Sky still has some surprising cost on some devices

[illwieckz]

Sky has much much smaller cost than before, which is very good.

But it looks we still have some curious cost from it.

I did some comparison on a Raspebrry Pi 5 (VideoCore 7), with low and lowest presets and disabling sky, on the plat23 default spectator scene.

	lowest	low
no sky (implies clear)	75 fps	73 fps
sky with clear	63 fps	61 fps
sky	60 fps	58 fps

I'm surprised that enabling sky costs 10fps for displaying a handful of surfaces.

Also, it looks like clearing is still faster on some devices, it brings a gain of 3 fps. I remember it was explicitly mentioned on the Raspberry PI 3 Mesa documentation (VideoCore 4), but that looks still true on the Raspberry Pi 5 (VideoCore 7).

So basically, switching from lowest to low preset makes the framerate goes from 75 fps to 58 fps, but all that 22% cost is lost in sky rendering and side effect of absence of clearing.

[illwieckz]

Sky with clouds, which are more complex, get a worst performance penalty. Here is the default spectator scene on chasm with the low preset:

	low
no sky	76 fps
sky with clear	40 fps
sky	38 fps

I forgot to mention all runs were done at 1920×1080 resolution.

[VReaperV]

surprising cost
Raspebrry Pi 5 (VideoCore 7)

Choose one

[illwieckz]

My question is not: “Can a computer from 2023 with a 64-bit 2.4GHz quad-core CPU and 8 GB of RAM and an OpenGL 3.1 GPU should be capable of rendering a game level in Quake 3 BSP format from 1999?”, we already know the answer is yes.

There is a reason people complain prices of the latest Pi are “too high compared to previous ones”, because their latest hardware is not anymore targeting the same market and same usages at all, their different products. I know people having been students in the recent years who had worse hardware as laptop bought brand new by their parents (4GB RAM with 32-bit Windows, RIP 😂️).

My question is: “If the rest of the map rendered in that scene has like, thousands of tris, why just a couple of sky tris would drop that much perf?”

[VReaperV]

I know people having been students in the recent years who had worse hardware as laptop bought brand new by their parents (4GB RAM with 32-bit Windows, RIP 😂️).

Those are not the only measures of whether a hardware is good.

why just a couple of sky tris would drop that much perf?

Shit hardware/shit drivers.