So what is the basic rendering frustum shape in RO\Unreal. Is it a circular frustum, or square\rectangle frustum or some sort of weirdo pentagonal frustum? I
Rendering Frustum?
- Thread starter jeffduquette
- Start date
hmmm...I give up...why shouldn't one use a circular frustum? Please elaborate. Why wouldn't one use a cone instead of a frustum?
So 70-degrees relative to what? Does it project 70-degrees from a point -- like the tip of a cone. Isn't it a frustum. The field view presumably projects into the level from a starting plane rather than a starting point. Does 70-degrees imply a 35-degree projection on either side of the small plane of the frustum? Or does 70-degrees assume a starting origin in front of the small plane of the frustum -- like a "virtual origin" in front of the monitor?
Last edited:
a circle would require yet another coordinate transformation, unlike a cut off pyramid frostum imo.
I actually wanted to say 80
Actutally iirc, it's more square on the ends.. more like
_
V
Reason being is on some foggy maps, you can sorta 'cheat' and look get a little further view by using the far 'corners' of the fustrum.
Maybe alittle help.. prob not.
from: http://udn.epicgames.com/Two/LevelOptimization.html#Frustum
"The frustum extends from the player's view to form a four-sided pyramid extended from the eye of the player outward"
Drax is right. We had a suggestions topic a while ago where someone suggested to make it round so that trick wouldn't work anymore.
Thanks for the link. This makes a bit more sense. But the origin isn't really a point -- right? I'm not peering through a pinhole toward the virtual scene depicted on the monitor. I am looking at the face of a monitor. The face of the monitor is the "eyes" of my virtual charachter. The virtual world projects from the rectangular face of the monitor into the rendered scene rather than a pinhole. If my virtual character is walking about the virtual world beyond the face of the monitor the initial plane of the rendering frustum is a rectangle -- a vertical slice through a pyramid shape forms a rectangular frustum. The face of the monitor is the small plane of the frustum. Rendering in the virtual scene starts from the rectangular face of the monitor and projects beyond the monitor forming the virtual scene. (Sorry -- much of this isn't directed at you Drax or your post, rather I was looking at some of the above posts and -- unfortunately feeling the need to elaborate.)
If I am peering through a sniper scope, or binoculars; Or like what I am typically doing when playing RO -- peering through a virtual tank telescope -- than the picture on the monitor is truncated into the circular shape formed by the walls\tube of the virtual telescopic sight. Moreover, the small plane of the rendering frustum is a circle. The rendering frustum starts with a circle. The start of the virtual scene for a telescopic scene is circular in shape therefore it is a circular frustum -- a cone with the pointy end sliced off. I suppose for those interested in semantics\”pedantics” this would be some sort of poly frustum with a large number of sides. But for my needs a circle is a decent enough approximation.
My question is not specifically geared to what a player sees in the virtual scene. I am interested in what is being rendered in the virtual world beyond the face of the monitor – be this a rectangular starting plane (rectangular frustum) or a circular starting plane (circular frustum -- telescope, binoculars). More is being rendered in a scene than what my virtual character can actually see. Thus the need for end fog distance, portals, antiportals, turning off terrain quads that are outside of the playing area, etc, etc. My interest is in the most efficient use of the fog end distance setting, portals and antiportals. I want to understand what is potentially being rendered in a given scene and to do that I want to know how the rendering frustum projects into any given virtual scene. Therefore I am interested in what the actual shapes of the rendering frustums are.
Last edited:
Thnx again Drax.
I was pondering this while staring at my toes in the shower this morning. I think I can get a reasonably close approximation of the rectangular and circular rendering frustums. I was fiddling about with this several months ago with the tank telescopic FOVs in RO-AB. I posted some of this for the IS2 in a discussion I was having with Amizaur. The same technique should give me a pretty good approximation for the various rendering frustums.
I was pondering this while staring at my toes in the shower this morning. I think I can get a reasonably close approximation of the rectangular and circular rendering frustums. I was fiddling about with this several months ago with the tank telescopic FOVs in RO-AB. I posted some of this for the IS2 in a discussion I was having with Amizaur. The same technique should give me a pretty good approximation for the various rendering frustums.
Last edited:
Pinhole eh? Have fun transforming that to screen coordinates
The near plane is there for a reason
![[TW]Ramm-Jaeger](/data/avatars/s/0/2.jpg?1568638684){kind=avatar}
Just for the record, the default RO FOV is 85 degree. And yes, it is a Rectangular (Pyramid) shaped frustrum with a near and far clipping plane. To be honest with you though, as far as optimizing the levels, you shouldn't have to really consider the frustrum. Just use the optimization tools built into the engine to make sure you aren't rendering too many polygons in a scene. Like walking around the level in wireframe mode and look at what you see being rendered.
Thanks Ramm-Jaeger. It's one of those things that is sort of nice to have some understanding on what is actually occuring in the virtual scene as the player moves about.