Re: [Openev-discuss] gv_view_area_render_to_func and glReadPixels - strange test RED=253 && GREEN=101

[Frank W. <war...@po...>]

Julien Demaria wrote:
> Yes, using a larger fingerprint should make my bad luck case almost impossible :)


Julien,

I have committed a code change to make it look like this:

                 const static char *signature = "glReadPixels() check signature";

                 scanline = row_of_chunks +
                     x_chunk * 3
                     + line * width * 3;

                 if( x_chunk_size * y_chunk_size >= strlen(signature) )
                     memcpy( scanline, signature, strlen(signature) );

                 glReadPixels( 0, y_chunk_size - line - 1,
                               MIN(x_chunk_size,width-x_chunk), 1,
                               GL_RGB, GL_UNSIGNED_BYTE, scanline );

                 if( x_chunk_size * y_chunk_size >= strlen(signature)
                     && memcmp( scanline, signature, strlen(signature)) == 0 )
                 {
                     CPLDebug( "OpenEV",
                               "glReadPixels() appears to have failed." );
                     errcode = 1;
                 }

This should be substantially safer.  Now to make sure this makes it into
OpenEV 2!  Mario?

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, war...@po...
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org