933 reputation
711
bio website excu.se
location Germany
age 32
visits member for 4 years, 3 months
seen Oct 17 at 17:21

Grew up on the countryside in Sweden, studied physics in Gothenburg and Waterloo, ON, Canada, worked four years in Germany, followed by two years in Sweden. This past year I've taken time off to work on my own indie game project, to be released later this year.

Private pilot since mid 2013.

Story of my life.


Jul
22
awarded  Yearling
May
15
comment How can I compare two quaternions for logical equality?
@bogglez true. Was hidden in the tl;dr text. :)
May
15
revised How can I compare two quaternions for logical equality?
deleted 1 character in body
May
15
answered How can I compare two quaternions for logical equality?
May
15
comment How can I compare two quaternions for logical equality?
Exactly, when you execute either rotation, you'll end up with the same orientation, but interpolate it (whether you lerp or slerp or some other fancy interpolation), you'll see it is turning different ways. And yes, the angle argument is negated, but that's the same as 2pi-angle, so it's turning the long way around the negated axes. Sometimes this is what you want though; it's just something to be aware of, q1 dot q2 > 0 results in the short turn, q1 dot q2 < 0 takes the long turn.
May
15
comment How can I compare two quaternions for logical equality?
+1, one nitpick though, q and -q represent the same orientation (which was being asked for), but not the same rotation. This is crucial when interpolating.
May
13
comment openGL Camera setup for Zoom in/out centered at point under cursor
@user3228921 you want to translate the camera without turning, the easiest way to do this using a look-at target is to move them in parallel. That is, if you have a vector v from the camera to the point-under-cursor, you add the same fraction of that vector to both the camera and the look-at target. That will shift the entire set-up without turning the camera.
May
12
comment Using same buffer for vertex and index data?
Excellent, thank you! Last paragraph is also exactly why I asked a question and didn't just test and see if it works.
May
12
accepted Using same buffer for vertex and index data?
May
12
comment Using same buffer for vertex and index data?
I certainly would not mix vertex and index data (ending up with non-uniform data), it's just laid out sequentially the way you're saying (padded for proper alignment of course). But I guess you're right. I'll get working on doing separate uploads.
May
12
comment Using same buffer for vertex and index data?
@PandaPajama I've considered that, but if it works it only means it works on my set up; undefined behavior is undefined you know. :) And I figured before I implement it either way, someone might already know.
May
12
asked Using same buffer for vertex and index data?
May
11
comment openGL Camera setup for Zoom in/out centered at point under cursor
@user3228921 I see, you're using gluLookAt. Either you ditch that function and manually control your camera orientation, or - if you insist on using gluLookAt - you'd have to translate your lookat-target exactly parallel to your camera. This seems a bit contrived, so unless you have a real good reason for using gluLookAt, I would advise against it.
May
11
revised openGL Camera setup for Zoom in/out centered at point under cursor
moved a comment into the answer
May
11
comment openGL Camera setup for Zoom in/out centered at point under cursor
@user3228921 I'm not sure exactly what you're trying to say. The idea is to keep the angle to your 'point-under-cursor' (or 'target' as I call it) constant. By keeping the orientation of the camera constant so the forward-vector doesn't change, and only moving it ('translating it', or 'dolly', however you want to call it) along the eye-target vector, that angle to your target will remain constant, but you will get closer so stuff will get bigger. Note that this is not what you normally call 'zoom' (where the field of view is reduced)
May
11
comment openGL Camera setup for Zoom in/out centered at point under cursor
@user3228921 Yes, you understood correctly, and no, if you don't turn the camera, only move it, the point under the cursor will not move on the screen.
May
11
answered openGL Camera setup for Zoom in/out centered at point under cursor
May
11
comment openGL Camera setup for Zoom in/out centered at point under cursor
The question is basically how to dolly the camera to get closer, while keeping a specific world space point fixed on screen. (Which incidentally means moving directly towards that point)
May
11
comment openGL Camera setup for Zoom in/out centered at point under cursor
@Evan not the cursor, the 'point under the cursor'.
Dec
16
awarded  Autobiographer