Draw ordering for points

[davidmanzanares]

We should be able to order the features (for drawing) on the client.

Doing it on JS is not a viable option if we want to order by a dynamic property: i.e. it is too slow to reorder per frame.

I would try to do a PoC with a psudo ordering mechanism implemented with WebGL. My idea is to divide the features into buckets and draw each tile one time per bucket and GPU filtering out the features that don't belong to the bucket.

[davidmanzanares]

Partially done with #70

The current implementation allows ordering the features based on the width property (this only works for points).

Example:

Default behavior (order is Maps API order, basically: no order): https://cartodb.github.io/renderer-prototype/example/mapbox.html#eyJhIjoidHhfMDEyNV9jb3B5X2NvcHkiLCJiIjoiIiwiYyI6ImRtYW56YW5hcmVzLWRlZDEzIiwiZCI6ImNhcnRvLXN0YWdpbmcuY29tIiwiZSI6IndpZHRoOiBzcXJ0KCRhbW91bnQvNTAwMCkqMjAqKHpvb20oKS80MDAwKzAuMDEpKjEuNVxuY29sb3I6IHJhbXAoJGNhdGVnb3J5LCBQcmlzbSlcbnN0cm9rZUNvbG9yOiAgICAgICByZ2JhKDAsMCwwLDAuNylcbnN0cm9rZVdpZHRoOiAgICAgIDIqem9vbSgpLzUwMDAwXG4iLCJmIjp7ImxuZyI6Mi4xNywibGF0Ijo0MS4zOH0sImciOjEzfQ==

Small points below: https://cartodb.github.io/renderer-prototype/example/mapbox.html#eyJhIjoidHhfMDEyNV9jb3B5X2NvcHkiLCJiIjoiIiwiYyI6ImRtYW56YW5hcmVzLWRlZDEzIiwiZCI6ImNhcnRvLXN0YWdpbmcuY29tIiwiZSI6IndpZHRoOiBzcXJ0KCRhbW91bnQvNTAwMCkqMjAqKHpvb20oKS80MDAwKzAuMDEpKjEuNVxuY29sb3I6IHJhbXAoJGNhdGVnb3J5LCBQcmlzbSlcbnN0cm9rZUNvbG9yOiAgICAgICByZ2JhKDAsMCwwLDAuNylcbnN0cm9rZVdpZHRoOiAgICAgIDIqem9vbSgpLzUwMDAwXG5vcmRlcjogZGVzYyh3aWR0aCgpKSIsImYiOnsibG5nIjoyLjE3LCJsYXQiOjQxLjM4fSwiZyI6MTN9

Small points on top: https://cartodb.github.io/renderer-prototype/example/mapbox.html#eyJhIjoidHhfMDEyNV9jb3B5X2NvcHkiLCJiIjoiIiwiYyI6ImRtYW56YW5hcmVzLWRlZDEzIiwiZCI6ImNhcnRvLXN0YWdpbmcuY29tIiwiZSI6IndpZHRoOiBzcXJ0KCRhbW91bnQvNTAwMCkqMjAqKHpvb20oKS80MDAwKzAuMDEpKjEuNVxuY29sb3I6IHJhbXAoJGNhdGVnb3J5LCBQcmlzbSlcbnN0cm9rZUNvbG9yOiAgICAgICByZ2JhKDAsMCwwLDAuNylcbnN0cm9rZVdpZHRoOiAgICAgIDIqem9vbSgpLzUwMDAwXG5vcmRlcjogYXNjKHdpZHRoKCkpIiwiZiI6eyJsbmciOjIuMTcsImxhdCI6NDEuMzh9LCJnIjoxM30=

@makella Can you take a look? Do you consider this good enough to put a low-priority label or something like that in this issue?

[makella]

@davidmanzanares great!
And yes, to me, this seems good enough for a first release BUT definitely hope we prioritize ordering by the count of features too (in the future!) and expand to lines as well.

Just to clarify, is there any way to order based on width + an attribute?
I'm pretty sure not, but just wanted to ask :)

[davidmanzanares]

@makella

Just to clarify, is there any way to order based on width + an attribute?

No, not yet

@rochoa Can we move this to next?

[rochoa]

Done.

[davidmanzanares]

If no one disagrees, I think we should expose the existing functionality in the documentation

[makella]

No objections from me. I do think that it was slowing some maps down and in those cases, people can order by in their data

[makella]

@davidmanzanares here is the issue i was seeing yesterday
#844