Skip to main content

Architecture

The renderer owns Tangram scenes and GPU resources. The layer package adapts it to deck.gl's device, viewport, and render-pass lifecycle.

The monorepo has two intentionally separate layers:

  1. @vis.gl/tangram-renderer contains scene loading, tile management, style evaluation, labels, and luma.gl resource/draw submission. Its ClassicWebGLRenderer receives a host-owned frame and render pass.
  2. @vis.gl/tangram-layers adapts that renderer to deck.gl's layer lifecycle. deck.gl supplies the device, viewport, resize events, and render pass; the adapter forwards them to Tangram and keeps the package dependency one-way.

The split is a foundation for future shared-device and WebGPU work. It avoids making the standalone Tangram renderer know about deck.gl while allowing a deck.gl application to compose Tangram basemaps with ordinary overlay layers.

Camera ownership​

The host-driven renderer uses cameraMode: 'external'. In this mode the host owns interaction, animation scheduling, view selection, and projection matrices. TangramLayer converts the active deck.gl viewport into Tangram's geographic frame and supplies deck.gl's view and projection matrices for every draw. A scene's cameras block cannot replace those matrices.

The package root also retains Tangram's perspective, flat, and isometric scene cameras for the classic Leaflet integration. Those compatibility cameras and their interaction helpers should move behind optional cameras and leaflet entrypoints as the renderer is decomposed. The intended package boundary is:

  • @vis.gl/tangram-renderer/core: scene loading, tiles, styles, labels, GPU resources, draw submission, geographic frame state, and externally supplied matrices;
  • @vis.gl/tangram-renderer/cameras: Tangram's perspective, flat, and isometric camera implementations;
  • @vis.gl/tangram-renderer/leaflet: Leaflet interaction, URL synchronization, and standalone render-loop ownership.

The current Scene still constructs View, and View still imports the classic camera factory. Therefore adding a core export today would only be a name, not a camera-free package boundary. The next structural tranche should inject view/camera policy into Scene, stop SceneLoader from synthesizing a camera in external mode, and then expose the new subpath once its dependency graph no longer reaches Leaflet or the classic cameras.

Style animation is separate from camera ownership. Animated styles continue to request host frames and may transform geometry using u_time, zoom, or custom shader uniforms. For example, the Albers projection example morphs vertices in its shader according to zoom; it does not animate or replace the camera. This means projection effects remain usable with deck.gl views, provided they do not assume a specific built-in Tangram projection matrix.