* Update to wgpu 0.9
* Fix validation error in WGSL shader
- This moves the hardcoded vertex positions and texture coordinates to
the vertex buffer.
- Replaces the two-triangle quad to 1 full-screen triangle (fixes#180)
- Rewrites the custom shader example to fix a bug with large surface
textures;
- The input texture size was used for the output texture, causing the
purple rectangle to appear very jumpy on large displays in full screen.
- The `ScalingRenderer` now exposes its clipping rectangle. The custom
shader example uses this for its own clipping rectangle, but it can
also be used for interacting with the border in general.
* Switch to `wgpu::include_wgsl!()`
- This is a nice little simplification.
- Thanks to @JMS55 for the suggestion!
- The dependencies are a mess!
- Had to fork `imgui-wgpu`, which sits between 0.12 and 0.13 (has support for `winit` 0.24, but not `wgpu` 0.7)
- This is a temporary fix for CI, until https://github.com/Yatekii/imgui-wgpu-rs/pull/44 is merged and a new release of `imgui-wgpu` is out
- The WIP `wgpu` 0.7 update in https://github.com/parasyte/pixels/pull/134 will be needed for `imgui-wgpu` 0.14
- Update MSRV for `imgui` 0.7
* Add Dear ImGui example
- Closes#90
* Change argument order to match `render_with`
* Remove unnecessary borrow
* Refactor error messages
* Add a space
* Refactor Gui field privacy
* Add a menu bar and allow the about window to be closed
- The local bool is necessary because the menu bar closures are not allowed to borrow `self` for mutable access while `imgui::Ui<'ui>` is alive.
- The token-based menu bar lifetime is even more verbose than this.
