render in wireframe...

OpenGL Development JOGL Development
#1

hey, ive been playing around with the gears demo a bit. i was wondering how i can render in wireframe… i tried adding:

gl.glPolygonMode(GL.GL_LINES, GL.GL_FRONT_AND_BACK);

to the end of the GearRenderer.init() method, but it doesnt change anything. I appreciate any comments, thanks.

#2

find where it says

  gl.glBegin(GL.GL_QUAD_STRIP);

and

  gl.glBegin(GL.GL_QUADS);

And change them to line primitives (say, GL_LINE_STRIP and GL_LINES)

Only problem is that they won’t draw quite right because the ording of the verticies are slightly different. Still, it might work well enough.

#3

You have the parameters for glPolygonMode in the wrong order.

gl.glPolygonMode( GL.GL_FRONT_AND_BACK, GL.GL_LINE );

does the trick.

#4

yep, that fixed it… thanks for your help

#5

Is changing the polygon mode the fastest way to do wireframe or is drawing lines the fastest?

#6

I suspect that would depend on the card you have and how they decided to build their driver.

Kev

#7

[quote]Is changing the polygon mode the fastest way to do wireframe or is drawing lines the fastest?
[/quote]
Regardless which is faster, changing the polygon mode is a better idea since the order of the vertex indexing changes with my suggestion (GL_QUAD_STRIP -> GL_LINE_STRIP etc) So that’s defintely a better way to go