Weird behavior when rotating in openGL

[socal swimmer]

.... I hate radians. I hate degrees too. why cant we just use one system? Do you know how much trouble it causes me that there are 2 systems?

 

 

AAGGHHHHHHH.....

 

The sin() and cos() functions needed radians, i gave them degrees. ie undefined behavior.

so nevermind on this whole post.

 

 

 

 

ok so pretty much i have been staring at this forever and i dont know what is wrong. I am using objective-C (with some C++, but not here) to write openGL apps. Currently, I have a wine glass type of object that can rotate around the Y axis (the global one, but the object is at the origin) when you press < or >. Then, y and h rotate it around the X axis (the global X, assuming the the oject is at the origin.

 

I'm using XCode 2.4.1

/* important variables:
       camz is how far away the object is drawn from the camera
       rotx is its orientation around the y axis (its rotation on the horizontal plane)
       rotz is its orientation around the X. */


// this resets everything, then rotates and translates to the orientation/position i want it drawn at
- (void) loadIdentity 
{
glLoadIdentity();
glTranslatef(-camx, -camy, -camz);


glRotatef(rotx, 0, 1, 0);

glRotatef(rotz, cos(rotx), 0, sin(rotx));


}



/*
* Called when the system thinks we need to draw.
*/
- (void) drawRect:(NSRect)rect
{
// Clear the screen and depth buffer
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );


[self loadIdentity];


glBegin(GL_TRIANGLES);
	glCallList(tube); //tube is the oject i am drawing
glEnd();	






[ [ self openGLContext ] flushBuffer ];
}

/* *****************************
   these next functions handle key presses, ie when
   i hit a key, these get called accordingly
******************************** */

//rotates around Y (up-down) axis
- (void) moveItLeft:(BOOL)left
{
if (left) {
	rotx += 5;
} else {
	rotx -= 5;
}	


}

//moves the object closer and farther away
- (void) moveItUp:(BOOL)up
{
if (up) {

	camz -= .2;
} else {
	camz += .2;
}	

}

//this actually rotates around the X axis, but i was too lazy to make it right
- (void) rotateAroundZAxis:(BOOL)up
{
if (up) {
	rotz += 5;
} else {
	rotz -= 5;
}	

}

 

so here is the problem. It starts up and displays the object fine. When i spin it horizontally, its fine. 5 degree jumps, all good. when i then rotate it around the X axis, its all good. However, when i try to rotate it around the Y axis after rotating it around the X, it rotates to random orientations in huge jumps.

 

if that made any sense, i would gladly appreciate your help.