marker support

[incanus]

Something I'd like to see is applying marker imagery points on the map, using a quad tree for efficiency, anti-rotating against angle changes to remain upright, and supporting z-indexing (markers closer to the bottom of the screen are in front of those closer to the top).

Basic POIs are done over in WebGL:

• POI markers & icons mapbox-gl-js#43
• https://github.com/mapbox/llmr/blob/master/js/render/drawpoint.js
• https://github.com/mapbox/llmr/blob/master/shaders/point.vertex.glsl
• https://github.com/mapbox/llmr/blob/master/shaders/point.fragment.glsl

What I want is the ability to replace this from the SDK:

https://dl.dropboxusercontent.com/u/575564/rotatepins.mov

I'm going to start working on this.

[kkaefer]

WebGL isn't using a quad tree.

[incanus]

Yeah, seeing this as I dig in. I will keep at this as a port over from current WebGL functionality, despite us possibly throwing this away as I'd like to get a bit more familiar with the whole style/bucket/parse/tag/vertex/shader/render flow we have for things like lines and fills.

After getting basic POI working, I'll look into arbitrary external content (GeoJSON/whatever) for drawing actual markers.

[incanus]

Getting there.

[incanus]

Breaking this down a bit:

• Get POI in the current stylesheet to render.
• Build out more POI in stylesheet as on WebGL.
• Handle arbitrary point data (GeoJSON etc.) with configurable markers.

[incanus]

First task done; next up is more Maki in the stylesheet, which hopefully looks better, then arbitrary data, which is a bigger hurdle.