Solved

OpenGL rendering context

Posted on 2000-04-01
9
506 Views
Last Modified: 2010-04-04
why i can create opengl rendering context only once (without closing my program).
When i start it 1st time, all is ok, but if i try to close opengl window (of course, i deactivate context, delete rendering context and release device context) and run it 2nd time without restarting whole application , i have error (zero result on wglCreateContext).
This error appear on new 3d-cards (all nvidia riva series)
0
Comment
Question by:programmerX
  • 5
  • 3
9 Comments
 
LVL 17

Expert Comment

by:inthe
ID: 2676263
just listening ..
 hi mike ;-)
0
 
LVL 10

Expert Comment

by:Lischke
ID: 2676423
:-) Hi Barry,
hi programmerX,

now that I managed after days of delay to log into E-E again, I can finally answer questions again. Quite happy about that :-) (non-cookie login does not work yet and I hate cookies :-().

Now to the question. What I need is a bit more information. You should be aware that MS explicitly states that you cannot set a pixel format twice for any DC. Hence, if you need to recreate a RC then do it without setting the pixel format again.

Ciao, Mike
0
 

Author Comment

by:programmerX
ID: 2677105
hi Mike,
it's sounds nice, but what i can do if user choose another pixel format for second start? (for example, he can choose new color depth).
My code looks like this:
    VideoHandle:={some window}.Handle;
    DC:=GetDeviceContext(VideoHandle);
    SetDCPixelFormat;
    RC := wglCreateContext(DC);
    wglMakeCurrent(DC, RC);
    ...
    {drawing here}
    ...
    wglMakeCurrent(DC, RC);
    wglDeleteContext(RC);
    ReleaseDC(VideoHandle, DC);
0
Gigs: Get Your Project Delivered by an Expert

Select from freelancers specializing in everything from database administration to programming, who have proven themselves as experts in their field. Hire the best, collaborate easily, pay securely and get projects done right.

 

Author Comment

by:programmerX
ID: 2677107
hi Mike,
it's sounds nice, but what i can do if user choose another pixel format for second start? (for example, he can choose new color depth).
My code looks like this:
    VideoHandle:={some window}.Handle;
    DC:=GetDeviceContext(VideoHandle);
    SetDCPixelFormat;
    RC := wglCreateContext(DC);
    wglMakeCurrent(DC, RC);
    ...
    {drawing here}
    ...
    wglMakeCurrent(DC, RC);
    wglDeleteContext(RC);
    ReleaseDC(VideoHandle, DC);
0
 

Author Comment

by:programmerX
ID: 2677111
i forgot to add:
  my program can run in windowed and fullscreen mode. To change video-mode (fullscreen) I choose it with ChangeDisplaySettings function
0
 
LVL 10

Expert Comment

by:Lischke
ID: 2677289
Well, that's the sad thing about OpenGL under Windows. The fact that you cannot reset the pixel format has caused many problems in the past. Somehow it must be possible, though, to reset a device context such that it appears to be like newly allocated, because you can restart your program, it will allocate a DC and for this a valid rendering context can be created. Perhaps playing around with the class styles for the window carrying the RC and GetDCEx will expose a workaround?

Ciao, Mike
0
 

Author Comment

by:programmerX
ID: 2677452
i'll try to add this code in opengl finalization:
 {somewindow}.Free;
 {somewindow}:={somewindow}.Create;
Can this code reset DC?
0
 
LVL 10

Accepted Solution

by:
Lischke earned 100 total points
ID: 2678103
I honestly hope so :-) How else can it work?

Ciao, Mike
0
 

Author Comment

by:programmerX
ID: 2688623
thanx for idea...it works fine
0

Featured Post

Live: Real-Time Solutions, Start Here

Receive instant 1:1 support from technology experts, using our real-time conversation and whiteboard interface. Your first 5 minutes are always free.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

The uses clause is one of those things that just tends to grow and grow. Most of the time this is in the main form, as it's from this form that all others are called. If you have a big application (including many forms), the uses clause in the in…
This article explains how to create forms/units independent of other forms/units object names in a delphi project. Have you ever created a form for user input in a Delphi project and then had the need to have that same form in a other Delphi proj…
This tutorial gives a high-level tour of the interface of Marketo (a marketing automation tool to help businesses track and engage prospective customers and drive them to purchase). You will see the main areas including Marketing Activities, Design …
This video shows how to quickly and easily add an email signature for all users on Exchange 2016. The resulting signature is applied on a server level by Exchange Online. The email signature template has been downloaded from: www.mail-signatures…

776 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question