Jump to content

  • Log In with Google      Sign In   
  • Create Account

Interested in a FREE copy of HTML5 game maker Construct 2?

We'll be giving away three Personal Edition licences in next Tuesday's GDNet Direct email newsletter!

Sign up from the right-hand sidebar on our homepage and read Tuesday's newsletter for details!


We're also offering banner ads on our site from just $5! 1. Details HERE. 2. GDNet+ Subscriptions HERE. 3. Ad upload HERE.


Drawing a 3d sphere.


Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.

  • You cannot reply to this topic
2 replies to this topic

#1 Azrael   Members   -  Reputation: 128

Like
Likes
Like

Posted 03 August 2001 - 06:53 AM

This is a very simple question for opengl fans, how do you draw a 3d sphere using open gl? , strips, fans, etc, any option will do. Im interested in also knowing how to draw a hemisphere.

Sponsor:

#2 core114   Members   -  Reputation: 122

Like
Likes
Like

Posted 03 August 2001 - 07:19 AM

you could use any of those really, depending on how you make the sphere

you can make the sphere itsself many ways
or you could do it the easy way and look at HELP and see

void gluSphere(
GLUquadricObj *qobj,
GLdouble radius,
GLint slices,
GLint stacks
);

that would work, but makes a sphere that doesn''t have a very even distribution of polygons

a better way for some things is to have 12 evenly distributed points on a sphere, that you could subdivide later if you want more

a top point (up)
along with 5 point around the top (at increments of 1/5 of 2PI and height of .5)

and 5 more around the botom (the same as above but rotated 1/10 of 2 PI and height of -.5)
and a bottom point (down)

it might be more clear like this
(i is just a struct that i used to hold all the stuff for the sphere, its not special)

i->radius = r;

i->point[0].start = VECTOR(0.0f, r, 0.0f);
i->point[11].start = VECTOR(0.0f, -r, 0.0f);

int n;
for (n = 0; n < 5; n++)
{
float a = PIx2*(n*.2f);
float b = PI*(1.0f/3.0f);
float c = PI-PI*(1.0f/3.0f);
i->point[1+n].start = VECTOR(cos(a)*sin(-b), cos(b), sin(a)*sin(-b)) * r;
a += PIx2*(.1f);
i->point[6+n].start = VECTOR(cos(a)*sin(-c), cos©, sin(a)*sin(-c)) * r;
}

now if you are not thinking this is too long, you could also make a sphere where the distribution isn''t uniform at all, like a point cloud or something...


#3 mittens   Moderators   -  Reputation: 1315

Like
Likes
Like

Posted 03 August 2001 - 03:43 PM

Hey hey, why not use the OGL Quadric objects? They are decently fast, and damn easy to use! If you are interested, NeHe has a couple of tuts on it... Go check it out (http://nehe.gamedev.net)

------------------------------
Trent (ShiningKnight)
E-mail me
OpenGL Game Programming Tutorials




Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.



PARTNERS