Comments on: Generating 2D random fractal terrains with F# http://www.bugfree.dk/blog/2009/03/06/generating-2d-random-fractal-terrains-with-f/ Not anti-anything, just pro-quality Thu, 16 Dec 2010 07:18:58 +0000 hourly 1 http://wordpress.org/?v=3.3 By: Bugfree.dk » Blog Archive » 2009 in retrospect http://www.bugfree.dk/blog/2009/03/06/generating-2d-random-fractal-terrains-with-f/comment-page-1/#comment-22121 Bugfree.dk » Blog Archive » 2009 in retrospect Mon, 28 Dec 2009 11:33:09 +0000 http://www.bugfree.dk/blog/2009/03/06/generating-2d-random-fractal-terrains-with-f/#comment-22121 [...] started to permeate C#, my language of choice. I learned a great deal about LINQ, about F# when I generated fractal terrains, about XSL when I had to jump through functional loops, and generally reading about functional [...] [...] started to permeate C#, my language of choice. I learned a great deal about LINQ, about F# when I generated fractal terrains, about XSL when I had to jump through functional loops, and generally reading about functional [...]

]]> By: bob http://www.bugfree.dk/blog/2009/03/06/generating-2d-random-fractal-terrains-with-f/comment-page-1/#comment-16398 bob Thu, 16 Jul 2009 13:26:26 +0000 http://www.bugfree.dk/blog/2009/03/06/generating-2d-random-fractal-terrains-with-f/#comment-16398 Here's one that doesn't build a list in memory: private const float MinDisplacement = 0.01f; public void Generate(float y1, float y2, float displace, Action callback) { if (displace == 1.0f) callback(y1); // subdivide if (displace >= MinDisplacement) { // pick a random midpoint float midpoint = Average(y1, y2) + Random(displace); Generate(y1, midpoint, displace / 2.0f, callback); callback(midpoint); Generate(midpoint, y2, displace / 2.0f, callback); } if (displace == 1.0f) callback(y2); } float Average(float a, float b) { return (a + b) / 2.0f; } // get a random value between -scale and scale private Random _rand = new Random(); float Random(float scale) { return (float)(_rand.NextDouble() - 0.5f) * scale; } Here’s one that doesn’t build a list in memory:

private const float MinDisplacement = 0.01f;

public void Generate(float y1, float y2, float displace, Action callback)
{
if (displace == 1.0f) callback(y1);

// subdivide
if (displace >= MinDisplacement)
{
// pick a random midpoint
float midpoint = Average(y1, y2) + Random(displace);

Generate(y1, midpoint, displace / 2.0f, callback);
callback(midpoint);
Generate(midpoint, y2, displace / 2.0f, callback);
}

if (displace == 1.0f) callback(y2);
}

float Average(float a, float b) { return (a + b) / 2.0f; }

// get a random value between -scale and scale
private Random _rand = new Random();
float Random(float scale)
{
return (float)(_rand.NextDouble() – 0.5f) * scale;
}

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