Background Perspective

Started by Yitcomics, Mon 02/03/2015 05:36:22

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Yitcomics

I've just recently started making adventure game,so I would some advice in making the background perspective.Do you usually go for one point or two point(any pros and cons),is making the background one point with the VP in the center bad?(for practical purposes,not artistic),I've heard someone say this but didn't explain why.Also how do I go about making the perspective in a scrolling background since the room will be quite long and it might look distorted.

I lack the experience in making adventure game background and I also recently just learn perspective for the first time,so any tips in creating the background would be useful,thanks.

Eric


ThreeOhFour

And in an interesting counterpoint to what I posted back then, I now use a perspective grid for everything, even clouds. :=

Yitcomics

Eric,interesting thread,learned a few things from it but there's is still some question that I hope to be answered

How do you handle one-point perspective in a scrolling background?
Is one point perspective with the VP in the center bad for scalling?

Eric

Quote from: ThreeOhFour on Mon 02/03/2015 09:11:34
And in an interesting counterpoint to what I posted back then, I now use a perspective grid for everything, even clouds. :=

WHAT?

cat

I once made a thread about scrolling rooms (http://www.adventuregamestudio.co.uk/forums/index.php?topic=31712.0). Sadly, since Imageshack does not work anymore, all pics are gone. I will try to find them if you are interested. The conclusion was to use different vanishing points for every building in the scene. This works because they will not be visible at the same time anyway.
As a result of the thread I made the background this way:

(a small bit with the tree is missing in the middle)

The advantage of one-point perspective is, that it is easy to draw. The disadvantage is the large scaling between foreground and background. If you limit the walkable area to an equidistant level from the vanishing point, you should be fine, though.

In any case, think twice before doing stairs or other complicate structures at a different angle than the vanishing lines - this can be a nightmare to construct (I know because I tried already)

Andail

How a character sprite scales depends on the position of the horizon, not the system of perspective (as long as we're not talking isometric or other non-convergent models). The lower horizon (towards frog perspective) the more drastic scaling, the higher horizon (toward bird perspective) the less.

Monsieur OUXX

#7
Yitcomics, you ask a very important question, which should be the starting point of any background.
The art of background perspective is way more subtle than it seems.

Here are a few traps into which beginners often fall:
1) Make sure your character is at maximum size when it's closest to the camera.
You don't want to draw your background with your character already at maximum size when it's walking at average distance from the camera, because then you'd have to scale him up when he walks towards the camera, and it would look ugly.
If needed, put some objects in the foreground of the scene, to forbid the character from walking too close

2) (in a low-res game) Try not to scale down your character unnecessarily.
Some character sprites don't support scaling down very well. It's not a big problem if the character "clearly" walks away from the camera. It becomes a problem when the character is always "almost completely scaled up" but "not completely scaled up", because then you get some dirty pixels or some pixel rows randomly missing, making him look weird (especially if he misses his nose or his eyes).
Therefore, either make the choice of clearly scaling him down (e.g. large scenes where the character is rather far away by design, e.g. a village marketplace), OR make the choice of keeping him at 100% scaling ratio even if he walks away/towards from the camera a little bit.

3) Find perspective tricks. Axonometric = A good perspective for beginners.
Point #2 just above means that you'll need to find tricks to keep your character at 100% scaling while avoiding a naive perspective (as seen in Maniac Mansion -- all rooms are just a stupid one-point perspective box, with horizontal objects).
Cat's post (just above) shows exactly how to make it right : just pretend you draw your scene like a two-points perspective, but for real you're drawing it with an axonometric perspective (that's a complicated word that means that all perspective lines actually remain parallel). That fools the eye easily.
Then, only with experience, you'll learn how to insert areas using axonometric perspective into a "real" perspective, to fool the eye constantly while keeping your character at 100% and using daring camera angles.

 

ThreeOhFour

Quote from: Eric on Tue 03/03/2015 04:56:06
Quote from: ThreeOhFour on Mon 02/03/2015 09:11:34
And in an interesting counterpoint to what I posted back then, I now use a perspective grid for everything, even clouds. :=

WHAT?

