StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
text
Body
copied!<p>I'm unable to find any problems with the code posted, and would suggest the problem is elsewhere. If it helps, my analysis of the code posted is that:</p> <p>The first six lines, dealing with _geomagnetic 0–5, effect a very simple low frequency filter, which assumes you call the method at regular intervals. So you end up with a version of the magnetometer vector, hopefully with high frequency jitter removed.</p> <p>The bzero zeroes the result, ready for accumulation.</p> <p>The lines down to the declaration and assignment to Hz take the magnetometer and accelerometer vectors and perform the cross product. So H(x, y, z) is now a vector at right angles to both the accelerometer (which is presumed to be 'down') and the magnetometer (which will be forward + some up). Call that the side vector.</p> <p>The invH and invA stuff, down to the multiplication of Az by invA ensure that the side and accelerometer/down vectors are of unit length.</p> <p>M(x, y, z) is then created, as the cross product of the side and down vectors (ie, a vector at right angles to both of those). So it gives the front vector.</p> <p>Finally, the three vectors are used to populate the matrix, taking advantage of the fact that the inverse of an orthonormal 3x3 matrix is its transpose (though that's sort of hidden by the way things are laid out — pay attention to the array indices). You actually set everything in the matrix directly, so the bzero wasn't necessary in pure outcome terms.</p> <p><code>glLoadMatrixf</code> is then the correct thing to use because that's how you multiply by an arbitrary column-major matrix in OpenGL ES 1.x.</p>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload