ori_sky
8625c52ee9
Some checks failed
Run ReCI Build Test / Explore-Gitea-Actions (push) Failing after 1m51s
The following patches are included: ## J2D: Rewrite text rendering This patch rewrites text rendering for `J2D::DrawString` to now construct a texture atlas for all ASCII-range glyphs in the FT font face, instead of constructing a texture for every glyph. This improves text rendering performance for several reasons: 1. Binding textures is relatively expensive as the GPU is required to do a context switch for internal data like texture parameters, and also cannot optimize for accesses to the same texture across draw calls. This patch removes the need to call `glBindTexture` more than once per call to `J2D::DrawString`. 2. As a consequence of the above, all glyphs for a given string can now be rendered in a single call to `glDrawArrays`. This is done by storing the cached texture coordinates on `CachedGlyph` and constructing a full array of vertices and texture coordinates for the entire string at once, resulting in only /one/ set of client-to-device attribute uploads and only one draw call, instead of being required to upload attribute data for each glyph separately. ## FontCache: Use map for efficient glyph lookup This patch updates `CachedFont` to now use an `std::map` for cached glyphs, instead of an `std::vector`. `std::map` allows O(log n) lookup, whereas `std::vector` only allows O(n) lookup. Note: `std::unordered_map` technically has better lookup complexity here, with amortized O(1) lookup. However, hashmaps have a higher inherent overhead than red-black trees so this would only be viable when going above around 1000 entries, which should never happen here for ASCII glyphs. Co-authored-by: Ori Sky Farrell <ori.sky.farrell+git@gmail.com> Reviewed-on: #23 Co-authored-by: ori_sky <redacted@ori.mx> Co-committed-by: ori_sky <redacted@ori.mx>