Performace and Lights

[Daemoc]

Is there much of a performance hit when using a high number of lights if they do not cast shadows? I have done tests with a ton of lights without issue myself, but I have pretty stout hardware.

Lets say I make a catwalk and I have lights running along both sides. I was wondering how much of an impact on low spec hardware it would be if I gave each light a small point light. No shadows of course.

Is there a soft limit I should not go over per map?

[Yue]

In my case, only with one light I have performance problems, my hardawre is about 15 years ago, in that case complex scenes would be for exclusive use of medium or high range. 

[reepblue]

Lights are cheap, it's the shadows you have to worry about for the most part.

[Daemoc]

I think I am going to run a few test maps with 10's to 100's of lights without shadows and see what the impact is on some low spec hardware. Some very simple maps, just a cube maybe? Something to really isolate the lights impact. I have access to a few windows machines with integrated graphics at work.

[reepblue]

I recall doing a similar test myself and I don't remember lights without shadows decreasing performance.

[Josh]

The slow step tends to be lights (especially point lights) that get redrawn each frame.

[Daemoc]

I ran a few tests myself and there is a definite impact on frame rate when a lot of lights are involved. It was odd though, the impact seemed to be non-linear. 1-10 really had no impact at all. 10-30 had a steady impact. 50+ tanked the frame rate in a hurry. I don't know how hardware dependent this is either.

The most important thing I learned is that you can have 10,000 lights on your map with no impact as long as they are not all being drawn at the same time. I will try to keep the light's on screen count under 10. I will also have to make sure the "detail" lights can be turned of on low spec machines.

[Josh]

On ‎7‎/‎2‎/‎2019 at 4:17 PM, Daemoc said:

The most important thing I learned is that you can have 10,000 lights on your map with no impact as long as they are not all being drawn at the same time. I will try to keep the light's on screen count under 10. I will also have to make sure the "detail" lights can be turned of on low spec machines.

I think this will be easy to do in a top-down game.