//sort grid squares by x coordinate
int IComparable.CompareTo(object obj)
{
collision_grid_square sq = (collision_grid_square)obj;
if (this.ix > sq.ix)
{
return(1);
}
if (this.ix < sq.ix)
{
return(-1);
}
return(0);
}
public collision_grid(Environment e, int _coarseness)
{
double mapx = 0.0, mapy = 0.0;
foreach (Wall w in e.walls)
{
if (w.line.p1.x > mapx)
{
mapx = w.line.p1.x;
}
if (w.line.p2.x > mapx)
{
mapx = w.line.p2.x;
}
if (w.line.p1.y > mapy)
{
mapy = w.line.p1.y;
}
if (w.line.p2.y > mapy)
{
mapy = w.line.p2.y;
}
}
//add some slack..
mapx += 50;
mapy += 50;
coarseness = _coarseness;
//mapx = 618 * 4;
//mapy = 885 * 4;
//coarseness = 20*4;
//Console.WriteLine(mapx.ToString()+ " " + mapy.ToString() + " " + coarseness.ToString());
gridx = (double)mapx / (double)coarseness;
gridy = (double)mapy / (double)coarseness;
grid = new collision_grid_square[coarseness, coarseness];
for (int x = 0; x < coarseness; x++)
{
for (int y = 0; y < coarseness; y++)
{
grid[x, y] = new collision_grid_square(x, y, x * gridx, y * gridy);
}
}
//Console.WriteLine("Grid square x_size = " + gridx.ToString());
//Console.WriteLine("Grid square y_size = " + gridy.ToString());
}
public collision_grid(Environment e, int _coarseness)
{
double mapx = 0.0, mapy = 0.0;
foreach (Wall w in e.walls)
{
if (w.line.p1.x > mapx)
mapx = w.line.p1.x;
if (w.line.p2.x > mapx)
mapx = w.line.p2.x;
if (w.line.p1.y > mapy)
mapy = w.line.p1.y;
if (w.line.p2.y > mapy)
mapy = w.line.p2.y;
}
//add some slack..
mapx += 50;
mapy += 50;
coarseness = _coarseness;
//mapx = 618 * 4;
//mapy = 885 * 4;
//coarseness = 20*4;
//Console.WriteLine(mapx.ToString()+ " " + mapy.ToString() + " " + coarseness.ToString());
gridx = (double)mapx / (double)coarseness;
gridy = (double)mapy / (double)coarseness;
grid = new collision_grid_square[coarseness, coarseness];
for (int x = 0; x < coarseness; x++)
for (int y = 0; y < coarseness; y++)
grid[x, y] = new collision_grid_square(x, y, x * gridx, y * gridy);
//Console.WriteLine("Grid square x_size = " + gridx.ToString());
//Console.WriteLine("Grid square y_size = " + gridy.ToString());
}
//ray-casting for detecting collisions with walls using the grid stucture
public List <collision_grid_square> cast_ray(double sx, double sy, double ex, double ey)
{
List <collision_grid_square> intersect = new List <collision_grid_square>();
double bsx = sx;
double bsy = sy;
double bex = ex;
double bey = ey;
double maxx = gridx * (coarseness) - 0.001;
double maxy = gridy * (coarseness) - 0.001;
double tslope = (ey - sy) / (ex - sx);
//clip ray within grid...
if (ex < 0.0)
{
ey = sy + tslope * (0 - sx);
ex = 0.0;
}
if (ex > maxx)
{
ey = sy + tslope * (maxx - sx);
ex = maxx;
}
if (ey < 0.0)
{
ex = sx + (1.0 / tslope) * (0 - sy);
ey = 0.0;
}
if (ey > maxy)
{
ex = sx + (1.0 / tslope) * (maxy - sy);
ey = maxy;
}
//calculate special vertical and horizontal cases...
double x0 = sx / gridx;
double x1 = ex / gridx;
double y0 = sy / gridy;
double y1 = ey / gridy;
//horizontal line, easy to calculate
if (y0 == y1)
{
bool reverse = false;
int sxi = (int)x0;
int exi = (int)x1;
int yi = (int)y0;
if (exi < sxi)
{
int temp = exi;
exi = sxi;
sxi = temp;
reverse = true;
}
for (int xi = sxi; xi <= exi; xi++)
{
intersect.Add(grid[xi, yi]);
}
if (reverse)
{
intersect.Reverse();
}
return(intersect);
}
//vertical line, easy to calculate
if (x0 == x1)
{
bool reverse = false;
int syi = (int)y0;
int eyi = (int)y1;
int xi = (int)x0;
if (eyi < syi)
{
int temp = eyi;
eyi = syi;
syi = temp;
reverse = true;
}
for (int yi = syi; yi <= eyi; yi++)
{
intersect.Add(grid[xi, yi]);
}
if (reverse)
{
intersect.Reverse();
}
return(intersect);
}
//we've handled the special vertical and horizontal cases...
