If you want more... - nicobabot/Multi-cameraculling GitHub Wiki

Camera culling 2D video explanation: https://www.youtube.com/watch?v=zCaurIC49I4

How to add more than one viewport: http://lazyfoo.net/tutorials/SDL/09_the_viewport/index.php

If you want to go deeper (Frustum Culling/ Frustum Culling + Quad Tri/ Occlusion Culling):

http://www.flipcode.com/archives/Frustum_Culling.shtml

http://gamedev.stackexchange.com/questions/100504/how-do-i-optimize-2d-visibility-cone-calculations