IntVector3 FindStartLoc(Random r, SideEdge edge)
{
int side = m_terrain.Width;
int yo = r.Next(0, side);
int zo = m_terrain.GetSurfaceLevel(MapCoord(yo, edge));
int yu = yo;
int zu = zo;
for (int y = yo - 1; y >= 0; --y)
{
int z = m_terrain.GetSurfaceLevel(MapCoord(y, edge));
if (z < zu)
{
zu = z;
yu = y;
}
if (z - 2 > zu)
{
break;
}
}
int yd = yo;
int zd = zo;
for (int y = yo + 1; y < side; ++y)
{
int z = m_terrain.GetSurfaceLevel(MapCoord(y, edge));
if (z < zd)
{
zd = z;
yd = y;
}
if (z - 2 > zd)
{
break;
}
}
int yf = zd < zu ? yd : yu;
var p2 = MapCoord(yf, edge);
return(m_terrain.GetSurfaceLocation(p2));
}
public bool CreateRiverPath()
{
int offset = m_random.Next();
m_riverPath = null;
for (int i = 0; i < 8; ++i)
{
SideEdge edge = (SideEdge)((i + offset) % 4);
var startLoc = FindStartLoc(m_random, edge);
var target = new MyTarget(m_terrain, startLoc, edge);
int maxNodeCount = 500000; // XXX this should reflect the map size
var res = AStar.Find(new IntVector3[] { startLoc }, target, maxNodeCount);
if (res.Status != AStarStatus.Found)
{
continue;
}
var riverPath = res.GetPathLocationsReverse().Select(p => p.ToIntVector2()).ToArray();
if (riverPath.Length < 100)
{
Trace.TraceInformation("retry, too short");
continue;
}
int tot = riverPath.Aggregate(0, (a, p) =>
a + MyMath.Min(p.X, p.Y, m_terrain.Width - p.X - 1, m_terrain.Height - p.Y - 1));
int avg = tot / riverPath.Length;
if (avg < 20)
{
Trace.TraceInformation("too close to edge, avg {0}", avg);
continue;
}
m_riverPath = riverPath;
return(true);
}
return(false);
}
IntVector2 MapCoord(int c, SideEdge edge)
{
switch (edge)
{
case SideEdge.Left:
return(new IntVector2(0, c));
case SideEdge.Top:
return(new IntVector2(c, 0));
case SideEdge.Right:
return(new IntVector2(m_terrain.Width - 1, c));
case SideEdge.Bottom:
return(new IntVector2(c, m_terrain.Height - 1));
default:
throw new Exception();
}
}
public MyTarget(TerrainData terrain, IntVector3 origin, SideEdge sourceSide)
{
m_terrain = terrain;
m_origin = origin;
m_sourceSide = sourceSide;
}
IntVector2 MapCoord(int c, SideEdge edge)
{
switch (edge)
{
case SideEdge.Left:
return new IntVector2(0, c);
case SideEdge.Top:
return new IntVector2(c, 0);
case SideEdge.Right:
return new IntVector2(m_terrain.Width - 1, c);
case SideEdge.Bottom:
return new IntVector2(c, m_terrain.Height - 1);
default:
throw new Exception();
}
}
IntVector3 FindStartLoc(Random r, SideEdge edge)
{
int side = m_terrain.Width;
int yo = r.Next(0, side);
int zo = m_terrain.GetSurfaceLevel(MapCoord(yo, edge));
int yu = yo;
int zu = zo;
for (int y = yo - 1; y >= 0; --y)
{
int z = m_terrain.GetSurfaceLevel(MapCoord(y, edge));
if (z < zu)
{
zu = z;
yu = y;
}
if (z - 2 > zu)
break;
}
int yd = yo;
int zd = zo;
for (int y = yo + 1; y < side; ++y)
{
int z = m_terrain.GetSurfaceLevel(MapCoord(y, edge));
if (z < zd)
{
zd = z;
yd = y;
}
if (z - 2 > zd)
break;
}
int yf = zd < zu ? yd : yu;
var p2 = MapCoord(yf, edge);
return m_terrain.GetSurfaceLocation(p2);
}
public MyTarget(TerrainData terrain, IntVector3 origin, SideEdge sourceSide)
{
m_terrain = terrain;
m_origin = origin;
m_sourceSide = sourceSide;
}
