QtOCC and Transparency

A little bit of debugging with GLIntercept revealed one of the problems - enabled clip planes in OpenGL. So I've modifies the callback routine to fix that as below.

/*!
\brief The OpenGL paint routine in the callback.
*/
void Qocc3dWidget::paintOCC( void )
{
GLboolean isPlaneActive[6];
int i;

glDisable( GL_LIGHTING );
glMatrixMode( GL_MODELVIEW );
glPushMatrix();
glLoadIdentity();
glMatrixMode( GL_PROJECTION );
glPushMatrix();
glLoadIdentity();

GLfloat left = -1.0f;
GLfloat right = 1.0f;
GLfloat bottom = -1.0f;
GLfloat top = 1.0f;
GLfloat depth = 1.0f;

for (i = 0; i < 6; i++)
{
isPlaneActive[i] = glIsEnabled(GL_CLIP_PLANE0 + i);
glDisable(GL_CLIP_PLANE0 + i);
}

glOrtho( left, right, bottom, top, 1.0, -1.0 );
glEnable( GL_BLEND );
glBlendFunc( GL_ONE, GL_ONE_MINUS_SRC_COLOR );

glBegin( GL_QUADS );
{
glColor4f ( 0.1f, 0.1f, 0.1f, 0.0f );
glVertex3d ( left, bottom, depth );
glVertex3d ( right, bottom, depth );
glColor4f ( 0.9f, 0.9f, 0.9f, 0.0f );
glVertex3d ( right, top, depth );
glVertex3d ( left, top, depth );
}
glEnd();

glDisable(GL_BLEND);
glPopMatrix();
glMatrixMode( GL_MODELVIEW );
glPopMatrix();

for (i = 0; i < 6; i++)
{
if (isPlaneActive[i])
{
glEnable(GL_CLIP_PLANE0 + i);
}
}
}

I'm still having problems with clipping when using some of the "Action" buttons to change the view orientation properly when clipping is active, unless I double up calls to SetProj like

void Qocc3dWidget::viewAxo()
{
if( !myView.IsNull() )
{
myView->SetProj( V3d_XnegYnegZpos );
myView->SetProj( V3d_XnegYnegZpos );
}
}

which looks really stupid but works! I'd like to be able to stop the grid from clipping, but that looks like I need to unpick the OpenCASCADE source from the inside. I'm still looking at that one.

Pete