Need Help

Hi guys,
I need some kind of information about layering. Is there any relationship b/w layering and how many textures supported by open gl versions??

Layering? That word has a very great many meanings in different contexts. So what exactly are you trying to do?

I am trying to create 8 windows. each will independent of each other. I need to refresh the all windows independently. How can i do this?? Thanks in advance.

No, it’s “what are you trying to do?”, not “how are you trying to do it?

So, what’s your intended end result? What are you trying to achieve by drawing 8 windows? Because there may be a way to do it that doesn’t involve drawing 8 windows.

In one window i need to put weather radar display, another window i need to draw a grid on top of it. Window transparency also i need to do. I hav tried sequential rendering. It takes more time to update the weather radar display, so i need to render all windows parallely. Is there any way to do this??

You can display your weather radar data into a texture on a thread A and use this texture on a thread B that display it

When the display of your weather radar data is finish on the thread A, then you can bind this texture
=> the thread B now display this refreshed texture instead the previous version of this texture

With this, thread A and thread B can to be asynchronous : the thread B always display the last wheater radar picture computed and the thread A can now spend more time than the thread B for to compute it
(the texture content used by the thread B is always the same until the thread A hasn’t bind the texture for to refresh the content of the texture see by the thread B)

What is the format of your weather radar data and how is it displayed ?
(this can perhaps to be optimised for to be make in real-time , cf. without the need to be make in a asynchronous thread)

Yes, this weather radar display will update in separate thread at the same time i need to draw some other things also like grids updation of other parameters… Can i use two draw calls at a same time… Updation of weather radar pattern in one thread… Displaying weather radar pattern in separate thread… And then some other parameter displays in seperate thread… Finally i am creating two threads for displays one thread for weather radar pattern updation… But two display threads giving segmentation fault… How can i achieve this?? Because that Weather radar display and other display has different viewports…

You say that you use differents viewports for each display, use you two distincts windows or only one window that is splitted in two ?

If you use two windows, I think that it"s better to create the two windows, cf. the two windows creations and mouse/keyboard/display functions registering, before to begin the threads separation

On other side, I see at http://stackoverflow.com/questions/2177038/call-opengl-functions-from-another-thread that GL don’t seem to always be thread safe

Markr Crossbones+ seem to say the same thing at http://www.gamedev.net/topic/475265-multithreading-opengl/

=> the better solution seem to handle the OpenGL window(s) creation(s)/handling in only one thread
(but you can handle the majority of computations on others threads, the only limit is that you can’t use OpenGL’s calls on them)

http://www.equalizergraphics.com/documentation/parallelOpenGLFAQ.html#one contain a compilation of questions/responses that can perhaps help you about this

Note that I have never test to use multiples thread with OpenGL … but it’s perhaps the time to begin :slight_smile:

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