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Modern Rendering Culling Techniques

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Re: Modern Rendering Culling Techniques

#21

Post by motorpixel »

Animats wrote: post #12

Occlusion culling is really tough in systems where users can add content to the world. Especially if there's translucency. As with windows (not Windows), or layered clothing. You're in a room without windows. Everything outside the room is culled. Frame rate is very high. Then you open the door and go outside into a large city. Some buildings have big windows showing the interior, so you can't cull the building inter…

Roblox just gave a talk at this exact intersection of topics (user generated content and high performance culling) last month at GDC.

https://schedule.gdconf.com/session/optimizing-a-large-time-...

Re: Modern Rendering Culling Techniques

#23

Post by snailmailman »

I've always wondered to what extent these culling techniques still work with raytracing? A reflective surface can bring a bunch of otherwise-offscreen things into the scene. Its what makes screen-space reflections look so bad sometimes, they can't reflect whats not on-screen.

Re: Modern Rendering Culling Techniques

#25

Post by Panzerschrek »

LarsDu88 wrote: post #4

PVS isn't that expensive to compute. Especially nowadays. I assume this is actually referring to the binary space partitioning techniques used in DOOM and improved in Quake, Half-Life, etc in the late 90s, early 2000s. The BSP tree was also extremely useful for optimizing netcode for games like Quake 3 Arena and games within that family and time period I believe.

PVS requires some hierarchical scene representation with no seams between walls. I know no other way to build such representation other than BSP. But BSP works fine only with pretty low-detail map geometry consisting of brushes. No large detail meshes or terrains can be used with it. If a game has a lot of open spaces or semi-open spaces it's nearly to impossible to build a BSP for it.

Re: Modern Rendering Culling Techniques

#26

Post by Animats »

motorpixel wrote: post #21
Animats wrote: post #12

Occlusion culling is really tough in systems where users can add content to the world. Especially if there's translucency. As with windows (not Windows), or layered clothing. You're in a room without windows. Everything outside the room is culled. Frame rate is very high. Then you open the door and go outside into a large city. Some buildings have big windows showing the interior, so you can't cull the building inter…

Roblox just gave a talk at this exact intersection of topics (user generated content and high performance culling) last month at GDC. https://schedule.gdconf.com/session/optimizing-a-large-time-...

Yes, although the GDC paper is paywalled.

But see Roblox's own summary at: [1]

[1] https://devforum.roblox.com/t/occlusion-culling-now-live-in-...

Re: Modern Rendering Culling Techniques

#27

Post by socalgal2 »

Panzerschrek wrote: post #25
LarsDu88 wrote: post #4

PVS isn't that expensive to compute. Especially nowadays. I assume this is actually referring to the binary space partitioning techniques used in DOOM and improved in Quake, Half-Life, etc in the late 90s, early 2000s. The BSP tree was also extremely useful for optimizing netcode for games like Quake 3 Arena and games within that family and time period I believe.

PVS requires some hierarchical scene representation with no seams between walls. I know no other way to build such representation other than BSP. But BSP works fine only with pretty low-detail map geometry consisting of brushes. No large detail meshes or terrains can be used with it. If a game has a lot of open spaces or semi-open spaces it's nearly to impossible to build a BSP for it.

PVS does not require a hierarchical representation. You can use any representation you want. In fact the one in the article itself is not hiearchical.
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