GLCapabilities Native Aquisition: Set alpha bits at last - due to it's auto setting by setSampleBuffers(true) and setBackgroundOpaque(false)

This bug lead to X11 GLCapabilities rgba: 8/8/8/1 - which ofc is invalid. Sideeffect was a bad selected GLXFB configuration
and the GLContext couldn't be made current.

Patch sets alpha bits reflecting reality carefully after opaque/samples. Added API doc note.

2 files changed, 28 insertions, 26 deletions

diff --git a/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXContext.java b/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXContext.java
index e6b74a769..e1e25be67 100644
--- a/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXContext.java
+++ b/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXContext.java
@@ -152,7 +152,7 @@ public abstract class X11GLXContext extends GLContextImpl {
             throw new InternalError("Given readDrawable but no driver support");
         }
     } catch (RuntimeException re) {
-        if(TRACE_SWITCH) {
+        if(DEBUG || TRACE_SWITCH) {
           System.err.println(getThreadName()+": Warning: X11GLXContext.glXMakeContextCurrent failed: "+re+", with "+
             "dpy "+toHexString(dpy)+
             ", write "+toHexString(writeDrawable)+
diff --git a/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXGraphicsConfiguration.java b/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXGraphicsConfiguration.java
index b5b80e0b3..95b1cc457 100644
--- a/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXGraphicsConfiguration.java
+++ b/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXGraphicsConfiguration.java
@@ -308,19 +308,6 @@ public class X11GLXGraphicsConfiguration extends X11GraphicsConfiguration implem
     }
 
     GLCapabilities res = new X11GLCapabilities(visualInfo, fbcfg, fbcfgid, glp);
-    res.setDoubleBuffered(glXGetFBConfig(display, fbcfg, GLX.GLX_DOUBLEBUFFER,     tmp, 0) != 0);
-    res.setStereo        (glXGetFBConfig(display, fbcfg, GLX.GLX_STEREO,           tmp, 0) != 0);
-    res.setHardwareAccelerated(glXGetFBConfig(display, fbcfg, GLX.GLX_CONFIG_CAVEAT, tmp, 0) != GLX.GLX_SLOW_CONFIG);
-    res.setDepthBits     (glXGetFBConfig(display, fbcfg, GLX.GLX_DEPTH_SIZE,       tmp, 0));
-    res.setStencilBits   (glXGetFBConfig(display, fbcfg, GLX.GLX_STENCIL_SIZE,     tmp, 0));
-    res.setRedBits       (glXGetFBConfig(display, fbcfg, GLX.GLX_RED_SIZE,         tmp, 0));
-    res.setGreenBits     (glXGetFBConfig(display, fbcfg, GLX.GLX_GREEN_SIZE,       tmp, 0));
-    res.setBlueBits      (glXGetFBConfig(display, fbcfg, GLX.GLX_BLUE_SIZE,        tmp, 0));
-    res.setAlphaBits     (glXGetFBConfig(display, fbcfg, GLX.GLX_ALPHA_SIZE,       tmp, 0));
-    res.setAccumRedBits  (glXGetFBConfig(display, fbcfg, GLX.GLX_ACCUM_RED_SIZE,   tmp, 0));
-    res.setAccumGreenBits(glXGetFBConfig(display, fbcfg, GLX.GLX_ACCUM_GREEN_SIZE, tmp, 0));
-    res.setAccumBlueBits (glXGetFBConfig(display, fbcfg, GLX.GLX_ACCUM_BLUE_SIZE,  tmp, 0));
-    res.setAccumAlphaBits(glXGetFBConfig(display, fbcfg, GLX.GLX_ACCUM_ALPHA_SIZE, tmp, 0));
     if (isMultisampleAvailable) {
       res.setSampleBuffers(glXGetFBConfig(display, fbcfg, GLX.GLX_SAMPLE_BUFFERS, tmp, 0) != 0);
       res.setNumSamples   (glXGetFBConfig(display, fbcfg, GLX.GLX_SAMPLES,        tmp, 0));
@@ -336,6 +323,20 @@ public class X11GLXGraphicsConfiguration extends X11GraphicsConfiguration implem
         res.setTransparentBlueValue(xrmask.getBlueMask());
         res.setTransparentAlphaValue(alphaMask);
     }
+    // ALPHA shall be set at last - due to it's auto setting by the above (!opaque / samples)    
+    res.setDoubleBuffered(glXGetFBConfig(display, fbcfg, GLX.GLX_DOUBLEBUFFER,     tmp, 0) != 0);
+    res.setStereo        (glXGetFBConfig(display, fbcfg, GLX.GLX_STEREO,           tmp, 0) != 0);
+    res.setHardwareAccelerated(glXGetFBConfig(display, fbcfg, GLX.GLX_CONFIG_CAVEAT, tmp, 0) != GLX.GLX_SLOW_CONFIG);
+    res.setRedBits       (glXGetFBConfig(display, fbcfg, GLX.GLX_RED_SIZE,         tmp, 0));
+    res.setGreenBits     (glXGetFBConfig(display, fbcfg, GLX.GLX_GREEN_SIZE,       tmp, 0));
+    res.setBlueBits      (glXGetFBConfig(display, fbcfg, GLX.GLX_BLUE_SIZE,        tmp, 0));
+    res.setAlphaBits     (glXGetFBConfig(display, fbcfg, GLX.GLX_ALPHA_SIZE,       tmp, 0));
+    res.setAccumRedBits  (glXGetFBConfig(display, fbcfg, GLX.GLX_ACCUM_RED_SIZE,   tmp, 0));
+    res.setAccumGreenBits(glXGetFBConfig(display, fbcfg, GLX.GLX_ACCUM_GREEN_SIZE, tmp, 0));
+    res.setAccumBlueBits (glXGetFBConfig(display, fbcfg, GLX.GLX_ACCUM_BLUE_SIZE,  tmp, 0));
+    res.setAccumAlphaBits(glXGetFBConfig(display, fbcfg, GLX.GLX_ACCUM_ALPHA_SIZE, tmp, 0));
+    res.setDepthBits     (glXGetFBConfig(display, fbcfg, GLX.GLX_DEPTH_SIZE,       tmp, 0));
+    res.setStencilBits   (glXGetFBConfig(display, fbcfg, GLX.GLX_STENCIL_SIZE,     tmp, 0));
     
