spheres.py
@@ -30,17 +30,19 @@
     """
     material_1 = vis.Material(colour=np.array([30, 144, 255]) / 255, alpha=0.6)
     # Define the first particle.
-    trajectory = np.random.uniform(-10, 10, (10, 10, 3))
-    mesh = vis.Sphere(radius=2.0, resolution=50, material=material_1)
-    particle = vis.Particle(name="Blue", mesh=mesh, position=trajectory, smoothing=True)
+    trajectory = np.random.uniform(-100, 100, (100, 1000, 3))
+    mesh = vis.Sphere(radius=2.0, resolution=10, material=material_1)
+    particle = vis.Particle(
+        name="Blue", mesh=mesh, position=trajectory, smoothing=False
+    )
 
     material_2 = vis.Material(colour=np.array([255, 140, 0]) / 255, alpha=1.0)
 
     # Define the second particle.
-    trajectory_2 = np.random.uniform(-10, 10, (10, 10, 3))
-    mesh_2 = vis.Sphere(radius=1.0, resolution=50, material=material_2)
+    trajectory_2 = np.random.uniform(-10, 10, (100, 1000, 3))
+    mesh_2 = vis.Sphere(radius=1.0, resolution=10, material=material_2)
     particle_2 = vis.Particle(
-        name="Orange", mesh=mesh_2, position=trajectory_2, smoothing=True
+        name="Orange", mesh=mesh_2, position=trajectory_2, smoothing=False
     )
 
     # Construct the visualizer and run
diff --git a/znvis/__init__.py b/znvis/__init__.py
index 0e45046..8e2b20e 100644
--- a/znvis/__init__.py
+++ b/znvis/__init__.py
@@ -21,6 +21,7 @@
 -------
 init file for the main ZnVis package.
 """
+from znvis import rendering
 from znvis.bounding_objects.bounding_box import BoundingBox
 from znvis.material.material import Material
 from znvis.mesh.custom import CustomMesh
@@ -37,4 +38,5 @@
     CustomMesh.__name__,
     BoundingBox.__name__,
     Material.__name__,
+    rendering.__name__,
 ]
diff --git a/znvis/material/material.py b/znvis/material/material.py
index e099d60..99db158 100644
--- a/znvis/material/material.py
+++ b/znvis/material/material.py
@@ -45,6 +45,8 @@ class Material:
             How reflective the material is.
     anisotropy: float
             How anisotopic the material is.
+    mitsuba_bsdf: mitsuba.bsdf (default: None)
+            Mitsuba bsdf object.
     """
 
