rtengine/docs/NOTES_renderer_v3.md

GFX/Renderer v3

• Build around draw indirect
• Keep many meshlets together in one large buffer
• Meshlet: 128 triangles
• Mesh: List of meshlets
• Do compute based culling per VIEW
• Each View gets a list of mesh-refs (expanded to meshlet refs), and associated transforms
• Optional:
  • These are, by default, permanent, allowing us to build a efficient bvh.
  • Mark nodes as deleted, only collapse once the entire subtree is deleted.

Draw/Materials:

• Culling outputs tri-idx, meshlet for every pixel (For hardware that supports it, this could use raytracing)
• Meshlet refers to a (sub)material (via index)
• Per tile, create a list of draw indirect commands and a read-back buffer containing the (sub-)material index for each draw (+ total nr of draws)
• CPU loops over materials, issueing draw indirect calls upon material changes
• The ref to a sub-material may be made via meshlet -> material and view type -> sub-material

Some (most) sub-materials could draw into a gbuffer.

SubMaterialData is baked into structs containing constants and/or bindless ids. Kept in one huge buffer SubMaterial:

• Data
• PSO Material:
• View Type -> SubMaterial

Frame Graph - Each view is a pass. Can re-use existing?

Renderer API:

• CreateMesh(data) -> MeshRef
• InstantiateMesh(MeshRef) -> MeshRef
• CreateView(type) -> View
• AddToView(MeshRef, Transform, Material) -> InstanceRef
• RemoveFromView(InstanceRef)
• UpdateInView(InstanceRef, Transform, Material)
• SetViewCamera(View, Camera)
• RenderView(View)
• CreateMaterial(NumSubMaterials, SubMaterialInfo*) -> Material
• CreateTexture(Format, W, H, NumMipLevels, Optional<InitialData*>) -> Texture
• EnqueueTextureUpdate(Texture, MipLevel, NewData)