/// <summary>
/// Creates a new HitGrid of the same size and sets its contents to the opposite of this one.
/// Does not set type or anything else!
/// </summary>
/// <returns>The inverted grid</returns>
public HitGrid Invert()
{
var result = new HitGrid(Width, Height, CellWidth, CellHeight);
for (int c = 0; c < Columns; c++)
{
for (int r = 0; r < Rows; r++)
{
result[c, r] = !this[c, r];
}
}
return(result);
}
public bool CollidesWith(HitGrid other)
{
if (!CheckBoundingBoxes(other))
{
return(false);
}
if (Radius <= MathUtility.DistanceRectPoint(Left + Radius, Top + Radius, other.Left, other.Top, other.Width, other.Height))
{
return(false);
}
var thisCenter = new Vector2(Left + Radius, Top + Radius);
var oCenter = new Vector2(other.Left + other.Width / 2f, other.Top + other.Height / 2f);
int rowStart = 0, rowMax = other.Rows, rowStep = 1;
int colStart = 0, colMax = other.Columns, colStep = 1;
if (thisCenter.X > oCenter.X)
{
colStart = other.Columns - 1;
colStep = colMax = -1;
}
if (thisCenter.Y > oCenter.Y)
{
rowStart = other.Rows - 1;
rowStep = rowMax = -1;
}
for (int row = rowStart; row != rowMax; row += rowStep)
{
for (int col = colStart; col != colMax; col += colStep)
{
if (!other[col, row])
{
continue;
}
var cellPos = new Vector2(other.Left + col * other.CellWidth, other.Top + row * other.CellWidth);
if (Radius > MathUtility.DistanceRectPoint(thisCenter.X, thisCenter.Y, cellPos.X, cellPos.Y, other.CellWidth, other.CellHeight))
{
return(true);
}
}
}
return(false);
}
public bool CollidesWith(HitGrid other)
{
// Find the X edges
var ax1 = Left;
var ax2 = Right;
var bx1 = other.Left;
var bx2 = other.Right;
if (ax2 < bx1 || ax1 > bx2)
{
return(false);
}
// Find the Y edges
var ay1 = Top;
var ay2 = Bottom;
var by1 = other.Top;
var by2 = other.Bottom;
if (ay2 < by1 || ay1 > by2)
{
return(false);
}
// Find the overlapping area
var ox1 = ax1 > bx1 ? ax1 : bx1;
var oy1 = ay1 > by1 ? ay1 : by1;
var ox2 = ax2 < bx2 ? ax2 : bx2;
var oy2 = ay2 < by2 ? ay2 : by2;
// Find the smallest tile size, and snap the top and left overlapping
// edges to that tile size. This ensures that corner checking works
// properly.
float tw, th;
if (CellWidth < other.CellWidth)
{
tw = CellWidth;
ox1 -= Left;
ox1 = (int)(ox1 / tw) * tw;
ox1 += Left;
}
else
{
tw = other.CellWidth;
ox1 -= other.Left;
ox1 = (int)(ox1 / tw) * tw;
ox1 += other.Left;
}
if (CellHeight < other.CellHeight)
{
th = CellHeight;
oy1 -= Top;
oy1 = (int)(oy1 / th) * th;
oy1 += Top;
}
else
{
th = other.CellHeight;
oy1 -= other.Top;
oy1 = (int)(oy1 / th) * th;
oy1 += other.Top;
}
// Step through the overlapping rectangle
for (float y = oy1; y < oy2; y += th)
{
// Get the row indices for the top and bottom edges of the tile
int ar1 = (int)(y - Top) / CellHeight;
int br1 = (int)(y - other.Top) / other.CellHeight;
int ar2 = (int)((y - Top) + (th - 1)) / CellHeight;
int br2 = (int)((y - other.Top) + (th - 1)) / other.CellHeight;
for (float x = ox1; x < ox2; x += tw)
{
// Get the column indices for the left and right edges of the tile
int ac1 = (int)(x - Left) / CellWidth;
int bc1 = (int)(x - other.Left) / other.CellWidth;
int ac2 = (int)((x - Left) + (tw - 1)) / CellWidth;
int bc2 = (int)((x - other.Left) + (tw - 1)) / other.CellWidth;
// Check all the corners for collisions
if ((this.CheckCellSafely(ac1, ar1) && other.CheckCellSafely(bc1, br1)) ||
(this.CheckCellSafely(ac2, ar1) && other.CheckCellSafely(bc2, br1)) ||
(this.CheckCellSafely(ac1, ar2) && other.CheckCellSafely(bc1, br2)) ||
(this.CheckCellSafely(ac2, ar2) && other.CheckCellSafely(bc2, br2)))
{
return(true);
}
}
}
return(false);
}
