Technical Writeup Posted on 09 August by Flafla2.

### Using Perlin Noise to Generate 2D Terrain and Water

The objective of this article is to present an easy-to-understand analysis of Ken Perlin's Improved Perlin Noise. The code in this article is written in C and is free to use. If you would prefer to just look at the final result, you can view the final source here. Perlin Noise is an extremely powerful algorithm that is used often in procedural content generation.

It is especially useful for games and other visual media such as movies. The man who created it, Ken Perlin, won an academy award for the original implementation. In this article I will be exploring his Improved Perlin Noisepublished in In game development, Perlin Noise can be used for any sort of wave-like, undulating material or texture. For example, it could be used for procedural terrain Minecraft -like terrain can be created with Perlin Noise, for examplefire effects, water, and clouds. These effects mostly represent Perlin noise in the 2 nd and 3 rd dimensions, but it can be extended into the 4 th dimension rather trivially.

Additionally Perlin Noise can be used in only 1 dimension for purposes such as side-scrolling terrain such as in Terraria or Starbound or to create the illusion of handwritten lines.

Also, if you extend Perlin Noise into an additional dimension and consider the extra dimension as time, you can animate it. For example, 2D Perlin Noise can be interpreted as Terrain, but 3D noise can similarly be interpreted as undulating waves in an ocean scene. Below are some pictures of Noise in different dimensions and some of their uses at runtime:. So as you can see, Perlin Noise has an application to many naturally-occurring phenomenon.

Now let's look into the mathematics and logic of the Perlin Noise Algorithm. NOTE: I would like to preface this section by mentioning that a lot of it is taken from this wonderful article by Matt Zucker. However, that article is based on the original Perlin Noise algorithm written in the early s. Thus, there are some key differences between my version and Zucker's.

So we have an x, y and z coordinate as input, and as the output we get a double between 0. So what do we do with this input? First, we divide the x, y, and z coordinates into unit cubes. Below is a representation of this concept in 2 dimensions:.It's time for a break! We've been playing with random functions that look like TV white noise, our head is still spinning thinking about shaders, and our eyes are tired.

Time to go out for a walk! We feel the air on our skin, the sun in our face. The world is such a vivid and rich place. Colors, textures, sounds. While we walk we can't avoid noticing the surface of the roads, rocks, trees and clouds. The unpredictability of these textures could be called "random," but they don't look like the random we were playing with before. How can we approximate this variety computationally?

This was the question Ken Perlin was trying to solve in the early s when he was commissioned to generate more realistic textures for the movie "Tron.

No biggie. The following is not the classic Perlin noise algorithm, but it is a good starting point to understand how to generate noise. In these lines we are doing something similar to what we did in the previous chapter. We are subdividing a continuous floating number x into its integer i and fractional f components. We use floor to obtain i and fract to obtain f. Then we apply rand to the integer part of xwhich gives a unique random value for each integer.

Go ahead and uncomment this line to see how this looks. We use the fract value store in f to mix the two random values. At this point in the book, we've learned that we can do better than a linear interpolation, right? Now try uncommenting the following line, which uses a smoothstep interpolation instead of a linear one. After uncommenting it, notice how the transition between the peaks gets smooth. In some noise implementations you will find that programmers prefer to code their own cubic curves like the following formula instead of using the smoothstep.

This smooth randomness is a game changer for graphical engineers or artists - it provides the ability to generate images and geometries with an organic feeling. Perlin's Noise Algorithm has been implemented over and over in different languages and dimensions to make mesmerizing pieces for all sorts of creative uses. Now that we know how to do noise in 1D, it's time to move on to 2D.

Similarly, if we want to obtain 3D noise we need to interpolate between the eight corners of a cube. This technique is all about interpolating random values, which is why it's called value noise.Simplex noise is a method for constructing an n -dimensional noise function comparable to Perlin noise "classic" noise but with fewer directional artifacts and, in higher dimensions, a lower computational overhead. Ken Perlin designed the algorithm in [1] to address the limitations of his classic noise function, especially in higher dimensions.

Whereas classical noise interpolates between the gradients at the surrounding hypergrid end points i.

Iso 6722 pdfThis reduces the number of data points. The triangles are equilateral in 2D, but in higher dimensions the simplices are only approximately regular. For example, the tiling in the 3D case of the function is an orientation of the tetragonal disphenoid honeycomb. Simplex noise is useful for computer graphics applications, where noise is usually computed over 2, 3, 4 or possibly 5 dimensions.