     colour: np.ndarray = np.array([59.0, 53.0, 97.0]) / 255
@@ -53,3 +55,5 @@ class Material:
     metallic: float = 0.0
     reflectance: float = 0.4
     anisotropy: float = 0.4
+
+    mitsuba_bsdf = None
diff --git a/znvis/rendering/__init__.py b/znvis/rendering/__init__.py
new file mode 100644
index 0000000..b200eb6
--- /dev/null
+++ b/znvis/rendering/__init__.py
@@ -0,0 +1,25 @@
+"""
+ZnVis: A Zincwarecode package.
+License
+-------
+This program and the accompanying materials are made available under the terms
+of the Eclipse Public License v2.0 which accompanies this distribution, and is
+available at https://www.eclipse.org/legal/epl-v20.html
+SPDX-License-Identifier: EPL-2.0
+Copyright Contributors to the Zincwarecode Project.
+Contact Information
+-------------------
+email: zincwarecode@gmail.com
+github: https://github.com/zincware
+web: https://zincwarecode.com/
+Citation
+--------
+If you use this module please cite us with:
+
+Summary
+-------
+Init file for the rendering module.
+"""
+from znvis.rendering.mitsuba import Mitsuba
+
+__all__ = [Mitsuba.__name__]
diff --git a/znvis/rendering/mitsuba.py b/znvis/rendering/mitsuba.py
new file mode 100644
index 0000000..2302950
--- /dev/null
+++ b/znvis/rendering/mitsuba.py
@@ -0,0 +1,165 @@
+"""
+ZnVis: A Zincwarecode package.
+License
+-------
+This program and the accompanying materials are made available under the terms
+of the Eclipse Public License v2.0 which accompanies this distribution, and is
+available at https://www.eclipse.org/legal/epl-v20.html
+SPDX-License-Identifier: EPL-2.0
+Copyright Contributors to the Zincwarecode Project.
+Contact Information
+-------------------
+email: zincwarecode@gmail.com
+github: https://github.com/zincware
+web: https://zincwarecode.com/
+Citation
+--------
+If you use this module please cite us with:
+
+Summary
+-------
+Mitsuba rendering module.
+"""
+import os
+
+import mitsuba as mi
+import numpy as np
+import open3d as o3d
+
+mi.set_variant("llvm_ad_rgb")
+
+
+# Default scene dict.
+default_scene_dict = {
+    "type": "scene",
+    "integrator": {"type": "path"},
+    "light": {"type": "constant", "radiance": {"type": "rgb", "value": 1.0}},
+    "sensor": {
+        "type": "perspective",
+        "fov": 60,
+        "thefilm": {
+            "type": "hdrfilm",
+            "width": 4096,
+            "height": 2160,
+        },
+        "thesampler": {
+            "type": "multijitter",
+            "sample_count": 20,
+        },
+    },
+}
+
+
+class Mitsuba:
+    """
+    Class for Mitsuba rendering.
+    """
+
+    def __init__(self, scene_dict: dict = None, update_camera: bool = True) -> None:
+        """
+        Initialize the Mitsuba renderer.
+
+        Parameters
+        ----------
+        scene_dict : dict (default = None)
+            Dictionary containing the scene information for Mitsuba.
+            The mesh objects will be added to this dictionary. Do not
+            include mesh material information here unless an additional
+            mesh is being added to the scene from outside of ZnVis.
+            If no dict is provided, a templated dict will be used.
+        update_camera : bool (default = True)
+            If True, the camera will be updated to look at the mesh center.
+            Set this to False if you want to use a custom camera which is
+            defined in the scene_dict.
+        """
+        if scene_dict is None:
+            scene_dict = default_scene_dict
+        self.scene_dict = scene_dict
+        self.update_camera = update_camera
+
+    def _update_camera(self, view_matrix: np.ndarray) -> None:
+        """
+        Update the camera to look at the mesh center.
+
+        Parameters
+        ----------
+        view_matrix : np.ndarray
+            View matrix for the camera from open3d.
+
+        Notes
+        -----
+        This function updates the camera in the scene_dict.
+        It should be called before rendering.
+        """
+        camera_position = view_matrix[:3, 3]
+        forward_direction = view_matrix[:3, 2]
+        camera_target = -1 * camera_position + forward_direction
+        up_direction = view_matrix[:3, 1]
+
+        view_matrix = mi.ScalarTransform4f.look_at(
+            origin=camera_position, target=camera_target, up=up_direction
+        )
+        self.scene_dict["sensor"]["to_world"] = view_matrix
+
+    def render_mesh_objects(
+        self,
+        mesh_objects: dict,
+        view_matrix: np.ndarray,
+        save_dir: str = "./",
+        save_name: str = "znvis_render.exr",
+    ):
+        """
+        Render mesh objects.
+
+        Parameters
+        ----------
+        mesh_objects : list
+            List of mesh objects to render.
+        view_matrix : np.ndarray
+            View matrix for the camera from open3d.
+        save_dir : str (default = "./")
+            Directory to save the rendered image.
+        save_name : str (default = "znvis_render.exr")
+            Name of the rendered image.
+
+        Returns
+        -------
+        Saves an image to disk.
+        """
+        # Update camera.
+        if self.update_camera:
+            self._update_camera(view_matrix)
+
+        # Add mesh objects to scene dict.
+        for mesh_name in mesh_objects:
+            bsdf = mesh_objects[mesh_name]["bsdf"]
+            material = mesh_objects[mesh_name]["material"]
+
+            # Convert to a tensor mesh.
+            # print(mesh_objects[mesh_name]["mesh"].material)
+            mesh = o3d.t.geometry.TriangleMesh.from_legacy(
+                mesh_objects[mesh_name]["mesh"]
+            )
+
+            if bsdf is None:
+                mesh.material.set_default_properties()
+                mesh.material.material_name = "defaultLit"
+                mesh.material.vector_properties["base_color"] = material.base_color
+                mesh.material.scalar_properties["roughness"] = material.base_roughness
+                mesh.material.scalar_properties["metallic"] = material.base_metallic
+                mesh.material.scalar_properties[
+                    "reflectance"
+                ] = material.base_reflectance
+                mesh.material.scalar_properties["anisotropy"] = material.base_anisotropy
+
+            # Convert to Mitsuba mesh
+            mitsuba_mesh = mesh.to_mitsuba(mesh_name, bsdf=bsdf)
+            # Add to scene dict.
+            self.scene_dict[mesh_name] = mitsuba_mesh
+
+        # Render the scene.
+        scene = mi.load_dict(self.scene_dict)
+
+        img = mi.render(scene)
+        bmp = mi.Bitmap(img)
+        bmp.write(os.path.join(save_dir, save_name))
diff --git a/znvis/visualizer/visualizer.py b/znvis/visualizer/visualizer.py
index 0370486..a41ae23 100644
--- a/znvis/visualizer/visualizer.py
+++ b/znvis/visualizer/visualizer.py
@@ -20,6 +20,9 @@
 -------
 Main visualizer class.
 """
+import os
+
+os.environ["OPENCV_IO_ENABLE_OPENEXR"] = "1"
 import pathlib
 import re
 import shutil
@@ -33,6 +36,7 @@
 from rich.progress import Progress, track
 
 import znvis
+from znvis.rendering import Mitsuba
 
 
 class Visualizer:
@@ -60,7 +64,8 @@ def __init__(
         number_of_steps: int = None,
         keep_frames: bool = False,
         bounding_box: znvis.BoundingBox = None,
-        video_format: str = "mp4",
+        video_format: str = "avi",
+        renderer: Mitsuba = Mitsuba(),
     ):
         """
         Constructor for the visualizer.
@@ -93,6 +98,7 @@ def __init__(
         self.frame_folder = self.output_folder / "video_frames"
         self.video_format = video_format
         self.keep_frames = keep_frames
+        self.renderer = renderer
 
         self.obj_folder = self.output_folder / "obj_files"
 