Sorry Eric!

Andail

Ok, technically there's not a specific piece of art we're critiquing here, but nonetheless it's an art theory discussion so it fits best in CL.

Yitcomics

#10
Cat,more picture examples would be great if you have the time to search for them

Monsieur thanks for replying,hmm if my game is hi-res I dont have to worry too much about scalling right?.But finding tricks for my characters to stay 100% is nice.
If you don't mind answering,I found your post from an old thread

Quote from: Monsieur OUXX on Fri 09/09/2011 15:46:16
Quote from: cat on Fri 09/09/2011 15:08:04
Perspective is faked here, as you can see on the lamps(?) on the left and right wall.

Indeed!
I had already posted the picutre below so time ago, but it also fits in this thread:
- The picture from Gemini Rue is a mix between 2 and 3.
- "Pure" one-point perspective (1) is rarely used because it causes the character's exagerated scaling that LostTrainDude is struggling with.


This is the Gemini Rue image


Can you elaborate more on this,I still don't understand what is Gemini Rue using,I guess figure 3 is an Axonometric right?but what is figure 2?
Also since i'm kinda of a noob on perspective the picture looks like one point perspective to me but from the post I presume it isnt?

Snarky

#11
Gemini Rue uses a form of 2, primarily: convergent perspective where different parts of the image have different vanishing points. (This screen also has a couple of perspective errors, particularly noticeable between the two rows of tables where the edges aren't parallel.)



You can see that as you go higher up in the image (or rather, higher up in the room, along the Z-dimension), the vanishing point also shifts up. This gives you some of the benefits of axonometric perspective (less scaling), while still looking more or less "realistic" like linear perspective. In a screen like this, most people won't even notice that the vanishing point isn't consistent, but it does depend on the content of the screen: you probably couldn't show the horizon without it looking noticeably wrong, for example.

Trapezoid

#12
One problem with axonometric/isometric is interiors need to have high ceilings, unless you're okay with odd cutoffs and black space. It's definitely something you can embrace, I'm not sure what you can do if you want to avoid cutaways and cross-sections.

Yitcomics

#13
Ok let's summarize a bit of all the points that I've learned

  • Pure one point perspective is not good for scalling and try to avoid too much scalling for low-res,but if it's high-res would you give one point perspective a pass or you would still say avoid it(If it has to much scaling)?

  • Axonometric tricks can help to make character stay 100%.

  • The Gemini Rue picture combine convergent perspective with different vanishing points and making the horizontal lines high enough to achieve Axonometric benefit and look more or less like a linear perspective.

  • When making a scrolling background,you can use different vanishing points to present each part,this work because the player can't see the whole picture.

  • (This information I got from Eric's thread)
    When using a 2 point perspective,you can do a slight cheat by keeping the horizon line above character's head and the vanishing points far apart and the lack of scaling on the character will not look too jarring.
Any last tips,insight,answer to the question on my first point,before I start making my backgrounds.

Andail

#14
I don't know why people think that the amount of view points affect character scaling. It doesn't. My last post was apparently ignored, but I'll try again:

A character scales down as it approaches the horizon (if there is one). The points in a 2 point perspective rest upon the horizon, just like in a 1 point system, so it doesn't matter if you have 1 or 2.

If you draw a picture with a relatively high horizon, the walkable area will likely equal a very limited distance in the z-direction, which is why there is less scaling. If you have a relatively low horizon, even a thin strip of walkable area will mean cover much more distance along the z-axis, and scaling will be more noticeable.

Monsieur OUXX

#15
Everything you summarized is true, Yitcomics.

