Ogre 14.3 released

by Pavel Rojtberg | Sep 22, 2024 | News

Ogre 14.3.0 was just released. This release contains some significant bug-fixes and feature additions, which we will discuss in more detail below. We recommend all users of the 14.x branch to update.

For a full overview of the changes, see the changelog.

Table of Contents

• 3D Gaussian Splatting and VET_HALF support
• Mesh Shader Support
• Wayland Support on Linux
• HighPy module for Python

3D Gaussian Splatting and VET_HALF support

Ogre 14.3 now comes with an example that shows how to render 3D gaussian splats alongside with normal mesh data.

To efficiently store the splats they were converted from the original .ply files to native ogre .mesh files which reduced the storage by 10x. See my blog post for the details of the procedure.

To achieve this reduction the new VET_HALFx types were introduced in Ogre, which allow storing vertex attributes using 16bit floating points.

As the most useful VET_HALF3 type is neither supported by D3D9 nor by D3D11, Ogre will transparently pad it to VET_HALF4 on loading. This approach maintains reduced file sizes on these render systems with a slight increase in loading time. It’s worth mentioning that all other rendering systems, such as Metal and Vulkan, do support VET_HALF3.

Mesh Shader Support

Initial mesh shader support has been introduced in Ogre. They are supported on GL3Plus via GL_NV_mesh_shader and on Vulkan via VK_EXT_mesh_shader. Although the loading and processing of these shaders is now supported in the OgreMain component, the rest of the pipeline still needs to be developed in upcoming releases. Specifically, the generation of the meshlet structure, which is essential for the effectiveness of mesh shaders, is not yet available. Storing this structure will likely require an update to the .mesh format, which must be handled carefully to ensure backward compatibility.

Wayland Support on Linux

Thanks to the contributions of “Joakim Haugen”, “benjaminvdh” and the work of yours truly, all OpenGL and the Vulkan RenderSystems can now be compiled on Linux without any X11 dependencies and will use the Wayland display server instead. This is particularly beneficial for running Ogre on embedded devices or through WSL.

If you use OgreBites, this feature is automatically available by setting the environment variable SDL_VIDEODRIVER=wayland to instruct SDL to use Wayland. There is also initial support for OgreBitesQt, but Wayland interoperability with Qt is still under development and not fully functional with Ogre yet.

HighPy module for Python

The new HighPy module enables Ogre to function as a lightweight Python renderer. As the name implies, this module offers a high-level API, allowing users to start using Ogre without the need to read the documentation.

If you want to render a mesh it is just:

import Ogre.HighPy as ohi
ohi.window_create("ohi_world", (800, 600))
ohi.mesh_show("ohi_world", "DamagedHelmet.glb", position=(0, 0, -3))
while ohi.window_draw("ohi_world") != 27: pass

This will load the gltf2 file using the Assimp Plugin and display it using our Filament-based PBR rendering pipeline.

want to add a GUI to that? Add

import Ogre.ImGui as ImGui
ohi.window_use_imgui("ohi_world", ImGui.ShowDemoWindow)

want to display an background image?

ohi.imshow("ohi_world", "image.png")

This will use the secure image-rs rust plugin to load most image formats.

Then there is Physics with the Bullet component and headless EGL rendering on Linux..

Another improvement to the Python bindings is that Ogre now works better with Python threading. Previously we would just hog the GIL preventing any other (python) thread to run. Now you can allow python threads while waiting for vsync by calling Ogre.Root.getSingleton().allowPyThread()

Finally, the Python modules are now part of the official Docs.

Ogre 14.2 released

by Pavel Rojtberg | Feb 26, 2024 | News

Ogre 14.2.0 was just released. This release contains some significant bug-fixes and feature additions, which we will discuss in more detail below. We recommend all users of the 14.x branch to update.

For a full overview of the changes, see the changelog.

Table of Contents

• ImGui based ConfigDialog
• Vertex Cache Optimization in MeshUpgrader
• Cleaned up samples
• Ecosystem Roundup
  • blender2ogre
  • ogre-meshviewer

ImGui based ConfigDialog

The ApplicationContext can now display a ImGui based ConfigDialog, when you call runRenderingSettingsDialog().
The advantage of using ImGui is that we can get rid of platform specific toolkits like Xaw, which is necessary on Linux to be Wayland compatible. For the other platforms, this merely unifies the UI.
Furthermore, if you are already using ImGui, you will be able to integrate the Rendering Settings into your existing UI using the DrawRenderingSettings method.

The platform specific getNativeConfigDialog() based Dialogs will be removed in a future release.

Vertex Cache Optimization in MeshUpgrader

MeshUpgrader now accepts the -optvtxcache flag to improve the vertex cache utilization of the given mesh.

This reorders the index buffer of the mesh such that triangles are rendered in order of proximity. If enabled, the MeshUpgrader will print the change of the “average cache miss ratio (ACMR)” metric. It measures the number of cache misses per triangle and thus ranges from 3.0 (all 3 vertices missed) to about 0.5 for a convenient mesh.

Note that the algorithm for this was present since Ogre 1.2, it was just not exposed anywhere unless you explicitly processed your meshes by hand.

If you want to know more about the topic, see here. The algorithm in ogre has quadratic complexity though, but should provide better results.

Cleaned up samples

To integrate the ImGui based ConfigDialog, the SampleBrowser and the Samples were refactored, and now resemble more idiomatic usage of Ogre, such as input filtering using the InputListenerChain and interaction with ApplicationContext. This refactoring also led to the removal of a significant amount of boilerplate code.

Ecosystem Roundup

blender2ogre

Thanks to the work of “Guillermo Ojea Quintana” blender2ogre now supports manually specified meshes for LOD levels – in addition to auto generating mesh LOD using Blender or Ogre. See the documentation for details.

Additionally, he did some profiling and we could resolve a rather embarrassing bottleneck resulting in a import and export speed improvement of 10x.

ogre-meshviewer

Again thanks to the contributions of “Guillermo Ojea Quintana”, ogre-meshviewer now has nice ImGui based RenderSystem config dialog, wireframe mode, better LOD level inspection and a “Open File” dialog.