Partial fix for Issue 114: GLCanvas canCreateOffscreenDrawable() function always returns true

Fixed the Windows implementation of this routine to check for the
presence of the WGL_ARB_pbuffer and WGL_ARB_pixel_format extensions.


git-svn-id: file:///usr/local/projects/SUN/JOGL/git-svn/svn-server-sync/jogl/trunk@238 232f8b59-042b-4e1e-8c03-345bb8c30851

3 files changed, 11 insertions, 2 deletions

diff --git a/src/net/java/games/jogl/GLDrawable.java b/src/net/java/games/jogl/GLDrawable.java
index aadc2b4fc..7c671c0b2 100644
--- a/src/net/java/games/jogl/GLDrawable.java
+++ b/src/net/java/games/jogl/GLDrawable.java
@@ -190,7 +190,9 @@ public interface GLDrawable extends ComponentEvents {
 
   /** Indicates whether this drawable is capable of fabricating a
       subordinate offscreen drawable for advanced rendering techniques
-      which require offscreen hardware-accelerated surfaces. */
+      which require offscreen hardware-accelerated surfaces. Note that
+      this method is only guaranteed to return a correct result once
+      your GLEventListener's init() method has been called. */
   public boolean canCreateOffscreenDrawable();
 
   /** Creates a subordinate offscreen drawable (pbuffer) for this
diff --git a/src/net/java/games/jogl/impl/windows/WindowsGLContext.java b/src/net/java/games/jogl/impl/windows/WindowsGLContext.java
index d26a88cc7..37a3f5359 100644
--- a/src/net/java/games/jogl/impl/windows/WindowsGLContext.java
+++ b/src/net/java/games/jogl/impl/windows/WindowsGLContext.java
@@ -61,6 +61,7 @@ public abstract class WindowsGLContext extends GLContext {
   private GLProcAddressTable glProcAddressTable;
   // Handle to GLU32.dll
   private long hglu32;
+  private boolean haveWGLARBPbuffer = true;
 
   private static final int MAX_PFORMATS = 256;
   private static final int MAX_ATTRIBS  = 256;
@@ -150,6 +151,8 @@ public abstract class WindowsGLContext extends GLContext {
 
     if (created) {
       resetGLFunctionAvailability();
+      haveWGLARBPbuffer = (isExtensionAvailable("WGL_ARB_pbuffer") &&
+                           isExtensionAvailable("WGL_ARB_pixel_format"));
       // Windows can set up sharing of display lists after creation time
       WindowsGLContext other = (WindowsGLContext) GLContextShareSet.getShareContext(this);
       if (other != null) {
@@ -681,4 +684,8 @@ public abstract class WindowsGLContext extends GLContext {
   protected static String hdcToString(long hdc) {
     return "0x" + Long.toHexString(hdc);
   }
+
+  protected boolean haveWGLARBPbuffer() {
+    return haveWGLARBPbuffer;
+  }
 }
diff --git a/src/net/java/games/jogl/impl/windows/WindowsOnscreenGLContext.java b/src/net/java/games/jogl/impl/windows/WindowsOnscreenGLContext.java
index 1838f62aa..de13be0a1 100644
--- a/src/net/java/games/jogl/impl/windows/WindowsOnscreenGLContext.java
+++ b/src/net/java/games/jogl/impl/windows/WindowsOnscreenGLContext.java
@@ -102,7 +102,7 @@ public class WindowsOnscreenGLContext extends WindowsGLContext {
   }
 
   public boolean canCreatePbufferContext() {
-    return true;
+    return haveWGLARBPbuffer();
   }
 
   public synchronized GLContext createPbufferContext(GLCapabilities capabilities,