according to Nate Robins Tutorial transformation I wanted to raise up the viewpoint along the y axis.
Beginning at gluLookAt(0.0, 0.0, 2.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0) I wanted to raise the “camera” along the y-axis. It should look like a view out of an elevator. The next step was gluLookAt( 0.0, 0.6, 2.0, 0.0, 0.6, 0.0, 0.0, 1.0, 0.0). But I was astonished that the line between the “camera” (0.0, 0.6, 2.0) and the aim (0.0, 0.6, 0.0) wasn’t parallel to the z-axis.
The “camera” was looking down to the aim.
Can anybody explain me why or what I have done wrong.
You are not doing anything wrong. If you are looking “down” with your gluLookAt then it cannot be parallel to the Z axis. If you wanted it to be along the Z axis you should have set both Y coordinates the same value.
>[QUOTE]Originally posted by >mikael_aronsson:
>[b]You are not doing anything wrong. If >you are looking “down” with your gluLookAt >then it cannot be parallel to the Z axis. >If you wanted it to be along the Z axis >you should have set both Y coordinates the >same value.
The next step was gluLookAt( 0.0, 0.6, 2.0, 0.0, 0.6, 0.0, 0.0, 1.0, 0.0).
As far as I know the first param trible of gluLookAt consits of the x, y, z coord. of eye, the second of the x, y, z coord. of the aim and the third is the up vector. If
I don’t have a problem with my eyes or a problem with number, the y coord. of eye and aim is both 0.6.
Ok, sorry, got it wrong there, make sure you are messing with the correct matrix, if you apply gluLookAt to the projection matrix for example you can get weird behavior.