Re: [osg-users] Outline Effect traversal crash
Hi Brian, Robert, all,
For object outlining I use cull callback that traverses node two times (its
a simple workaround for two pass techniques). I use well known technique
rendering back faces in wireframe (
http://en.wikipedia.org/wiki/Cel-shaded_animation) prior regular rendering.
It was mentioned several times on osg-users. To outline selected node You
just need to call node-setCullCallback(new OutlineCallback), there is no
need to tweak the scene graph structure. To change outline color You could
use emissive color tweaking on object material, J-S was mentioning it some
time ago
http://www.mail-archive.com/osg-users@lists.openscenegraph.org/msg21935.html
class OutlineCallback : public osg::NodeCallback
{
public:
OutlineCallback();
/** Line width for outline effect */
void setLineWidth(float lineWidth);
float getLineWidth() const;
/** Sets required states */
void resetStateSet();
virtual void operator()(osg::Node *node, osg::NodeVisitor *nv);
protected:
osg::ref_ptrosg::StateSet _stateSet;
};
OutlineCallback::OutlineCallback()
{
resetStateSet();
setLineWidth(3.0);
}
void OutlineCallback::resetStateSet()
{
if (!_stateSet)
_stateSet = new osg::StateSet;
osg::StateSet *ss = _stateSet.get();
ss-setRenderBinDetails(200, RenderBin);
ss-setMode(GL_LIGHTING, osg::StateAttribute::OFF |
osg::StateAttribute::OVERRIDE);
for (unsigned int unit=0;unit4;++unit)
ss-setTextureMode(unit, GL_TEXTURE_2D, osg::StateAttribute::OFF |
osg::StateAttribute::OVERRIDE);
osg::PolygonMode *polygonMode = dynamic_castosg::PolygonMode
*(ss-getAttribute(osg::StateAttribute::POLYGONMODE));
if (!polygonMode)
{
polygonMode = new osg::PolygonMode;
ss-setAttribute(polygonMode, osg::StateAttribute::ON);
}
polygonMode-setMode(osg::PolygonMode::BACK, osg::PolygonMode::LINE);
osg::CullFace *cullFace = dynamic_castosg::CullFace
*(ss-getAttribute(osg::StateAttribute::CULLFACE));
if (!cullFace)
{
cullFace = new osg::CullFace;
ss-setAttribute(cullFace, osg::StateAttribute::ON);
}
cullFace-setMode(osg::CullFace::FRONT);
osg::Depth *depth = dynamic_castosg::Depth
*(ss-getAttribute(osg::StateAttribute::DEPTH));
if (!depth)
{
depth = new osg::Depth;
ss-setAttribute(depth, osg::StateAttribute::ON);
}
depth-setFunction(osg::Depth::LEQUAL);
}
void OutlineCallback::setLineWidth(float width)
{
osg::LineWidth *lineWidth = dynamic_castosg::LineWidth
*(_stateSet-getAttribute(osg::StateAttribute::LINEWIDTH));
if (!lineWidth)
{
lineWidth = new osg::LineWidth;
_stateSet-setAttribute(lineWidth, osg::StateAttribute::ON);
}
lineWidth-setWidth(width);
}
float OutlineCallback::getLineWidth() const
{
osg::LineWidth *lineWidth = dynamic_castosg::LineWidth
*(_stateSet-getAttribute(osg::StateAttribute::LINEWIDTH));
return lineWidth ? lineWidth-getWidth() : 1.0;
}
void OutlineCallback::operator()(osg::Node *node, osg::NodeVisitor *nv)
{
if (nv-getVisitorType() == osg::NodeVisitor::CULL_VISITOR)
{
osgUtil::CullVisitor *cv = dynamic_castosgUtil::CullVisitor *(nv);
if (cv)
{
cv-pushStateSet(_stateSet.get());
traverse(node, cv);
cv-popStateSet();
}
}
traverse(node, nv);
}
Regards,
Maciej
2009/5/21 Robert Osfield robert.osfi...@gmail.com
Hi Brian,
It sounds like you may have hit upon a threading bug in the Outline
effect. Try changing the viewer threading mode to either
SingleThreaded or CullDrawThreadPerCamera, if this works then there
is an threading issue with changing display lists or StateSet's at the
same time that these objects are being rendered. Changing the
DataVariance to STATIC is the usually the best way to solve this, but
you can also double buffer the problem structures.
Robert.
On Thu, May 21, 2009 at 5:29 PM, Brian Stewart jbstew...@pobox.com
wrote:
Hi,
I switched my code around to where the model was being added from the
main loop rather than the update traversal, and it was still crashing. On
closer examination I noticed that the crashes were occurring during the
render traversal, so I began to suspect the effect itself. When I replaced
the effect with an instance of osgFX::Scribe, then everything worked
correctly. So something was amiss in the Outline effect itself. I was using
it only because I did not know about the Scribe effect, which is better for
my purposes anyway.
