wglShareLists question.

[Nutty]

The wglShareLists function enables multiple OpenGL rendering contexts to share a single display-list space.

BOOL wglShareLists(
HGLRC hglrc1, // OpenGL rendering context with which to share
// display lists
HGLRC hglrc2 // OpenGL rendering context to share display lists
);

Parameters
hglrc1
Specifies the OpenGL rendering context with which to share display lists.
hglrc2
Specifies the OpenGL rendering context to share display lists with hglrc1. The hglrc2 parameter should not contain any existing display lists when wglShareLists is called.

The amazing M$ documentation makes it virtually impossible for me to decide which bloody Rendering context it means for each paramter.

Which is the original Rendering context (the one associated with the frame buffer when opening the window), rc1, or rc2?

It looks like rc2 to me. That right?

ta,
Nutty

[This message has been edited by Nutty (edited 10-01-2002).]

[PH]

RC1 is the original one.

[V-man]

Why does this matter? You should be able to swap them, no?

V-man

[solarforge]

Originally posted by V-man:
Why does this matter? You should be able to swap them, no?

V-man

It matters if your creating textures in one context and sharing with another -- if you create in the second context (I think this is right... then normally the texture can't be used by the _first_ context because you haven't shared the resources of the second context...

Ummm... I hope that's clear...

Leathal.

[davepermen]

if i interpet it correctly, the second parameter is "source" and the first is "destiny"..

but on the other hand, how about they both share their stuff together, so that each one has the others data.. then it wouldn't mather (i think thats what v-man ment..)

[Asgard]

I had to find out the hard way that the order actually matters. I had created a context with a couple of texture and program objects and then created a new context that should also have access to those objects. Of course, I accidentally called wglShareLists with the contexts swapped and was wondering why I didn't get any textures in the second context, even though I had just called wglShareLists before.
So watch the parameter order with wglShareLists or it'll cost you hours of frustration, anger, and whatnot ;-)

[knackered]

I'm more interested in why you're using wglsharelists, nutty?

[Humus]

Saving texture memory I suppose, would be wasteful to upload the same textures to two different contexts.
I always use wglShareLists when doing render to texture with WGL_ARB_render_texture.

[knackered]

Yes, but you can use your main RC to render to the pbuffer - why use another+sharelists? Surely it would just cause an unnecessary stall as the new RC is switched to?

[ToolChest]

the pbuffer has its own device context, how do you do that?