imgui 1.92 hands the backend a list of dirty rectangles when its font atlas
grows, but thin3d could only replace a whole mip level, so every new glyph
re-uploaded the entire atlas.
Adds DrawContext::UpdateTextureRegions, taking a batch of regions so each
backend can submit them together:
- Vulkan: packs the regions into the push pool and issues a single
vkCmdCopyBufferToImage from the init command buffer, transitioning only
the level being written.
- OpenGL: new TEXTURE_SUBIMAGE init step. The existing sub-image path is a
render command needing an active render pass and a texture slot, which
doesn't fit here. Rows are packed caller-side since GLES2 lacks
GL_UNPACK_ROW_LENGTH.
- D3D11: UpdateSubresource with a box, no staging texture needed.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
From 947aa9c97 to 98a66d8c8 on the docking branch - the latest release there,
plus the viewport fixes that landed on top of it. The only local changes to
upstream files are the "#undef new" hack at the top of imgui.h and enabling
IMGUI_DISABLE_OBSOLETE_FUNCTIONS in imconfig.h; both re-applied.
1.92 reworked fonts and textures, so the thin3d backend now advertises
ImGuiBackendFlags_RendererHasTextures and creates/updates/destroys imgui's
textures on request instead of building the font atlas itself. ImTextureIDs
below 256 now index those, above it the per-frame temp textures as before.
thin3d can't replace part of a texture yet, so an update re-uploads the whole
thing - fine for an atlas that only changes when a new glyph appears.
Also: AddRect() swapped its thickness and flags parameters in 1.92.8.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
