- Background placement code now just generates static symbol buffers
- Don't render GeometryTiles until their symbols are loaded. This is necessary for the CrossTileSymbolIndex to successfully prevent flicker.
- SymbolInstances are transferred to SymbolBucket for use on foreground during collision detection
- Symbols are sorted on foreground by sorting their index buffer but leaving vertex buffers intact (only works within one segment)
- Vertical glyphs are generated at same time as horizontal glyphs. `reprojectLineLabels` chooses which one to use at render time and hides the other.
- Icons are now always represented with a single collision box, even if they're placed along a line (this means their rotation alignment may be wrong, but the approach of representing them with multiple collision boxes wasn't very accurate either).
- Generate vertices for new debug collision boxes and collision circles
- Only add symbols within tile boundaries (reduces work, avoids double-draw)
- Update symbol_projection.cpp to support line label projection calls from CollisionIndex.
Port of https://github.com/mapbox/mapbox-gl-js/pull/5101: adds a new render pass `Pass3D` before any other rendering wherein we render layers with 3D passes (fill-extrusion layers) to offscreen framebuffers, sharing a depth renderbuffer between those layers in order to render 3D space correctly. Those framebuffers are saved on the RenderLayers and copied back to the map during the translucent pass. Rendering to offscreen framebuffers before we do any clear + draw means we can avoid expensive framebuffer restores.
- AnnotationData.updateData() was not completely thread safe. Calling it from the renderer thread instead of the main thread fixes this
- Since we moved the coalescing of updates out of the map and into the renderer frontend implementations, the updateData was called too much, resulting in degraded performance. Moving it into the renderer makes sure it gets coalesced again.
- Make renderer frontend responsible for creating a BackendScope on render
- encapsulate backend scope handling on cleanup and low memory in renderer impl
