API
Babylon Lite API|
SurfaceContext

Interface SurfaceContext

Per-canvas rendering surface — owns the GPU canvas context, swapchain format, MSAA configuration, and the list of RenderingContexts (scenes, effect renderers, frame-graph contexts, sprite/text renderers) that present to this canvas.

The EngineContext is itself a SurfaceContext (the primary one, bound to the canvas passed into createEngine). Additional surfaces for auxiliary canvases are created via createSurface. GPU resources (textures, buffers, pipelines, bind groups) live on the EngineContext (device-scoped) and are shared across all surfaces of the same engine — only the swapchain output is per-surface.

interface SurfaceContext {
    canvas: RenderCanvas;
    engine: EngineContext;
    format: GPUTextureFormat;
    maxDevicePixelRatio: number;
    msaaSamples: number;
    scRT: RenderTarget;
}

Hierarchy (View Summary)

Index
canvas engine format maxDevicePixelRatio msaaSamples scRT
canvas: RenderCanvas

Canvas this surface presents to.

engine: EngineContext

Owning engine. For the engine's primary surface this points back to the engine itself (engine.engine === engine).

format: GPUTextureFormat

Swapchain texture format for this surface. Use as the format for offscreen RTs that will be composited onto this surface. When sRGB is enabled (see SurfaceOptions.srgb) this is the *-srgb view format that pipelines and the swapchain RenderTarget render through, not the format passed to GPUCanvasContext.configure() (that is _configureFormat).

maxDevicePixelRatio: number

Clamps the effective device pixel ratio used for this surface's swapchain backing store. The backing store is sized at min(devicePixelRatio, maxDevicePixelRatio) * cssPixels. maxDevicePixelRatio = 1 renders at native CSS-pixel resolution (no DPR upscaling); the default Infinity is unclamped (full devicePixelRatio). Mutable at runtime — set before the next resizeSurface to take effect (mirrors Babylon setHardwareScalingRatio).

msaaSamples: number

MSAA sample count for the main render pass into this surface (1 or 4).

scRT: RenderTarget

Surface-owned color-only render target that wraps this canvas's swapchain texture. Its _colorTexture/_colorView are re-acquired from context.getCurrentTexture() once per frame (see _refreshScRT), so it is always single-sample and carries no depth. Render/post-process/copy tasks target it (or resolve into it) to present to the canvas. It is _eager — buildRenderTarget and disposeRenderTarget both no-op on it and the surface owns its textures, so its shared _descriptor must never be mutated.