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rt: simple real-time ray tracing

this uses the vulkan ray tracing extension to path trace a scene. the geometry comes from one or more bvh modules which collect input for bottom level acceleration structures.

the rt module uses hero wavelength spectral sampling for accurate colour reproduction.

(scene: nikita sky demo)

connectors

• output the rendered beauty image
• tex an array connector for input textures, connect to an i-jpglst or i-lut module
• blue blue noise texture as input lut, as those provided by christoph
• irr irradiance buffer, that is: beauty output divided by albedo
• albedo fake diffuse albedo for use with svgf, demodulated from the irradiance buffer
• gbuf packed normal and depth of the first intersection

the tex connector expects an array of input textures, as the i-jpglst module provides, or the i-lut module if you pass a .txt file with a list of filenames.

you can download a blue noise texture from this github issue. this was too large to just ship with the vkdt distribution.

parameters

this still changes so often.. be careful to trust this text.

• cam position, direction, and up vector of the camera
• fog homogeneous global background fog
• spp samples per pixel
• envmap filename of the environment map, 2:1 aspect latitude/longitude, .hdr preferably 8k
• cam mode use custom camera in this module, or grab camera, simulation time, and fog from another module
• cam_mod if cam mode is set to another module, this is the other module's name
• cam_inst if cam mode is set to another module, this is the other module's instance
• sampler choose which path space sampler to use for rendering: path tracing/env-nee, markov chain path guiding
• wd width of the render in pixels
• ht height of the render in pixels

the sampler dropdown list includes simple path tracing with optional next event estimation to the envmap, as well as markov chain path guiding based on the publication:
Lucas Alber, Johannes Hanika, and Carsten Dachsbacher. Real-time Markov chain path guiding for global illumination and single scattering. Proc. ACM Comput. Graph. Interact. Tech., 8(1), 2025.