@@ -192,7 +198,7 @@ def _create_movie(self):
         image storing thread can run to completion before
         this one is called. (GIL stuff)
         """
-        images = [f.as_posix() for f in self.frame_folder.glob("*.png")]
+        images = [f.as_posix() for f in self.frame_folder.glob("*.exr")]
 
         # Sort images by number
         images = sorted(images, key=lambda s: int(re.search(r"\d+", s).group()))
@@ -258,10 +264,26 @@ def _take_screenshot(self, vis):
         -------
         Takes a screenshot and dumps it
         """
-        vis.export_current_image(
-            (self.output_folder / f"screenshot_{self.counter}.png").as_posix()
+        old_state = self.interrupt  # get old state
+        self.interrupt = 0  # stop live feed if running.
+        mesh_dict = {}
+
+        for item in self.particles:
+            mesh_dict[item.name] = {
+                "mesh": item.mesh_list[self.counter],
+                "bsdf": item.mesh.material.mitsuba_bsdf,
+                "material": item.mesh.o3d_material,
+            }
+
+        view_matrix = vis.scene.camera.get_view_matrix()
+        self.renderer.render_mesh_objects(
+            mesh_dict, view_matrix, save_name=f"frame_{self.counter}.exr"
         )
 
+        # Restart live feed if it was running before the export.
+        if old_state == 1:
+            self._continuous_trajectory(vis)
+
     def _initialize_particles(self):
         """
         Initialize the particles in the simulation.
@@ -346,14 +368,27 @@ def save_callable():
             """
             Function to be called on thread to save image.
             """
-            self.vis.export_current_image(
-                (self.frame_folder / f"frame_{self.counter:0>6}.png").as_posix()
+            mesh_dict = {}
+
+            for item in self.particles:
+                mesh_dict[item.name] = {
+                    "mesh": item.mesh_list[self.counter],
+                    "bsdf": item.mesh.material.mitsuba_bsdf,
+                    "material": item.mesh.o3d_material,
+                }
+
+            view_matrix = self.vis.scene.camera.get_view_matrix()
+            self.renderer.render_mesh_objects(
+                mesh_dict,
+                view_matrix,
+                save_dir=self.frame_folder,
+                save_name=f"frame_{self.counter:0>6}.exr",
             )
+
             self.save_thread_finished = True
 
         with Progress() as progress:
             task = progress.add_task("Saving scenes...", total=self.number_of_steps)
-            # while self.counter < (self.number_of_steps - 1):
             while not progress.finished:
                 time.sleep(1 / self.frame_rate)
 

From c8caa670ace7755a30d503bba214aa7df26fd80d Mon Sep 17 00:00:00 2001
From: SamTov <tovey.samuel@gmail.com>
Date: Tue, 10 Oct 2023 16:00:16 +0200
Subject: [PATCH 03/13] Add materail example

---
 examples/material_spheres.py   | 71 ++++++++++++++++++++++++++++++++++
 znvis/material/material.py     |  3 +-
 znvis/rendering/mitsuba.py     | 18 +++------
 znvis/visualizer/visualizer.py | 17 +++++---
 4 files changed, 89 insertions(+), 20 deletions(-)
 create mode 100644 examples/material_spheres.py

diff --git a/examples/material_spheres.py b/examples/material_spheres.py
new file mode 100644
index 0000000..d8be0a7
--- /dev/null
+++ b/examples/material_spheres.py
@@ -0,0 +1,71 @@
+"""
+ZnVis: A Zincwarecode package.
+License
+-------
+This program and the accompanying materials are made available under the terms
+of the Eclipse Public License v2.0 which accompanies this distribution, and is
+available at https://www.eclipse.org/legal/epl-v20.html
+SPDX-License-Identifier: EPL-2.0
+Copyright Contributors to the Zincwarecode Project.
+Contact Information
+-------------------
+email: zincwarecode@gmail.com
+github: https://github.com/zincware
+web: https://zincwarecode.com/
+Citation
+--------
+If you use this module please cite us with:
+
+Summary
+-------
+Tutorial script to visualize simple spheres over a random trajectory.
+"""
+import numpy as np
+
+import znvis as vis
+
+import mitsuba as mi
+
+
+if __name__ == "__main__":
+    """
+    Run the simple spheres example.
+    """
+    # Particle 1 definition
+    hairy = mi.load_dict({'type': 'conductor',
+'material': 'Au'}
+)
+    material_1 = vis.Material(colour=np.array([30, 144, 255]) / 255, alpha=0.6, mitsuba_bsdf=hairy)
+    
+    # Define the first particle.
+    trajectory = np.random.uniform(-100, 100, (100, 1000, 3))
+    mesh = vis.Sphere(radius=2.0, resolution=10, material=material_1)
+    particle = vis.Particle(
+        name="Blue", mesh=mesh, position=trajectory, smoothing=False
+    )
+
+    # Define the second particle.
+    bsdf_smooth_plastic = mi.load_dict({
+    'type': 'plastic',
+    'diffuse_reflectance': {
+        'type': 'rgb',
+        'value': [0.1, 0.27, 0.36]
+    },
+    'int_ior': 1.9
+})
+    material_2 = vis.Material(
+        colour=np.array([255, 140, 0]) / 255, 
+        alpha=1.0, 
+        mitsuba_bsdf=bsdf_smooth_plastic
+        )
+
+    # Define the second particle.
+    trajectory_2 = np.random.uniform(-10, 10, (100, 1000, 3))
+    mesh_2 = vis.Sphere(radius=1.0, resolution=10, material=material_2)
+    particle_2 = vis.Particle(
+        name="Orange", mesh=mesh_2, position=trajectory_2, smoothing=False
+    )
+
+    # Construct the visualizer and run
+    visualizer = vis.Visualizer(particles=[particle, particle_2], frame_rate=20)
+    visualizer.run_visualization()
diff --git a/znvis/material/material.py b/znvis/material/material.py
index 99db158..e727760 100644
--- a/znvis/material/material.py
+++ b/znvis/material/material.py
@@ -55,5 +55,4 @@ class Material:
     metallic: float = 0.0
     reflectance: float = 0.4
     anisotropy: float = 0.4
-
-    mitsuba_bsdf = None
+    mitsuba_bsdf: object = None
diff --git a/znvis/rendering/mitsuba.py b/znvis/rendering/mitsuba.py
index 2302950..4357d73 100644
--- a/znvis/rendering/mitsuba.py
+++ b/znvis/rendering/mitsuba.py
@@ -26,7 +26,7 @@
 import numpy as np
 import open3d as o3d
 
