# Questions tagged [tessellation]

The process of breaking down polygons into finer pieces.

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1 vote
526 views

### How to subdivide an octahedron into a sphere?

For a game I'm making, I have to tessellate an octahedron into a sphere on the GPU (shaders). What I've done is I've successfully tessellated the faces, but I'm having trouble subdividing more spaces, ...
165 views

### How I can compute normals vectors for a tessellated terrain?

I would like compute normals vectors for a tessellated terrain generated procedurally, in order to use them for a basic lighting. I don't know how I could do it. I can do it in the Tessellation ...
1 vote
128 views

### glPatchParameteri(GL_PATCH_VERTICES, 4) causes access violation

I'm trying to create a tessellated terrain, for this purposes I'm following the LearnOpenGL tutorial: https://learnopengl.com/Guest-Articles/2021/Tessellation/Tessellation However, when I set the ...
137 views

### Tessellation shaders not working, no objects drawing on screen

Using this tutorial https://learnopengl.com/Guest-Articles/2021/Tessellation/Tessellation and this tutorial https://www.youtube.com/watch?v=21gfE-zUym8 I implemented tessellation shaders that I haven'...
187 views

### How to replicate the dynamic LOD system for characters from Messiah (2000) in Unity?

I watched this video on youtube and got really curious about replicating the "character system" that it covers. This article linked in the video description goes into further detail on the ...
13k views

### When mapping the surface of a sphere with tiles, how might you deal with polar distortion?

It's easy to deal with the way locations interact on a clean Cartesian grid. It's just vanilla math. And you can kind of ignore the geometry of the sphere's surface for a bunch of it if you want to ...
1 vote
1k views

### Manually writing a dx11 tessellation shader

I am looking for resources on what are the steps of manually implementing tessellation (I happen to be using Unity CG, but any help is appreciated). Today it seems that it is all the rage to hide ...
1 vote
441 views

### Why is my tessellation output failing to reach my geometry shader?

I'm attempting to render grass using GLSL tessellation and geometry shaders. For vertex input, I'm using position and normal. For reference, here's an image of the grassy field without tessellation (...
157 views

### How does the InsideTessFactor affect points of a triangle in a DirectX11 domain shader?

I found this example in this Chinese language document. In the image above, I can understand the value of SV_TessFactor because for every side of this triangle, ...
381 views

### Writing Hull shader in directx

hey i am studying different types of shaders in directx. and it comes to hull shader. so i write hlsl codes for both constant hull shader and control point hull shader in same file in visual studio ...
567 views

### DirectX 11 generate normals for tessellated triangles

I've spent a couple days looking for an answer to this - How can I access the newly created triangles of tessellation and generate normals for them? I've followed much of the shader code from the ...
1 vote
2k views

### How do you animate/collide against a tessellated mesh?

Now that I have a implemented tessellation for my mesh, I am trying to understand how I can leverage the generated primitives. Example: I have the following track mesh generated procedurally, it ...
1k views

### OpenGL Tessellation Shader Not Working

I've been trying to play around with tessellation shaders in OpenGL for a couple of hours now, but I'm having trouble to get it to work. I've been following The Little Grasshopper Triangle ...
6k views

### Subdividing a polygon into boxes of varying size

I would like to be pointed to information / resources for creating algorithms like the one illustrated on this blog, which is a subdivision of a polygon (in my case a voronoi cell) into several boxes ...
1 vote
94 views

### How to fix this terrain behavior?

EDIT: This is for In game Terraforming, kind of like in life is feudal. https://www.google.com/search?q=life+is+feudal+terraforming&rlz=1C1CHBF_enUS792US792&source=lnms&tbm=isch&sa=X&...
2k views

### Unity Standard surface shader with tessellation

So I'm experimenting with tesselation to try and make a custom snowshader and after I finnaly manage to compile the shader without any errors. The plane I'm using the shader on simply become ...
810 views

### Unity 5: How to make a Unity 5 Physically Based shader Catmull-Clark subdivision tessellation for increase LOD if possible using visual scripting?

I'm using Amplify shader visual scripting to make tessellation and increment level of detail of the 3d mesh. But is not applying Catmull-Clark subdivision round smoothness. And my model still looks ...
1 vote
188 views

### Approximating Subdivision Surfaces with Gregory Patches for Hardware Tessellation

I'm trying to implement the approach (http://research.microsoft.com/en-us/um/people/cloop/sga09.pdf). Unfortunately I'm not quite clear regarding the formulas in chapter 3, I am hoping to get some ...
2k views

### Accessing vertex Input in surf directly without vert's out parameter In Tessellation Shader

I can get the vertex Input in vertex shader as follows: o.worldPos = v.vertex.xyz; But how do I get the worldPos directly without filling the out parameter in ...
1 vote
330 views

### Breaking up a 2d shape into small triangles

I have a "piece of cloth" (2d shape) that I'm applying soft-body physics to. This works great when the shape is a square and I can create a regular grid of vertices between which are hung the cloth's ...
1 vote
414 views

### render trajectory of particle in forcefield using GLSL shader

I want to visualize flow of particles in some forcefield e.g. electromagetic, gravitional or potential flow in fluid (streamlines); I was thinking to use Geometry Shader which would look like this (...
72 views

