Hi, does the osgProducer::Viewer (I use osg 1.2) is suppose to work if
the WGL_ARB_PIXEL_FORNAT is not supported? It seems fall in an
infinite loop ( in the method VisualChooser::choose( Display *dpy, int
screen, bool strict_adherence) ) when this extension is not
supported. The variable "failed" is always true (can not be change to
false) so the while(failed) is always executed The code is:
VisualInfo *VisualChooser::choose( Display *dpy, int screen, bool
strict_adherence)
{
if (_vinfo)
return _vinfo;
if (_visual_attributes.empty())
setSimpleConfiguration();
int vid;
bool failed = false;
WGLExtensions *ext = WGLExtensions::instance();
if (ext && ext->isSupported(WGLExtensions::ARB_pixel_format))
{
do
{
std::vector<int> attribs;
for (std::vector<VisualAttribute>::const_iterator
i=_visual_attributes.begin(); i!=_visual_attributes.end(); ++i)
applyAttribute(*i, attribs);
attribs.push_back(0);
unsigned int num_formats;
failed = !ext->wglChoosePixelFormat(*dpy,
&attribs.front(), 0, 1, &vid, &num_formats) || num_formats == 0;
if (failed)
{
// **** DRIVER BUG? It seems that some ATI cards don't support
// **** the WGL_SWAP_METHOD_ARB attribute. Now we try to remove
// **** it from the attribute list and choose a pixel
format again.
for (std::vector<int>::iterator k=attribs.begin();
k!=attribs.end(); ++k)
{
if (*k == WGL_SWAP_METHOD_ARB)
{
// attribute come in sequential attribute,paramter pairs
// as WGL specifications so we need to delete
two entries
attribs.erase(k,k+2);
break;
}
}
failed = !ext->wglChoosePixelFormat(*dpy,
&attribs.front(), 0, 1, &vid, &num_formats) || num_formats == 0;
}
if (failed)
{
if (strict_adherence || _visual_attributes.empty())
break;
std::cerr << "Producer::VisualChooser: the requested
visual is not available, trying to relax attributes..." << std::endl;
_visual_attributes.pop_back();
}
} while (failed);
}
if (failed || !ext || !ext->isSupported(WGLExtensions::ARB_pixel_format))
{
std::cerr << "Producer::VisualChooser: unable to setup a valid
visual with WGL extensions, switching to compatibility mode" <<
std::endl;
failed = false;
do
{
PIXELFORMATDESCRIPTOR pfd;
ZeroMemory(&pfd, sizeof(pfd));
pfd.nSize = sizeof(pfd);
pfd.nVersion = 1;
pfd.dwFlags = PFD_DRAW_TO_WINDOW;
pfd.iLayerType = PFD_MAIN_PLANE;
for (std::vector<VisualAttribute>::const_iterator
i=_visual_attributes.begin(); i!=_visual_attributes.end(); ++i)
{
if (i->attribute() == UseGL) pfd.dwFlags
|= PFD_SUPPORT_OPENGL;
if (i->attribute() == DoubleBuffer) pfd.dwFlags
|= PFD_DOUBLEBUFFER | PFD_SWAP_EXCHANGE;
if (i->attribute() == Stereo) pfd.dwFlags
|= PFD_STEREO;
if (i->attribute() == RGBA)
pfd.iPixelType = PFD_TYPE_RGBA;
if (i->attribute() == BufferSize)
pfd.cColorBits = i->parameter();
if (i->attribute() == RedSize) pfd.cRedBits
= i->parameter();
if (i->attribute() == GreenSize)
pfd.cGreenBits = i->parameter();
if (i->attribute() == BlueSize) pfd.cBlueBits
= i->parameter();
if (i->attribute() == AlphaSize)
pfd.cAlphaBits = i->parameter();
if (i->attribute() == AccumRedSize)
pfd.cAccumRedBits = i->parameter();
if (i->attribute() == AccumGreenSize)
pfd.cAccumGreenBits = i->parameter();
if (i->attribute() == AccumBlueSize)
pfd.cAccumBlueBits = i->parameter();
if (i->attribute() == AccumAlphaSize)
pfd.cAccumAlphaBits = i->parameter();
if (i->attribute() == DepthSize)
pfd.cDepthBits = i->parameter();
if (i->attribute() == StencilSize)
pfd.cStencilBits = i->parameter();
if (i->attribute() == AuxBuffers)
pfd.cAuxBuffers = i->parameter();
}
pfd.cAccumBits = pfd.cAccumRedBits + pfd.cAccumGreenBits +
pfd.cAccumBlueBits + pfd.cAccumAlphaBits;
vid = ChoosePixelFormat(*dpy, &pfd);
if ( vid != 0 )
{
// Is this additional check neccessary ?
