liked your video pretty interesting, only critique is you kinda speak too soft. Had to crank the volume. Enunciation! :)
The Graphics: Episode 1 - Shadow Maps
@blacklab , @stooh,@GlenTennis cheers for the comments :)
@Jazz2 I was once told that my eyebrows were my best feature... I don't know whether to take it as an insult or a compliment.
@tescovee, yeah, still having issues, also going through a bit of a cold at the moment. I'm looking for a vocal coach at the moment to improve my singing (being welsh it's pretty much compulsory), hopefully that will help with my elecution. the other video I've just done is using a shure sm58 mic which although being great for live stuff, if uber bassy. and seeing as I don't have a proper vocal booth setup, I have a metric shit tonne of noise on the high end, (giggidy).
@ZelyreA good place to go with describing field of vision would be to do with angles on lenses (same thing really). It is graphics but at a much more down the the metal mathematical type stage. Viewing Matrices are a pain in the face. with field of view, just show the difference between pictures taken with a wide angle lens (fisheye to about 24mm) then a telephoto (150+mm), the wider the angle the more severe the vertical shapes in a photo with distort when you tilt it, with a telephoto lens, you get a narrower field of vision and therefore there is less effect of perspective and you get a much "flatter" image. ... ok I give up. this IS a difficult topic to explain :D
Great video. It's good to have those nagging questions put to rest. I fully expect beard writing in your next video (you brought this upon your self).
The video was quite good in giving a quick explanation on how shadow maps work, it could however have been a bit clearer on why shadow maps end up aliased and thus answering the original question, i.e. the main reason why they are aliased isn't because they are rendered in lower resolution, but because they are rendered in ligthspace, not screenspace. Rendering them at a higher resolution can make the aliasing smaller, but it can't make it go away completely, as you always end up essentially stretching a lightspace image over the scene and depending from where you look at it, it can always be stretched out extremely and thus pixelate. The lightspace/screenspace aspects where demonstrated quite nicely in the beginning of the video, but then not really connected back in answering the original aliasing problem. The final graphic also obscures the issue, as it makes it look like the shadow is evenly distributed, while in reality the shadowmap gets stretched out onto the wall. That's also why shadows in raytracing look better, they are rendered in screenspace, thus there is no stretching and no aliasing.
@MostlyBearded I'm trying! honest :S
@Grumbel
Yeah, of course. This is what I kinda lost in the last diagram, and you're right, it did come across like it was evenly distributed. I'll put my hands up and say that by that point I was too lazy to stick the whole shebang in, so ended up just fobbing off with some unclear text :D
quick early morning sketch of what is happening.
yeah, so as @Grumbel said, the view from the light is always from that view, and as it's projected onto the surface the pixels that make up the depth map can get horrible distorted and enlarged.
beeteedubs I'm working on another one just going over some simple concepts but I'm off for a week so it may be mid week it may be weekend. It's going to be a look at maps and what they are, why we use the, and any foibles they have etc. and I'm not just adlibbing this one, so it should be alot clearer :D
Thanks for this video! I've always wondered about shadows in games. To someone like me who knows virtually nothing about programming and 3D graphics it's very interesting to learn about something we've all seen but only a few understand.
It would be a lot of work, but a video explaining how shadows are handled in different games would be incredibly interesting. I'd even love just an article explaining the difference between these shadows, Doom 3's shadows etc. Also my mind suddenly explodes thinking of a game like Uncharted where you're walking through a jungle full of shadows!
Or if you know of articles online that have already been written that you can recommend that works too. Thanks again!
@kickinthehead I'm not in a hurry to do any more on shadows at least not for a while, There are a few ways to decide where shadows are, If you're interested look up Shadow Maps, Ray Tracing, Shadow Volumes, there's probably more that I have forgotten. This is an "old" video in that it's describing stuff that is not so forward looking , nowadays you have things like cascading shadow maps (where the resolution improves the closer it is to the players viewport) and filtering so you can get soft shadows etc (if you have a point light or directional light there will be no fade at the edge of the shadow, which is incredibly unrealistic, to get a light that sharp would be incredibly difficult in real life. And of course light bounces around off surfaces and causes colour bleeding and lighting you may not expect (this is sometimes called ambient lighting, and is faked sometimes with a small multiplier to the colour components in the scene). There's also a tonne of things that are currently happening with Post-Processing and multiple render passes (After the scene has been sttored in a buffer ready to be rendered onto the screen, we can do a variety of things to it. i'll be covering this in an upcoming video). A good place to start if you're interested is http://developer.nvidia.com/content/gpu-gems-part-i-natural-effects and it's free to download and peruse. That and the book Real-Time Rendering http://www.amazon.co.uk/Real-Time-Rendering-Third-Tomas-Akenine-Moller/dp/1568814240/ref=sr_1_1?ie=UTF8&qid=1329158056&sr=8-1 is probably the first place I would look.
