public Bitmap TerrainToBitmap (Bitmap mapbmp)
        {
            FastBitmap unsafeBMP = new FastBitmap (mapbmp);
            unsafeBMP.LockBitmap ();
            //DateTime start = DateTime.Now;
            //MainConsole.Instance.Info("[MAPTILE]: Generating Maptile Step 1: Terrain");

            // These textures should be in the AssetCache anyway, as every client connecting to this
            // region needs them. Except on start, when the map is recreated (before anyone connected),
            // and on change of the estate settings (textures and terrain values), when the map should
            // be recreated.
            RegionSettings settings = m_scene.RegionInfo.RegionSettings;

            // the four terrain colors as HSVs for interpolation
            HSV hsv1 = new HSV (computeAverageColor (settings.TerrainTexture1, defaultColor1));
            HSV hsv2 = new HSV (computeAverageColor (settings.TerrainTexture2, defaultColor2));
            HSV hsv3 = new HSV (computeAverageColor (settings.TerrainTexture3, defaultColor3));
            HSV hsv4 = new HSV (computeAverageColor (settings.TerrainTexture4, defaultColor4));

            float levelNElow = (float)settings.Elevation1NE;
            float levelNEhigh = (float)settings.Elevation2NE;

            float levelNWlow = (float)settings.Elevation1NW;
            float levelNWhigh = (float)settings.Elevation2NW;

            float levelSElow = (float)settings.Elevation1SE;
            float levelSEhigh = (float)settings.Elevation2SE;

            float levelSWlow = (float)settings.Elevation1SW;
            float levelSWhigh = (float)settings.Elevation2SW;

            float waterHeight = (float)settings.WaterHeight;

            ITerrainChannel heightmap = m_scene.RequestModuleInterface<ITerrainChannel> ();
            float sizeRatio = m_scene.RegionInfo.RegionSizeX / (float)Constants.RegionSize;
            for (float y = 0; y < m_scene.RegionInfo.RegionSizeY; y += sizeRatio) {
                float rowRatio = y / (m_scene.RegionInfo.RegionSizeY - 1); // 0 - 1, for interpolation
                for (float x = 0; x < m_scene.RegionInfo.RegionSizeX; x += sizeRatio) {
                    float columnRatio = x / (m_scene.RegionInfo.RegionSizeX - 1); // 0 - 1, for interpolation

                    float heightvalue = getHeight (heightmap, (int)x, (int)y);

                    if (heightvalue > waterHeight) {
                        // add a bit noise for breaking up those flat colors:
                        // - a large-scale noise, for the "patches" (using an doubled s-curve for sharper contrast)
                        // - a small-scale noise, for bringing in some small scale variation
                        //float bigNoise = (float)TerrainUtil.InterpolatedNoise(x / 8.0, y / 8.0) * .5f + .5f; // map to 0.0 - 1.0
                        //float smallNoise = (float)TerrainUtil.InterpolatedNoise(x + 33, y + 43) * .5f + .5f;
                        //float hmod = heightvalue + smallNoise * 3f + S(S(bigNoise)) * 10f;
                        float hmod =
                            heightvalue; // 0 - 10

                        // find the low/high values for this point (interpolated bilinearily)
                        // (and remember, x=0,y=0 is SW)
                        float low = levelSWlow * (1f - rowRatio) * (1f - columnRatio) +
                                    levelSElow * (1f - rowRatio) * columnRatio +
                                    levelNWlow * rowRatio * (1f - columnRatio) +
                                    levelNElow * rowRatio * columnRatio;
                        float high = levelSWhigh * (1f - rowRatio) * (1f - columnRatio) +
                                     levelSEhigh * (1f - rowRatio) * columnRatio +
                                     levelNWhigh * rowRatio * (1f - columnRatio) +
                                     levelNEhigh * rowRatio * columnRatio;
                        if (high < low) {
                            // someone tried to fool us. High value should be higher than low every time
                            float tmp = high;
                            high = low;
                            low = tmp;
                        }