bool rev = false;
//make sure we are going left-to-right
//if not, swap the points
if (sx > ex)
{
double temp = sx;
sx = ex;
ex = temp;
rev = true;
temp = ey;
ey = sy;
sy = temp;
}
//does our line slope up or down?
bool up = true;
if (sy > ey)
{
up = false;
}
collision_grid_square to_add = null;
// try
// {
//add the current grid square
to_add = grid[(int)(sx / gridx), (int)(sy / gridy)];
// }
//catch (Exception e)
//{
// Console.WriteLine(bsx.ToString() + " " + bsy.ToString() + " " + bex.ToString() + " " + bey.ToString());
// Console.WriteLine(sx.ToString() + " " + sy.ToString() + " " + ex.ToString() + " " + ey.ToString());
// Console.WriteLine(e.Source);
// Console.WriteLine(e.Message);
// Console.WriteLine(e.StackTrace);
// Console.WriteLine("own sqaure...");
// throw (e);
//}
to_add.ix = sx;
intersect.Add(to_add);
double slope = Math.Abs((ey - sy) / (ex - sx));
double invslope = 1.0 / slope;
//vertical intersections
//we must find the first intersection now
double py = Math.Floor(sy / gridy) * gridy;
double incy = gridy;
if (up)
{
py += gridy + 0.001;
}
else
{
py -= 0.001;
incy = -incy;
}
double px = sx + Math.Abs((py - sy)) / slope;
double incx = invslope * gridy;
while (true)
{
if (px > ex)
{
break;
}
if (up)
{
if (py > ey)
{
break;
}
}
else
{
if (py < ey)
{
break;
}
}
try
{
to_add = grid[(int)(px / gridx), (int)(py / gridy)];
}
catch (Exception e)
{
Console.WriteLine(bsx.ToString() + " " + bsy.ToString() + " " + bex.ToString() + " " + bey.ToString());
Console.WriteLine(sx.ToString() + " " + sy.ToString() + " " + ex.ToString() + " " + ey.ToString());
Console.WriteLine("Vertical..." + ((int)(px / gridx)).ToString() + " " + ((int)(py / gridy)).ToString());
Console.WriteLine(px.ToString() + " " + py.ToString() + " " + ex.ToString() + " " + ey.ToString());
Console.WriteLine(e.Source);
Console.WriteLine(e.Message);
Console.WriteLine(e.StackTrace);
//throw (e);
}
to_add.ix = px;
intersect.Add(to_add);
px += incx;
py += incy;
}
//horizontal intersections...
slope = (ey - sy) / (ex - sx);
invslope = 1.0 / slope;
px = Math.Floor(sx / gridx) * gridx + gridx + 0.01;
py = sy + (px - sx) * slope;
incx = gridx;
incy = gridx * slope;
while (true)
{
if (px > ex)
{
break;
}
if (up)
{
if (py > ey)
{
break;
}
}
else
{
if (py < ey)
{
break;
}
}
try
{
to_add = grid[(int)(px / gridx), (int)(py / gridy)];
}
catch (Exception e)
{
Console.WriteLine(bsx.ToString() + " " + bsy.ToString() + " " + bex.ToString() + " " + bey.ToString());
Console.WriteLine(sx.ToString() + " " + sy.ToString() + " " + ex.ToString() + " " + ey.ToString());
Console.WriteLine("Horizontal..." + ((int)(px / gridx)).ToString() + " " + ((int)(py / gridy)).ToString());
Console.WriteLine(px.ToString() + " " + py.ToString() + " " + ex.ToString() + " " + ey.ToString());
Console.WriteLine(e.Source);
Console.WriteLine(e.Message);
Console.WriteLine(e.StackTrace);
throw (e);
}
to_add.ix = px;
if (!intersect.Contains(to_add))
{
intersect.Add(to_add);
}
px += incx;
py += incy;
}
//now we sort the grid squares so they are in
//increasing x order
intersect.Sort();
//but if our line actually goes right to left,
//we need to reverse the order
if (rev)
{
intersect.Reverse();
}
return(intersect);
}