-mi.set_variant("llvm_ad_rgb")
+mi.set_variant("cuda_ad_rgb")
 
 
 # Default scene dict.
@@ -36,7 +36,7 @@
     "light": {"type": "constant", "radiance": {"type": "rgb", "value": 1.0}},
     "sensor": {
         "type": "perspective",
-        "fov": 60,
+        "fov": 90,
         "thefilm": {
             "type": "hdrfilm",
             "width": 4096,
@@ -44,7 +44,7 @@
         },
         "thesampler": {
             "type": "multijitter",
-            "sample_count": 20,
+            "sample_count": 64,
         },
     },
 }
@@ -91,15 +91,7 @@ def _update_camera(self, view_matrix: np.ndarray) -> None:
         This function updates the camera in the scene_dict.
         It should be called before rendering.
         """
-        camera_position = view_matrix[:3, 3]
-        forward_direction = view_matrix[:3, 2]
-        camera_target = -1 * camera_position + forward_direction
-        up_direction = view_matrix[:3, 1]
-
-        view_matrix = mi.ScalarTransform4f.look_at(
-            origin=camera_position, target=camera_target, up=up_direction
-        )
-        self.scene_dict["sensor"]["to_world"] = view_matrix
+        self.scene_dict["sensor"]["to_world"] = mi.ScalarTransform4f(view_matrix)
 
     def render_mesh_objects(
         self,
@@ -162,4 +154,6 @@ def render_mesh_objects(
 
         img = mi.render(scene)
         bmp = mi.Bitmap(img)
+
+        bmp = bmp.convert(mi.Bitmap.PixelFormat.RGB, mi.Struct.Type.UInt8, True)
         bmp.write(os.path.join(save_dir, save_name))
diff --git a/znvis/visualizer/visualizer.py b/znvis/visualizer/visualizer.py
index a41ae23..b764202 100644
--- a/znvis/visualizer/visualizer.py
+++ b/znvis/visualizer/visualizer.py
@@ -37,6 +37,7 @@
 
 import znvis
 from znvis.rendering import Mitsuba
+import numpy as np
 
 
 class Visualizer:
@@ -62,9 +63,9 @@ def __init__(
         output_folder: typing.Union[str, pathlib.Path] = "./",
         frame_rate: int = 24,
         number_of_steps: int = None,
-        keep_frames: bool = False,
+        keep_frames: bool = True,
         bounding_box: znvis.BoundingBox = None,
-        video_format: str = "avi",
+        video_format: str = "mp4",
         renderer: Mitsuba = Mitsuba(),
     ):
         """
@@ -198,7 +199,7 @@ def _create_movie(self):
         image storing thread can run to completion before
         this one is called. (GIL stuff)
         """
-        images = [f.as_posix() for f in self.frame_folder.glob("*.exr")]
+        images = [f.as_posix() for f in self.frame_folder.glob("*.png")]
 
         # Sort images by number
         images = sorted(images, key=lambda s: int(re.search(r"\d+", s).group()))
@@ -267,17 +268,21 @@ def _take_screenshot(self, vis):
         old_state = self.interrupt  # get old state
         self.interrupt = 0  # stop live feed if running.
         mesh_dict = {}
-
+        mesh_center = []
         for item in self.particles:
             mesh_dict[item.name] = {
                 "mesh": item.mesh_list[self.counter],
                 "bsdf": item.mesh.material.mitsuba_bsdf,
                 "material": item.mesh.o3d_material,
             }
+            mesh_center.append(item.mesh_list[self.counter].get_axis_aligned_bounding_box().get_center())
 
         view_matrix = vis.scene.camera.get_view_matrix()
+
         self.renderer.render_mesh_objects(
-            mesh_dict, view_matrix, save_name=f"frame_{self.counter}.exr"
+            mesh_dict, 
+            view_matrix,
+            save_name=f"frame_{self.counter}.png"
         )
 
