Hi Robert Thanks for the stack of code! One thing I probably didn't make clear in my first email is I am not intersecting with the mouse. This is a VR type application, so the input device is just an object that can be placed anywhere in the scene. This is why I was representing it as a sphere in 3d space.
So looking at this code. I guess a way to proceed is to implement my own intesector for intersecting with a sphere. Once I have intersections working with the sphere I can then use this code as a base for working out the texture coordinates. Does this sound reasonable? Cheers Michael On Wed, Jan 14, 2009 at 8:02 PM, Robert Osfield <[email protected]>wrote: > Hi Michael, > > In the svn or 2.7.x dev series of the OSG there is a convinience event > callback in osgViewer/ViewerEventHandlers called > InteractiveImageHandler, this is used to direct mouse events into > osg::Image subclasses, such as used by the new osgWidget::Browser, > osgWidget::PdfReader and osgWidget::VncClient classes. The code that > is relevant to you is the InteractiveImageHandler::mousePoistion(..) > method. This computes the mouse coords in the local image coords, > accounting for any geometry that the image is textured on to: > > bool InteractiveImageHandler::mousePosition(osgViewer::View* view, > osg::NodeVisitor* nv, const osgGA::GUIEventAdapter& ea, int& x, int > &y) const > { > osgUtil::LineSegmentIntersector::Intersections intersections; > bool foundIntersection = view==0 ? false : > (nv==0 ? view->computeIntersections(ea.getX(), ea.getY(), > intersections) : > view->computeIntersections(ea.getX(), ea.getY(), > nv->getNodePath(), intersections)); > > if (foundIntersection) > { > > osg::Vec2 tc(0.5f,0.5f); > > // use the nearest intersection > const osgUtil::LineSegmentIntersector::Intersection& > intersection = *(intersections.begin()); > osg::Drawable* drawable = intersection.drawable.get(); > osg::Geometry* geometry = drawable ? drawable->asGeometry() : 0; > osg::Vec3Array* vertices = geometry ? > dynamic_cast<osg::Vec3Array*>(geometry->getVertexArray()) : 0; > if (vertices) > { > // get the vertex indices. > const > osgUtil::LineSegmentIntersector::Intersection::IndexList& indices = > intersection.indexList; > const > osgUtil::LineSegmentIntersector::Intersection::RatioList& ratios = > intersection.ratioList; > > if (indices.size()==3 && ratios.size()==3) > { > unsigned int i1 = indices[0]; > unsigned int i2 = indices[1]; > unsigned int i3 = indices[2]; > > float r1 = ratios[0]; > float r2 = ratios[1]; > float r3 = ratios[2]; > > osg::Array* texcoords = > (geometry->getNumTexCoordArrays()>0) ? geometry->getTexCoordArray(0) : > 0; > osg::Vec2Array* texcoords_Vec2Array = > dynamic_cast<osg::Vec2Array*>(texcoords); > if (texcoords_Vec2Array) > { > // we have tex coord array so now we can compute > the final tex coord at the point of intersection. > osg::Vec2 tc1 = (*texcoords_Vec2Array)[i1]; > osg::Vec2 tc2 = (*texcoords_Vec2Array)[i2]; > osg::Vec2 tc3 = (*texcoords_Vec2Array)[i3]; > tc = tc1*r1 + tc2*r2 + tc3*r3; > } > } > } > > osg::TexMat* activeTexMat = 0; > osg::Texture* activeTexture = 0; > > if (geometry->getStateSet()) > { > osg::TexMat* texMat = > > dynamic_cast<osg::TexMat*>(geometry->getStateSet()->getTextureAttribute(0,osg::StateAttribute::TEXMAT)); > if (texMat) activeTexMat = texMat; > > osg::Texture* texture = > > dynamic_cast<osg::Texture*>(geometry->getStateSet()->getTextureAttribute(0,osg::StateAttribute::TEXTURE)); > if (texture) activeTexture = texture; > } > > if (activeTexMat) > { > osg::Vec4 tc_transformed = osg::Vec4(tc.x(), tc.y(), > 0.0f,0.0f) * activeTexMat->getMatrix(); > tc.x() = tc_transformed.x(); > tc.y() = tc_transformed.y(); > } > > if (dynamic_cast<osg::TextureRectangle*>(activeTexture)) > { > x = int( tc.x() ); > y = int( tc.y() ); > } > else if (_image.valid()) > { > x = int( float(_image->s()) * tc.x() ); > y = int( float(_image->t()) * tc.y() ); > } > > > return true; > } > > return false; > } > > Robert. > > On Tue, Jan 13, 2009 at 11:56 PM, Michael <[email protected]> > wrote: > > Hi > > > > I am using TriangleFunctor to do some very simple collision detection. > > Essentially I have a virtual pen (the collision detection is treated as a > > sphere on the tip of the pen) that I am testing for collisions against > other > > geometry in the scene. The geometry I am testing against is loaded from > OBJ > > files using osgDB::readNodeFile(). Once I have found a collision with the > > pen, I would like to update a texture image (drawing on the virtual > object). > > However, I am unsure how to access the texture coordinates for the > triangle > > I have just tested with. > > > > How am I able to do this with TriangleFunctor? Or, is there another > method I > > should be using for my collision detection that will give me access to > the > > texture coordinates of the triangle. > > > > Thanks > > Michael > > > > _______________________________________________ > > osg-users mailing list > > [email protected] > > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >
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