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>
Turns out these were needed after all. For some reason, on Windows and
Mac, <algorithm> gets auto-included by something else so I don't notice
when it's missing, and MSVC's include dependency tracker doesn't see it
either.
Fixes bugs on mobile with texture scaling + auto max quality texturing
(since that generates mipmaps with blits from an image which was just generated from
compute, making proper barriers very critical).
We're already in GENERAL so probably not worth to transfer to DST just
to do even more transfers due to the silliness of GenerateMip.
I'm planning to rework the whole texture upload thing to be far more
optimal with some kind of TextureUploadManager
Fixes#13987
