[libcvd-members] libcvd/cvd gl_helpers.h

[Edward Rosten]

CVSROOT:        /cvsroot/libcvd
Module name:    libcvd
Changes by:     Edward Rosten <edrosten>        11/02/18 11:39:34

Modified files:
        cvd            : gl_helpers.h 

Log message:
        Compute alignment in glDrawPixels to work around buggy drivers.

CVSWeb URLs:
http://cvs.savannah.gnu.org/viewcvs/libcvd/cvd/gl_helpers.h?cvsroot=libcvd&r1=1.47&r2=1.48

Patches:
Index: gl_helpers.h
===================================================================
RCS file: /cvsroot/libcvd/libcvd/cvd/gl_helpers.h,v
retrieving revision 1.47
retrieving revision 1.48
diff -u -b -r1.47 -r1.48
--- gl_helpers.h        12 Nov 2010 14:07:31 -0000      1.47
+++ gl_helpers.h        18 Feb 2011 11:39:34 -0000      1.48
@@ -23,6 +23,7 @@
 
 #include <iostream>
 #include <map>
+#include <utility>
 
 #include <cvd/image_ref.h>
 #include <cvd/image.h>
@@ -523,13 +524,31 @@
                glColor4f(c.red, c.green, c.blue, c.alpha);
        }
 
+       namespace Internal{
+                       static inline int alignof(const void* ptr)
+                       {
+                               size_t p = (size_t)ptr;
+
+                               if(p&3)
+                                       if(p&1)
+                                               return 1;
+                                       else 
+                                               return 2;
+                               else
+                                       if(p&4)
+                                               return 4;
+                                       else
+                                               return 8;
+                       }
+       }
+
        /// Draw an image to the frame buffer at the current raster position.
        /// Use glRasterPos to set the current raster position
        /// @param i The image to draw
        ///@ingroup gGL
        template<class C> inline void glDrawPixels(const SubImage<C>& i)
        {
-               ::glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+               ::glPixelStorei(GL_UNPACK_ALIGNMENT, 
std::min(Internal::alignof(i[0]), Internal::alignof(i[1])));
                ::glPixelStorei(GL_UNPACK_ROW_LENGTH, i.row_stride());
                ::glDrawPixels(i.size().x, i.size().y, gl::data<C>::format, 
gl::data<C>::type, i.data());
                ::glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);