         # Restart live feed if it was running before the export.
@@ -382,7 +387,7 @@ def save_callable():
                 mesh_dict,
                 view_matrix,
                 save_dir=self.frame_folder,
-                save_name=f"frame_{self.counter:0>6}.exr",
+                save_name=f"frame_{self.counter:0>6}.png",
             )
 
             self.save_thread_finished = True

From 88d4270fb26a03c7d05915ff277cff98ad0908e7 Mon Sep 17 00:00:00 2001
From: SamTov <tovey.samuel@gmail.com>
Date: Wed, 14 Feb 2024 17:46:55 +0100
Subject: [PATCH 04/13] updates

---
 examples/material_spheres.py   | 37 ++++++++++++++++------------------
 znvis/visualizer/visualizer.py | 11 +++++-----
 2 files changed, 23 insertions(+), 25 deletions(-)

diff --git a/examples/material_spheres.py b/examples/material_spheres.py
index d8be0a7..7183e64 100644
--- a/examples/material_spheres.py
+++ b/examples/material_spheres.py
@@ -20,23 +20,21 @@
 -------
 Tutorial script to visualize simple spheres over a random trajectory.
 """
+import mitsuba as mi
 import numpy as np
 
 import znvis as vis
 
-import mitsuba as mi
-
-
 if __name__ == "__main__":
     """
     Run the simple spheres example.
     """
     # Particle 1 definition
-    hairy = mi.load_dict({'type': 'conductor',
-'material': 'Au'}
-)
-    material_1 = vis.Material(colour=np.array([30, 144, 255]) / 255, alpha=0.6, mitsuba_bsdf=hairy)
-    
+    hairy = mi.load_dict({"type": "conductor", "material": "Au"})
+    material_1 = vis.Material(
+        colour=np.array([30, 144, 255]) / 255, alpha=0.6, mitsuba_bsdf=hairy
+    )
+
     # Define the first particle.
     trajectory = np.random.uniform(-100, 100, (100, 1000, 3))
     mesh = vis.Sphere(radius=2.0, resolution=10, material=material_1)
@@ -45,19 +43,18 @@
     )
 
     # Define the second particle.
-    bsdf_smooth_plastic = mi.load_dict({
-    'type': 'plastic',
-    'diffuse_reflectance': {
-        'type': 'rgb',
-        'value': [0.1, 0.27, 0.36]
-    },
-    'int_ior': 1.9
-})
+    bsdf_smooth_plastic = mi.load_dict(
+        {
+            "type": "plastic",
+            "diffuse_reflectance": {"type": "rgb", "value": [0.1, 0.27, 0.36]},
+            "int_ior": 1.9,
+        }
+    )
     material_2 = vis.Material(
-        colour=np.array([255, 140, 0]) / 255, 
-        alpha=1.0, 
-        mitsuba_bsdf=bsdf_smooth_plastic
-        )
+        colour=np.array([255, 140, 0]) / 255,
+        alpha=1.0,
+        mitsuba_bsdf=bsdf_smooth_plastic,
+    )
 
     # Define the second particle.
     trajectory_2 = np.random.uniform(-10, 10, (100, 1000, 3))
diff --git a/znvis/visualizer/visualizer.py b/znvis/visualizer/visualizer.py
index b764202..fa75b38 100644
--- a/znvis/visualizer/visualizer.py
+++ b/znvis/visualizer/visualizer.py
@@ -37,7 +37,6 @@
 
 import znvis
 from znvis.rendering import Mitsuba
-import numpy as np
 
 
 class Visualizer:
@@ -275,14 +274,16 @@ def _take_screenshot(self, vis):
                 "bsdf": item.mesh.material.mitsuba_bsdf,
                 "material": item.mesh.o3d_material,
             }
-            mesh_center.append(item.mesh_list[self.counter].get_axis_aligned_bounding_box().get_center())
+            mesh_center.append(
+                item.mesh_list[self.counter]
+                .get_axis_aligned_bounding_box()
+                .get_center()
+            )
 
         view_matrix = vis.scene.camera.get_view_matrix()
 
         self.renderer.render_mesh_objects(
-            mesh_dict, 
-            view_matrix,
-            save_name=f"frame_{self.counter}.png"
+            mesh_dict, view_matrix, save_name=f"frame_{self.counter}.png"
         )
 
         # Restart live feed if it was running before the export.

From 5a9e434f391c0868fb96ae264502f487053810eb Mon Sep 17 00:00:00 2001
From: SamTov <tovey.samuel@gmail.com>
Date: Tue, 14 May 2024 12:36:47 +0200
Subject: [PATCH 05/13] Fix render camera transform

