From 5cf1364e81cde91f3bb39145f4e5a58262ec2746 Mon Sep 17 00:00:00 2001
From: Matt <matt@excalamus.com>
Date: Sat, 17 Dec 2022 00:54:22 -0500
Subject: [PATCH] Check for OpenGL before running meshviewer

Previously, the command would dispatch regardless of the OpenGL
status.  In cases where OpenGL was unavailable, the process would
continue, start the client, and then run into an OpenGL error.
End-users would sometimes not be informed of errors.

This change checks for OpenGL prior to dispatch, alerting the user of
any errors.
---
 bin/meshviewer     | 9 ++++++---
 mesh/meshviewer.py | 9 +++++----
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/bin/meshviewer b/bin/meshviewer
index 968fba3..725a636 100644
--- a/bin/meshviewer
+++ b/bin/meshviewer
@@ -91,7 +91,8 @@ from psbody.mesh.meshviewer import (
     MESH_VIEWER_DEFAULT_HEIGHT,
     ZMQ_HOST,
     MeshViewerLocal,
-    MeshViewerRemote)
+    MeshViewerRemote,
+    _test_for_opengl)
 
 
 logging.basicConfig(level=logging.INFO)
@@ -374,6 +375,8 @@ def take_snapshot(client, args):
 
 
 if __name__ == "__main__":
-    args = parser_root.parse_args()
-    dispatch_command(args)
+    if _test_for_opengl():
+        args = parser_root.parse_args()
+        dispatch_command(args)
+
     sys.exit(0)
diff --git a/mesh/meshviewer.py b/mesh/meshviewer.py
index e457759..b7d774d 100755
--- a/mesh/meshviewer.py
+++ b/mesh/meshviewer.py
@@ -95,14 +95,15 @@ def _run_self(args, stdin=None, stdout=None, stderr=None):
 
 
 def _test_for_opengl():
+    print("Checking OpenGL...")
     try:
-        # from OpenGL.GLUT import glutInit
         GLUT.glutInit()
     except Exception as e:
+        print("OpenGL not available")
         print(e, file=sys.stderr)
-        print('failure')
-    else:
-        print('success')
+        return False
+    print("Success!")
+    return True
 
 
 test_for_opengl_cached = None