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https://github.com/Ed94/VEFontCache-Odin

A port of Vertex Engine GPU Font Cache for the Odin programming language
https://github.com/Ed94/VEFontCache-Odin

font-atlas minimalist odin-lang text-rendering

Last synced: 18 days ago
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A port of Vertex Engine GPU Font Cache for the Odin programming language

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README 

        
# VE Font Cache : Odin Port



This is a port of the [VEFontCache](https://github.com/hypernewbie/VEFontCache) library.



Its original purpose was for use in game engines, however its rendeirng quality and performance is more than adequate for many other applications.



See: [docs/Readme.md](docs/Readme.md) for the library's interface.



## Building



See [scripts/Readme.md](scripts/Readme.md) for building examples or utilizing the provided backends.



Currently the scripts provided & the library itself were developed & tested on Windows. There are bash scripts for building on linux (they build on WSL but need additional testing).



The library depends on freetype, harfbuzz, & stb_truetype to build.  

Note: freetype and harfbuzz could technically be gutted if the user removes their definitions, however they have not been made into a conditional compilation option (yet).



## Changes from orignal



* Font Parser & Glyph shaper are abstracted to their own warpper interface

* ve_fontcache_loadfile not ported (ust use core:os or os2, then call load_font)

* Macro defines have been coverted (mostly) to runtime parameters

* Support for hot_reloading

* Curve quality step interpolation for glyph rendering can be set on a per font basis.



## TODOs



### Additional Features:



* Support for freetype (WIP, Currently a mess... and slow)

* Add ability to conditionally compile dependencies (so that the user may not need to resolve those packages).

* Ability to set a draw transform, viewport and projection

  * By default the library's position is in unsigned normalized render space

  * Could implement a similar design to sokol_gp's interface



### Optimization:



* Check if its better to store the glyph vertices if they need to be re-cached to atlas or directly drawn.

* Look into setting up multi-threading by giving each thread a context

  * There is a heavy performance bottleneck in iterating the text/shape/glyphs on the cpu (single-thread) vs the actual rendering *(if doing thousands of drawing commands)*

  * draw_text can provide in the context a job list per thread for the user to thenk hookup to their own threading solution to handle.

  * Context would need to be segregated into staged data structures for each thread to utilize

    * This would need to converge to the singlar draw_list on a per layer basis. The interface expects the user to issue commands single-threaded unless, its assumed the user is going to feed the gpu the commands & data through separate threads as well (not ideal ux).

  * How the contexts are given jobs should be left up to the user (can recommend a screen quadrant based approach in demo examples)



Failed Attempts:



* Attempted to chunk the text to more granular 'shapes' from `draw_list` before doing the actual call to `draw_text_shape`. This lead to a larger performance cost due to the additional iteration across the text string.

* Attempted to cache the shape draw_list for future calls. Led to larger performance cost due to additional iteration in the `merge_draw_list`.

  * The shapes glyphs must still be traversed to identify if the glyph is cached. This arguably could be handled in `shape_text_uncached`, however that would require a significan't amount of refactoring to identify... (and would be more unergonomic when shapers libs are processing the text)