/// <summary>
/// Intersect a line-of-sight line segment with a list of line segments.
/// </summary>
private static CSightSegment _IntersectLOSRayWithLines(List <CVisibilityBlockingSegment> Segs, Vector2 Start, Vector2 End, float Radius)
{
CSightSegment result = new CSightSegment();
Vector2 la = Start;
Vector2 lb = End;
Vector2 ld = (lb - la).normalized;
float minT = (lb - la).magnitude;
if (minT > Radius)
{
minT = Radius;
lb = la + ld * minT;
}
// TODO: Not sure if this epsilon is needed.
minT += 0.01f;
Vector2 hitPoint = Vector2.zero;
int segID = -1;
for (int i = 0; i < Segs.Count; ++i)
{
CVisibilityBlockingSegment seg = Segs[i];
float t = 0.0f;
Vector2 hp;
if (CIntersections.LineVsLine(la, lb, seg.mA, seg.mB, out t, out hp))
{
if (t >= 0 && t <= minT)
{
hitPoint = hp;
minT = t;
segID = i;
}
}
}
result.mAngle = Mathf.Atan2(ld.x, ld.y);
result.mStart = la;
result.mEnd = lb;
result.mSegID = segID;
if (segID != -1)
{
float len = (hitPoint - la).magnitude;
result.mEnd = la + ld * len;
}
return(result);
}
/// <summary>
/// Get a list of points for building a line-of-site punch out.
/// </summary>
public static List <CSightSegment> GenerateLOSPoints(CUserWorldView WorldView, Vector2 StartPos, float Radius)
{
Vector2 start = StartPos;
if (CGame.VarShowVisLines.mValue)
{
CDebug.DrawCircle(Vector3.up, StartPos.ToWorldVec3(), Radius, Color.red, false);
CDebug.DrawYRectQuad(start.ToWorldVec3(), 0.25f, 0.25f, new Color(1.0f, 0.4f, 0.2f, 0.4f), false);
}
List <CVisibilityBlockingSegment> culledSegs = new List <CVisibilityBlockingSegment>();
List <CVisibilityBlockingSegment> visSegs = WorldView.GetVisSegments();
// Get wall segments that intersect view radius.
// TODO: Speed up with acceleration structure.
for (int i = 0; i < visSegs.Count; ++i)
{
CVisibilityBlockingSegment seg = visSegs[i];
Vector2 hitA;
Vector2 hitB;
bool OpenA, OpenB;
if (CIntersections.LineVsCircle(seg.mA, seg.mB, StartPos, Radius, out hitA, out hitB, out OpenA, out OpenB))
{
culledSegs.Add(new CVisibilityBlockingSegment(hitA, hitB));
if (CGame.VarShowVisLines.mValue)
{
CDebug.DrawLine(hitA.ToWorldVec3(), hitB.ToWorldVec3(), Color.black, false);
}
}
}
List <CSightSegment> lineSegs = new List <CSightSegment>();
if (culledSegs.Count == 0)
{
// TODO: Could precalculate this and store it, but this only helps improve best case.
int count = 46;
float interval = (Mathf.PI * 2.0f) / count;
for (int i = 0; i < count; ++i)
{
CSightSegment seg = new CSightSegment();
lineSegs.Add(seg);
seg.mEnd = new Vector2(Mathf.Sin(i * interval) * Radius, Mathf.Cos(i * interval) * Radius) + StartPos;
}
}
else
{
// Find closest intersection points when casting a ray to each segment vertex.
