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Runtime.Graphics.Scene.Renderable (Visera.Runtime.Graphics.Scene.Renderable)

Defines the per-instance data model, mesh abstraction, and renderable interface used by the scene and draw-list extraction.

FInstanceData

Unified per-instance data for both 2D and 3D renderables. Uploaded to the GPU as a storage buffer (SSBO) and accessed in shaders via StructuredBuffer<InstanceData> (Set 1, Binding 0).

Member Type Description
Transform FTransform3x4F 3×4 affine transform (row-major, matches Slang float3x4).
Color FVector4F Per-instance color / tint (RGBA).
CustomData FVector4F Shader-specific data (e.g. UV origin + extent for sprites).

sizeof(FInstanceData) == 80, standard layout.

FMesh

GPU mesh data stored in storage buffers. The PSO has no vertex input state; all vertex data is fetched by the shader via SSBO (StructuredBuffer<FVertex>). Index data uses a traditional index buffer bound via BindIndexBuffer.

Member Type Description
VertexBuffer FRHIBufferID Storage buffer holding vertex data.
IndexBuffer FRHIBufferID Index buffer.
VertexCount UInt32 Number of vertices.
IndexCount UInt32 Number of indices.
IndexType ERHIIndexType UInt16 or UInt32.

FRenderableMeta

Plain struct holding extracted draw-command data. Used by FGraphics::Draw(const FRenderableMeta&) and by scripting bindings (no C++ virtuals). Data is captured at submit time so nothing crosses the thread boundary.

Member Type Description
InstanceData FInstanceData Transform, color, custom data.
Material TSharedPtr<FMaterial> Material; required.
Mesh TSharedPtr<FMesh> Mesh geometry; nullptr = sprite quad path.

IRenderable

Abstract interface for C++ renderables. Implementations provide instance data, material and optional mesh. ToRenderableMeta() builds FRenderableMeta from the virtual getters; FGraphics::Draw(const IRenderable&) calls it and stores the result (no TSharedPtr<IRenderable> is kept).

Method Return Description
GetInstanceData() FInstanceData Pure virtual. Returns the instance's transform, color and custom data.
GetMaterial() TSharedPtr<FMaterial> Pure virtual. Returns the material used by this renderable.
GetMesh() TSharedPtr<FMesh> Virtual. Returns mesh geometry; default nullptr uses the built-in sprite quad path (Draw(6, N)). Override to provide custom geometry (DrawIndexed).
ToRenderableMeta() FRenderableMeta Builds meta from the three getters; used by Draw(const IRenderable&).

Instancing pipeline

  1. Game (or script) calls GFX->Draw(renderable) or GFX->Draw(FRenderableMeta) each frame; data is captured immediately.
  2. After OnPreRender, the engine calls GFX->Render(Window) to send accumulated draws, camera and lights to the Graphics thread.
  3. Graphics thread runs BatchAndSort on FRenderData::DrawCommands → FRenderList (batches by Material + Mesh).
  4. UploadInstanceBuffers creates a per-batch SSBO and descriptor set at Set 1.
  5. Draw passes bind Set 0 (material) + Set 1 (instance SSBO) and issue Draw(6, N) or DrawIndexed(IndexCount, N).

See also