Forgive me if this has bee nasked multiple times but I want to check if I''m understanding some stuff right: Whenever a quad, triangle or other shape is drawn, the vertices (using glVertext3f )are specified in relation to the origin glTranslatef moves the origin with relation to where it currently is. glRotatef rotates the axes wherever the origin happens to be. glLoadIdentity puts the origin on the surface of the screen in the middle, ie the screen itself is z = 0 and the center of screen is the origin. Thanks.

Pretty much I think.

you''ve gotta be careful about the order you do rotations and translations in, depending on what you want to rotate/move (object or worldspace)

and you also have to be careful about which matrix you''re transforming (modelview or projection)

Hope this helps

Happy New Year!

Khrob

no, completely wrong....


just kidding... posting here instead of lionhead now I see....

Thanks Khrob.

lucid I still read some of the lionhead threads but I like to spread out my newbieness so people don''t get as annoyed. Do you go by the same name there?

lucid - havent posted.. hell, havent even _been_ to lionhead in weeks!

eNo - no worries! I spent ages at least twice getting my camera movement routines to work... (second time I was being very silly in my radians to degrees conversion, but not having the transforms in the right order didn''t help!)

HAPPY NEW YEAR!!!

well, it is here in perth!

I''m with you on the newbieness thing!! I like to give the lionhead, this one, opengl (beginners and advanced) a little of my ignorance each, rather than all of it to one!

Ok, to try to explain the transform stack without adding to much confusion....

1) The last transform (translation, rotation, scaling) is applyed to the vertex first.

2) the "camera" aka the origin never movies in the GL_MODLEVIEW matrix.

3) "camera" transform are always applied to the modleview matrix inverted. i.e. glTranslated(-camx,-camy,-camz);

anotherwords if you did the following...

glTranslated(0.0,2.0,0.5);
glRotated(0.0,45.0,0);

glVertex(....)

Then the vertex in question would be rotated 45 degrees around the y axis then moved 2 units along the y and 0.5 units along the z axis.
Hope this dosnt confuse you too much! Any questions ask!

Glad someone around here can give a useful answer

Good one avianRR!

I try!

l8r,
Rob
http://tannara.2y.net/

glRotatef(angle, vx, vy, vz);
angle in degrees; where vx,vy,vz is the vector which we wish to rotate.

this is one thing that i did learn in graphics class.

it''''s all about a good time!
-Jamie