Even without deferred rendering, why the limitation? I am sure there is a limit in the standart pipeline but can't I just pass as much as light info to shaders now, the result is just slightly longer shaders
There is no limitation per se,but with per-pixel lighting(and pretty much all lighting is done per-pixel nowadays) you would have to run your shader program exactly 2073600 times for a FullHD resolution....and that's every frame. So 60 times a second. Now imagine doing the lighting calculations for one light source....not too complex, few multiplications and that's all....but if you have several lights....then it's just way too much for any graphics card. A "slightly longer" program that has to run over 2 million times a frame is not really acceptable.
