commit fca614bf0f40d81f4a58d8187fdc6f460a42c346
Author: Leszek Koltunski <leszek@koltunski.pl>
Date:   Sun Dec 12 00:26:00 2021 +0100

    Add a glGetError() call to the main render loop.

diff --git a/src/main/java/org/distorted/library/main/DistortedScreen.java b/src/main/java/org/distorted/library/main/DistortedScreen.java
index 915af60..57156bf 100644
--- a/src/main/java/org/distorted/library/main/DistortedScreen.java
+++ b/src/main/java/org/distorted/library/main/DistortedScreen.java
@@ -191,6 +191,13 @@ public class DistortedScreen extends DistortedFramebuffer
       mToBeBlittedFBO=0;
       }
 
+    int err = GLES30.glGetError();
+
+    if( err!=GLES30.GL_NO_ERROR )
+      {
+      android.util.Log.e("D", "DISTORTED: OpenGL error "+err);
+      }
+
     return numrender+1;
     }