Okay guys you don't have to help me anymore

[K.I.L.E.R]

..until I hit the next chapter in the book.

I asked the teacher the questions you guys didn't answer and I cleared up some other stuff too.

It all makes sense now.

OpenGL draws the entire scene before anything else, THEN it proceeds to apply modelview transformations and THEN it applies perspective transformations.

Also you cannot have a spherical frustrum because it's not supported in the hardware or through OGL.
You have to apply tricks in order to create a spherical frustrum.

 

[Rolf N]

..until I hit the next chapter in the book.

I asked the teacher the questions you guys didn't answer and I cleared up some other stuff too.

It all makes sense now.

OpenGL draws the entire scene before anything else, THEN it proceeds to apply modelview transformations and THEN it applies perspective transformations.

What!?
Hell, no!

OpenGL transforms vertices with whatever the current matrices are at the time the vertices are submitted. This can very well vary over the course of the frame.

I.e. you can do

glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(whatever);

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
//draw something leftish
glTranslatef(-0.5f,0.0f,2.0f);
draw_thingy();
//draw *the same thing* again, rightish
glLoadIdentity();
glTranslatef(+0.5f,0.0f,2.0f);
draw_thingy();

Yes, this works. And if what your teacher taught you was true, it wouldn't work. So there.

Also you cannot have a spherical frustrum because it's not supported in the hardware or through OGL.

Correct.
A frustum is a pyramid with a chopped-off tip. It has finite volume bound by six planes. A "spherical frustum" cannot fit that description.

 

[K.I.L.E.R]

Thanks.
I must have misheard the teacher or the teacher misheard me.

 

[Jimmers]

Also you cannot have a spherical frustrum because it's not supported in the hardware or through OGL.

Why would you want to do that? A peripherial vision effect? Does'nt the human eye already do that?

 

[K.I.L.E.R]

Why would you want to do that? A peripherial vision effect? Does'nt the human eye already do that?

Can you explain what you mean?

 

[Simon F]

Also you cannot have a spherical frustrum because it's not supported in the hardware or through OGL.
You have to apply tricks in order to create a spherical frustrum.

"Spherical"???

Do you mean a "truncated cone" rather than a "truncated rectangular pyramind"?

 

[K.I.L.E.R]

Yes.

"Spherical"???

Do you mean a "truncated cone" rather than a "truncated rectangular pyramind"?

 

[Intel17]

Just curious, what college are you currently going to in order to learn GL?

 

[K.I.L.E.R]

I'm not going to collegel. I'm going to university.
It's VUT.

Just curious, what college are you currently going to in order to learn GL?