// Did anyone encountered a situation where
// ChoosePixelFormat returned PXIELFORMAT worse than required ?
_visual_id = static_cast<unsigned int>(vid);
VisualInfo pfd;
DescribePixelFormat(*dpy, _visual_id,
sizeof(PIXELFORMATDESCRIPTOR), &pfd);
bool boolOK = true;
for (std::vector<VisualAttribute>::const_iterator
i=_visual_attributes.begin(); i!=_visual_attributes.end(); ++i)
{
if (i->attribute() == UseGL) boolOK &=
!!( pfd.dwFlags & PFD_SUPPORT_OPENGL );
if (i->attribute() == DoubleBuffer) boolOK &=
!!( pfd.dwFlags & ( PFD_DOUBLEBUFFER | PFD_SWAP_EXCHANGE ) );
if (i->attribute() == Stereo) boolOK &=
!!( pfd.dwFlags & PFD_STEREO );
if (i->attribute() == RGBA) boolOK &=
pfd.iPixelType == PFD_TYPE_RGBA;
if (i->attribute() == BufferSize) boolOK &=
pfd.cColorBits >= i->parameter();
if (i->attribute() == RedSize) boolOK &=
pfd.cRedBits >= i->parameter();
if (i->attribute() == GreenSize) boolOK &=
pfd.cGreenBits >= i->parameter();
if (i->attribute() == BlueSize) boolOK &=
pfd.cBlueBits >= i->parameter();
if (i->attribute() == AlphaSize) boolOK &=
pfd.cAlphaBits >= i->parameter();
if (i->attribute() == AccumRedSize) boolOK &=
pfd.cAccumRedBits >= i->parameter();
if (i->attribute() == AccumGreenSize) boolOK &=
pfd.cAccumGreenBits >= i->parameter();
if (i->attribute() == AccumBlueSize) boolOK &=
pfd.cAccumBlueBits >= i->parameter();
if (i->attribute() == AccumAlphaSize) boolOK &=
pfd.cAccumAlphaBits >= i->parameter();
if (i->attribute() == DepthSize) boolOK &=
pfd.cDepthBits >= i->parameter();
if (i->attribute() == StencilSize) boolOK &=
pfd.cStencilBits >= i->parameter();
if (i->attribute() == AuxBuffers) boolOK &=
pfd.cAuxBuffers >= i->parameter();
}
if ( !boolOK )
vid = 0;
}
if( vid == 0 )
{
failed = true;
if (strict_adherence || _visual_attributes.empty())
break;
std::cerr << "Producer::VisualChooser: the requested
visual is not available, trying to relax attributes..." << std::endl;
_visual_attributes.pop_back();
}
} while (failed);
}
if (failed)
{
std::cerr << "Producer::VisualChooser: could not choose the
pixel format" << std::endl;
return 0;
}
_visual_id = static_cast<unsigned int>(vid);
// we set _vinfo for compatibility, but it's going to be unused
// because the pixel format is usually chosen by visual ID rather
// than by descriptor.
_vinfo = new VisualInfo;
DescribePixelFormat(*dpy, _visual_id,
sizeof(PIXELFORMATDESCRIPTOR), _vinfo);
return _vinfo;
}
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