From 306f45fbf267bfead75877462210d5cca902e8b9 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Tue, 26 Jan 2010 17:04:55 +0000
Subject: [PATCH] From Laurens Voerman, "Wile working with pbuffers I noticed
 that the Win32 implementation uses the attribute WGL_PBUFFER_LARGEST_ARB.

> quote from http://www.opengl.org/registry/specs/ARB/wgl_pbuffer.txt
>    The following attributes are supported by wglCreatePbufferARB:
>
>      WGL_PBUFFER_LARGEST_ARB     If this attribute is set to a
>                                  non-zero value, the largest
>                                  available pbuffer is allocated
>                                  when the allocation of the pbuffer
>                                  would otherwise fail due to
>                                  insufficient resources.  The width
>                                  or height of the allocated pbuffer
>                                  never exceeds <iWidth> and <iHeight>,
>                                  respectively.  Use wglQueryPbufferARB
>                                  to retrieve the dimensions of the
>                                  allocated pbuffer.

It notifies the user when the size is not as requested, but I could find no way for the program to detect this. I've added two lines to write the new size back into the _traits, I think this is appropriate, but I am not absolutely sure.

In PixelBufferX11 was no support, so I've added GLX_LARGEST_PBUFFER(_SGIX) support, with the same writeback to the _trais.


I have tested the GLX_LARGEST_PBUFFER version on linux and the WGL_PBUFFER_LARGEST_ARB with windows, all tested with the modified autocapture I just submitted.


"autocapture --pbuffer --window 100 100 18192 18192 cow.osg.\[0,0,-22.7\].trans"
gives me a 4096x4096 image on my windows machine,
and a 8192x8192 image on linux."
---
 src/osgViewer/PixelBufferWin32.cpp |  2 ++
 src/osgViewer/PixelBufferX11.cpp   | 44 ++++++++++++++++++++++++++++--
 2 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/src/osgViewer/PixelBufferWin32.cpp b/src/osgViewer/PixelBufferWin32.cpp
index 84819cd4c..f36b4f96f 100644
--- a/src/osgViewer/PixelBufferWin32.cpp
+++ b/src/osgViewer/PixelBufferWin32.cpp
@@ -632,6 +632,8 @@ void PixelBufferWin32::init()
         osg::notify(osg::NOTICE) << "PixelBufferWin32::init(), pbuffer created with different size then requsted" << std::endl;
         osg::notify(osg::NOTICE) << "\tRequested size (" << _traits->width << "," << _traits->height << ")" << std::endl;
         osg::notify(osg::NOTICE) << "\tPbuffer size (" << iWidth << "," << iHeight << ")" << std::endl;
+        _traits->width  = iWidth;
+        _traits->height = iHeight;
     }
 
     _initialized = true;    
diff --git a/src/osgViewer/PixelBufferX11.cpp b/src/osgViewer/PixelBufferX11.cpp
index fee2e3590..8fe65282d 100644
--- a/src/osgViewer/PixelBufferX11.cpp
+++ b/src/osgViewer/PixelBufferX11.cpp
@@ -250,6 +250,8 @@ void PixelBufferX11::init()
                     attributes.push_back( _traits->width );
                     attributes.push_back( GLX_PBUFFER_HEIGHT );
                     attributes.push_back( _traits->height );
+                    attributes.push_back( GLX_LARGEST_PBUFFER );
+                    attributes.push_back( GL_TRUE );
                     attributes.push_back( 0L );
                     
                     _pbuffer = glXCreatePbuffer(_display, fbconfigs[i], &attributes.front() );
@@ -257,7 +259,22 @@ void PixelBufferX11::init()
                 }
             }
         }
+        if (_pbuffer)
+        {
+            int iWidth = 0;
+            int iHeight = 0;
+            glXQueryDrawable(_display, _pbuffer, GLX_WIDTH  , (unsigned int *)&iWidth);
+            glXQueryDrawable(_display, _pbuffer, GLX_HEIGHT , (unsigned int *)&iHeight);
 
+            if (_traits->width != iWidth || _traits->height != iHeight)
+            {
+                osg::notify(osg::NOTICE) << "PixelBufferX11::init(), pbuffer created with different size then requsted" << std::endl;
+                osg::notify(osg::NOTICE) << "\tRequested size (" << _traits->width << "," << _traits->height << ")" << std::endl;
+                osg::notify(osg::NOTICE) << "\tPbuffer size (" << iWidth << "," << iHeight << ")" << std::endl;
+                _traits->width  = iWidth;
+                _traits->height = iHeight;
+            }
+        }
         XFree( fbconfigs );
     }
 #endif
@@ -267,9 +284,30 @@ void PixelBufferX11::init()
     if (!_pbuffer && haveSGIX_pbuffer)
     {
         GLXFBConfigSGIX fbconfig = glXGetFBConfigFromVisualSGIX( _display, _visualInfo );
-
-        _pbuffer = glXCreateGLXPbufferSGIX(_display, fbconfig, _traits->width, _traits->height, 0 );
-
+        typedef std::vector <int> AttributeList;
+       
+        AttributeList attributes;
+        attributes.push_back( GLX_LARGEST_PBUFFER_SGIX );
+        attributes.push_back( GL_TRUE );
+        attributes.push_back( 0L );
+        
+        _pbuffer = glXCreateGLXPbufferSGIX(_display, fbconfig, _traits->width, _traits->height,  &attributes.front() );
+        if (_pbuffer)
+        {
+            int iWidth = 0;
+            int iHeight = 0;
+            glXQueryGLXPbufferSGIX(_display, _pbuffer, GLX_WIDTH_SGIX , (unsigned int *)&iWidth);
+            glXQueryGLXPbufferSGIX(_display, _pbuffer, GLX_HEIGHT_SGIX, (unsigned int *)&iHeight);
+                                                                                        
+            if (_traits->width != iWidth || _traits->height != iHeight)
+            {
+                osg::notify(osg::NOTICE) << "PixelBufferX11::init(), SGIX_pbuffer created with different size then requsted" << std::endl;
+                osg::notify(osg::NOTICE) << "\tRequested size (" << _traits->width << "," << _traits->height << ")" << std::endl;
+                osg::notify(osg::NOTICE) << "\tPbuffer size (" << iWidth << "," << iHeight << ")" << std::endl;
+                _traits->width =  iWidth;
+                _traits->height = iHeight;
+            }
+        }
         XFree( fbconfig );
     }
 #endif