---
 znvis/mesh/custom.py       |  4 +++-
 znvis/mesh/cylinder.py     |  2 +-
 znvis/mesh/mesh.py         |  1 +
 znvis/mesh/sphere.py       |  2 +-
 znvis/rendering/mitsuba.py | 12 +++++++++++-
 5 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/znvis/mesh/custom.py b/znvis/mesh/custom.py
index ef25d0a..0a208e3 100644
--- a/znvis/mesh/custom.py
+++ b/znvis/mesh/custom.py
@@ -45,6 +45,7 @@ class CustomMesh(Mesh):
     """
 
     file: str = None
+    scale: float = 1.0
 
     def create_mesh(
         self, starting_position: np.ndarray, starting_orientation: np.ndarray = None
@@ -65,9 +66,10 @@ def create_mesh(
         """
         mesh = o3d.io.read_triangle_mesh(self.file)
         mesh.compute_vertex_normals()
+        mesh.scale(self.scale, center=mesh.get_center())
         mesh.translate(starting_position.astype(float))
         if starting_orientation is not None:
-            matrix = rotation_matrix(np.array([0, 0, 1]), starting_orientation)
+            matrix = rotation_matrix(self.base_direction, starting_orientation)
             mesh.rotate(matrix)
 
         return mesh
diff --git a/znvis/mesh/cylinder.py b/znvis/mesh/cylinder.py
index 6ada1bf..cde29eb 100644
--- a/znvis/mesh/cylinder.py
+++ b/znvis/mesh/cylinder.py
@@ -81,7 +81,7 @@ def create_mesh(
         cylinder.compute_vertex_normals()
         cylinder.translate(starting_position.astype(float))
         if starting_orientation is not None:
-            matrix = rotation_matrix(np.array([0, 0, 1]), starting_orientation)
+            matrix = rotation_matrix(self.base_direction, starting_orientation)
             cylinder.rotate(matrix)
 
         return cylinder
diff --git a/znvis/mesh/mesh.py b/znvis/mesh/mesh.py
index 39dcb63..ca27e81 100644
--- a/znvis/mesh/mesh.py
+++ b/znvis/mesh/mesh.py
@@ -40,6 +40,7 @@ class Mesh:
     """
 
     material: Material = Material()
+    base_direction = np.array([1, 0, 0])
 
     def __post_init__(self):
         """
diff --git a/znvis/mesh/sphere.py b/znvis/mesh/sphere.py
index 85487cd..0021dcf 100644
--- a/znvis/mesh/sphere.py
+++ b/znvis/mesh/sphere.py
@@ -69,7 +69,7 @@ def create_mesh(
         sphere.compute_vertex_normals()
         sphere.translate(starting_position.astype(float))
         if starting_orientation is not None:
-            matrix = rotation_matrix(np.array([0, 0, 1]), starting_orientation)
+            matrix = rotation_matrix(self.base_direction, starting_orientation)
             sphere.rotate(matrix)
 
         return sphere
diff --git a/znvis/rendering/mitsuba.py b/znvis/rendering/mitsuba.py
index 4357d73..2ab2f43 100644
--- a/znvis/rendering/mitsuba.py
+++ b/znvis/rendering/mitsuba.py
@@ -91,7 +91,17 @@ def _update_camera(self, view_matrix: np.ndarray) -> None:
         This function updates the camera in the scene_dict.
         It should be called before rendering.
         """
-        self.scene_dict["sensor"]["to_world"] = mi.ScalarTransform4f(view_matrix)
+        to_world_matrix = np.linalg.inv(view_matrix)
+
+        # Step 2: Adjust the coordinate system by flipping the Z-axis
+        z_flip_matrix = np.array(
+            [[-1, 0, 0, 0], [0, 1, 0, 0], [0, 0, -1, 0], [0, 0, 0, 1]]
+        )
+        adjusted_to_world_matrix = np.dot(to_world_matrix, z_flip_matrix)
+
+        self.scene_dict["sensor"]["to_world"] = mi.ScalarTransform4f(
+            adjusted_to_world_matrix
+        )
 
     def render_mesh_objects(
         self,

From ae83e47105624a48f02f1b74c8db63795f26b5d0 Mon Sep 17 00:00:00 2001
From: SamTov <tovey.samuel@gmail.com>
Date: Tue, 14 May 2024 12:40:35 +0200
Subject: [PATCH 06/13] Update pre-commit and linting

---
 .pre-commit-config.yaml        | 2 +-
 examples/material_spheres.py   | 1 +
 znvis/__init__.py              | 2 +-
 znvis/rendering/__init__.py    | 1 +
 znvis/rendering/mitsuba.py     | 7 ++++---
 znvis/visualizer/visualizer.py | 1 +
 6 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 209ad2f..3b9d647 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -4,7 +4,7 @@ fail_fast: true
 
 repos:
   - repo: https://github.com/psf/black
-    rev: 24.2.0
+    rev: 24.4.2
     hooks:
       - id: black
 
diff --git a/examples/material_spheres.py b/examples/material_spheres.py
index 7183e64..6081e76 100644
--- a/examples/material_spheres.py
+++ b/examples/material_spheres.py
@@ -20,6 +20,7 @@
 -------
 Tutorial script to visualize simple spheres over a random trajectory.
 """
+
 import mitsuba as mi
 import numpy as np
 
diff --git a/znvis/__init__.py b/znvis/__init__.py
index 458e1ec..ba99d48 100644
--- a/znvis/__init__.py
+++ b/znvis/__init__.py
@@ -21,8 +21,8 @@
 -------
 init file for the main ZnVis package.
 """
-from znvis import rendering
 
