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apatriarca
Member Since 03 Jul 2006Offline Last Active Today, 05:59 AM
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 Age 31 years old
 Birthday February 11, 1985

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#5114262 Quaternions and matrices
Posted by apatriarca on 04 December 2013  03:14 AM
#5110747 question about quadratic bezier patch
Posted by apatriarca on 20 November 2013  07:12 AM
#5110713 question about quadratic bezier patch
Posted by apatriarca on 20 November 2013  03:02 AM
#5110503 question about quadratic bezier patch
Posted by apatriarca on 19 November 2013  10:51 AM
Let P(i, j) be the control points of the quadratic Bézier surface patches, C(P0, P1, P2, t) represents a quadratic Bézier curve with control points P0, P1 and P2 with parameter t and S(u, v) the quadratic Bézier surface patch equation. We are trying to explains to you that
S(u, 0.7) = C( C(P(0,0), P(0, 1), P(0,2), 0.7) , C(P(1,0), P(1, 1), P(1,2), 0.7) , C(P(2,0), P(2, 1), P(2,2), 0.7) , u).
#5110435 question about quadratic bezier patch
Posted by apatriarca on 19 November 2013  05:45 AM
That's latex code. It look like it is less readable than I assumed. I don't know how to write equations in this forum anymore (the eqn tag does not seem to work and I can't upload images from 3rd party services).
If you fix one of the two coordinates (for example v = 0.7 as in your example), the corresponding basis polynomials B_j(v) becomes constants. You can thus sum the terms P_ij B_j(v) for 0 <= j <= 2 to obtains the control points for a quadratic curve depending only on the parameter u.
#5110403 question about quadratic bezier patch
Posted by apatriarca on 19 November 2013  03:08 AM
EDIT: Corrected some typos in formulae.
#5109399 Which is Best Zbrush or Blender?
Posted by apatriarca on 15 November 2013  04:42 AM
#5104995 Array.Sort performance issue
Posted by apatriarca on 28 October 2013  04:30 AM
#5101530 lightuser data in Lua
Posted by apatriarca on 15 October 2013  07:29 AM
function f(user, logger) User.setName(user, "name") User.setGroup(user, "group") Logger.output(logger, "User is set.") endThis isn't really what you were asking, but I think the only way to associate methods to data exported to lua is to use full user data. You can't do it using lightdata.
#5098736 How do I use multithreading?
Posted by apatriarca on 04 October 2013  07:24 AM
#5096079 Matrix storage layout and multiplication order woes
Posted by apatriarca on 23 September 2013  01:32 AM
I think your are mixing different concepts which should be separated. Columnmajor and rowmajor have nothing to do with the order of multiplication. They are simply different ways to store a matrix in memory. You can have columnmajor matrices and use row vectors or rowmajor matrices and use column vectors. The order of multiplication is given by the choice of row or column vectors. When you use column vectors you have to multiply the matrix on the left and then the transformations go from the right to the left. On the other hand, if you use row vectors, you have to multiply the matrix on the right and transformations go from left to right. So, in your case you have to compose the transformations as L*P while in OpenGL (and basically everywhere in mathematics) we usually do P*L. Have I misunderstood your post and your are already doing it?
#5095940 Should you work with limitations or overcome them?
Posted by apatriarca on 22 September 2013  08:27 AM
#5095937 Matrix storage layout and multiplication order woes
Posted by apatriarca on 22 September 2013  08:10 AM
#5094886 Is Win32 API sufficient to make a user interface like the latest Visual Studio
Posted by apatriarca on 18 September 2013  03:43 AM
As of QT, well, it is nice and crossplatform technology, tho if you want to see it in action, just look at the EA Origin desktop client  it is horrible and very laggy.
You shouldn't judge a framework like Qt by looking at one bad example. Qt has been successfully used in a lot of different software. Autodesk Maya interface use Qt for example. I have worked with both win32 and Qt and Qt is much better in my opinion..
#5081908 Techniques to avoid skinny triangles with constrained delaunay triangulation
Posted by apatriarca on 31 July 2013  06:13 AM
Are you implementing the constrained Delaunay triangulation yourself? If you do not want skinny triangles you have to introduce additional points and construct a conforming Delaunay triangulation. This means you also have to increase the triangle count relative to your constrained triangulation.