     try { 
         res.setPbufferFloatingPointBuffers(glXGetFBConfig(display, fbcfg, GLXExt.GLX_FLOAT_COMPONENTS_NV, tmp, 0) != GL.GL_FALSE);
@@ -429,18 +430,7 @@ public class X11GLXGraphicsConfiguration extends X11GraphicsConfiguration implem
     // Note: use of hardware acceleration is determined by
     // glXCreateContext, not by the XVisualInfo. Optimistically claim
     // that all GLCapabilities have the capability to be hardware
-    // accelerated.
-    res.setHardwareAccelerated(true);
-    res.setDepthBits     (glXGetConfig(display, info, GLX.GLX_DEPTH_SIZE,       tmp, 0));
-    res.setStencilBits   (glXGetConfig(display, info, GLX.GLX_STENCIL_SIZE,     tmp, 0));
-    res.setRedBits       (glXGetConfig(display, info, GLX.GLX_RED_SIZE,         tmp, 0));
-    res.setGreenBits     (glXGetConfig(display, info, GLX.GLX_GREEN_SIZE,       tmp, 0));
-    res.setBlueBits      (glXGetConfig(display, info, GLX.GLX_BLUE_SIZE,        tmp, 0));
-    res.setAlphaBits     (glXGetConfig(display, info, GLX.GLX_ALPHA_SIZE,       tmp, 0));
-    res.setAccumRedBits  (glXGetConfig(display, info, GLX.GLX_ACCUM_RED_SIZE,   tmp, 0));
-    res.setAccumGreenBits(glXGetConfig(display, info, GLX.GLX_ACCUM_GREEN_SIZE, tmp, 0));
-    res.setAccumBlueBits (glXGetConfig(display, info, GLX.GLX_ACCUM_BLUE_SIZE,  tmp, 0));
-    res.setAccumAlphaBits(glXGetConfig(display, info, GLX.GLX_ACCUM_ALPHA_SIZE, tmp, 0));
+    // accelerated.    
     if (isMultisampleEnabled) {
       res.setSampleBuffers(glXGetConfig(display, info, GLX.GLX_SAMPLE_BUFFERS, tmp, 0) != 0);
       res.setNumSamples   (glXGetConfig(display, info, GLX.GLX_SAMPLES,        tmp, 0));
@@ -456,6 +446,18 @@ public class X11GLXGraphicsConfiguration extends X11GraphicsConfiguration implem
         res.setTransparentBlueValue(xrmask.getBlueMask());
         res.setTransparentAlphaValue(alphaMask);
     }
+    // ALPHA shall be set at last - due to it's auto setting by the above (!opaque / samples)
+    res.setHardwareAccelerated(true);
+    res.setDepthBits     (glXGetConfig(display, info, GLX.GLX_DEPTH_SIZE,       tmp, 0));
+    res.setStencilBits   (glXGetConfig(display, info, GLX.GLX_STENCIL_SIZE,     tmp, 0));
+    res.setRedBits       (glXGetConfig(display, info, GLX.GLX_RED_SIZE,         tmp, 0));
+    res.setGreenBits     (glXGetConfig(display, info, GLX.GLX_GREEN_SIZE,       tmp, 0));
+    res.setBlueBits      (glXGetConfig(display, info, GLX.GLX_BLUE_SIZE,        tmp, 0));
+    res.setAlphaBits     (glXGetConfig(display, info, GLX.GLX_ALPHA_SIZE,       tmp, 0));
+    res.setAccumRedBits  (glXGetConfig(display, info, GLX.GLX_ACCUM_RED_SIZE,   tmp, 0));
+    res.setAccumGreenBits(glXGetConfig(display, info, GLX.GLX_ACCUM_GREEN_SIZE, tmp, 0));
+    res.setAccumBlueBits (glXGetConfig(display, info, GLX.GLX_ACCUM_BLUE_SIZE,  tmp, 0));
+    res.setAccumAlphaBits(glXGetConfig(display, info, GLX.GLX_ACCUM_ALPHA_SIZE, tmp, 0));
 
     return GLGraphicsConfigurationUtil.addGLCapabilitiesPermutations(capsBucket, res, drawableTypeBits);
   }