+from znvis import rendering
 from znvis.bounding_objects.bounding_box import BoundingBox
 from znvis.material.material import Material
 from znvis.mesh.custom import CustomMesh
diff --git a/znvis/rendering/__init__.py b/znvis/rendering/__init__.py
index b200eb6..d852917 100644
--- a/znvis/rendering/__init__.py
+++ b/znvis/rendering/__init__.py
@@ -20,6 +20,7 @@
 -------
 Init file for the rendering module.
 """
+
 from znvis.rendering.mitsuba import Mitsuba
 
 __all__ = [Mitsuba.__name__]
diff --git a/znvis/rendering/mitsuba.py b/znvis/rendering/mitsuba.py
index 2ab2f43..d9f07bc 100644
--- a/znvis/rendering/mitsuba.py
+++ b/znvis/rendering/mitsuba.py
@@ -20,6 +20,7 @@
 -------
 Mitsuba rendering module.
 """
+
 import os
 
 import mitsuba as mi
@@ -149,9 +150,9 @@ def render_mesh_objects(
                 mesh.material.vector_properties["base_color"] = material.base_color
                 mesh.material.scalar_properties["roughness"] = material.base_roughness
                 mesh.material.scalar_properties["metallic"] = material.base_metallic
-                mesh.material.scalar_properties[
-                    "reflectance"
-                ] = material.base_reflectance
+                mesh.material.scalar_properties["reflectance"] = (
+                    material.base_reflectance
+                )
                 mesh.material.scalar_properties["anisotropy"] = material.base_anisotropy
 
             # Convert to Mitsuba mesh
diff --git a/znvis/visualizer/visualizer.py b/znvis/visualizer/visualizer.py
index 3f2a185..bfa88f3 100644
--- a/znvis/visualizer/visualizer.py
+++ b/znvis/visualizer/visualizer.py
@@ -20,6 +20,7 @@
 -------
 Main visualizer class.
 """
+
 import os
 
 os.environ["OPENCV_IO_ENABLE_OPENEXR"] = "1"

From a45584f0cfa81e063de33caaf7750f2ecff5be21 Mon Sep 17 00:00:00 2001
From: SamTov <tovey.samuel@gmail.com>
Date: Tue, 14 May 2024 12:41:16 +0200
Subject: [PATCH 07/13] Add mitsuba to requirements

---
 requirements.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/requirements.txt b/requirements.txt
index 5d6ab30..5523ac0 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,3 +3,4 @@ numpy
 pytest
 rich
 opencv-python
+mitsuba

From 7208e2c16983422c252681355ddeed94e50e484c Mon Sep 17 00:00:00 2001
From: SamTov <tovey.samuel@gmail.com>
Date: Tue, 14 May 2024 13:09:46 +0200
Subject: [PATCH 08/13] Correct bare except

---
 .github/workflows/publish-to-pypi.yaml | 2 +-
 .github/workflows/pytest.yaml          | 4 +---
 znvis/rendering/mitsuba.py             | 6 +++++-
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/publish-to-pypi.yaml b/.github/workflows/publish-to-pypi.yaml
index b992088..1b62e73 100644
--- a/.github/workflows/publish-to-pypi.yaml
+++ b/.github/workflows/publish-to-pypi.yaml
@@ -14,7 +14,7 @@ jobs:
       - name: Set up Python 3.9
         uses: actions/setup-python@v1
         with:
-          python-version: 3.9
+          python-version: 3.11
       - name: Install pypa/build
         run: >-
           python -m
diff --git a/.github/workflows/pytest.yaml b/.github/workflows/pytest.yaml
index 842c7b3..db96fc6 100644
--- a/.github/workflows/pytest.yaml
+++ b/.github/workflows/pytest.yaml
@@ -14,9 +14,7 @@ jobs:
       fail-fast: false
       matrix:
         python-version:
-        - 3.8
-        - 3.9
-        - "3.10"
+        - "3.11"
     steps:
       - uses: actions/checkout@v3
       - name: Set up Python ${{ matrix.python-version }}
diff --git a/znvis/rendering/mitsuba.py b/znvis/rendering/mitsuba.py
index d9f07bc..9825ccd 100644
--- a/znvis/rendering/mitsuba.py
+++ b/znvis/rendering/mitsuba.py
@@ -27,7 +27,11 @@
 import numpy as np
 import open3d as o3d
 
-mi.set_variant("cuda_ad_rgb")
+try:
+    mi.set_variant("cuda_ad_rgb")
+except AttributeError:
+    mi.set_variant("scalar_rgb")
+    # mi.set_variant("llvm_ad_rgb")
 
 
 # Default scene dict.

From e9bc6cdb865eb4bf061e2f14eb9e09d2bea3b0fe Mon Sep 17 00:00:00 2001
From: SamTov <tovey.samuel@gmail.com>
Date: Tue, 14 May 2024 13:20:28 +0200
Subject: [PATCH 09/13] Change dataclass to fields

