【转帖】rendering Polygonal Paperspace Viewports
 

rendering polygonal paperspace viewports
rendering polygonal paperspace viewports
hello,
i have a question about rendering non-rectangular paper space viewports. i am currently using a clip boundary to do the clipping as shown in the examples but i haven't seen a way to handle non-rectangular viewports.
i know that you need to use the m_nrcxxxx member data but i'm not sure how. any advice would be great appreciated.
here is the update method:
void
newformavectorizeview::update()
{
device()->setdrawcontext(drawcontext());
if ( !device()->poverallview.isnull() ) {
odgematrix3d xmodel2paperspace = device()->poverallview->objecttodevicematrix().inverse() *
objecttodevicematrix() * geteyetoworldtransform();
seteyetooutputtransform( xmodel2paperspace );
}
else {
odgematrix3d xeyetodc = eyetoscreenmatrix();
seteyetooutputtransform(xeyetodc);
}
m_eyeclip.m_bclippingfront = false;
m_eyeclip.m_bclippingback = false;
m_eyeclip.m_bdrawboundary = true;
m_eyeclip.m_vnormal = viewdir();
m_eyeclip.m_ptpoint = target();
m_eyeclip.m_points.clear();
odgevector2d halfdiagonal( fieldwidth()/2.0, fieldheight()/2.0 );
m_eyeclip.m_points.append( odgepoint2d::korigin - halfdiagonal );
m_eyeclip.m_points.append( odgepoint2d::korigin + halfdiagonal );
m_eyeclip.m_xtoclipspace = getworldtoeyetransform();
pushclipboundary( &m_eyeclip );
odgsbasevectorizeview::update();
popclipboundary();
}
thanks!

first, notice that viewport clipping by rasterizer is much better then software viewport clipping (which you get by pushclipboundary).
for windgi device we have exgigdigeometry:ushviewportclip, that is called from exgdivectorizeview::update(). since wingdi device doesn't have z-buffer, we also use odgiorthoclipper in case front/back clip.
for opengl device we use stencil, see odgsopenglvectorizeview::beginviewvectorization().
sincerely yours,
george udov
quote:
originally posted by george udov
first, notice that viewport clipping by rasterizer is much better then software viewport clipping (which you get by pushclipboundary).
for windgi device we have exgigdigeometry:ushviewportclip, that is called from exgdivectorizeview::update(). since wingdi device doesn't have z-buffer, we also use odgiorthoclipper in case front/back clip.
for opengl device we use stencil, see odgsopenglvectorizeview::beginviewvectorization().
opengl and gdi are not options for us. is there any way to have oda do the clipping using pushclipboundary?
thanks.

odvectorizeex sample in 1.12beta contains sample of using software non-rectangular clipping (exsimpleview::update())
sincerely yours,
george udov