159 reputation
6
bio website johncalsbeek.com
location Santa Monica, CA
age 25
visits member for 3 years, 3 months
seen Jan 7 at 5:10

I’m a professional game programmer. I’m interested in physics, data-oriented design, parallelism, lock-free programming, SIMD programming, cache optimization, compilers, and procedural content generation.


Nov
25
comment How to find camera position and rotation from a 4x4 matrix?
@LukasSchmelzeisen If you have an affine transformation matrix, then it should match the form where the upper-left 3x3 is R, a rotation matrix, and where the last column is T, at which point the expression in question should be identical to -(R^T)T.
Nov
25
comment How to find camera position and rotation from a 4x4 matrix?
@LukasSchmelzeisen It should work, but it may not apply to your situation. If M changes from one space to another, then that expression picks off the last column of M^-1, which is the translation in the original space that reverses the translation performed by M. If M can be thought of as moving a camera to the origin, then that expression produces the position of the camera in the original space.
Feb
13
awarded  Autobiographer
Jan
6
accepted Is it possible to split a single sample from a discrete uniform distribution into two samples from two smaller distributions?
Jan
5
asked Is it possible to split a single sample from a discrete uniform distribution into two samples from two smaller distributions?
Dec
13
comment How to find camera position and rotation from a 4x4 matrix?
The camera position is just solving the equation that user7530 also posted. Because R is a rotation matrix, transposing it does the same thing as taking its inverse; so you can think of it as transforming the value in reverse.
Nov
24
comment How to find camera position and rotation from a 4x4 matrix?
That's correct.
Nov
22
revised How to find camera position and rotation from a 4x4 matrix?
fix camera position expression
Nov
22
comment How to find camera position and rotation from a 4x4 matrix?
"Affine transformation" means that the transformation can do anything a linear transformation can do (rotate, scale, shear) plus also translate. The $4 \times 4$ homogeneous matrix is capable of doing perspective projections, but this one doesn't—as would be expected by convention for something called the "camera matrix." The remaining intrinsic parameters, in this case, would control the projection.
Nov
22
awarded  Teacher
Nov
21
answered How to find camera position and rotation from a 4x4 matrix?
Jun
30
awarded  Scholar
Jun
30
comment Is there such a thing as the “edge-face dual” of a polyhedron, and is the “edge-face dual” of a cube a rhombic dodecahedron?
Thanks. I think the rhombic dodecahedron is what I asked for, but not actually what I want. I'm probably gonna have to give up face-transitivity in the end.
Jun
30
accepted Is there such a thing as the “edge-face dual” of a polyhedron, and is the “edge-face dual” of a cube a rhombic dodecahedron?
Jun
30
awarded  Student
Jun
30
asked Is there such a thing as the “edge-face dual” of a polyhedron, and is the “edge-face dual” of a cube a rhombic dodecahedron?
Jun
9
revised How do I get the square root of a complex number?
it's -> its
Jun
9
suggested suggested edit on How do I get the square root of a complex number?
Jun
4
awarded  Supporter
Jun
4
awarded  Editor