Was VHS really that bad?

[Drew Sebastino]

NovaSquirrel's mom (my aunt) is married to someone who owns one.

I had no clue that anyone on this forum was that closely related to anyone else.

With certain developers prioritizing lighting complexity over frame rate, <= 30 fps has become common.

I personally think that 60fps should be the golden standard, in that making a game run at 60fps should be your first priority. I'd much rather play a game that runs at 720p @ 60fps than one at 1080p @ 30fps. I might be a little bias though about framerate over resolution though because I have fairly bad vision and I'm too stubborn to wear my glasses so 720p doesn't look any different than 1080p to me. I just think that you should at least try to match the framerate of an (NTSC) NES game.

I'm just curious, but do any GameCube/Xbox/PS2 games have it to where the background casts shadows, and not just the main character or something else? I mean like this:

Standard HDMI: 720p, 1080i, or 1080p/30High speed HDMI: 1080p/120 (enough for 3D) or 4K/30

Is there such thing as a super high speed HDMI cable, like 4K/60 or 120?

[rainwarrior]

Espozo, I actually made those shadow-volume images. Ha ha. I wrote that program 9 years ago: http://rainwarrior.ca/dragon/effects.html

By the way, "shadow mapping" is a lot more common in games than shadow volumes, but I'm sure you read that in the wikipedia article you took the image from.

[Drew Sebastino]

By the way, "shadow mapping" is a lot more common in games than shadow volumes, but I'm sure you read that in the wikipedia article you took the image from.

I just did a google images search. I did read it now though. I've noticed that in some games, shadows from a flat wall or something will sometimes actually look like a bilinear filtered staircase, which is probably because of a low resolution shadow map. Have shadow volumes started to rise in popularity now? Another thing I'm curious about is that is the shadow map actually just another polygon located over whatever the shadow is being casted on, or is the texture of the surface underneath it actually altered, if that makes sense? Either way, I'd imagine that something like ink in Splatoon is kind of similar to an opaque shadow map in how it's rendered? Sorry to get off on a tangent.

[rainwarrior]

Shadow mapping requires hardware support for a depth texture. I think everything has had this since around about the PS2 era.

Shadow volumes has fewer requirements, but typically results in a lot more pixels rendered, and extra calculation, so it's not as performance effective usually. In a lot of earlier games only a few objects would be allowed to cast shadows, or other methods might be employed (e.g. just projecting the object on a flat plane and rendering it as black).

Once shadow mapping was available in hardware it became the dominant method and still is, so far as I've seen. The telltale sign of shadow mapping is that you can see the "pixels" in the shadow map. Just find something where the shadow is falling at an oblique angle or some other case where the resolution is poor, and you will see some boxy/fuzzy edges on it. Shadow Volumes are resolution-independent so they're always crisp.

I know Doom 3 used shadow volumes. I don't really have a list of other games that might use them.

[tepples]

Doom 3 also hit upon an independent reinvention of "depth fail", a shadow volume rendering technique that it turned out a couple Creative Labs engineers had patented (US Patent 6,384,822). I seem to remember that the design-around put in place for the 4Q 2011 GPL release of id Tech 4, the engine of Doom 3, cost a bit of performance. Perhaps shadow mapping grew in use as another design-around.

[rainwarrior]

Doom 3 also hit upon an independent reinvention of "depth fail", a shadow volume rendering technique that it turned out a couple Creative Labs engineers had patented (US Patent 6,384,822). I seem to remember that the design-around put in place for the 4Q 2011 GPL release of id Tech 4, the engine of Doom 3, cost a bit of performance. Perhaps shadow mapping grew in use as another design-around.

Their patented method wasn't really as big a deal as it sounds. It was basically just a minor optimization for generating depth volumes. There are other ways to generate depth volumes, just that very specific optimization got patented. It's a patent on one implementation of shadow volumes, not a patent on all shadow volumes.

Also, this patent was long enough ago that the GPU pipelines have significantly advanced. We have hull/tesselation/domain/geometry/compute shader steps in the graphics pipeline now that can do a lot of the work on the GPU.

Shadow volumes are less popular than shadow maps for two main reasons. The first is that they tend to produce a high volume of pixel fill. The second is that it produces "hard" shadows. There are many good techniques for shadow mapping that allow softening/fading of the shadow edges, which is a commonly requested feature. I think techniques for softening shadow volumes exist, but they're less practical. I don't believe the patent is a significant deterrent (it's not in any way essential to shadow volumes).

[Drew Sebastino]

Realistically though, how could they really even tell if someone copied his implementation, how could anyone even tell?

I think everything has had this since around about the PS2 era.

How processing intensive is it for these systems though, even if it is in hardware, because they never seem to use it. I guess this "shadow map" is actually written over polygons in hardware, in that it isn't like there's a higher priority alpha blended texture over it? I still don't get how something like paint or blood is rendered on top of something.

[rainwarrior]

Realistically though, how could they really even tell if someone copied his implementation, how could anyone even tell?

There are diagnostic debugging tools for GPUs that would make it relatively easy to check. I think games that use shadow volumes are uncommon enough that it might not be very hard to check most of them, if you were interested in enforcing your patent.

How processing intensive is it for these systems though, even if it is in hardware, because they never seem to use it. I guess this "shadow map" is actually written over polygons in hardware, in that it isn't like there's a higher priority alpha blended texture over it? I still don't get how something like paint or blood is rendered on top of something.

A shadow map is like if you projected a texture from the point of view of the light. Imagine putting a stencil over a light, and seeing the shape it makes. The stencil is the texture, the shape is the projected texture. Instead of projecting a colour or pattern on the scene, it projects a depth value. If the projected shadow value is deeper than the object, it gets light, if it's shallower, it's in shadow.

You make the shadow map basically by rendering the whole scene again (or just the shadow-casters) from the point of view of the light. If you're naive about it and make everything cast shadows, this would double your render time with just 1 light, triple it with 2 lights, etc. (An oversimplification, but roughly true.) You reduce the shadow map calculation time by reducing shadow casters, reducing the number of shadow casting lights, reducing the resolution of the shadow maps, etc.

People have been using versions of these techniques for shadows since the 1970s. They are scalable, and there are solutions that can fit pretty much any level of hardware/performance you need to meet.

[Sik]

I've never even seen an HD CRT in real life.

NovaSquirrel's mom (my aunt) is married to someone who owns one.

Over here there's one that I can't tell whether it's a CRT or LCD (it has depth but not too much). In any case its ability to somehow make Mega 3's composite output look crystal clear (pixels with hard edges) and without any forced deinterlacing makes it awesome. (I should note down the model, I know it's a Philips one).

I know Doom 3 used shadow volumes. I don't really have a list of other games that might use them.

We should probably look at the Dreamcast, because ironically its hardware made shadow volumes trivial (i.e. the exact opposite of everything else).