This is an extension of the Vulkan ray tracing tutorial.
We will discuss the vkCmdTraceRaysIndirectKHR command, which allows the
width, height, and depth of a trace ray command to be specifed by a
buffer on the device, rather than directly by the host. As a demonstration,
this example will add colorful lanterns to the scene that add their own light
and shadows, with a finite radius of effect. A compute shader will calculate
scissor rectangles for each lantern, and an indirect trace rays command will
dispatch rays for lanterns only within those scissor rectangles.
