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.

1 files changed, 19 insertions, 18 deletions

diff --git a/src/jogl/classes/jogamp/opengl/egl/EGLGraphicsConfiguration.java b/src/jogl/classes/jogamp/opengl/egl/EGLGraphicsConfiguration.java
index 214b36493..73867fb40 100644
--- a/src/jogl/classes/jogamp/opengl/egl/EGLGraphicsConfiguration.java
+++ b/src/jogl/classes/jogamp/opengl/egl/EGLGraphicsConfiguration.java
@@ -209,24 +209,6 @@ public class EGLGraphicsConfiguration extends MutableGraphicsConfiguration imple
             return false;
         }        
                 
-        if(EGL.eglGetConfigAttrib(display, config, EGL.EGL_RED_SIZE, val)) {
-            caps.setRedBits(val.get(0));
-        }
-        if(EGL.eglGetConfigAttrib(display, config, EGL.EGL_GREEN_SIZE, val)) {
-            caps.setGreenBits(val.get(0));
-        }
-        if(EGL.eglGetConfigAttrib(display, config, EGL.EGL_BLUE_SIZE, val)) {
-            caps.setBlueBits(val.get(0));
-        }
-        if(EGL.eglGetConfigAttrib(display, config, EGL.EGL_ALPHA_SIZE, val)) {
-            caps.setAlphaBits(val.get(0));
-        }
-        if(EGL.eglGetConfigAttrib(display, config, EGL.EGL_STENCIL_SIZE, val)) {
-            caps.setStencilBits(val.get(0));
-        }
-        if(EGL.eglGetConfigAttrib(display, config, EGL.EGL_DEPTH_SIZE, val)) {
-            caps.setDepthBits(val.get(0));
-        }
         if(EGL.eglGetConfigAttrib(display, config, EGL.EGL_SAMPLES, val)) {
             caps.setSampleBuffers(val.get(0)>0?true:false);
             caps.setNumSamples(val.get(0));
@@ -262,6 +244,25 @@ public class EGLGraphicsConfiguration extends MutableGraphicsConfiguration imple
                 caps.setTransparentAlphaValue(val.get(0)==EGL.EGL_DONT_CARE?-1:val.get(0));
             } */
         }
+        // ALPHA shall be set at last - due to it's auto setting by the above (!opaque / samples)
+        if(EGL.eglGetConfigAttrib(display, config, EGL.EGL_RED_SIZE, val)) {
+            caps.setRedBits(val.get(0));
+        }
+        if(EGL.eglGetConfigAttrib(display, config, EGL.EGL_GREEN_SIZE, val)) {
+            caps.setGreenBits(val.get(0));
+        }
+        if(EGL.eglGetConfigAttrib(display, config, EGL.EGL_BLUE_SIZE, val)) {
+            caps.setBlueBits(val.get(0));
+        }
+        if(EGL.eglGetConfigAttrib(display, config, EGL.EGL_ALPHA_SIZE, val)) {
+            caps.setAlphaBits(val.get(0));
+        }
+        if(EGL.eglGetConfigAttrib(display, config, EGL.EGL_STENCIL_SIZE, val)) {
+            caps.setStencilBits(val.get(0));
+        }
+        if(EGL.eglGetConfigAttrib(display, config, EGL.EGL_DEPTH_SIZE, val)) {
+            caps.setDepthBits(val.get(0));
+        }
         return GLGraphicsConfigurationUtil.addGLCapabilitiesPermutations(capsBucket, caps, drawableTypeBits );
     }