Just for learning purpose I want to build a really simple 2D openGL Engine, so I'm really curious to understand how the most famous Engines work (or at least which is your idea).
I know that using a SpriteBatches the engine performs a single drawing call per SpriteBatch while drawing simple sprites every sprite needs a drawing call. Let's say that I'm only interested in drawing separated sprites without a SpriteBatch.
Here is my idea for simple Sprites drawing:
I suppose they are represented through a plane and a texture. Every plane has a set of vertices and indices and a common shader (let's keep it simple).
The sprites are stored in a sort of array and for each sprites the engine needs to set a VBO with the vertices of the current plane and call glBindBuffer, glBufferData, set the shaders and call glDrawElements.
The VBO is then cleared and the previous operations are repeated for the next sprite.
Could it be a common routine to draw sprites?
About the SpriteBatch I suppose that the big difference is that the VBO stores the vertices of every plane once and for this reason it is able to draw all the sprites in a single glDrawElements call.
Am I on the right way or my "suppositions" are totally wrong?