<div dir="ltr"><div>Hi Andrew,</div><div><br></div><div>When you say you have a isometric view, to be clear, you mean you have an orthographic projection of the scene? The OSG itself support orthographic projection via the osg::Camera's ProjectionMatrix, the intersection. It can only account for this if the IntersectionVisitor knows about it's setting. <br></div><div><br></div><div>Have you tried the osgViewer::View(er)::computeIntersections(..) method?</div><div><br></div><div>This method knows about the View's Camera so can account for it's projection matrix.<br></div><div><br></div><div>Robert.<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, 14 Apr 2020 at 23:35, OpenSceneGraph Users <<a href="mailto:osg-users@lists.openscenegraph.org">osg-users@lists.openscenegraph.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Hi,</div><div>I am having a lot of problems with picking with LineSegmentIntersector in OSG 3.6.5.</div><div><br></div><div> </div><div>I have reduced the problem to a a simple cube, center 0.5,0.5,0.5 with a boundingSphere radius of 1.2142</div><div><br></div><div>I create the intersection with ( x , y are screen coordinates)</div><div><br></div><div style="background-color:rgb(250,250,250);border-color:rgb(187,187,187);border-style:solid;border-width:1px"><code><div><span style="color:rgb(0,0,0)">picker</span><span style="color:rgb(102,102,0)">=</span><span style="color:rgb(0,0,136)">new</span><span style="color:rgb(0,0,0)"> osgUtil</span><span style="color:rgb(102,102,0)">::</span><span style="color:rgb(102,0,102)">LineSegmentIntersector</span><span style="color:rgb(0,0,0)"> </span><span style="color:rgb(102,102,0)">(</span><span style="color:rgb(0,0,0)"> osgUtil</span><span style="color:rgb(102,102,0)">::</span><span style="color:rgb(102,0,102)">Intersector</span><span style="color:rgb(102,102,0)">::</span><span style="color:rgb(0,0,0)">WINDOW</span><span style="color:rgb(102,102,0)">,</span><span style="color:rgb(0,0,0)"> x</span><span style="color:rgb(102,102,0)">,</span><span style="color:rgb(0,0,0)"> y </span><span style="color:rgb(102,102,0)">);</span><span style="color:rgb(0,0,0)"><br>osgUtil</span><span style="color:rgb(102,102,0)">::</span><span style="color:rgb(102,0,102)">IntersectionVisitor</span><span style="color:rgb(0,0,0)"> iv </span><span style="color:rgb(102,102,0)">(</span><span style="color:rgb(0,0,0)"> picker </span><span style="color:rgb(102,102,0)">);</span><span style="color:rgb(0,0,0)"><br>getCamera</span><span style="color:rgb(102,102,0)">()-></span><span style="color:rgb(0,0,0)">accept </span><span style="color:rgb(102,102,0)">(</span><span style="color:rgb(0,0,0)"> iv </span><span style="color:rgb(102,102,0)">);</span><span style="color:rgb(0,0,0)"><br><br></span></div></code></div><div><br><br></div><div>When I am "close" to the model geometry in an isometric view ( the cube fills,say, 50% of the screen), this works perfectly. I get the exact intersections coordinates I expect.</div><div><br></div><div>When I "pull the camera back" from the geometry and the object is much smaller on the screen, the intersections fail.</div><div><br></div><div>After much debugging, the problem is that the intersector fails the test of the intersection of the line with the bounding sphere of my model geometry</div><div><br></div><div>Specifically I send up in</div><div><br></div><div> <div style="background-color:rgb(250,250,250);border-color:rgb(187,187,187);border-style:solid;border-width:1px"><code><div><span style="color:rgb(0,0,136)">bool</span><span style="color:rgb(0,0,0)"> </span><span style="color:rgb(102,0,102)">LineSegmentIntersector</span><span style="color:rgb(102,102,0)">::</span><span style="color:rgb(0,0,0)">intersects</span><span style="color:rgb(102,102,0)">(</span><span style="color:rgb(0,0,136)">const</span><span style="color:rgb(0,0,0)"> osg</span><span style="color:rgb(102,102,0)">::</span><span style="color:rgb(102,0,102)">BoundingSphere</span><span style="color:rgb(102,102,0)">&</span><span style="color:rgb(0,0,0)"> bs</span><span style="color:rgb(102,102,0)">)</span></div></code></div><br></div><div><br></div><div>The BoundingSphere is in "model space" , and correct, but the _start and _end points used in the calculation are incorrect to intersect the sphere in model space and so the intersection fails.<br></div><div><br></div><div><div style="background-color:rgb(250,250,250);border-color:rgb(187,187,187);border-style:solid;border-width:1px"><code><div><span style="color:rgb(0,0,0)">_start </span><span style="color:rgb(102,102,0)">{</span><span style="color:rgb(0,0,0)">_v</span><span style="color:rgb(102,102,0)">=</span><span style="color:rgb(0,102,102)">0x000001ba7308d300</span><span style="color:rgb(0,0,0)"> </span><span style="color:rgb(102,102,0)">{</span><span style="color:rgb(0,102,102)">13.227287349450325</span><span style="color:rgb(102,102,0)">,</span><span style="color:rgb(0,0,0)"> </span><span style="color:rgb(102,102,0)">-</span><span style="color:rgb(0,102,102)">2.9785854231569449</span><span style="color:rgb(102,102,0)">,</span><span style="color:rgb(0,0,0)"> </span><span style="color:rgb(102,102,0)">-</span><span style="color:rgb(0,102,102)">5.5167534692525066</span><span style="color:rgb(102,102,0)">}</span><span style="color:rgb(0,0,0)"> </span><span style="color:rgb(102,102,0)">}</span><span style="color:rgb(0,0,0)"><br>_end </span><span style="color:rgb(102,102,0)">{</span><span style="color:rgb(0,0,0)">_v</span><span style="color:rgb(102,102,0)">=</span><span style="color:rgb(0,102,102)">0x000001ba7308d318</span><span style="color:rgb(0,0,0)"> </span><span style="color:rgb(102,102,0)">{</span><span style="color:rgb(0,102,102)">11.072576448741074</span><span style="color:rgb(102,102,0)">,</span><span style="color:rgb(0,0,0)"> </span><span style="color:rgb(102,102,0)">-</span><span style="color:rgb(0,102,102)">5.1332963238661939</span><span style="color:rgb(102,102,0)">,</span><span style="color:rgb(0,0,0)"> </span><span style="color:rgb(102,102,0)">-</span><span style="color:rgb(0,102,102)">7.6714332827528793</span><span style="color:rgb(102,102,0)">}</span><span style="color:rgb(0,0,0)"> </span><span style="color:rgb(102,102,0)">}</span></div></code></div><br>Any ideas what is going on. It seems although the vector of start and end is the correct vector ( or the "closer" picking would not work), something is wrong in the transformation into model space.</div><div><br></div><div>Thx</div><div>Andrew<br></div></div>
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