Update documentation for GLES3 and gl3_usefbo

doc/030_configuration.md

@@ -8,7 +8,7 @@ with the defaults and the options that can be set through the menu.
 
 ## Choosing a Renderer
 
-Yamagi Quake II ships with 3 renderers:
+Yamagi Quake II ships with 4 renderers:
 
 * The **OpenGL 3.2** renderer: This renderer was developed for the needs
   of modern graphics hardware and is usually the best choice for OpenGL
@@ -17,6 +17,11 @@ Yamagi Quake II ships with 3 renderers:
   rendering looks mostly the same on all GPU drivers. Depending on the
   display, the default lighting may be too bright or too dark, it can be
   adjusted through the menu or through the *vid_gamma* cvar.
+* The **OpenGL ES3** renderer: This is pretty much the same as the
+  OpenGL 3.2 renderer (and uses the same cvars for configuration), but
+  uses OpenGL ES 3.0 instead of "desktop" OpenGL, so it also works on
+  the Raspberry Pi 4, for example. Reportedly it also has slightly
+  better performance on Wayland, at least with the open source AMD drivers.
 * The **OpenGL 1.4** renderer: This is a slightly enhanced version of
   the original OpenGL renderer shipped in 1997 with the retail release.
   It's provided for older graphics cards, not able to run the OpenGL 3.2

doc/040_cvarlist.md

@@ -9,7 +9,7 @@ have been renamed. The prefixes are:
 * `cl_`: Client.
 * `gl_`: Common to all OpenGL renderers.
 * `gl1_`: OpenGL 1.4 renderer.
-* `gl3_`: OpenGL 3.2 renderer.
+* `gl3_`: OpenGL 3.2 and OpenGL ES3 renderers.
 * `ogg_`: Ogg/Vorbis music playback.
 * `r_`: Common to all renderers.
 * `s_`: Sound system.
@@ -349,7 +349,8 @@ it's `+set busywait 0` (setting the `busywait` cvar) and `-portable`
 
 * **vid_renderer**: Selects the renderer library. Possible options are
   `gl1` (the default) for the old OpenGL 1.4 renderer, `gl3` for the
-  OpenGL 3.2 renderer and `soft` for the software renderer.
+  OpenGL 3.2 renderer, `gles3` for the OpenGL ES3 renderer
+  and `soft` for the software renderer.
 
 
 ## Graphics (GL renderers only)
@@ -388,7 +389,7 @@ it's `+set busywait 0` (setting the `busywait` cvar) and `-portable`
   look a bit better (no flickering) by using the stencil buffer.
 
 
-## Graphics (OpenGL 3.2 only)
+## Graphics (OpenGL 3.2 and OpenGL ES3 only)
 
 * **gl3_debugcontext**: Enables the OpenGL 3.2 renderers debug context,
   e.g. prints warnings and errors emitted by the GPU driver.  Not
@@ -423,6 +424,11 @@ it's `+set busywait 0` (setting the `busywait` cvar) and `-portable`
   colorless (greyscale-only), like in the original soft renderer.
   Default is `1`.
 
+* **gl3_usefbo**: When set to `1` (the default), an OpenGL Framebuffer
+  Object is used to implement a warping underwater-effect (like the
+  software renderer has). Set to `0` to disable this, in case you don't
+  like the effect or it's too slow on your machine.
+
 
 ## Graphics (Software only)
 

doc/090_filelists.md

@@ -34,6 +34,7 @@ level.
 # Renderer libraries:
 /ref_gl1.dll
 /ref_gl3.dll
+/ref_gles3.dll
 /ref_soft.dll
 
 # The Executables: