Sign in to follow this  
JorenJoestar

Cel-shading...

Recommended Posts

Hi everyone, I'm here because I need an info. I'm developing a game, and my desire is to do the graphic using the cel-shading. Two question arouse: how textures are used in a cel-shading engine? And the most difficult...how does Nintendo do to obtain such a beautiful graphic? Thinking of games like Zelda Twilight Princess, Super Mario Galaxy, Super Smash Bros Brawl (and also Melee...) I'm stunned. It is a great graphic, I love it! Do you have some hint about doing something like that? Thanks in advice!

Share this post


Link to post
Share on other sites
The basic idea is to take the normal of the light source and then get the normal of the face of your polygon. Then take the dot product of those 2 normals and use that as an indicie in an array of 1D color intensity values.

OpenGL Super Bible has a good article about this topic. Hope that helps. =)

-- Brandon Fogerty
www.brandonfogerty.com

Share this post


Link to post
Share on other sites
If you want to check a Nintendo game that really does a good job on cell-shading, then take a look at Zelda, The Wind Waker. I might be wrong, but the other games you mentioned are not really using cell-shading I think.

Nevertheless, these games look "cartoonish" because the colorfull graphics. But that's not really a matter of advanced techniques. I think most Nintendo games are still using pretty classic rendering techniques (Wii and Gamecube are not doing fancy shading like a XBox 360 or PC), but with very good (colorfull) textures, and a lovely design --> a good artist job.

The Twilight Princess has some mysterious gloom all over the game. I think its made with a (simple) type of HDR/blooming, like you can also see in Shadow of the Colossus for the PS2.

Mario Galaxy seems to be using somewhat more advanced techniques, like bumpMapping and cubeMap reflections. But what really gives it a soft cartoonish touch, is the blueish shading around objects and the furry grass on planets/objects. I think this blue shading is made with some sort of anistropic lighting shader.

As for the cell-shading, games like The Wind Waker ussually use pretty simple, yet colorfull textures. If you look at a cartoon on the TV, you usually don't see small details either; each character/object is drawn with a couple of bright colors, and the "shadow bands" that are typical for cell-shading.


So in short, making a cartoon/cell-shaded game is not really a matter of using advanced shaders. But you need to have a skilled artist(someone who's good at drawing comics?) with lots of fantasy and whom can play around with colors.

Greetings,
Rick

Share this post


Link to post
Share on other sites
Yeah, I agree with spek that most of the "magic" is in the artwork for games like Wind Waker. Cel-shading is a relatively simple and common technique these days, it's fairly easy to pull off either with fixed-function or programmable shaders. I don't really see anything special going on with Smash Bros. Brawl either, just looks like quality artwork. Same for Mario Galaxy, which makes use of an older fixed-function GPU feature called environment-mapped bump-mapping. The same technique can be easily replicated in shaders these days, but I think is still available in D3D9.

Share this post


Link to post
Share on other sites
Quote:
Original post by spek
Mario Galaxy seems to be using somewhat more advanced techniques, like bumpMapping and cubeMap reflections. But what really gives it a soft cartoonish touch, is the blueish shading around objects and the furry grass on planets/objects. I think this blue shading is made with some sort of anistropic lighting shader.

The soft/velvet effect is usually called "rim lighting". It's pretty simple, you can find one description of the maths here. Basically you use the viewing direction and the surface normal to highlight edges which are side-on (or nearly side-on) to the viewer.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this