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Dr. Krunklehorn

Member Since 02 Dec 2012
Offline Last Active Oct 15 2013 02:04 PM

Posts I've Made

In Topic: Modify Tessellation shader to make equilateral triangles?

13 December 2012 - 11:08 AM

are these the kinds of triangles you want to end up with?


That's actually a perfect demonstration of what I am trying to avoid. The method shown in that video is exactly
why cube based spheres get distorted.

Notice the vertex density on the top of the sphere, compared to the vertex density around what would be
the corner of the original cube.

Already there is a big difference: the triangles on top of the sphere are stretched out and the ones near the
original corner point are very small and clustered.

Now if the camera in my planet application was to fly around on ground level, the effect of this distortion
would be easily noticeable. A mountain range around a clustered corner is going to look much better
then a mountain range around the stretched areas on top.

Equilateral triangles is the solution here. They stay the same size all the way around the sphere.

In Topic: Modify Tessellation shader to make equilateral triangles?

12 December 2012 - 10:25 PM

I think I speak in the name of some of the other nearly 249 people when I say that I don't have a good answer to your question. Posted Image


Ah okay that's fine. I was hoping someone else had come across a similar problem with the default tessellation pattern in DX11.

I've done a ton of research since I first posted this question. Articles, PDF's, white papers, tech demos etc. have all helped me
get a better understanding of what the domain shader actually see's and what I have to work with in it.

I'm going to see if I can find a way to do this in the domain shader. (cracks are a fix-later problem) If I can't, that's fine too. I
have an excellent plan to use the geometry shader instead.

What I'd like to be sure of is the performance difference though. If I were to mimic the tessellation shader in the geometry
shader, would the geometry shader method operate slow-er enough to call it a big deal?

My thought was why do you require equilateral triangles to be generated?


If I was to subdivide a cube into more and more quads then map that to a radius, the result has an ugly distortion around
the corners. Using equilateral triangles from an icosahedron base nearly solves this problem because it is the highest
order platonic solid you can make. I.E: it is the best "base" to start from if you want to avoid that corner distortion side
effect of the cube method.

In Topic: Modify Tessellation shader to make equilateral triangles?

12 December 2012 - 01:51 PM

*Bump* nearly 250 views and 0 replies. =T

In Topic: Quad tree LOD, but with triangles?

06 December 2012 - 08:15 PM

Should I ask for that to happen? I wonder if I could pm a mod or something.

In Topic: Quad tree LOD, but with triangles?

06 December 2012 - 02:25 PM

Alright so last night I got hardware tessellation going smoothly, but the actual triangles it creates are not
exactly what I am looking for: http://puu.sh/1xFx7

I would like to change the Tessellator so it generates equilateral triangles like this: http://puu.sh/1xFIx

Could I do this in Hull and Domain shaders?

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