1 files changed, 51 insertions, 0 deletions
diff --git a/src/net/java/games/jogl/impl/windows/WindowsGLContextFactory.java b/src/net/java/games/jogl/impl/windows/WindowsGLContextFactory.java
index 726091bf1..1c976c355 100644
--- a/src/net/java/games/jogl/impl/windows/WindowsGLContextFactory.java
+++ b/src/net/java/games/jogl/impl/windows/WindowsGLContextFactory.java
@@ -43,6 +43,7 @@ import java.awt.Component;
 import java.awt.GraphicsConfiguration;
 import java.awt.GraphicsDevice;
 import java.awt.Rectangle;
+import java.io.File;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.util.HashMap;
@@ -74,6 +75,56 @@ public class WindowsGLContextFactory extends GLContextFactory {
     AccessController.doPrivileged( new PrivilegedAction() {
       public Object run() {
         Runtime.getRuntime().addShutdownHook( new ShutdownHook() );
+        
+        // Test for whether we should enable the single-threaded
+        // workaround for ATI cards. It appears that if we make any
+        // OpenGL context current on more than one thread on ATI cards
+        // on Windows then we see random failures like the inability
+        // to create more OpenGL contexts, or having just the next
+        // OpenGL SetPixelFormat operation fail with a GetNextError()
+        // code of 0 (but subsequent ones on subsequently-created
+        // windows succeed). These kinds of failures are obviously due
+        // to bugs in ATI's OpenGL drivers. Through trial and error it
+        // was found that specifying
+        // -DJOGL_SINGLE_THREADED_WORKAROUND=true on the command line
+        // caused these problems to completely disappear. Therefore at
+        // least on Windows we try to enable the single-threaded
+        // workaround before creating any OpenGL contexts. In the
+        // future, if problems are encountered on other platforms and
+        // -DJOGL_SINGLE_THREADED_WORKAROUND=true works around them,
+        // we may want to implement a workaround like this on other
+        // platforms.
+        
+        // The algorithm here is to try to find the system directory
+        // (assuming it is on the same drive as TMPDIR, exposed
+        // through the system property java.io.tmpdir) and see whether
+        // a known file in the ATI drivers is present; if it is, we
+        // enable the single-threaded workaround.
+
+        // If any path down this code fails, we simply bail out -- we
+        // don't go to great lengths to figure out if the ATI drivers
+        // are present. We could add more checks here in the future if
+        // these appear to be insufficient.
+
+        String tmpDirProp = System.getProperty("java.io.tmpdir");
+        if (tmpDirProp != null) {
+          File file = new File(tmpDirProp);
+          if (file.isAbsolute()) {
+            File parent = null;
+            do {
+              parent = file.getParentFile();
+              if (parent != null) {
+                file = parent;
+              }
+            } while (parent != null);
+            // Now the file contains just the drive letter
+            file = new File(new File(new File(file, "windows"), "system32"), "atioglxx.dll");
+            if (file.exists()) {
+              SingleThreadedWorkaround.shouldDoWorkaround();
+            }
+          }
+        }
+
         return( null );
       }
     });