I wrote some opengl code with C on windows, fully compatible with OpenGL ES. So without any changes (except a couple of context creation code) it worked on ios perfectly in terms of compilation, but has some problems with the result produced.
I can say the code has no problem because it works as it should on windows but it looks weird on ios.
It is like the polygons on the side that is close to camera are like not drawn. They appear as I rotate the object and another set vanishes. Here is a comparison image;






