I've been recently working on 2d isometric tile engine using XNA as school project. I've set up the engine to limit drawing only to what is inside the camera view. Problem is as soon as I start zooming out and therefore increasing the amount of tiles to be drawn the framerate starts to drop really fast. Around 100x100x3 (3 is the amount of layers for grass, roads etc) draw calls is enough to go from 60 to 50 FPS.
So how do other tile based games handle drawing large areas? For example I remember in OpenTTD you could zoom pretty far out and have huge maps (something like 2048x2048) yet it was really smooth. Thank you in advance for any solution/different approach you might have.
Also I'm new here, so hi again! I hope this is the right section for this topic.