Does gluLookAt() have a limit on smallest argument size?

Question

I have an OpenGL program which works when I call this:

gluLookAt(0.1,0.1,0.1, 0,0,0, 0,0.1,0);

... but not when I call this:

gluLookAt(0.01,0.01,0.01, 0,0,0, 0,0.01,0);

(In the latter case, a blank screen occurs.)

Does gluLookAt have a minimum/maximum floating point argument size?

Drawing is done about the origin, within a radius of ~10-6.

Well now your camera position will be different. That might affect what you can see. — Joseph Mansfield, Mar 05 '13 at 19:02
Sorry, I should have mentioned, the drawing is all done about the origin and within the 10^-6 scale, — FreelanceConsultant, Mar 05 '13 at 19:04

score 0 · Answer 1 · answered Mar 05 '13 at 19:13

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Check your value of gluPerspective's minimum draw distance:

gluPerspective(45.0, (double)window.GetWidth() / (double)window.GetHeight(), 0.1d, 2000.0d);

This will not work because everything is in-front of 0.1.

answered Mar 05 '13 at 19:13

FreelanceConsultant

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score 0 · Answer 2 · answered Mar 05 '13 at 19:14

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gluLookAt should work fine with your arguments. However, you are changing the camera position (as @sftrabbit says). Your new position might be too close to the object to see it.

You should check what is the near-plane distance in your perspective matrix setup (possibly your gluPerspective() call?).

answered Mar 05 '13 at 19:14

Liosan

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That was exactly the problem. (See my answer below.) – FreelanceConsultant Mar 05 '13 at 20:19

Does gluLookAt() have a limit on smallest argument size?

2 Answers2