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

[Robert Osfield]

Hi Ronny,

I don't recall any specific changes to view matrix management between
OSG-3.2.1 and OSG-3.4.0.  I'm also not aware of any bugs being reported
that look relevant to this what you are describing.

Printing out two sets of view matrices for the two versions without the
view's being identical isn't useful.  Try to create the exactly same input
conditions - for instance by explictly setting the view matrix.  The mouse
input are another variable you'd need to standardize.

Also when describing the problem you'll need to do more than saying a
"vertical offset", this has so many different possible interpretations that
it's pointless even starting to guess what you mean.

Robert.



On 14 April 2016 at 12:02, Ronny Hatteland <ronnyhatteland at gmail.com> wrote:

> 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]
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=66808#66808
>
>
>
>
>
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