// TODO: There are still redundant casts to shared segment verts.
for (int i = 0; i < culledSegs.Count; ++i)
{
CVisibilityBlockingSegment seg = culledSegs[i];
float offset = 0.001f;
Vector2 shift;
float angle = Mathf.Atan2((seg.mA - start).x, (seg.mA - start).y);
shift.x = Mathf.Sin(angle - offset) * Radius + start.x;
shift.y = Mathf.Cos(angle - offset) * Radius + start.y;
lineSegs.Add(_IntersectLOSRayWithLines(culledSegs, start, shift, Radius));
shift.x = Mathf.Sin(angle + offset) * Radius + start.x;
shift.y = Mathf.Cos(angle + offset) * Radius + start.y;
lineSegs.Add(_IntersectLOSRayWithLines(culledSegs, start, shift, Radius));
angle = Mathf.Atan2((seg.mB - start).x, (seg.mB - start).y);
shift.x = Mathf.Sin(angle - offset) * Radius + start.x;
shift.y = Mathf.Cos(angle - offset) * Radius + start.y;
lineSegs.Add(_IntersectLOSRayWithLines(culledSegs, start, shift, Radius));
shift.x = Mathf.Sin(angle + offset) * Radius + start.x;
shift.y = Mathf.Cos(angle + offset) * Radius + start.y;
lineSegs.Add(_IntersectLOSRayWithLines(culledSegs, start, shift, Radius));
if (CGame.VarShowVisLines.mValue)
{
//CDebug.DrawYRectQuad(seg.mA.ToWorldVec3(), 0.25f, 0.25f, new Color(1.0f, 0.4f, 0.2f, 0.4f), false);
//CDebug.DrawYRectQuad(seg.mB.ToWorldVec3(), 0.25f, 0.25f, new Color(0.2f, 0.4f, 1.0f, 0.4f), false);
CDebug.DrawLine(seg.mA.ToWorldVec3(), seg.mB.ToWorldVec3(), Color.red, false);
}
}
// Sort intersections by angle.
lineSegs.Sort((x, y) =>
{
if (x.mAngle > y.mAngle)
{
return(1);
}
if (x.mAngle < y.mAngle)
{
return(-1);
}
return(0);
});
// Cull redundant intersections.
for (int i = 0; i < lineSegs.Count; ++i)
{
int s1 = lineSegs[i].mSegID;
if (s1 == -1)
{
continue;
}
int s2 = lineSegs[(i + 1) % lineSegs.Count].mSegID;
int s3 = lineSegs[(i + 2) % lineSegs.Count].mSegID;
if (s1 == s2 && s1 == s3)
{
lineSegs.RemoveAt((i + 1) % lineSegs.Count);
--i;
}
}
// Regenerate circular caps.
for (int i = 0; i < lineSegs.Count; ++i)
{
CSightSegment s1 = lineSegs[i];
CSightSegment s2 = lineSegs[(i + 1) % lineSegs.Count];
if (s1.mSegID == -1 && s2.mSegID == -1)
{
float angleD = s2.mAngle - s1.mAngle;
if (i == lineSegs.Count - 1)
{
angleD = s2.mAngle + Mathf.PI * 2 - s1.mAngle;
}
int count = (int)(angleD / 0.1f);
float interval = angleD / count;
for (int j = 1; j < count; ++j)
{
float newAngle = s1.mAngle + interval * j;
Vector2 shift;
shift.x = Mathf.Sin(newAngle) * Radius + s1.mStart.x;
shift.y = Mathf.Cos(newAngle) * Radius + s1.mStart.y;
CSightSegment s = new CSightSegment();
s.mStart = s1.mStart;
s.mEnd = shift;
lineSegs.Insert(i + 1, s);
++i;
}
if (CGame.VarShowVisLines.mValue)
{
CDebug.DrawLine(s1.mEnd.ToWorldVec3(), s2.mEnd.ToWorldVec3(), Color.white, false);
}
}
}
if (CGame.VarShowVisLines.mValue)
{
for (int i = 0; i < lineSegs.Count; ++i)
{
CSightSegment s = lineSegs[i];
if (s.mSegID != -1)
{
CDebug.DrawLine(s.mStart.ToWorldVec3(), s.mEnd.ToWorldVec3(), Color.green, false);
}
else
{
CDebug.DrawYRectQuad(s.mEnd.ToWorldVec3(), 0.25f, 0.25f, Color.magenta, false);
CDebug.DrawLine(s.mStart.ToWorldVec3(), s.mEnd.ToWorldVec3(), Color.blue, false);
}
}
}
}
return(lineSegs);
}