Thank you!
Brian
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Re: [osg-users] Outline Effect traversal crash
Hi Maciej, Thank you for the example. It seems to be a lot faster than what I was doing earlier. Before when a node was selected, I removed it from its parent, created an osgFX::Scribe effect and placed it under the parent, and then reattached my node under that. But there was a slight delay between when the node disappeared, and when it reappeared selected. Because the nodes are buildings placed on geo-specific high-resolution imagery, this had the curious effect of make the building appear to be push into the terrain temporarily, and then spring back into position with the Scribe effect applied. Thanks for the links to the post and to the cel-shading article - those helped a lot! I did have one question about the new selection method you demonstrated. It makes the building appear to be all white, since the texture is turned off. Is this correct? I tried disabling that part of the code, but now the backfaced outlines are not enough to make the object stand out. What I would really like to do is outline the object in a striking color (say bright yellow, or something) and then render the textured object with a slight cast if the same color. Is this possible in OSG? I have searched though the archives, but without a lot of success yet. Just a pointer to some techniques that might work, or to a forum thread I missed would be a great help! Thank you! Cheers, Brian -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=12792#12792 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Outline Effect traversal crash
Hello Brian, It makes the building appear to be all white, since the texture is turned off. Is this correct? I tried disabling that part of the code, but now the backfaced outlines are not enough to make the object stand out. What I would really like to do is outline the object in a striking color (say bright yellow, or something) and then render the textured object with a slight cast if the same color. Is this possible in OSG? I have searched though the archives, but without a lot of success yet. Just a pointer to some techniques that might work, or to a forum thread I missed would be a great help! What you would need to get that effect would be to have the outline's stateset contain a material with a bright yellow emissive color (and enable GL_LIGHTING) and then change the main pass's stateset to give the material a slight yellow tint. Just a bit though, because it will be added to the main material color (diffuse * texture) so you don't want to drown that out completely with the emissive color. Play around with these things, you should be able to get what you want. Hope this helps, J-S -- __ Jean-Sebastien Guayjean-sebastien.g...@cm-labs.com http://www.cm-labs.com/ http://whitestar02.webhop.org/ ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Outline Effect traversal crash
Hi Robert, Thanks for that clarification, as my understanding of where nodes should be added and removed was exactly backwards. I did paraphrase my code extensively, because there was a lot of unrelated code - but I guess I didn't include enough. I went to create a simpler example using osgcompositeviewer as a starting point, when I noticed that it is doing exactly the same thing that I am trying to, only in the handle() function of osgaGA::GUIEventHandler, which is called during the event traversal of frame(). When you said it's best to avoid modifying the scenegraph during a traversal, did that specifically mean the Update Traversal, when NodeCallbacks are called, and that modifications in event callbacks are OK? Thank you! Cheers, Brian -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=12675#12675 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Outline Effect traversal crash
Hi, I switched my code around to where the model was being added from the main loop rather than the update traversal, and it was still crashing. On closer examination I noticed that the crashes were occurring during the render traversal, so I began to suspect the effect itself. When I replaced the effect with an instance of osgFX::Scribe, then everything worked correctly. So something was amiss in the Outline effect itself. I was using it only because I did not know about the Scribe effect, which is better for my purposes anyway. Thank you! Brian -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=12692#12692 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
[osg-users] Outline Effect traversal crash
Hi,
I am trying to implement a mechanism by which selected objects in my scene are
highlighted. Searching the forum I found a reference to the Outline effect (an
implementation of osgFX::Effect) on Ulrich Hertlein's web site
(http://www.sandbox.de/osg/), and I have attempted to integrate it into our app
- however, most of the time, whenever the object which is outlined first comes
into view, the app crashes in osg::NodeCallback::traverse, because the
_nestedCallback member is corrupted. This is on Windows Vista-64, running OSG
2.6.1 built with Visual Studio 2008, in Debug mode. We are running OSG
multithreaded, and all my code setting up the effect is called from
osg::NodeCallback::operator() on the render thread. The general flow is as
follows:
Code:
osg::NodeCallback::operator()
{
osg::PositionAttitudeTransform* modelTransform; // local transform to
position the model in the world
osg::Node* someChild; // some model
osg::ref_ptrosgFX::Effect fxNode = new osgFX::Outline();
fxNode-addChild( someChild );
modelTransform-addChild( fxNode.get() );
}
Am I missing something obvious? If not, ideas or debugging strategies would
also be greatly appreciated!
Thank you!
Brian
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