I'm trying to build an OpenGL ES 2.0 rendering system on Android. I have one FloatBuffer, in which I put all vertex data. Currently, I just allocate it with a huge number of bytes and ignore draw calls if they would overfill the buffer at that size. Is there a way to dynamically resize the buffer? If i just freed the buffer and reallocated it after every render, I imagine that would be very slow.
Is there a way to dynamically resize the buffer?
No. Your current approach looks fine. You may want to extend it, that if the data doesn't fit in the current buffer, that you create a new, bigger one and fill it with the new data.
Unfortunately OpenGL-ES doesn't have a function as OpenGL-3 does which allows you to copy data between buffer objects. Using that you could to a copy between BOs that stay entirely in GPU memory, so that you'd have to update only the missing parts.
If i just freed the buffer and reallocated it after every render, I imagine that would be very slow.
It will not increase performance for sure, that's right. Depending on your actual implementation it may have a huge impact on performance, that's right. So I advise against doing this.