[osg-users] Different results from camera->getViewMatrix() in OSG 3.4.0 compared to OSG 3.2.1

[Ronny Hatteland]

Hi,

I have some code for doing picking of objects on the screen:


Code:
float dX = ea.getX();
float dY = ea.getY();

osg::ref_ptr<osg::Camera> camera = view->getCamera();

// compute model to window transform
// Model*View*Projection*WindowMatrix
osg::Matrixd matrix;
matrix.postMult(camera->getViewMatrix());
matrix.postMult(camera->getProjectionMatrix());
osg::Matrixd windowMatrix = camera->getViewport()->computeWindowMatrix();
matrix.postMult(windowMatrix);

osg::Matrixd inverse;
inverse.invert(matrix);

// get the coordinates in screen-space:
osg::Vec3 mouseloc = osg::Vec3(dX, dY, 0) * inverse;
osg::Vec3 normalizedMouseRay = (osg::Vec3(dX, dY, 1) * inverse) - mouseloc;
osg::Plane _dragPlane(osg::Vec4d(0, 1, 0, 0));


Which was working perfectly fine in OSG 3.2.1.
However, when I updated to OSG 3.4.0 a vertical offset was introduced, which seems to be constant regardless of the camera.

Positioning the camera at approximately the same place in both cases, and looking at the matrices, it looks like the offset was introduced already by the getViewMatrix() method, value[3][3]:


Code:
matrix.postMult(camera->getViewMatrix());
3.4.0:
[0] {1.0000000000000000, 0.00000000000000000, 0.00000000000000000, 0.00000000000000000}
[1] {0.00000000000000000, 0.00000000000000000, -1.0000000000000000, 0.00000000000000000}
[2] {0.00000000000000000, 1.0000000000000000, 0.00000000000000000, 0.00000000000000000}
[3] {-1009.2817596644163, 216.03970056772232, -509.02834880430618, 1.0000000000000000}
3.2.1:
[0] {1.0000000000000000, 0.00000000000000000, 0.00000000000000000, 0.00000000000000000}
[1] {0.00000000000000000, 0.00000000000000000, -1.0000000000000000, 0.00000000000000000}
[2] {0.00000000000000000, 1.0000000000000000, 0.00000000000000000, 0.00000000000000000}
[3] {-1061.2815714627504, 239.85043859481812, -599.72003111232948, 1.0000000000000000}

matrix.postMult(camera->getProjectionMatrix());
3.4.0:
[0] {1.7748398086904795, 0.00000000000000000, 0.00000000000000000, 0.00000000000000000}
[1] {0.00000000000000000, 0.00000000000000000, 1.0000000000000200, 1.0000000000000000}
[2] {0.00000000000000000, 3.8461539872299335, 0.00000000000000000, 0.00000000000000000}
[3] {-1791.3134452375832, 830.92195573850609, 509.02834880411638, 509.02834880430618}
3.2.1
[0] {1.7748398086904795, 0.00000000000000000, 0.00000000000000000, 0.00000000000000000}
[1] {0.00000000000000000, 0.00000000000000000, 1.0000000000000200, 1.0000000000000000}
[2] {0.00000000000000000, 3.8461539872299335, 0.00000000000000000, 0.00000000000000000}
[3] {-1883.6047812616794, 922.50172074030797, 599.72003111214144, 599.72003111232948}

WindowMatrix
3.4.0:
[0] {960.00000000000000, 0.00000000000000000, 0.00000000000000000, 0.00000000000000000}
[1] {0.00000000000000000, 443.00000000000000, 0.00000000000000000, 0.00000000000000000}
[2] {0.00000000000000000, 0.00000000000000000, 0.50000000000000000, 0.00000000000000000}
[3] {960.00000000000000, 581.00000000000000, 0.50000000000000000, 1.0000000000000000}
3.2.1
[0] {960.00000000000000, 0.00000000000000000, 0.00000000000000000, 0.00000000000000000}
[1] {0.00000000000000000, 443.00000000000000, 0.00000000000000000, 0.00000000000000000}
[2] {0.00000000000000000, 0.00000000000000000, 0.50000000000000000, 0.00000000000000000}
[3] {960.00000000000000, 443.00000000000000, 0.50000000000000000, 1.0000000000000000}

matrix.postMult(windowMatrix); 
3.4.0:
[0] {1703.8462163428603, 0.00000000000000000, 0.00000000000000000, 0.00000000000000000}
[1] {960.00000000000000, 581.00000000000000, 1.0000000000000100, 1.0000000000000000}
[2] {0.00000000000000000, 1703.8462163428605, 0.00000000000000000, 0.00000000000000000}
[3] {-1230993.6925759460, 663843.89704746008, 509.02834880421130, 509.02834880430618}
3.2.1
[0] {1703.8462163428603, 0.00000000000000000, 0.00000000000000000, 0.00000000000000000}
[1] {960.00000000000000, 443.00000000000000, 1.0000000000000100, 1.0000000000000000}
[2] {0.00000000000000000, 1703.8462163428605, 0.00000000000000000, 0.00000000000000000}
[3] {-1232529.3601433760, 674344.23607071838, 599.72003111223546, 599.72003111232948}

inverse
3.4.0:
[0] {0.00058670300251959689, 1.0310124207250091e-007, 4.3757801540539190e-008, -2.0254518695206543e-010}
[1] {0.00000000000000000, 0.00000000000000000, 0.00058690742768229540, 0.00000000000000000}
[2] {-10086449333416.564, 5087071672824.5107, 2159033860383.4014, -9993690301.8739624}
[3] {10086449333416.104, -5087071672823.5625, -2159033860383.7642, 9993690301.8740635}
3.2.1
[0] {0.00058743635625737895, -2.9889246175079844e-007, -1.1953825839478168e-007, 4.9838665751483716e-010}
[1] {0.00000000000000000, 0.00000000000000000, 0.00058690742768229540, 0.00000000000000000}
[2] {-10634237608903.178, 6009305617996.5537, 2403345750271.9492, -10020184930.042784}
[3] {10634237608902.719, -6009305617995.6123, -2403345750272.2324, 10020184930.042881}


Is this a bug or is there a reason why this is different between the two versions?

Thank you!

Cheers,
Ronny[/code]

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