public void RecalculateFromPosition(Point viewerPosition)
{
// Test from each corner of source square to center of target square
PointF[] cornersToTest = { new PointF(viewerPosition.X, viewerPosition.Y),
new PointF(viewerPosition.X + 1, viewerPosition.Y),
new PointF(viewerPosition.X, viewerPosition.Y + 1),
new PointF(viewerPosition.X + 1, viewerPosition.Y + 1) };
this.VisibilityMap = null;
foreach (var point in cornersToTest)
{
VisibilityMap cornerMap = this.GenerateVisibilityMapForPosition(point);
if (this.VisibilityMap == null)
{
this.VisibilityMap = cornerMap;
}
else
{
for (int x = 0; x < cornerMap.Width; ++x)
{
for (int y = 0; y < cornerMap.Height; ++y)
{
this.VisibilityMap[x, y] = (OcclusionLevel)Math.Min((int)this.VisibilityMap[x, y], (int)cornerMap[x, y]);
}
}
}
}
// Calculate cover spots
for (int x = 0; x < this.VisibilityMap.Width; ++x)
{
for (int y = 0; y < this.VisibilityMap.Height; ++y)
{
if (this.VisibilityMap[x, y] == OcclusionLevel.Obscured)
{
if (TestSquare(x, y - 1) == OcclusionLevel.Visible ||
TestSquare(x, y + 1) == OcclusionLevel.Visible ||
TestSquare(x - 1, y) == OcclusionLevel.Visible ||
TestSquare(x + 1, y) == OcclusionLevel.Visible)
{
this.VisibilityMap[x, y] = OcclusionLevel.Cover;
}
}
}
}
//PointF centerOfSquare = new PointF((float)viewerPosition.X + 0.5f, (float)viewerPosition.Y + 0.5f);
//this.VisibilityMap = this.GenerateVisibilityMapForPosition(centerOfSquare);
//this.TestCorners(viewerPosition);
}
private void TestCorners(Point viewerPosition)
{
List <PointF> cornersToTest = new List <PointF>();
if (this.VisibilityMap[viewerPosition.X - 1, viewerPosition.Y - 1] != OcclusionLevel.Obscured &&
(this.VisibilityMap[viewerPosition.X, viewerPosition.Y - 1] == OcclusionLevel.Obscured ||
this.VisibilityMap[viewerPosition.X - 1, viewerPosition.Y] == OcclusionLevel.Obscured))
{
// test upper left corner, wall either above or left
cornersToTest.Add(new PointF((float)viewerPosition.X, (float)viewerPosition.Y));
}
if (this.VisibilityMap[viewerPosition.X + 1, viewerPosition.Y - 1] != OcclusionLevel.Obscured &&
(this.VisibilityMap[viewerPosition.X, viewerPosition.Y - 1] == OcclusionLevel.Obscured ||
this.VisibilityMap[viewerPosition.X + 1, viewerPosition.Y] == OcclusionLevel.Obscured))
{
// test upper right corner, wall either above or right
cornersToTest.Add(new PointF((float)viewerPosition.X + 1, (float)viewerPosition.Y));
}
if (this.VisibilityMap[viewerPosition.X - 1, viewerPosition.Y + 1] != OcclusionLevel.Obscured &&
(this.VisibilityMap[viewerPosition.X, viewerPosition.Y + 1] == OcclusionLevel.Obscured ||
this.VisibilityMap[viewerPosition.X - 1, viewerPosition.Y] == OcclusionLevel.Obscured))
{
// test lower-left corner, wall either left or bottom
cornersToTest.Add(new PointF((float)viewerPosition.X, (float)viewerPosition.Y + 1));
}
if (this.VisibilityMap[viewerPosition.X + 1, viewerPosition.Y + 1] != OcclusionLevel.Obscured &&
(this.VisibilityMap[viewerPosition.X, viewerPosition.Y + 1] == OcclusionLevel.Obscured ||
this.VisibilityMap[viewerPosition.X + 1, viewerPosition.Y] == OcclusionLevel.Obscured))
{
// test lower-right corner, wall either right or bottom
cornersToTest.Add(new PointF((float)viewerPosition.X + 1, (float)viewerPosition.Y + 1));
}
// if we have corners to test, then run through the whole visibility map from that corner and union it to our result
foreach (var point in cornersToTest)
{
VisibilityMap cornerMap = this.GenerateVisibilityMapForPosition(point);
for (int x = 0; x < cornerMap.Width; ++x)
{
for (int y = 0; y < cornerMap.Height; ++y)
{
this.VisibilityMap[x, y] = this.VisibilityMap[x, y] == OcclusionLevel.Obscured ? OcclusionLevel.Obscured : cornerMap[x, y];
}
}
}
}
private VisibilityMap GenerateVisibilityMapForPosition(PointF viewerLocation)
{
VisibilityMap visData = new VisibilityMap(this.Max.X - this.Min.X, this.Max.Y - this.Min.Y);
for (int x = this.Min.X; x < this.Max.X; ++x)
{
for (int y = this.Min.Y; y < this.Max.Y; ++y)
{
PointF targetLocation = new PointF((float)x + 0.5f, (float)y + 0.5f);
visData[x - this.Min.X, y - this.Min.Y] = this.GetOcclusion(viewerLocation, targetLocation);
}
}
return(visData);
}