What is vulkanrt?

VulkanRT (Vulkan Ray Tracing) isn't a standalone thing like Vulkan itself. Instead, it refers to the ray tracing capabilities within the Vulkan API. It's not a separate API or library; rather, it's a set of extensions and features added to Vulkan to enable hardware-accelerated ray tracing.

Here's what you should know about Vulkan ray tracing:

• Extensions: Ray tracing in Vulkan is enabled through extensions. Developers need to explicitly enable these extensions in their applications to access ray tracing functionality. The specific extensions depend on the Vulkan version and the hardware capabilities.

• Shader Stages: Vulkan ray tracing uses specialized shader stages:

  • Ray Generation Shaders: Initiate the ray tracing process.
  • Miss Shaders: Executed when a ray doesn't intersect any geometry.
  • Closest Hit Shaders: Executed when a ray intersects geometry, providing the closest intersection point.
  • Any Hit Shaders: Can be used for early ray termination (if an intersection is found, the shader can signal to stop further ray traversal).
  • Intersection Shaders: Used for custom intersection testing. (Generally less common than Closest Hit)

• Acceleration Structures: Efficiently accelerate ray-scene intersection testing. Vulkan uses acceleration structures (like BVHs - Bounding Volume Hierarchies) to cull rays that are unlikely to intersect with geometry. These structures are built and managed within the Vulkan API.

• Hardware Dependency: Vulkan ray tracing relies on hardware support. Your GPU must have dedicated ray tracing hardware (e.g., dedicated ray tracing cores) to effectively utilize these features. Software ray tracing is possible, but significantly less performant.

• Portability: While aiming for cross-platform compatibility, the specific implementation details and performance might vary depending on the hardware and driver.

• Complexity: Implementing ray tracing in Vulkan is generally more complex than using rasterization alone, requiring a deeper understanding of the ray tracing pipeline and the relevant shader stages.

In short, VulkanRT is the collection of Vulkan extensions and features that bring hardware-accelerated ray tracing to Vulkan applications. It's not a separate API but an extension of the existing Vulkan capabilities. To use it, developers need to use the appropriate extensions, understand the ray tracing pipeline stages, and manage acceleration structures.