Add the CONTRIBUTING.md from godot-demo-projects.

other/demos.rst

@@ -1,4 +1,152 @@
 Contributing demo projects
 ==========================
 
-TODO
+Thanks for your interest in contributing to the
+`Godot demo projects <https://github.com/godotengine/godot-demo-projects>`__!
+
+Demo submission criteria
+------------------------
+
+Please follow these guidelines for submitting new demos or improving
+existing demos:
+
+-  The demo must work with the latest Godot version of the branch you’re
+   submitting to.
+
+-  The demo must follow all of the Godot style guides:
+
+   -  `Project
+      organization <https://docs.godotengine.org/en/stable/tutorials/best_practices/project_organization.html>`__
+   -  `GDScript style
+      guide <https://docs.godotengine.org/en/stable/tutorials/scripting/gdscript/gdscript_styleguide.html>`__
+
+      -  In GDScript, type hints should be used whenever possible to
+         improve runtime performance and ease code maintenance. The
+         **Debug > GDScript > Warnings > Untyped Declaration** project
+         setting is set to **Warn** on most existing demos to enforce
+         this. This setting should also be configured to **Warn** on new
+         demos.
+
+   -  `C# style
+      guide <https://docs.godotengine.org/en/stable/tutorials/scripting/c_sharp/c_sharp_style_guide.html>`__
+   -  `Shaders style
+      guide <https://docs.godotengine.org/en/stable/tutorials/shaders/shaders_style_guide.html>`__
+
+-  The demo should not be overcomplicated. Simplicity is usually
+   preferred.
+
+-  The submitted files must be freely redistributable and modifiable,
+   including for commercial use. This applies to art assets as well.
+
+   -  In practice, this means the following licenses are accepted for
+      art assets:
+
+      -  CC0 1.0 (or similar public domain dedications)
+      -  CC BY 3.0/4.0
+      -  CC BY-SA 3.0/4.0
+
+   -  Licenses such as “Royalty-free” (without clarification), CC BY-NC
+      or CC BY-ND are **not** accepted.
+
+-  To allow demos to be cloned quickly, file sizes should be kept
+   reasonable for all files submitted. Try to keep the demo project
+   files’s download size below 20 MB, unless there is a good reason to
+   have a larger demo (e.g. if high-quality textures are *required* to
+   show off an effect).
+
+   -  You can check this by creating a ZIP file containing the project
+      files, then removing ``.godot/`` within the ZIP file.
+   -  For 3D demos, consider relying on Godot’s procedural generation
+      abilities (such as
+      `NoiseTexture2D <https://docs.godotengine.org/en/stable/classes/class_noisetexture2d.html>`__)
+      to decrease file size.
+
+Submission criteria for new demos
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+If you are submitting a new demo:
+
+-  Make sure it includes a ``README.md`` file similar to the other
+   demos.
+
+-  Make sure a short description (1-3 lines) is set in the Project
+   Settings.
+
+-  Make sure the project has a ``icon.webp`` in lossless WebP [1]_
+   format that is 128×128 pixels, with its path defined in the Project
+   Settings. This allows the icon to remain crisp on hiDPI displays.
+
+-  Make sure the project includes a ``screenshots/`` folder containing a
+   screenshot in lossless WebP [1]_ format similar to the other demos.
+   It’s recommended to stick to only 1 screenshot, but you may add
+   multiple screenshots if required. The screenshot should be in
+   1280×720 resolution, without visible window borders.
+
+   -  The ``screenshots/`` folder must contain an empty ``.gdignore``
+      file to prevent Godot from importing screenshots as resources.
+
+-  Make sure the demo has keyboard and controller input support (plus
+   mouse if relevant). Explicit touch input support is a bonus, but not
+   required.
+
+   -  For keyboard events, WASD configurations must use *physical* key
+      locations in the Input Map to allow them to work out of the box on
+      non-QWERTY keyboard layouts.
+
+Visual considerations
+^^^^^^^^^^^^^^^^^^^^^
+
+-  Unless the project requires a different stretch mode and aspect, use
+   the ``canvas_items`` stretch mode and ``expand`` stretch aspect in
+   the Project Settings. Configure anchors for Control nodes correctly,
+   so that `multiple
+   resolutions <https://docs.godotengine.org/en/stable/tutorials/rendering/multiple_resolutions.html>`__
+   and aspect ratios are supported.
+
+-  Demos that don’t update their visual output often (such as UI demos)
+   must have **Low Processor Mode** enabled in the Project Settings.
+   This must be left disabled in demos where constant redrawing is
+   expected (such as most “game” demos).
+
+-  For greater performance and compatibility, use the **Compatibility**
+   rendering method in 2D demos that don’t require advanced graphics
+   functionality.
+
+   -  In 3D demos or 2D demos that require advanced graphics
+      functionality, use the **Forward+** rendering method (**Mobile**
+      is automatically used on mobile platforms in this case).
+
+-  In 3D projects, set **Rendering > Textures > Default Filters >
+   Anisotropic Filtering Level** to **16×** in the Project Settings.
+   Make sure all materials use the relevant anisotropic sampler mode
+   (**Nearest Mipmaps Anisotropic** or **Linear Mipmaps Anisotropic**).
+
+-  In 3D projects, set **Rendering > Anti Aliasing > Quality > MSAA 3D**
+   to **4×**.
+
+   -  In projects that use demanding graphics features such as SDFGI,
+      set **Rendering > Anti Aliasing > Quality > Screen Space AA** to
+      **FXAA** instead as this is faster.
+
+-  Use graphics options that perform reasonably well on low-end to
+   mid-range hardware. Demanding graphics options should not be enabled
+   by default, unless they’re the entire point of the demo.
+
+If you are submitting a copy of a demo translated to C
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+-  Please ensure that there is a good reason to have this demo
+   translated. We don’t want to have multiple copies of every single
+   project, as this makes maintenance more difficult.
+
+-  Please ensure that the code mirrors the original as closely as
+   possible.
+
+-  In the ``project.godot`` file and in the ``README.md``, include “with
+   C#” in the title, and also include a link to the original in the
+   ``README.md``.
+
+.. [1]
+   You can use `Squoosh <https://squoosh.app/>`__ to convert images to
+   WebP. Make sure to enable the Lossless option, as it’s not the
+   default.