For higher dimensions, n -spheres around n -simplex corners are not densely enough packed, reducing the support of the function and making it zero in large portions of space. Simplex noise is most commonly implemented as a two- three- or four-dimensional functionbut can be defined for any number of dimensions. An implementation typically involves four steps: coordinate skewing, simplical subdivision, gradient selection, and kernel summation.

The resulting coordinate x', y', Once the above is determined, the values of the internal coordinate xi', yi', Then the resulting simplex is composed of the vertices corresponding to an ordered edge traversal from 0, 0, In other words, start with the zero coordinate, and successively add ones starting in the value corresponding to the largest internal coordinate's value, and ending with the smallest.

For example, the point 0. The yi' coordinate is the largest so it is added first. It is then followed by the xi' coordinate, and finally zi'. Each simplex vertex is added back to the skewed hypercube's base coordinate, and hashed into a pseudo-random gradient direction.

The hash can be implemented in numerous ways, though most often uses a permutation table or a bit manipulation scheme. Care should be taken in the selection of the set of gradients to include, in order to keep directional artifacts to a minimum. First, the unskewed coordinate of each of the vertices is determined using the inverse formula.

This point is subtracted from the input coordinate in order to obtain the unskewed displacement vector. This unskewed displacement vector is used for two purposes:.

Uses of implementations in 3D and higher for textured image synthesis are covered by U. Patent 6,if the algorithm is implemented using the specific techniques described in any of the patent claims. From Wikipedia, the free encyclopedia. The advantages of simplex noise over Perlin noise: Simplex noise has a lower computational complexity and requires fewer multiplications. Simplex noise has a well-defined and continuous gradient almost everywhere that can be computed quite cheaply.

Simplex noise is easy to implement in hardware. Simplex noise OpenSimplex noise Perlin noise Wavelet noise. Value noise. Procedural generation Computer graphics Video games Fractal landscapes. Noise physics and telecommunications. Channel noise level Circuit noise level Effective input noise temperature Equivalent noise resistance Equivalent pulse code modulation noise Impulse noise audio Noise figure Noise floor Noise shaping Noise spectral density Noise, vibration, and harshness NVH Phase noise Pseudorandom noise Statistical noise.

List of noise topics Acoustics Colors of noise Interference communication Noise generator Spectrum analyzer Thermal radiation. Low-pass filter Median filter Total variation denoising Wavelet denoising.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

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Note: this image has already had a treshold applied. I want it without the treshold.

I've been looking all over the internet for 2 days now. There are plenty of links explaining noise and a lot of code, but none in JavaScript, and whenever I try to convert it, I get weird results. Here are some of my attemps:. I think part of the problem might stem from the use of the bitwise operators in JavaScript, where it is difficult to enforce the type of a number. I'd also be willing to grant a bounty for any information pertaining to the parameters that could lead to a pattern similar to the image I posted before threshold or any optimization tips since I'll need this to run as fast as possible in JavaScript nonetheless.

I did something like this a while back, however I used midpoint displacement. If you can figure out whats going on it could be helpful. I will be using the code found on this Gist. I know this is pretty old, but maybe it can still be useful for someone else. The app allows to tweak every parameter involved in noise calculation and rendering and to save the resulting texture. It also adds the parameters to the URL, so that it can be shared.

For example, this configuration produces a texture very similar to the one you showed.

Diy attic liftLearn more. Asked 8 years, 4 months ago. Active 1 year, 5 months ago.Senior Newbie Medals: 2. Generating "True" 2D Perlin Noise. After reading material and trying out different examples for days I feel like I have hit a brick wall. Please note in advance I have read most posts and the wiki article on this topic, I'm just looking for some good advice.

Top termux tsu appI've been working on a 2D terrain generation system for a new game I'm working on, and after some reading decided to shoot for a Perlin noise powered implementation. Finally an implementation I can seem to understand! After running the code and finally getting some visual output I felt relief at first, and then slowly annoyance.

How to dissolve peg 6000 in waterBelow are samples of my output. I'm annoyed because this "random" noise seems to generate features which appear as horizontal or vertical compostions of mountains or ponds. There are virtually no diagonal lines and very few circular formations. I went back to the original article to discover that the implementation was not Perlin noise, but instead a variation of value noise.

So I scrap my pervious implementation and start again. Well so I thought, but once I test the code and find that for all possible inputs I was getting 0 from each call to the smoothNoise function. Again, I feel like I have hit a brick wall, and I need to ask advice before I keep wasting any more of my time.

