Kobra

Kobra is a 3D rendering engine written in C++ using the Vulkan API. It is designed with research development in mind, so that more time can be spent towards experimentation rather than implementation. This project is still in progress.

Current Features

Kobra targets physically-based path-tracing pipelines. Currently, only path-tracing with OptiX/CUDA is supported (see the Upcoming section for platforms that will be supported in the future).

However, Kobra provides other facilities that enables convenient development of rendering applications, such as rasterization (with customizable shader programs) and UI rendering (currently built directly off of ImGui).

These facilities can be accessed as layers; for example, ForwardRenderer, UI, and Denoiser are layers which perform computations related to forward rendering, UI rendering, and image denoising. Multiple layers can be sequentially dispatched in the same command buffer. The documentation for such operations are still in development.

Furthermore, Kobra provides an (basic) interface for editing scenes and rendering, shown below:

Note that this is not final by any means, and any suggestions for improving this interface are welcome.

Scenes are currently specified with a file describing components in the entity-component system; see scenes/ for examples. The file specification for scenes is not fixed, and still being developed.

Layers

The following list includes the currently available layers.

• MeshMemory: manages mesh memory, which is often shared across other layers
• ForwardRenderer: performs forward rendering, with customizable ShaderPrograms
• UI: does UI rendering, by attaching user-defined ImGuiAttachment objects
• Denoiser: denoises input images
• Framer: renders a plain image to the swapchain; useful for raytracing, where the image is generated outside of Vulkan
• System: manages raytracing buffers and acceleration structures for a given scene
• ArmadaRTX: performs raytracing of arbitrary programs; the functionality of the RTX kernels can be programmed via AttachmentRTX objects -- see path_tracer.cuh and restir.cuh in the include/armada/ directory for examples

Renders

The following are example renders generated from Kobra's OptiX path tracer (+AI denoising).

Bathroom [1]

Breakfast Room [1]

Fireplace [1]

Kitchen [2]

Living Room [1]

San Miguel [1]

Sibenik [1]

[1] McGuire Computer Graphics Archive

[2] Rendering Resources

Upcoming

• [ ] Revive the GLSL path tracer (using RadeonRays as backend)
• [ ] VulkanRTX port
• [ ] Implement an applet for presenting image difference with various metrics (e.g. MAPE, FLIP)