looking and moving up and down(pitch) using glRotate()

**Crossbow** · 06-13-2002

I have a OpenGL program that is like a space simulator. I have the thing correctly turning and flying straight, but things start to get difficult when I try to look up and down. To look up and down, or pitch, I have the program increase pitch by one is down and decrease if up, when the up or down key is pressed. Then, in the draw function, I have the glRotatef function rotate on the x axis up and down according to pitch. Like:

Code:

glRotatef(pitch,1.0f,0,0);

And this works fine if I am facing along the x axis(0(360) or 180 degrees), but say I face 90 degrees on the z axis, the screen rotates around in a circle. I hope you follow me on this. I can't figure out how to fix this, so any suggestions would be great. Thanks!

**no-one** · 06-14-2002

if i get what your saying correctly, it's because at 90 degrees you should be rotating on the z axis to go up and down... the way you are attempting to do this is fairly complicated,
you could try

Code:

void gluLookAt(
  GLdouble eyex,      
  GLdouble eyey,      
  GLdouble eyez,      
  GLdouble centerx,   
  GLdouble centery,   
  GLdouble centerz,   
  GLdouble upx,       
  GLdouble upy,       
  GLdouble upz        
);

eyex, eyey, eyez 
The position of the eye point. 
centerx, centery, centerz 
The position of the reference point. 
upx, upy, upz 
The direction of the up vector.

and/or look into vector math and trigonomotry...

**Crossbow** · 06-14-2002

Ok, I looked up that function and it will work, but there is one thing I don't know about it, and that is the up vector. When I change the values it doesn't seem to have any effect. What does it do?

**no-one** · 06-15-2002

it specifies the up "Vector" technically its the up Axis

so if you use (0.0,1.0,0.0) then positive y is up
if you use (0.0,-1.0,0.0) negative y is up
if you us (1.0,0.0,0.0) positive x is up

get it?

using decimal points wont really change anything...

Thread: looking and moving up and down(pitch) using glRotate()

Thread Tools

Search Thread

Display

looking and moving up and down(pitch) using glRotate()