### Merging tesselated terrain with manually modelled

In my flighsim visual system I am rendering large scale terrain using fixed grid mesh which is tesselated and displaced using height map. But for some relative small area (usually airports) we have ...
847 views

### OpenGL Tessellation makes point

A little problem with my tessellation shader. I try to implement a simple tessellation shader but it only makes points. Here's my vertex shader : ...
36k views

### What's the difference between displacement mapping and height mapping?

What's the difference between displacement mapping and height mapping and what is the connection to adaptive tessellation?
1 vote
338 views

### OpenGL tesselation doesn't change geometry shape

I implemented tessellation control and evaluation shaders in OpenGL, but the effect it has on my terrain was not what I expected. I expected that the low poly-count curves and shapes on the terrain ...
970 views

### Checking if shapes will tessellate

I'm trying to figure out where to start with getting code together to check if a shape tessellates. An example: Consider that the shapes cannot be rotated, just as-is. A 'compound' shape (as seen in ...
1k views

### How to achieve a layered terrain simlar to Godus

I'm currently playing around with a few examples and techniques for terrain generation and suddenly remembered the game Godus - seen below. Youtube clip of Godus Looking at the material above, it ...
16k views

### What are Hull, Domain and Geometry shaders used for?

I've done my fair share of 3D game programming for my (former) employer, and also in my own custom engines for my own indie games. Initially, I started with Direct3D 9, and D3DX9, which pretty much ...
426 views

### Tessellation won't render

I am starting to work with tessellation and have some problems right in the beginning. I try to render a quad made of two triangles with tessellation, but nothing appears on the screen. But as soon as ...
13k views

### How does hardware tessellation work?

I would just like someone to explain in relativly clear terms how hardware tessellation works considering it is the new buzzword with DX11. Thanks.
3k views

### Unity3D - How to tessellate 2D sprites?

I use dynamic vertex lighting on 2D sprites. On larger sprites the lighting is uglier than on smaller ones. This is because every sprite is just a quad of two triangles. Not enough vertices there for ...
2k views

### Calculating normals after displacement mapping

I'm using C++, DX11 and tessellation. After tessellating a triangle I apply displacement mapping to the new vertices. But they still have the original triangle's normal so the lighting calculation ...
5k views

I have the generic tessellation evaluation shader for triangles but I need to make it work for quads. Is there any chance someone could explain what is happening here and point me in the right ...
1 vote
272 views

### Technique suggestion to render corroded pipes in 3D

We currently have a lot of data relating to cracks/corrosion/deformations in metal pipes which at present, can be viewed in a crude flat/2D application which makes the metal anomalies hard to spot. ...
7k views

Correct me if I'm wrong, but both the Geometry Shader and the Tessellation Shader jobs are to generate vertices in the Graphic Pipeline. What I would like to know is how they are different and when ...
1k views

### Easiest way to smoothen coarse mesh with HLSL?

I've browsed through a couple of presentations and papers about DX11 tessellation and they all say that one of the most common usages of tessellation is to take a coarse (low poly) mesh, smoothen it ...
3k views

### Do the predefined HLSL semantics carry any meaning?

I'd say there are 3 kinds of HLSL semantics: SV_* group - these are "system value" semantics which DO carry special meanings (e.g. assign special input/output data ...
1 vote
3k views

### Infinite / Treadmilling Hexagonal Grid

So, I can happily render an infinite square grid by moving said grid whenever the camera moves out of a grid square, ...
9k views

### What is the role of tessellation in terrain?

I'm relatively new to graphically programming and I've been looking into ways to render larger heightened terrain. I keep seeing comments directing me to disregard things such as geometry clipmaps, in ...
1 vote
1k views

### Tessellation cracks

i'm trying to a mesh tessellate with dx11 with the tessellation factor calculated by the size of the triangle and the distance to the screen. I do the same operation on the 3 edges of the triangle, ...
419 views

I'm testing the triangle tessellation from the link http://prideout.net/blog/?p=48#shaders . All the shader are compiled correctly, but when I try to link the program using the command: ...
801 views

### How is displacement tessellation done?

I'm curious because I was thinking that displacement mapping is done in the shader file only inside the domain shader. Am I correct or is it both implemented in the rendering section of the mesh and ...
1 vote
884 views

### Building a tessellated texture

In games like Minecraft the textures such as grass when lined up side-by-side it looks like one big perfect texture. When I make a texture it's never even and you can see the different blocks. How do ...
2k views

### DirectX 11, using Tessellation & Geometry shader in a single pass

Before all, sorry for my poor english ! With DirectX 11, i'm trying to create a random map full with GPU. Using Hull shader stage, I'm managing LOD with tessellation. Using Domain shader stage, I'm ...
3k views

### How to subdivide a quad?

I'm working with OpenGL and I'm importing from a file coordinates for quads in the following format: ...
2k views

### Tessellating to a curve?

I'm creating a game engine, and I'm trying to define a 3D model format I want to use. I haven't come across a format that quite does what I want. My game engine assumes a shader model 5+ environment. ...
2k views

### Tessellation Texture Coordinates

Firstly some info - I'm using DirectX 11 , C++ and I'm a fairly good programmer but new to tessellation and not a master graphics programmer. I'm currently implementing a tessellation system for a ...
8k views

### Generating triangles from a square grid

I have a 2D square grid of values representing terrain elevations, and I want to generate triangles from that grid to make a 3D view of the terrain. My first thought was to split each square ...