From cf5324430014c0a24c33e7191bafa16e65e82b4d Mon Sep 17 00:00:00 2001
From: Jeremy Nimmer <jeremy.nimmer@tri.global>
Date: Thu, 31 Oct 2024 07:09:50 -0700
Subject: [PATCH] [examples] Drop CI requirement for DISPLAY

---
 .bazelrc                   |  4 ----
 .github/ci_setup.bash      | 23 +----------------------
 .github/workflows/main.yml |  4 ----
 examples/ball_bin.yaml     |  6 ++++--
 4 files changed, 5 insertions(+), 32 deletions(-)

diff --git a/.bazelrc b/.bazelrc
index 9e7be94..b8df98f 100644
--- a/.bazelrc
+++ b/.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
 
diff --git a/.github/ci_setup.bash b/.github/ci_setup.bash
index e129028..537d324 100755
--- a/.github/ci_setup.bash
+++ b/.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
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index c37134d..efda4d7 100644
--- a/.github/workflows/main.yml
+++ b/.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
diff --git a/examples/ball_bin.yaml b/examples/ball_bin.yaml
index 5f8f611..8d274c5 100644
--- a/examples/ball_bin.yaml
+++ b/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