Uni.GUI

Texture API

UiApp owns external Dear ImGui textures.

• Create a texture with UiApp::TextureCreate().
• Destroy it with UiApp::TextureDestroy() or UiTexture::Destroy().
• Use UiTexture as a lightweight handle/view for CPU pixel writes (Pixels(), PixelsAt(), Clear(), MarkFullUpdate(), MarkUpdateRect()).
• Retrieve the opaque handle with UiTexture::Handle() or UiApp::TextureGetHandle().

Design notes

• Texture registration now goes through Dear ImGui's user texture API instead of a global snapshot registry.
• GPU destruction is deferred until the backend acknowledges ImTextureStatus_WantDestroy, so resizing and destruction remain safe across frames.
• Upload helpers preserve WantCreate vs WantUpdates, which keeps first-frame texture uploads correct.
• No global texture mutexes are used; the lifecycle is owned by the active UiApp instance.