[examples] Drop CI requirement for DISPLAY

.bazelrc

@@ -5,10 +5,6 @@ common --keep_going=yes
 build --test_output=errors
 build --test_summary=terse
 
-# Inject DISPLAY into test runner environment for tests that use X.
-build --test_env=DISPLAY
-build --sandbox_add_mount_pair=/tmp/.X11-unix
-
 # Add `bazel test --config=lint` shortcut for linting.
 build:lint --test_tag_filters=lint
 

.github/ci_setup.bash

@@ -2,25 +2,4 @@
 
 set -euxo pipefail
 
-# Downgrade mesa per https://github.com/RobotLocomotion/drake/issues/18726.
-sudo apt-get --assume-yes --allow-downgrades install \
- xvfb \
- libegl1 \
- libegl-mesa0=22.0.1-1ubuntu2 \
- libgbm1=22.0.1-1ubuntu2 \
- libgl1-mesa-dri=22.0.1-1ubuntu2 \
- libglapi-mesa=22.0.1-1ubuntu2 \
- libglx-mesa0=22.0.1-1ubuntu2
-
-cat << EOF | sudo tee /lib/systemd/system/xvfb.service
-[Unit]
-After=network.target
-
-[Service]
-ExecStart=/usr/bin/Xvfb :99 -screen 0 1280x1024x24 -ac +extension GLX +extension RANDR +render -noreset
-
-[Install]
-WantedBy=multi-user.target
-EOF
-
-sudo systemctl --now --quiet enable /lib/systemd/system/xvfb.service
+sudo apt-get --assume-yes install libegl1

.github/workflows/main.yml

@@ -10,10 +10,6 @@ on:
     branches:
       - main
 
-env:
-  # Always use the Xvfb service's display.
-  DISPLAY: ":99"
-
 jobs:
   bazel_test:
     runs-on: ubuntu-latest

examples/ball_bin.yaml

@@ -60,8 +60,10 @@ cameras:
   vtk_camera:
     name: vtk_camera
     renderer_name: vtk
-    renderer_class: !RenderEngineVtkParams {}
-    show_rgb: True  # Use a live on-screen preview.
+    renderer_class: !RenderEngineVtkParams
+      backend: EGL
+    # For `show_rgb: True` you must also set the `backend: GLX` on prior line.
+    show_rgb: False
     width: 1024
     height: 1024
     fps: 8.0