The goal of this project is to create Random continental sized islands which can be used for various game usage. Each region should follow standard terrestrial biome model, (rainfal over temature). This also seeks to create strong coast lines, with interseting features. To create this type of terrian this project follow the following model outlined in this file.
- Site - a point which represents the point of influence (generally in the center of the cell)
- Vertex - a point which defineds the endpoints of edges of a cell. This may also be defined as corner.
- Edge - a line Segment which is defined by two vertexs which is the boarder between two cells
- Cell - a polygon shape that has one site a set of edges and a set of vertexs that define the polygon.
- Blue Noise - Noise generated randomly but filtered through a set of algorithm(s) to reach a defined result. (Gaussian Noise)
Starting with a voronio graph allowed for a variety of polygons of a varied size. Voronio is an assemelaton of edges, where each line sites evenly between 2 sites. Sites are randomly generated positions. This allows for a for some very sharp polygons ranging from 3 - 9 sides, where a vertex is defined by the overlap of 2 lines. Although this is a good start we have shapes that are way to sharp (the angle of the lines coming out of a vertex is either very high (70-120 degrees) or very low (0-20).
A Common practice when working with voronio is to do a relaxation algorithm. Due to some of the variation and randomness of the site generation, it can create some undesired resaults, (sharp corners, short edges, disportionate cell size). This wil morph the graph from a set of hard noise to blue noise defined by polygon sites with 3-9 sides of random but well distrubuted sizes (minimal range).
In this case adding some random variation will give a mix of sharp and smooth angles, giving a more realistic look to our biome bounds. The algorthem will average all of the vertex locations and then move the site towards the center of these vertexs a d distance, randomly ignoring one edge, or ignoring this site completey. When the relaxation is done we will destroy all edges, and vertexs, redrawing the vorionio graph with the new site positions. This algorithm runs an x number of times, or until no site moves a significate amount (less than d).
Petels Relaxation algorithm was removed from the demo version. This algorithm does a similar thing as the above, but rather it averages the vertexs based on its nieghboring vertexs. This keeps edges from becoming to small due to the above alogrithm (this is very insignificate on average and was removed).
Now the sites (regions of influence) are defined our next goal is to assign tempature and moisture, to do this elevation is needed. Assigning a ocean height, generally setting this below the random elevaton generation will make sure that we ony create islands near land masses (rather than our in the middle of the ocean). Also this algorithm will need a way to create mountians with large variation of hills and flat land masses. This starts by picking random points (in the C# version another vorioni graph was created then the above algorithms where applied to garrentee seperation between of the points). These points of infuence that are generated are called "High Points" This is the algorthm used.
|8r/x*|sin(d*1000/x)|+ (2^b)/x|
Where x is the vector distance (sqrt((s.x-h.x)^2 + (s.y-h.y)^2)) of a site from a high point.
r is the Range of variation (defined r >= 0) where at 0 there is no variation cuz there is no range (d and r are bound)
d is the distance Variation (this will create more variation as it increases, and at 0 it will have no variation) (d's domain is >= 0).
b is the slope of the line (defined b > 0).
This function is clamped between 1 and 0. where 1 is extreme mountain and 0 is extreme valley.
Once all highpoints are defined we will generate the land running each site through this algorithm creating our first land masses.