---
 znvis/bounding_objects/bounding_box.py | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/znvis/bounding_objects/bounding_box.py b/znvis/bounding_objects/bounding_box.py
index 26814d2..eb75ada 100644
--- a/znvis/bounding_objects/bounding_box.py
+++ b/znvis/bounding_objects/bounding_box.py
@@ -21,7 +21,7 @@
 Create  bounding box.
 """
 
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 
 import numpy as np
 import open3d as o3d
@@ -43,10 +43,12 @@ class BoundingBox:
     colour : np.ndarray shape=(3,)
     """
 
-    center: np.ndarray = np.array([0, 0, 0])
-    box_size: np.ndarray = np.array([1.0, 1.0, 1.0])
-    rotation_matrix: np.ndarray = np.array([[1, 0, 0], [0, 1, 0], [0, 0, 1]])
-    colour: np.ndarray = np.array([0.0, 0.0, 0.0])
+    center: np.ndarray = field(default_factory=lambda: np.array([0, 0, 0]))
+    box_size: np.ndarray = field(default_factory=lambda: np.array([1.0, 1.0, 1.0]))
+    rotation_matrix: np.ndarray = field(
+        default_factory=lambda: np.array([[1, 0, 0], [0, 1, 0], [0, 0, 1]])
+    )
+    colour: np.ndarray = field(default_factory=lambda: np.array([0.0, 0.0, 0.0]))
 
     def __call__(self) -> o3d.geometry.TriangleMesh:
         """

From 89fd0f1479c850c3533054c9eabfd060731ca431 Mon Sep 17 00:00:00 2001
From: SamTov <tovey.samuel@gmail.com>
Date: Tue, 14 May 2024 13:23:04 +0200
Subject: [PATCH 10/13] More dataclass changes

---
 znvis/material/material.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/znvis/material/material.py b/znvis/material/material.py
index 595f664..0a19393 100644
--- a/znvis/material/material.py
+++ b/znvis/material/material.py
@@ -22,7 +22,7 @@
 Material parent class.
 """
 
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 
 import numpy as np
 
@@ -50,7 +50,9 @@ class Material:
             Mitsuba bsdf object.
     """
 
-    colour: np.ndarray = np.array([59.0, 53.0, 97.0]) / 255
+    colour: np.ndarray = field(
+        default_factory=lambda: np.array([59.0, 53.0, 97.0]) / 255
+    )
     alpha: float = 1.0
     roughness: float = 0.5
     metallic: float = 0.0

From 0b0c0d46efd7c25c79e1244159ab49e991379130 Mon Sep 17 00:00:00 2001
From: SamTov <tovey.samuel@gmail.com>
Date: Tue, 14 May 2024 13:46:11 +0200
Subject: [PATCH 11/13] More dataclass refactoring

---
 znvis/mesh/mesh.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/znvis/mesh/mesh.py b/znvis/mesh/mesh.py
index bf63ae8..c84d16b 100644
--- a/znvis/mesh/mesh.py
+++ b/znvis/mesh/mesh.py
@@ -20,7 +20,7 @@
 Module for the mesh parent class.
 """
 
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 
 import numpy as np
 import open3d as o3d
@@ -41,7 +41,7 @@ class Mesh:
     """
 
     material: Material = Material()
-    base_direction = np.array([1, 0, 0])
+    base_direction = field(default_factory=lambda: np.array([1, 0, 0]))
 
     def __post_init__(self):
         """

From e22fffa3bc91d2774237fb2be200a2b18972e6b1 Mon Sep 17 00:00:00 2001
From: SamTov <tovey.samuel@gmail.com>
Date: Tue, 14 May 2024 13:49:56 +0200
Subject: [PATCH 12/13] More updates

---
 znvis/mesh/mesh.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/znvis/mesh/mesh.py b/znvis/mesh/mesh.py
index c84d16b..49bb772 100644
--- a/znvis/mesh/mesh.py
+++ b/znvis/mesh/mesh.py
@@ -40,7 +40,7 @@ class Mesh:
             A ZnVis material class.
     """
 
-    material: Material = Material()
+    material: Material = field(default_factory=lambda: Material())
     base_direction = field(default_factory=lambda: np.array([1, 0, 0]))
 
     def __post_init__(self):

From da0c7284fabe4c6c4f4a6ec912b214731d5377de Mon Sep 17 00:00:00 2001
From: SamTov <tovey.samuel@gmail.com>
Date: Tue, 14 May 2024 13:57:34 +0200
Subject: [PATCH 13/13] Add type to dataclass

---
 znvis/mesh/mesh.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/znvis/mesh/mesh.py b/znvis/mesh/mesh.py
index 49bb772..252a4b0 100644
--- a/znvis/mesh/mesh.py
+++ b/znvis/mesh/mesh.py
@@ -41,7 +41,7 @@ class Mesh:
     """
 
     material: Material = field(default_factory=lambda: Material())
-    base_direction = field(default_factory=lambda: np.array([1, 0, 0]))
+    base_direction: np.ndarray = field(default_factory=lambda: np.array([1, 0, 0]))
 
     def __post_init__(self):
         """