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Cesium is a JavaScript library for creating 3D globes and 2D maps in a web browser without a plugin. It uses WebGL for hardware-accelerated graphics, and is cross-platform, cross-browser, and tuned for dynamic-data visualization.

http://cesiumjs.org/

THis is just the readme for the Perlin Noise Function in SnowMaterials

The snow slope is used to blend a white color with the texture of the terrain. Now that slope amplitude is modulated by perlin noise. THere is a 2D texture of random noise used which is used for generating random values. A random float is generated by interpolating a 2D texture with a 3D coordinate. In the current implementation the 3D coordinate is the model space position. This has the nice property that as you pan around, the snow drifts are fixed with the terrain, not the camera.

The 3D noise function was writted by Stefan Gustafson from 2004.

In snow materials one can change the repetition scale

SCALE = 100000;

Change the persistance

persistance = 0.5

Change how much noise is added to the slope

NoiseFraction = 0.4 (according to Snow paper)

Change the number of octaves to add in

orders = 5

Visit the Downloads page or use the npm module:

npm install cesium

Have questions? Ask them on the forum.

Interested in contributing? See CONTRIBUTING.md.

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