问题
I'm having a bit of a problem with Apples EAGLView and Texture2D. If I create an instance of EAGLView and draw some textures, it works great. However, whenever I create a second instance of EAGLView, the textures in the new view(s) aren't drawn.
Being new to OpenGL, I've got absolutely now clue as to what is causing this behavior. If somebody would like to help, I've created a small project that reproduces the behavior. The project can be found at http://www.cocoabeans.se/OpenGLESBug.zip
Many thanks,
Tim Andersson
Update
I tried using sharegroups but I'm not really sure if I used them correctly. However, it did change the behavior slightly; instead of the texture drawing only in the first instantiated view, it now draws the texture in the last instantiated view and draws white rectangles in the other views. I don't know if that is better or worse, but at least something is showing up in the other views now.
This is driving me crazy and I would be very grateful if somebody could help me with this problem. I've updated the project at http://www.cocoabeans.se/OpenGLESBug.zip to reflect the changes.
Cheers,
Tim
Second Update
After trying some more things, it seems that the problem is related to Apple's Texture2D class, though I'm not sure exactly what is causing the behavior. I think the best thing to do is to write my own texture class (it will help me understand how OpenGL handles textures, which will probably come in handy).
回答1:
(Haven't downloaded your code.)
The OpenGL drawing contexts are different if you just use two EAGLViews (the code in that base class creates and owns the GL context as well as render/frame/depth buffers). If you generate/bind some textures in one context, they won't be available in the other. You can share contexts if you like using a sharegroup (see this question for more: How to use OpenGL ES on a separate thread on iphone?). Or define the textures (if small) in both places, etc.
来源：https://stackoverflow.com/questions/2275656/textures-not-drawing-if-multiple-eaglviews-are-used