Irrlicht performance tips

[ItsBritneyBitch]

Hi everyone, I'm developing a Irrlicht project (i guess pretty much everyone here is ) so I was wondering what Irrlicht-specific optimizations or performance stuff should be taken into account, and I couldn't find any similar post. Please contribute as much as you can. I'll start:

1) Enable backface culling (default) and sort your vertices/indices accordingly.
2) Try to reduce the use of trigonometric functions and square roots (i.e using getDistanceFromSQ(...) instead of getDistanceFrom(...))

[fmx]

I haven't used irrlicht properly in a while, but from what I know of it

biggest suggestion i can make for improving performance with irrlicht:

Use as less Nodes as possible!

this includes:
- batching polygons to minimise drawcalls (each node is equivalent to a single drawcall at best!)
- only render what you need (cull nodes that are not visible)
- sort nodes by shader (or renderpass), followed by material (or textures)
- instead of using irrlicht animators, perform animations on GPU

other noticeable gains will come from trivial C/C++ optimizations like unrolling small For loops, using smallest possible variable types, const-correctness, etc

Ofcourse, it also depends mostly on WHAT game (or application) irrlicht is being used to make, because there would be a tonne of other performance optimising options available depending on specific requirements (such as transparency sorting, managing lights, LOD, terrains, etc)

[CuteAlien]

Use octrees for large static level-geometry. Consider recompiling Irrlicht and experimenting with the octree defines. Alternatively mark static meshes as such (set hardwaremappinghint to EHM_STATIC).

And always the most import rules of optimization: Profile first!

[hendu]

^ I second that. Do nothing unless your profiler tells you it's a bottleneck. Code for style, not for speed until it's time to profile.

[REDDemon]

There's no funny in optimizing code. First achieve nice results. Optimize only if needed and you'll make games.

[ItsBritneyBitch]

Thanks guys for the replies. I don't want to make my program faster (as of now), as you said that's what profilers are for. I just want to know stuff I should keep in mind beforehand, like overkill functions or features of Irrlicht, so I can design my framework properly and avoid refactoring huge amounts of code later. For example, using mesh buffers required to rewrite a large portion of my application.