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04-11-2003, 05:23 AM
Hello opengl gurus,

I have a sphere that I used gluSphere to create. I read a jpg file of the earth and put this texture to the sphere. What I want to do is to be able to rotate the sphere around the x and y axis. I have read several reports about the dreaded gimbal lock problem. I think this is my problem as well. Here is the code that I am using to rotate the sphere.

glTranslatef(-(x_Translation), 0.0, y_Translation);

glRotatef(x_Rotation, 1.0f, 0.0f, 0.0);
glRotatef(y_Rotation, 0.0f, 1.0f, 0.0);
glRotatef(z, 0.0f, 0.0f, 1.0f);


//Draw the sphere object and the trajectory
gluSphere(quadObj, 0.7, 30, 30);

But the sphere rotates in every direction. Can someone help me with setting this up to where the sphere will only rotate around the x and y axis. I am a beginner so I don't know anything about quaternions.

Thanks http://www.opengl.org/discussion_boards/ubb/confused.gif

04-11-2003, 05:26 AM
I forgot to add that I am using the z rotation to turn the globe up so that the poles are on the y-axis.

nexusone
04-11-2003, 06:57 AM
I guess you want it to spin on planets axis???
You will need to rotate it on the Z-axis, then adjust the x/y axis rotations for correct orintation of planet.

look at my textured sphere demo on my website called glball.
www.angelfire.com/linux/nexusone/ (http://www.angelfire.com/linux/nexusone/)

hcdlt
04-11-2003, 09:46 AM
yeah, he's right...
FIRST rotate around Z, THEN the actual rotation on the X and Y-axis.