https://github.com/nolmoonen/terrain3

Geometry clipmap to represent procedural FBM terrain that uses analytical normals.
https://github.com/nolmoonen/terrain3

clipmap fbm glsl opengl procedural terrain

Last synced: 2 months ago
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Geometry clipmap to represent procedural FBM terrain that uses analytical normals.

• Host: GitHub
• URL: https://github.com/nolmoonen/terrain3
• Owner: nolmoonen
• Created: 2022-02-07T16:03:58.000Z (almost 3 years ago)
• Default Branch: main
• Last Pushed: 2024-07-10T20:20:09.000Z (6 months ago)
• Last Synced: 2024-07-11T00:02:55.166Z (6 months ago)
• Topics: clipmap, fbm, glsl, opengl, procedural, terrain
• Language: C++
• Homepage:
• Size: 40.7 MB
• Stars: 2
• Watchers: 1
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
![](doc/splash.gif)

`terrain3` procedurally generates terrain and represents it with varying levels

of detail using a geometry clipmap. The terrain itself is created using

fractional Brownian motion where the accumulated derivative of the noise values

is used to scale the accumulated values. The analytical derivative of the

terrain is found, using which the normal of the terrrain is calculated with

little to no additional overhead. The terrain height and gradient values are

calculated using an OpenGL compute shader.

## Controls

* Hit `ENTER` for a demo.

* Use `F1`, `F2`, `F3`, `F4` to toggle wireframe, debug drawing, terrain

  normals, and debug information.

* Use the middle mouse button to rotate, use shift and the middle mouse button

  to pan, and use the scroll wheel to zoom.

## Performance

At its most detailed level, the terrain is represented with a resolution of

ten centimeters. The above image displays movement at about 200 meters per

second, which a system with a Ryzen 5 2600 and an RTX 2070 takes roughly

`0.013-0.017` ms to update the terrain and `0.14-0.18` ms to render it at 1080p.

## System requirements and dependencies

Windows 10 and C++17. Building is tested with MSVC, but other compilers should work as

well. The following third-party dependencies are included:

* [glad2](https://gen.glad.sh/) for loading OpenGL and WGL.

* [imgui](https://github.com/ocornut/imgui) for rendering text.

* [stb](https://github.com/nothings/stb) for reading and writing PNG files.

* [Poly Haven](https://polyhaven.com/) for grass and cliff textures.

## Resources

* _Terrain Rendering Using GPU-Based Geometry Clipmaps_  

  Asirvatham, A. and Hoppe, H. [[link]](https://hhoppe.com/gpugcm.pdf)  

  The technique presented in this paper is used to represent the terrain at

  multiple resolutions.

* _Geometry Clipmaps: Simple Terrain Rendering with Level of Detail_  

  Savage, M. [[link]](https://mikejsavage.co.uk/blog/geometry-clipmaps.html)  

  Article on the above paper with helpful practical information.

* _OpenGL ES SDK for Android Tutorial_  

  Arm

  Software [[link]](https://arm-software.github.io/opengl-es-sdk-for-android/terrain.html#terrainIntroduction)  

  The code of this repository forms the base of this project.

* _Value Noise Derivatives_  

  Quillez,

  I. [[link]](https://iquilezles.org/www/articles/morenoise/morenoise.htm)  

  This article explains how derivatives can be extracted from value noise and

  how these derivatives can be used to make interesting terrain.