private void waterWeatherBtn_Click(object sender, EventArgs e)
{
waterWeatherBtn.Enabled = false;
btnNoise.Enabled = false;
// parames that the errosion class needed see droplet class for more info
ErosionParams erosionParams = new ErosionParams();
erosionParams.Kq = 10;
erosionParams.Kw = 0.001f;
erosionParams.Kr = 0.9f;
erosionParams.Kd = 0.02f;
erosionParams.Ki = 0.1f;
erosionParams.minSlope = 0.05f;
erosionParams.g = 20;
// how many droplets you want
int iterations = (int)nudWeatheringDroplets.Value;
// run it
Droplet droplet = new Droplet();
droplet.genDropletErosion(iterations, erosionParams, heightMap.noiseMap);
// draw it
DrawMap();
waterWeatherBtn.Enabled = true;
btnNoise.Enabled = true;
//seamlessMeridianBtn.Enabled = true;
}
public void genDropletErosion(int iterations, ErosionParams erosionParams, double[,] hMap)
{
Random rnd = new Random();
float Kq = erosionParams.Kq,
Kw = erosionParams.Kw,
Kr = erosionParams.Kr,
Kd = erosionParams.Kd,
Ki = erosionParams.Ki,
minSlope = erosionParams.minSlope,
Kg = erosionParams.g * 2;
//TempData<Point2[HMAP_SIZE*HMAP_SIZE]> erosion;
float flt = 0;
//erosion.fillMem32(*(uint32_t*)&flt);
int MAX_PATH_LEN = hMap.GetLength(0) * 4;
//int t0 = get_ref_time();
uint longPaths = 0, randomDirs = 0, sumLen = 0;
for (int iter = 0; iter < iterations; ++iter)
{
//if ((iter&0x3FFF) == 0 && iter!=0) show_splash("Calculating erosion", (iter+0.5f)/iterations);
int xi = rnd.Next(0, hMap.GetLength(0) - 1);
int zi = rnd.Next(0, hMap.GetLength(1) - 1);
float xp = xi, zp = zi;
float xf = 0, zf = 0;
float h = (float)hMap[xi, zi];
float s = 0, v = 0, w = 1;
//vec4f scolor = zero4f();
//if (xi + 1 >= hMap.GetLength(0)) xi = 0;
//if (zi + 1 >= hMap.GetLength(1)) zi = 0;
float h00 = h;
float h10 = (float)hMap[xi + 1, zi];
float h01 = (float)hMap[xi, zi + 1];
float h11 = (float)hMap[xi + 1, zi + 1];
float dx = 0, dz = 0;
uint numMoves = 0;
for (; numMoves < MAX_PATH_LEN; ++numMoves)
{
// calc gradient
float gx = h00 + h01 - h10 - h11;
float gz = h00 + h10 - h01 - h11;
//== better interpolated gradient?
// calc next pos
dx = (dx - gx) * Ki + gx;
dz = (dz - gz) * Ki + gz;
float dl = (float)Math.Sqrt(dx * dx + dz * dz);
if (dl <= float.Epsilon)
{
// pick random dir
float a = (float)(rnd.Next() * (Math.PI * 2));
dx = (float)Math.Cos(a);
dz = (float)Math.Sin(a);
++randomDirs;
}
else
{
dx /= dl;
dz /= dl;
}
float nxp = xp + dx;
float nzp = zp + dz;
// sample next height
int nxi = (int)Math.Floor(nxp);
int nzi = (int)Math.Floor(nzp);
float nxf = nxp - nxi;
float nzf = nzp - nzi;
if (nxi + 1 >= hMap.GetLength(0))
{
nxi = 0;
}
if (nxi < 0)
{
nxi = hMap.GetLength(0) - 2;
}
if (nzi + 1 >= hMap.GetLength(1))
{
nzi = 0;
}
if (nzi < 0)
{
nzi = hMap.GetLength(1) - 2;
}
float nh00 = (float)hMap[nxi, nzi];
float nh10 = (float)hMap[nxi + 1, nzi];
float nh01 = (float)hMap[nxi, nzi + 1];
float nh11 = (float)hMap[nxi + 1, nzi + 1];
float nh = (nh00 * (1 - nxf) + nh10 * nxf) * (1 - nzf) + (nh01 * (1 - nxf) + nh11 * nxf) * nzf;
// if higher than current, try to deposit sediment up to neighbour height
if (nh >= h)
{
float tds = (nh - h) + 0.001f;
if (tds >= s)
{
// deposit all sediment and stop
tds = s;
DEPOSIT_AT(xi, zi, (1 - xf) * (1 - zf), hMap, tds);
DEPOSIT_AT(xi + 1, zi, xf * (1 - zf), hMap, tds);
DEPOSIT_AT(xi, zi + 1, (1 - xf) * zf, hMap, tds);
DEPOSIT_AT(xi + 1, zi + 1, xf * zf, hMap, tds);
(h) += tds;
s = 0;
break;
}
DEPOSIT_AT(xi, zi, (1 - xf) * (1 - zf), hMap, tds);
DEPOSIT_AT(xi + 1, zi, xf * (1 - zf), hMap, tds);
DEPOSIT_AT(xi, zi + 1, (1 - xf) * zf, hMap, tds);
DEPOSIT_AT(xi + 1, zi + 1, xf * zf, hMap, tds);
(h) += tds;
s -= tds;
v = 0;
}
// compute transport capacity
float dh = h - nh;
float slope = dh;
//float slope=dh/sqrtf(dh*dh+1);
float q = Math.Max(slope, minSlope) * v * w * Kq;
// deposit/erode (don't erode more than dh)
float ds = s - q;
if (ds >= 0)
{
// deposit
ds *= Kd;
//ds=minval(ds, 1.0f);
DEPOSIT_AT(xi, zi, (1 - xf) * (1 - zf), hMap, ds);
DEPOSIT_AT(xi + 1, zi, xf * (1 - zf), hMap, ds);
DEPOSIT_AT(xi, zi + 1, (1 - xf) * zf, hMap, ds);
DEPOSIT_AT(xi + 1, zi + 1, xf * zf, hMap, ds);
(dh) += ds;
s -= ds;
}
else
{
// erode
ds *= -Kr;
ds = Math.Min(ds, dh * 0.99f);
for (int z = zi - 1; z <= zi + 2; ++z)
{
float zo = z - zp;
float zo2 = zo * zo;
for (int x = xi - 1; x <= xi + 2; ++x)
{
float xo = x - xp;
float tw = 1 - (xo * xo + zo2) * 0.25f;
if (tw <= 0)
{
continue;
}
tw *= 0.1591549430918953f;
ERODE(x, z, tw, hMap, ds);
}
}
dh -= ds;
s += ds;
}
// move to the neighbour
v = (float)Math.Sqrt(v * v + Kg * dh);
w *= 1 - Kw;
xp = nxp; zp = nzp;
xi = nxi; zi = nzi;
xf = nxf; zf = nzf;
h = nh;
h00 = nh00;
h10 = nh10;
h01 = nh01;
h11 = nh11;
}
if (numMoves >= MAX_PATH_LEN)
{
//debug("droplet #%d path is too long!", iter);
++longPaths;
}
sumLen += numMoves;
}
}