                        HSV hsv;
                        if (hmod <= low) hsv = hsv1; // too low
                        else if (hmod >= high) hsv = hsv4; // too high
                        else {
                            // HSV-interpolate along the colors
                            // first, rescale h to 0.0 - 1.0
                            hmod = (hmod - low) / (high - low);
                            // now we have to split: 0.00 => color1, 0.33 => color2, 0.67 => color3, 1.00 => color4
                            if (hmod < 1f / 3f) hsv = interpolateHSV (ref hsv1, ref hsv2, hmod * 3f);
                            else if (hmod < 2f / 3f) hsv = interpolateHSV (ref hsv2, ref hsv3, (hmod * 3f) - 1f);
                            else hsv = interpolateHSV (ref hsv3, ref hsv4, (hmod * 3f) - 2f);
                        }
                        //get the data from the original image
                        Color hsvColor = hsv.ToColor ();
                        unsafeBMP.SetPixel ((int)(x / sizeRatio),
                                           (int)(((m_scene.RegionInfo.RegionSizeY - 1) - y) / sizeRatio), hsvColor);
                    } else {
                        // We're under the water level with the terrain, so paint water instead of land
                        unsafeBMP.SetPixel ((int)(x / sizeRatio),
                                           (int)(((m_scene.RegionInfo.RegionSizeY - 1) - y) / sizeRatio), WATER_COLOR);
                    }
                }
            }
            if (m_mapping != null) {
                SaveCache ();
                m_mapping.Clear ();
            }
            unsafeBMP.UnlockBitmap ();
            //MainConsole.Instance.Info("[MAPTILE]: Generating Maptile Step 1: Done in " + (DateTime.Now - start).TotalSeconds + " ms");
            return unsafeBMP.Bitmap ();
        }
        // interpolate two colors in HSV space and return the resulting color
        static HSV interpolateHSV (ref HSV c1, ref HSV c2, float ratio)
        {
            if (ratio <= 0f) return c1;
            if (ratio >= 1f) return c2;

            // make sure we are on the same side on the hue-circle for interpolation
            // We change the hue of the parameters here, but we don't change the color
            // represented by that value
            if (c1.h - c2.h > 180f) c1.h -= 360f;
            else if (c2.h - c1.h > 180f) c1.h += 360f;

            return new HSV (c1.h * (1f - ratio) + c2.h * ratio,
                           c1.s * (1f - ratio) + c2.s * ratio,
                           c1.v * (1f - ratio) + c2.v * ratio);
        }
        public Bitmap TerrainToBitmap(Bitmap mapbmp)
        {
            FastBitmap unsafeBMP = new FastBitmap(mapbmp);

            unsafeBMP.LockBitmap();
            //DateTime start = DateTime.Now;
            //MainConsole.Instance.Info("[MAPTILE]: Generating Maptile Step 1: Terrain");

            // These textures should be in the AssetCache anyway, as every client conneting to this
            // region needs them. Except on start, when the map is recreated (before anyone connected),
            // and on change of the estate settings (textures and terrain values), when the map should
            // be recreated.
            RegionSettings settings = m_scene.RegionInfo.RegionSettings;

            // the four terrain colors as HSVs for interpolation
            HSV hsv1 = new HSV(computeAverageColor(settings.TerrainTexture1, defaultColor1));
            HSV hsv2 = new HSV(computeAverageColor(settings.TerrainTexture2, defaultColor2));
            HSV hsv3 = new HSV(computeAverageColor(settings.TerrainTexture3, defaultColor3));
            HSV hsv4 = new HSV(computeAverageColor(settings.TerrainTexture4, defaultColor4));

            float levelNElow  = (float)settings.Elevation1NE;
            float levelNEhigh = (float)settings.Elevation2NE;

            float levelNWlow  = (float)settings.Elevation1NW;
            float levelNWhigh = (float)settings.Elevation2NW;

            float levelSElow  = (float)settings.Elevation1SE;
            float levelSEhigh = (float)settings.Elevation2SE;

            float levelSWlow  = (float)settings.Elevation1SW;
            float levelSWhigh = (float)settings.Elevation2SW;

            float waterHeight = (float)settings.WaterHeight;

