Added README documentation

Author: ErikReider

README.md

@@ -31,6 +31,55 @@ Install like so:
 sudo ninja -C build/ install
 ```
 
+## Debugging
+
+SceneFX includes the same debugging tools and environment variables as upstream wlroots does, but with some extra goodies.
+
+### Environment variables:
+
+- `WLR_RENDERER_ALLOW_SOFTWARE=1`: Use software rendering
+- `WLR_SCENE_DEBUG_DAMAGE=rerender`: Re-render the whole display on each commit (don't use damage)
+- `WLR_SCENE_DEBUG_DAMAGE=highlight`: Highlights where damage has occurred (where SwayFX get's re-rendered)
+- `WLR_SCENE_DISABLE_DIRECT_SCANOUT=1`: Disable direct scanout (always composites, even fullscreen windows)
+- `WLR_SCENE_DISABLE_VISIBILITY=1`: Disables culling of non-visible regions of a window/buffer (an example would be a small window fully covered by an opaque window)
+- `WLR_SCENE_HIGHLIGHT_TRANSPARENT_REGION=1`: Highlights the transparent areas of a window/buffer
+- `WLR_EGL_NO_MODIFIERS=1`: Disables modifiers for EGL
+
+### Tracy profiling
+
+Optional [Tracy](https://github.com/wolfpld/tracy) profiling can be enabled for an extra good view of when and what is happening.
+
+#### Enabling:
+
+Note: These instructions will enable basic profiling
+
+1. Add SceneFX as a subproject to your compositor
+2. Import it as a subproject dependency
+3. Run `meson subprojects download` to download the tracy project into the subproject directory
+4. Compile SceneFX with `-Dtracy_enable=true` (and `--buildtype=debugoptimized` if using meson).
+5. Start your compositor
+6. Start the `tracy-profiler` and connect to the running compositor (The version of the profiler should not matter, but if any issues are encountered, try using a version that matches the subproject).
+
+To enable more advanced profiling, the compositor in question needs to be run by the root user which comes with its own drawbacks, like DBus not working out of the box. A recommended way of doing this is by running your compositor with the `-E` sudo flag, such as `sudo -E sway`.
+
+To enable DBus, you need to give the root user access to the DBus session bus by adding the following lines to the `/etc/dbus-1/session-local.conf` file (you might have to create said file), and reboot your system.
+
+```xml
+<!-- /etc/dbus-1/session-local.conf -->
+<!-- Allow root to access session bus -->
+<busconfig>
+  <policy context="mandatory">
+    <allow user="root"/>
+  </policy>
+</busconfig>
+```
+
+#### Additional tracy documentation
+
+The links below are helpful when learning how to use tracy:
+
+- https://github.com/wolfpld/tracy/releases/latest/download/tracy.pdf
+- https://www.youtube.com/watch?v=ghXk3Bk5F2U
 
 ---
 [Join our Discord](https://discord.gg/qsSx397rkh)