It's all essentially maths and physics, people often underestimate how artistic maths,physics and programming can be. Myself, who went through school wanting to do "arty" things was always pushed to kinda disregard the more sciencey subjects. I now know that this is nonsense, and there should be a larger push trying to get people interested in both subjects.
These videos are not gospel/airtight by any means, there's stuff that I find interesting and I think that other people might like too, They're meant to be a holistic view of something that you can easily get out of your depth in, the one I'm currently working on when I read it out loud comes to about 7 minutes so far, I want to get it to at least half that :S
I like it, but maybe u can talk a bit louder in the next video? If u want u can send the soundfile to me and I edit it a bit.
This is great stuff and i hope you'll continue the series. It could be like Digital Foundry for laypeople. Suggestions: Why does screen tearing happen? Why is it so hard to prevent clipping issues? Why does high latency in online games cause the characteristic jumping/stuttering motions?
@JDW519 There's a couple of ways of doing reflections, the old traditional way it by actually having a mirrored scene on the other side of the "mirror" (This is for true reflections like when you look directly at a mirror) this has also been used in racing games for shiny road surface . The other way is to "render to texture", which is done by placing a camera facing out of the "mirror", rendering that as an image, and then texturing that onto the mirror object. I'm not entirely sure but I think portal uses this to do the portals (I know narbucular drop did, because the resolution wasn't great on the texture). As for reflections like that on a car or arbitrary surface, you have to use reflection maps ... I'll go through this a bit better in my next two vids. :)
Ive got so many mods on Skyrim, it looks great if it wasnt for the shadows, cant wait for a fix for that.
@Robster Thanks for the vid, I think I understood it!
Although may I suggest you boost your mic levels in post, or move your mic closer so your voice doesn't fade into the tranquil Welsh air.
@Sweep said:
Can the next video be on Why Everything Made Using The Unreal Engine Looks Like It Was Shat Out By The Lubricant Monster?
Seconded. Can you shed light on the lack of saturation and contrast in Unreal projects?
this was a fantastic video on an occurrence seen regularly that is rarely explained well. i'd love to see what else you can put into layman's for us
Thanks for this, would love to see more. This was on my mind since it was so distracting in Skyrim, compared to everything else being beautiful.
Cheers guys, sorry for not getting the next part up fast, I've literally (after procrastinating forEVER) just taken the footage today, and it's my day off tomorrow so that should hopefully be up late tomorrow
I'll try and respond to everyone on here, but sometimes I'm a bit late, so sorry about that:
@Claude Sorry for the lateness, I hadn't seen the shadows in silent hill, until I youtube'd it a minute ago. The shadows seem to be such a large part of that game I think it's only right they have such an overwhelming presence, still fairly disconcerting though (like any silent hill game then)
@lucasrizoli Brief??, hopefully the next one will be more succinct, and include a hamster...
@Peetabix thanks, I grow it myself (the beard that is), although I did shave it the other week and was devestated when I couldn't curl it as good :(
@nick_verissimo Cheers, like I said, hopefully tomorrow or day after, if not I am a bad person
@ectoplasma oh god don't I know about the sound issues, I have a fairly decent mic but no pre-amp, and my voice is usually mumbly anyway, may put subtitles on the next one, (and speak louder), cheers for the offer though, maybe in the future .
@1p these all seem like awesome topics. the first one I did was kinda impromptue, and hopefully the others will be more holistic and easy to cover, I also want to present them in slightly different ways each time.
@Bourbon_Warrior There may be a fix but it'll take quite a re-haul of the renderer, lets hope so though
@bbokhart , @Grimey , @buzz_clik ,@Beomoose ,@Mr_Spinnington ,@JimmyPancakes,@Mordi Cheers fellas, I'll sort another one out asap,
@jorbear yes, yes it could be
@Eviternal I'm in south wales, definitely not tranquil welsh air here. Audio will be sorted out soon, In the latest video I've just this minute recorded I've answered Sweep & Your question about unreal (but I must admit instead of researching and looking up specs and that, I've just theorised...)
@SUPER_STANO thanks, it's much better on fire though. this was going to be a video teaching that stuff, but I got distracted, will carry on showing in depth step by step moves etc in a few weeks.
Great video and info! I had to watch it a few times though to understand completely. I'm not really a person who works with graphics or anything. I just find the "Behind the scenes/How it's done" on video games interesting hehe.
@SUPER_STANO said:
Informative but then I clicked on your other video...HYPNOTIZING
*video*
HAH! Same. I must agree, you are amazing at that!
I really liked the video, even though I already have an idea of how shadow maps work. I hope you continue to get in depth on more topics. One criticism is to make sure you try and speak as clearly as possible and maybe slow down a bit. Its just your accent and the quality of the audio makes it a bit hard to follow for people who are not used to that specific accent.
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