Portal Performance

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Misery
Posts: 157
Joined: Sun Nov 04, 2018 4:57 pm

Portal Performance

Post by Misery »

How resource intensive are portals, and what exactly affects it? How many portals can you create before it's likely to affect performance?
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Graf Zahl
Lead GZDoom+Raze Developer
Lead GZDoom+Raze Developer
Posts: 48320
Joined: Sat Jul 19, 2003 10:19 am
Location: Germany

Re: Portal Performance

Post by Graf Zahl »

That depends on the graphics hardware you target. On older hardware even a single portal can cause some noticable slowdown, while on modern mid-range and high end cards you may get away with multiple complex portals before they affect performance too much.

One thing you need to remember is that the sky is also a portal, so an indoor portal in an area with no sky is cheap, but a portal in an area where some sky can be seen will require a full stencil pass - and if both your main view and the portal show some sky it will definitely be too much for older hardware (i.e. OpenGL 3.x or OpenGL 4.0)

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