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[AGAL / Stage3D] Outline / Silhouette Shader

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Hi Everybody,

i search for a good Outline Shader - So that i draw the Outline of my Mesh. I don't need complete Toon Shading or things like that. Just a Outline from my Mesh.

I have found this paper:


And i have try to implement it in AGAL, with this Result:

va0 = VertexPosition
va3 = VertexNormal
vc0 = WorldToScreenMatrix
vc4 = CameraPosition
vc20 = Constants (.y = 0.04)

"sub vt0, va0,vc4\n" +
"dp3 vt1, va3, vt0\n" +
"slt vt2, vc20.x,vt1\n" +
"mov vt3, vc20.y\n" +
"mul vt4, vt2, va3.xyz\n" +
"mul vt4, vt4, vt3\n" +
"add vt5, va0, vt4\n"+
"m44 op ,vt5 vc0\n"

fc20 = Constants,x= 0.1
fc8 = Color

"tex ft0 v1 fs0<2d,linear,repeat,linear,mipnone>\n" +
"slt ft1 v4.x fc20.x\n" +
"mul ft2 ft1 fc8\n"

so, but there nothing happens - Or a white screen. Have somebody some cool Outline Shader or know what is wrong with my?

Greeting Stimpy Edited by Stimpy1983

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I have figured out, that my code can't be working because all my Normals look up. So i have a plane 2d mesh , not a picture - a mesh , but all my vertexes are on the X/Y Axis. All my Normals are going up. The shader takes the angle between cam position and normal, if i understood right. So that can't be working....

Have somebody an idea how to draw an outline for a mesh where the normals are all in the same direction?!

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You need some value to distinguish between your model and the background. Often the depth and normal is take, but an alpha value (character = 1, background =0) will do the job too. Then use a sobel filter to detect the edges.

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was going to suggest using edge detections too, rendering back-facing polys will also work if you do that with a slightly enlarged version of the model.
both have their costs through.

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