From 3436961bb5c01d659d09be134368f4f69460cef9 Mon Sep 17 00:00:00 2001
From: MW
Date: Sat, 26 May 2007 13:40:19 +0000
Subject: Start of rewrite 5279!

---
 Common/OpenSim.Framework/HeightMapGenHills.cs | 149 ++++++++++++++++++++++++++
 1 file changed, 149 insertions(+)
 create mode 100644 Common/OpenSim.Framework/HeightMapGenHills.cs

(limited to 'Common/OpenSim.Framework/HeightMapGenHills.cs')

diff --git a/Common/OpenSim.Framework/HeightMapGenHills.cs b/Common/OpenSim.Framework/HeightMapGenHills.cs
new file mode 100644
index 0000000..6a729da
--- /dev/null
+++ b/Common/OpenSim.Framework/HeightMapGenHills.cs
@@ -0,0 +1,149 @@
+/*
+* Copyright (c) OpenSim project, http://sim.opensecondlife.org/
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are met:
+*     * Redistributions of source code must retain the above copyright
+*       notice, this list of conditions and the following disclaimer.
+*     * Redistributions in binary form must reproduce the above copyright
+*       notice, this list of conditions and the following disclaimer in the
+*       documentation and/or other materials provided with the distribution.
+*     * Neither the name of the <organization> nor the
+*       names of its contributors may be used to endorse or promote products
+*       derived from this software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED BY <copyright holder> ``AS IS'' AND ANY
+* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+* DISCLAIMED. IN NO EVENT SHALL <copyright holder> BE LIABLE FOR ANY
+* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+* 
+*/
+
+using System;
+
+namespace OpenSim.Framework.Terrain
+{
+    public class HeightmapGenHills
+    {
+        private Random Rand = new Random();
+        private int NumHills;
+        private float HillMin;
+        private float HillMax;
+        private bool Island;
+        private float[] heightmap;
+
+        public float[] GenerateHeightmap(int numHills, float hillMin, float hillMax, bool island)
+        {
+            NumHills = numHills;
+            HillMin = hillMin;
+            HillMax = hillMax;
+            Island = island;
+
+            heightmap = new float[256 * 256];
+
+            for (int i = 0; i < numHills; i++)
+            {
+                AddHill();
+            }
+
+            Normalize();
+
+            return heightmap;
+        }
+
+        private void AddHill()
+        {
+            float x, y;
+            float radius = RandomRange(HillMin, HillMax);
+
+            if (Island)
+            {
+                // Which direction from the center of the map the hill is placed
+                float theta = RandomRange(0, 6.28f);
+
+                // How far from the center of the map to place the hill. The radius
+                // is subtracted from the range to prevent any part of the hill from
+                // reaching the edge of the map
+                float distance = RandomRange(radius / 2.0f, 128.0f - radius);
+
+                x = 128.0f + (float)Math.Cos(theta) * distance;
+                y = 128.0f + (float)Math.Sin(theta) * distance;
+            }
+            else
+            {
+                x = RandomRange(-radius, 256.0f + radius);
+                y = RandomRange(-radius, 256.0f + radius);
+            }
+
+            float radiusSq = radius * radius;
+            float distSq;
+            float height;
+
+            int xMin = (int)(x - radius) - 1;
+            int xMax = (int)(x + radius) + 1;
+            if (xMin < 0) xMin = 0;
+            if (xMax > 255) xMax = 255;
+
+            int yMin = (int)(y - radius) - 1;
+            int yMax = (int)(y + radius) + 1;
+            if (yMin < 0) yMin = 0;
+            if (yMax > 255) yMax = 255;
+
+            // Loop through each affected cell and determine the height at that point
+            for (int v = yMin; v <= yMax; ++v)
+            {
+                float fv = (float)v;
+
+                for (int h = xMin; h <= xMax; ++h)
+                {
+                    float fh = (float)h;
+
+                    // Determine how far from the center of this hill this point is
+                    distSq = (x - fh) * (x - fh) + (y - fv) * (y - fv);
+                    height = radiusSq - distSq;
+
+                    // Don't add negative hill values
+                    if (height > 0.0f) heightmap[h + v * 256] += height;
+                }
+            }
+        }
+
+        private void Normalize()
+        {
+            float min = heightmap[0];
+            float max = heightmap[0];
+
+            for (int x = 0; x < 256; x++)
+            {
+                for (int y = 0; y < 256; y++)
+                {
+                    if (heightmap[x + y * 256] < min) min = heightmap[x + y * 256];
+                    if (heightmap[x + y * 256] > max) max = heightmap[x + y * 256];
+                }
+            }
+
+            // Avoid a rare divide by zero
+            if (min != max)
+            {
+                for (int x = 0; x < 256; x++)
+                {
+                    for (int y = 0; y < 256; y++)
+                    {
+                        heightmap[x + y * 256] = ((heightmap[x + y * 256] - min) / (max - min)) * (HillMax - HillMin);
+                    }
+                }
+            }
+        }
+
+        private float RandomRange(float min, float max)
+        {
+            return (float)Rand.NextDouble() * (max - min) + min;
+        }
+    }
+}
-- 
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