Dynamic Text Authoring

[psuong]

I'm currently trying to figure out the best way to rebuild dynamic text elements. Currently static elements are pretty easy since vertices are just resized to accommodate for a new screen resolution.

Dynamic text can be described in two ways:

1. Fixed length, but with variable chars
2. Variable length and variable chars

Generally, I think it would be better if any changing text is considered dynamic despite being fixed length or variable length.

The RebuildRenderHierarchySystem currently has an implementation to try to build dynamic text last (although it doesn't work the way I'd like it to work). The idea is that all static elements are rebuilt first and the vertices generated are copied to the Canvas entity's Vertex buffer. The index buffer doesn't need to change because these elements are static. Dynamic text should be built last. so the idea would be.

So the general steps are:

1. Collect all images, static text, and dynamic text entities
2. Rebuild the vertices for image and static text
3. When image and static text are rebuilt, then we build dynamic text entities. The vertices and indices will now have to change and so will the vertex/index span the entities refer to. This is because all dynamic text is built last so we don't interfere with the static bunch.

I'll need to rework the RebuildRenderHierarchy system to better support this because entities are collected amongst different threads. I'll also be updating this discussion/forum feature from Github as public notes as I try to figure it out.

[psuong]

So far I've added a way to convert a floating point to a character array.

https://github.com/InitialPrefabs/UGUIDOTS/blob/feature/dynamic-text/UGUIDOTS.Common/NumericUtils.cs

Next is figuring point 3. The spans need to be rebuilt.

[psuong]

This has been a very fun process in trying to figure out how to rebuild text dynamically. Currently, what I have is that all static elements are built first and all dynamic elements are built last. All dynamic texts are put in a min priority queue so that we process earlier submesh indices first.

I will have to do some optimizations for the min heap, because I only did a naive implementation, but here is a video of what it currently looks like with two different fonts and the text updating every frame.

truly-dynamic-text-with-2-different-fonts.mov

[psuong]

#68 Min heap optimization issue placed here.