transform symbol vertices outside of shaders

[ansis]

Broader context: #4704

I'm working on transforming symbol vertices in javascript. Each frame the vertices are shifted, offset, projected and added to buffers as gl coordinates. Doing the transform outside of shaders let's us have full access to the line geometry which let's us render better in pitched views.

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I'm working on this in the cpu-label-transform branch.

I've hacked in a rough implementation that is mostly working, but it's currently taking ~20ms to run. I'm working on a bunch of relatively low-hanging optimizations that will hopefully cut that down significantly.

@ChrisLoer @kkaefer

[ansis]

Update: it's getting faster ~10ms but not quite there yet. Still some clear optimization opportunities.

[ansis]

Update:

This is getting closer. The cpu vertex transformation is now taking roughly 1-2ms on a large map on my computer.

I ended up moving as much work as possible back to the shader:

• the final matrix multiply to move from label plane coords to gl coords
• corner extrusion and rotation
• all point label rendering (in progress)

I still need to:

• remove old, dead code
• clean up new code
• finish up point label optimization

And then:

• rebase on master with pitch-scaling work

[mourner]

@ansis 1-2ms sounds fantastic!

[ChrisLoer]

@ansis That's awesome! I just checked out the branch and it's running nice and smooth in my browser.