Hello,
I seek advice to draw an outline. I want to draw an outline on small objects (about 10 000 triangles). The objects’ size stays the same always.
The technique I use basically scales up the object to draw the outline like the basic outline in the Toon Shading unitypackage.
However, the smaller the object, the less precise the pixels become. So drawing an outline by scaling up a small object doesn’t lead to very good results.
To get a good result, I need to turn on the anti aliasing to 16x!
Questions:
Am I using the right technique based on the situation I described?
Knowing that I cannot change the scale of the objects, any suggestions to get a finer and crisper outline, without having to rely too much on anti aliasing?
Would a shader using edge-detection in post-process be a better solution or a shader using the depth&Normals texture?
If 16x anti aliasing really is the way to go, can I select which specific objects to apply it to? This could let me apply a lower setting to other objects.
I combined the Xray Shader with the Toon shader, so that the toon outline falls off based on facing ratio. Was trying to simulate a glow effect. But this also has the interesting effect where, if the outline on the object is really thin, and the falloff rather steep, it makes it so the edge of the outline doesn’t have a sharp aliased edge, but rather looks quite smooth.
Look here
The problems with this is, I’m too nubbish to figure out how to get the toonOutline\Xray effect to render behind the diffuse surface and still maintain the proper blending modes. And also, if you set the outline color to black, it doesn’t render, cause blend One One mode makes black dissapear, I don’t know the proper mode. But if you fixed those two things, and this might work pretty well for you. This also has the benefit of working on SM1.1 and is quite fast.
The other issue with this method is that, it’s based on the facing ratio, so for a smooth falloff, the geometry also must be smooth and rounded. This means for low poly jagged models it won’t work. But I was thinking, instead of making it falloff based on the facing ration, could you make it falloff based on the distance from the edge somehow? I am just now learning cg and vector math, so I don’t know how this would be done, but am trying to figure it out.
Possibly a simple solution would be to use alpha blending on your outlines, and fade out the alpha based on object distance, so the smaller outlines would appear less strong (and thus the artifacts would look less bad). I once used a similar trick for tire tracks on tarmac with good results.