RenderBuffer

The RenderBuffer class is the base abstract class for managing render target buffers. It handles texture attachments, size management, and frame buffer operations. Concrete implementations are:

• RenderBufferTexture2D — for single 2D texture render targets
• RenderBufferCubeMap — for cube map (6-face) render targets

Constructor

constructor(renderer: any, size?: Vec | number[])

Creates an uninitialized render buffer with default size 512x512. The actual texture initialization happens via attachTexture().

Properties

renderer : Renderer

The owning renderer instance.

size : Vec

Buffer resolution (width, height). When modified, all attached textures are automatically resized to match.

type : RenderBufferType

Either RenderBufferType.TEXTURE (2D) or RenderBufferType.CUBE_MAP. Set automatically on first texture attachment.

dirty : boolean

True if the buffer has been modified and needs updating. Use setUpdated(true/false) to toggle.

attachments : Record<string, any>

Map of texture attachments keyed by attachment name (e.g., COLOR_ATTACHMENT_0). Each value is a TextureRenderer instance.

frameBuffer

Returns the underlying framebuffer object for rendering into this buffer (abstract).

Methods

attachTexture(texture: Texture): Promise<void>

Attaches a texture as a render target. Throws if:

• The attachment slot is already occupied by another texture
• The texture type doesn’t match an existing buffer (can’t mix 2D and cube maps)
• The buffer is already initialized with a different type

The texture’s renderTargetAttachment property determines which attachment slot it occupies. After attaching, the texture is marked as RENDER_TARGET and resized to match the buffer size.

detachTexture(texture: Texture)

Removes a texture from an attachment slot and deletes the corresponding texture renderer. Throws if:

• No texture is attached to that slot
• The provided texture doesn’t match the one actually attached

getTextureRenderer(attachment: string)

Returns the TextureRenderer for a given attachment name.

getTexture(attachment: string)

Returns the underlying Texture for a given attachment name.

setUpdated(updated: boolean)

Toggles the dirty flag. true means “buffer is up to date” (not dirty), false means “needs update”.

update(drawFunc: DrawFunc)

Executes a draw function within the buffer’s render target. For 2D buffers, calls beginUpdate() / drawFunc / endUpdate(). For cube maps, renders all 6 faces with pre-configured view matrices (looking outward on each axis face).

The draw function receives optional parameters:

type DrawFunc = (face?: CubeMapFace, viewMatrix?: Mat4, projectionMatrix?: Mat4) => void

saveVertexBufferState() / restoreVertexBufferState()

Saves and restores the bound vertex buffer state (abstract methods, concrete implementations must override).

readPixels

Reads pixel data from the buffer (abstract base returns undefined).

Abstract Methods (must be overridden)

• beginUpdate() — Bind the FBO and prepare for rendering into this buffer
• endUpdate() — Restore default framebuffer
• destroy() — Clean up all resources including FBO and texture renderers
• frameBuffer (getter) — Return the WebGL framebuffer object

RenderBufferType Enum

enum RenderBufferType {
    UNINITIALIZED = 0,
    TEXTURE = 1,
    CUBE_MAP = 2
}

CubeMapFace Enum

Defines the six faces of a cube map:

• NONE — for 2D buffer updates
• POSITIVE_X, NEGATIVE_X (+X and -X faces)
• POSITIVE_Y, NEGATIVE_Y (+Y and -Y faces)
• POSITIVE_Z, NEGATIVE_Z (+Z and -Z faces)