Image redraw on Windows

OpenGL OpenGL: Advanced Coding
1

I posted the following message on the newsgroup and didn’t get any response and was hoping that I could get some help from you guys.

I have an application that has been ported from Unix (SGI & HP) to Windows (NT & 2000). In the OpenGL/X environment we relied on the backing store capability to handle the window repair and I’ve been trying to locate the equivalent functionality in MS Windows. I have searched this newsgroup with deja.com and couldn’t find anything.

The reason for using the backing store is that we often have a large amount of dynamic data which can be slow to repaint when the screen needs updating because of dialog windows coming up & down.

If there isn’t a replacement for the backing store, what other methods could be used to resolve this problem without doing a full redraw? I have considered keeping the back buffer in-sync with the front buffer and using this update the display when necessary. Since I haven’t tested this method out yet, is this a reasonable approach or is there a better method?

Thanks in advance for any help you might provide.
-Keith

2

I think the buffer region extension is what you’re looking for. Look up WGL_ARB_buffer_region.

  • Matt
3

Thanks for the reply. However, it looks like wgl_arb_buffer_region is a pretty new extention, which I’m guessing, wouldn’t be available for many drivers.

What I was hoping for was that Windows would have something equivalent to the Unix backing store. Does anyone know if this is available?

-Keith

4

You can try these extensions:
GL_WIN_swap_hint + GL_Autodesk_valid_back_buffer_hint
GL_KTX_buffer_region

Autodesk OpenGL Extension Specifications

5

Thanks for the information. Does anyone know how much support there is for these extentions?

Thanks.
-Keith

6

Our latest drivers support all of these extensions, including WGL_ARB_buffer_region. Not sure if the Autodesk one is in 6.31, though.

  • Matt
7

Trying this:
setting the render window’s class style to CS_SAVE_BITS,then the window don’t receive WM_PAINT message when the dialogs move down and up.