            ITerrainChannel heightmap = m_scene.RequestModuleInterface <ITerrainChannel>();
            float           sizeRatio = m_scene.RegionInfo.RegionSizeX / (float)Constants.RegionSize;

            for (float y = 0; y < m_scene.RegionInfo.RegionSizeY; y += sizeRatio)
            {
                float rowRatio = y / (m_scene.RegionInfo.RegionSizeY - 1); // 0 - 1, for interpolation
                for (float x = 0; x < m_scene.RegionInfo.RegionSizeX; x += sizeRatio)
                {
                    float columnRatio = x / (m_scene.RegionInfo.RegionSizeX - 1); // 0 - 1, for interpolation

                    float heightvalue = getHeight(heightmap, (int)x, (int)y);

                    if (heightvalue > waterHeight)
                    {
                        // add a bit noise for breaking up those flat colors:
                        // - a large-scale noise, for the "patches" (using an doubled s-curve for sharper contrast)
                        // - a small-scale noise, for bringing in some small scale variation
                        //float bigNoise = (float)TerrainUtil.InterpolatedNoise(x / 8.0, y / 8.0) * .5f + .5f; // map to 0.0 - 1.0
                        //float smallNoise = (float)TerrainUtil.InterpolatedNoise(x + 33, y + 43) * .5f + .5f;
                        //float hmod = heightvalue + smallNoise * 3f + S(S(bigNoise)) * 10f;
                        float hmod =
                            heightvalue; // 0 - 10

                        // find the low/high values for this point (interpolated bilinearily)
                        // (and remember, x=0,y=0 is SW)
                        float low = levelSWlow * (1f - rowRatio) * (1f - columnRatio) +
                                    levelSElow * (1f - rowRatio) * columnRatio +
                                    levelNWlow * rowRatio * (1f - columnRatio) +
                                    levelNElow * rowRatio * columnRatio;
                        float high = levelSWhigh * (1f - rowRatio) * (1f - columnRatio) +
                                     levelSEhigh * (1f - rowRatio) * columnRatio +
                                     levelNWhigh * rowRatio * (1f - columnRatio) +
                                     levelNEhigh * rowRatio * columnRatio;
                        if (high < low)
                        {
                            // someone tried to fool us. High value should be higher than low every time
                            float tmp = high;
                            high = low;
                            low  = tmp;
                        }

                        HSV hsv;
                        if (hmod <= low)
                        {
                            hsv = hsv1;              // too low
                        }
                        else if (hmod >= high)
                        {
                            hsv = hsv4;                    // too high
                        }
                        else
                        {
                            // HSV-interpolate along the colors
                            // first, rescale h to 0.0 - 1.0
                            hmod = (hmod - low) / (high - low);
                            // now we have to split: 0.00 => color1, 0.33 => color2, 0.67 => color3, 1.00 => color4
                            if (hmod < 1f / 3f)
                            {
                                hsv = interpolateHSV(ref hsv1, ref hsv2, hmod * 3f);
                            }
                            else if (hmod < 2f / 3f)
                            {
                                hsv = interpolateHSV(ref hsv2, ref hsv3, (hmod * 3f) - 1f);
                            }
                            else
                            {
                                hsv = interpolateHSV(ref hsv3, ref hsv4, (hmod * 3f) - 2f);
                            }
                        }
                        //get the data from the original image
                        Color hsvColor = hsv.toColor();
                        unsafeBMP.SetPixel((int)(x / sizeRatio),
                                           (int)(((m_scene.RegionInfo.RegionSizeY - 1) - y) / sizeRatio), hsvColor);
                    }
                    else
                    {
                        // We're under the water level with the terrain, so paint water instead of land
                        unsafeBMP.SetPixel((int)(x / sizeRatio),
                                           (int)(((m_scene.RegionInfo.RegionSizeY - 1) - y) / sizeRatio), WATER_COLOR);
                    }
                }
            }
            if (m_mapping != null)
            {
                SaveCache();
                m_mapping.Clear();
            }
            unsafeBMP.UnlockBitmap();
            //MainConsole.Instance.Info("[MAPTILE]: Generating Maptile Step 1: Done in " + (DateTime.Now - start).TotalSeconds + " ms");
            return(unsafeBMP.Bitmap());
        }