A few more tips  (I hope I'm not redundant to Eric, I didn't quite get it) :

About the vanishing lines.
- The Gemini Rue image is another interesting trick to fool the eye. I'd even say it's the second mostly used trick in point n' click games : using several vanishing points instead of only one makes the vanishing lines more parallel to one antoher, yet not completely parallel.
--> This way you get the advantage of the axonometric perspective (not much scaling going on), but not its inconvenience (when all lines are parallel, it's looking a bit artificial). Be careful when you use that, though, because it can be hard to decide where to position the several vanishing points, and what distance you should leave between them. If you don't dispatch them with care, you'll end up "breaking" your perspective. The most common case is : your character looks like he has the same height in the foreground and in the background when compared to the ceiling height (that's what you want), BUT he suddenly looks too tall or too small compared to a table or any object not using the same vanishing line as the ceiling/floor, depending on whether he's walking near the foreground of the table or its background. To sumarize: several vanishing points mean you break the correspondance between the scales of the scene's objects depending along which vanishing lines you drew the objects.

Note that Maniac Mansion (not the example I posted, but other rooms where you can see the side walls) is already doing that in most rooms : the left wall uses one vanishing point, and the right wall uses another vanishing point. Therefore, it's the same while being different: In Gemini Rue, the several vanishing points are used to manipulate the vanishing lines of all objects that are in the scene's horizontal plane (the floor, the tables, etc.). In Maniac Mansion, the several vanishing points are used to manipulate the vanishing lines of objects in the vertical planes (the walls).
I think it's better used in Gemini Rue, because as Andail pointed out, it's combined with a high camera. Which means the vanishing point (if there was only one) would be far outside the picture anyway. Therefore, the vanishing lines would already be much more parallel to one another. Therefore, it's less noticeable that you used an additional trick to make them look even more parallel.


About the scaling : yes, it's true that it's less of a problem if you use high resolution.
However there is a second annoying thing: if you design your scene with a very low camera and a pure one-point perspective, then, as Andail pointed out, there will be much scaling happening in very little walking space. That's not a problem in itself, but the sudden scale change might become a bit noticeable if the character suddenly walks from the background to the foregounrd (and vice versa). It might look like he suddenly goes from "tiny" to "huge" and it might not be very smooth due to AGS engine's limitations. General rule of thumb: Don't put your camera to close to the ground ;)
 

Yitcomics

#16
I guess I better get started on those backgrounds,I really appreciate on all the advise that has been given.Just some final thoughts,
I'm currently making a game similar to Clock Tower which unfortunately uses pure one point perspective for most of its scene.
But I guess they handle the scaling problem by restricting its movement by just left and right,and hand drawn scale when scaling is needed.

I have given some thought on this,whether I should just use the same view and restrict my movement like Clock Tower or use different camera views,
which all of the advice that has been given is going to help me with that.Whatever the choice I'm gonna make,this thread has been helpful and next
time I'm bringing my backgrounds for all of you to criticize.

loominous

#17
If the straight lines of normal 1-3 point perspective grids feel restrictive and uninspiring - I personally can't stand them - there's a case to be made that these don't reflect how we experience the world.

Thing is, since our eyes are curved lenses, we experience what's known in the camera world as 'lens distortion'.



You can observe the phenomenon by standing somewhat close to a wall, and looking at the ceiling line, which should appear quite curved, if you think about it.

You can recreate this by using 4-5 point perspective, or simply using a distortion effect on the perspective grid/image.


Personally I prefer a sort of curved two/three point perspective, and just wing the upper/lower vanishing point, in practice it looks like so (I don't usually do the the vertical grid in the last picture):


Perspective grid, with arbitrary curvature (I like it for rooms, and fits the kind of curves I tend to naturally use when I sketch freely):


Process








This kind of distortion isn't problem free, since, to be technically correct, any moving sprites would have to have the distortion dynamically applied to them. But unless you're going for extreme curvature, it's usually not a problem.

So if you're allergic to straight lines, this approach is an option (though I can't vouch for its technical correctness).

Edit:
Two grids (the one in the example is called grid_02
Looking for a writer

Denture Alley Lurker

Yitcomics, if your not allergic to straight lines, there is a nice little free program called Carapace V1.0, made by some guy at Epicgames. Just Google it. It works well for me.:)

Eric

Quote from: loominous on Tue 31/03/2015 10:14:08
Perspective grid, with arbitrary curvature (I like it for rooms, and fits the kind of curves I tend to naturally use when I sketch freely):=

Any chance you have a higher res version of this you wouldn't mind sharing for us to try out?

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