Dr. Krunklehorn

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About Dr. Krunklehorn

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  1. [quote name='Steve_Segreto' timestamp='1355379109' post='5010086']are these the kinds of triangles you want to end up with? [/quote] 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.
  2. [quote name='Álvaro' timestamp='1355344204' post='5009950'] 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. [img]http://public.gamedev.net//public/style_emoticons/default/smile.png[/img] [/quote] 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? [quote name='phantom' timestamp='1355345960' post='5009963'] My thought was why do you require equilateral triangles to be generated? [/quote] 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.
  3. *Bump* nearly 250 views and 0 replies. =T
  4. Continued from: [url="http://www.gamedev.net/topic/635357-quad-tree-lod-but-with-triangles/"]http://www.gamedev.n...with-triangles/[/url] [b]Details:[/b] I'm in the proccess of procedural planet generation; so far I'm doing the sphere work. Currently my sphere is a subdivided icosahedron. (20 sides all equilateral triangles) Before, when I was subdividing using a software algorithm, one triangle would be split into four children across the midpoints forming something close to a sierpinski triangle every iteration...like this: [url="http://puu.sh/1xFIx"]http://puu.sh/1xFIx[/url] As you can see, each triangle subdivided created more and more equilateral triangles. But now that I am using the GPU to tessellate in HLSL, the result is definately not what I am looking for: [url="http://puu.sh/1xFx7"]http://puu.sh/1xFx7[/url] [b]Questions:[/b] Is there anything I can do in the Hull and Domain shaders to change the tessellation so that it subdivides into sets of equilateral triangles like the first image? Should I be using the geometry shader for something like this? If so, would it be slower then the tessellator? Thanks for the time
  5. Quad tree LOD, but with triangles?

    Should I ask for that to happen? I wonder if I could pm a mod or something.
  6. Quad tree LOD, but with triangles?

    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?
  7. Quad tree LOD, but with triangles?

    Oh that's right! I can just use heightmap data for collisions. Awesome! I'm going to work on moving everything to the GPU right away.
  8. Quad tree LOD, but with triangles?

    Thanks! My current LOD system was more of a crude test to just get subdivision working on the fly. By the looks of it I really should be doing this on the geometry shader like you said. EDIT: Wait...your saying I can send the base icosahedron data (only 12 vertices) to the GPU and then do tessellation and heightmap stuff right there? None of this needs actually needs to be on the CPU side? As far as hardware tessellation goes, how would I get the data back from the GPU to use with collision? Assuming that [i]is[/i] even possible, wouldn't the data be behind by one frame when I go to calculate with it?
  9. Quad tree LOD, but with triangles?

    [u][b]If TL;DR then skip past the line...[/b][/u] Hello gamedev! I am a high school student working on a procedural planet engine in my spare time using DirectX 11 and C++. Four weeks ago I was 100% new to DirectX 11, but I have learned a lot just by reading tutorials and getting inspiration from tech demos. So far I'm taking the Icosahedron approach to generating a sphere. There's a lot of blogs, articles and theory on this, but not much raw code examples specifically for DX11 C++...most of them I have found are for OpenGL. It took me three weeks, but I managed to write my own version of Andrew True's nifty counterclockwise method. ([url="http://www.gamedev.net/page/resources/_/technical/graphics-programming-and-theory/procedural-planets-part-1-structure-r2074"]here[/url]) I've created wrapper functions for properly subdividing and merging these triangles, now I need to work on dynamic LOD. Unfortunately he doesn't seem to be active anymore, his website is gone, and he never posted anything on LOD with his tactic. :C So for the last week I've been trying to come up with the best solution to triangle based LOD. I've read up on various methods like quad trees, RTIN and ROAM, but they all deal with cube quads mapped to the sphere. I obviously need a different approach. ________________________________________________________ So I need something that works with my subdivided Icosahedron. The first method I tried was very basic. I check distance on all triangles. If the distance was greater then a certain value I would subdivide the triangle, and vice versa for merging children back into a parent. At first this method was extreeeeemly expensive. I wasn't able to get past 3 subdivisions before the number of sqrt() calls per frame was taking a tole on my FPS. I've optimized it since then by only checking distance on triangles of the current and previous LOD levels, but it's still waayyy too slow and it's all done on the CPU side. My goal is to be able to go from planet to surface...seamlessly...but I can't figure out how I would do this. Am I wrong about chunked LOD? Can RTIN, ROAM, or quad trees work with my triangle setup somehow?