And if they are, does Perlin noise not feature this? JGO Kernel Medals: No you shouldn't have noticeable defects along the grid.

Games published by our own members! Check 'em out! Junior Devvie Medals: 4 Exp: 3 years.One of other common form of noise is perlin noise. What differentiates it from value noise is that instead of interpolating the values, the values are based on inclinations. Because noise in general is a pretty complex topic I recommend you to read the tutorials on white noise and value noise first.

Perlin noise is a specific implementation of gradient noise for multiple dimensions. This first implementation will, just like in the previous noise tutorials, be just in one dimension. We start with the 1d value noise shader.

**Generating 1D Perlin Noise With Python**

That means we start by generating a random inclination. After generating the inclination we get the value of the line with the chosen generated inclination based on the fractional part of our value. For proper smoothing, we have to generate the line for the next cell too. The line is then on the left of the cell center, so we have to use negative values approaching zero for our variable. To get those values, we simply subtract 1 from our fractional part.

That way when we generate values on the left of the segment we start with 0 - 1 which equals -1 and approach 1 - 1 which equals 0. The next step is similar to what we did for easing the interpolation, we want the value of the line of the previous cell at the beginning of the segment and the line of the next segment at the end.

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So we simply interpolate between those values based on where on the segment we are. Those changes are in the Random.

Noun modifiers exercises pdfInstead we interpolate the fraction in multiple dimensions and take the dot product with generated vectors of cells. To make the lines we generate with the dot product go to zero near the cell point itself, we scale the vector. Using the dot product this way means that we can use multiple dimensions as input well, but output will always be limited to one dimension.

The first step of the implementation is generating 4 vectors in the 4 nearest cells, similarly to value noise. For that we can simply use the rand2dTo2d function we wrote in the white noise tutorial. Similarly to the 1d gradient noise, we want those vectors to point into all directions, not just to the top right in the 0 to 1 range like the random function returns.

To fix that, we simply take the output of the random function, multiply it by 2 and subtract 1 again, the operations will automatically be applied to all components of the vector even though we only write down the scalar values.

Then we generate the values again. They start at 0 at the cell, and then become bigger the further away they go. For the lower left cell, which is equivalent to the previous cell in the 1d example, we can simply use the fraction as a vector as it is 0 at the cell and the y component becomes bigger the more we go up and the x component grows as we look further to the right, both increasing the absolute value of the result. On the lower right cell, we subtract 1, 0 from the value, so the vector will be smallest in the lower right corner and grow as we go left or up.

Similarly to the 1d example we can also see here, that the value is negative when we approach the cell from the lower side, giving us continuous functions passing 0 at the cell position.

And in the same matter we subtract 0, 1 from the fraction before taking the dot product with the upper left corner and subtract 1, 1 in case of the upper right corner. First the upper and lower pairs and then between the interpolated results. Now that we have the whole noise function, we can now display it. Because the function fluctuates around 0 and approximately goes up and down by about 0. It looks very similar to the 3d value noise shader we wrote, but instead of just writing the random values to the values to interpolate in the innermost loop, we generate a random direction based on the cell.

Then we also generate the comparison vector by subtracting the same value we used to get the cell from the fractional vector.This tutorial builds on the foundation laid by previous tutorials.

### Simplex noise

If you completed the Curves and Splines tutorial then you're good to go. Let's begin by creating a default quad object. This object has a mesh with two triangles that form a square with a width and height of one unit each. We can make the quad more interesting by giving it a material with a nice texture. We could use any image as a texture, but we're going to create one procedurally.

For this we need a material to assign the texture to, so create one and have the quad use it instead of the default. Then create a TextureCreator component script and attach it to the quad as well.

To create a texture, we need to know how many pixels it should have. We'll create a square texture, so we can control its size with a single resolution variable. Let's give it a default of We will create the texture when our component awakens. As we won't use transparency, the texture's format is RGB.

The fourth argument of the texture's constructor indicates that we want to use mipmaps. We also give it a descriptive name. Then we grab the MeshRenderer component of the game object.

Unreal engine aes key finderBecause we're only using it with our quad object, it should exist so we directly assign the texture to its material. Without filling the texture this doesn't make much sense. So let's add a FillTexture method that uses a double loop to make all the pixels red. After setting the pixels, you have to call the texture's Apply method otherwise the changes won't show up.

Don't like red? What about green? Go ahead and change the color, but do this while still in play mode. You will see that Unity recompiles the code just fine, but the texture stays red.

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