Core/AreaTriggers: Fix triggering of client areatriggers for some shapes

2 files changed, 92 insertions, 18 deletions

diff --git a/src/server/game/Entities/Object/Position.cpp b/src/server/game/Entities/Object/Position.cpp
index d91c55eb84a..aa391a0d062 100644
--- a/src/server/game/Entities/Object/Position.cpp
+++ b/src/server/game/Entities/Object/Position.cpp
@@ -62,38 +62,109 @@ Position Position::GetPositionWithOffset(Position const& offset) const
     return ret;
 }
 
-bool Position::IsWithinBox(Position const& center, float xradius, float yradius, float zradius) const
+bool Position::IsWithinBox(Position const& boxOrigin, float length, float width, float height) const
 {
     // rotate the WorldObject position instead of rotating the whole cube, that way we can make a simplified
     // is-in-cube check and we have to calculate only one point instead of 4
 
     // 2PI = 360*, keep in mind that ingame orientation is counter-clockwise
-    double rotation = 2 * M_PI - center.GetOrientation();
+    double rotation = 2 * M_PI - boxOrigin.GetOrientation();
     double sinVal = std::sin(rotation);
     double cosVal = std::cos(rotation);
 
-    float BoxDistX = GetPositionX() - center.GetPositionX();
-    float BoxDistY = GetPositionY() - center.GetPositionY();
+    float BoxDistX = GetPositionX() - boxOrigin.GetPositionX();
+    float BoxDistY = GetPositionY() - boxOrigin.GetPositionY();
 
-    float rotX = float(center.GetPositionX() + BoxDistX * cosVal - BoxDistY*sinVal);
-    float rotY = float(center.GetPositionY() + BoxDistY * cosVal + BoxDistX*sinVal);
+    float rotX = float(boxOrigin.GetPositionX() + BoxDistX * cosVal - BoxDistY * sinVal);
+    float rotY = float(boxOrigin.GetPositionY() + BoxDistY * cosVal + BoxDistX * sinVal);
 
     // box edges are parallel to coordiante axis, so we can treat every dimension independently :D
-    float dz = GetPositionZ() - center.GetPositionZ();
-    float dx = rotX - center.GetPositionX();
-    float dy = rotY - center.GetPositionY();
-    if ((std::fabs(dx) > xradius) ||
-        (std::fabs(dy) > yradius) ||
-        (std::fabs(dz) > zradius))
+    float dz = GetPositionZ() - boxOrigin.GetPositionZ();
+    float dx = rotX - boxOrigin.GetPositionX();
+    float dy = rotY - boxOrigin.GetPositionY();
+    if ((std::fabs(dx) > length) ||
+        (std::fabs(dy) > width)  ||
+        (std::fabs(dz) > height))
         return false;
 
     return true;
 }
 
-bool Position::IsWithinDoubleVerticalCylinder(Position const* center, float radius, float height) const
+bool Position::IsWithinVerticalCylinder(Position const& cylinderOrigin, float radius, float height, bool isDoubleVertical) const
 {
-    float verticalDelta = GetPositionZ() - center->GetPositionZ();
-    return IsInDist2d(center, radius) && std::abs(verticalDelta) <= height;
+    float verticalDelta = GetPositionZ() - cylinderOrigin.GetPositionZ();
+    bool isValidPositionZ = isDoubleVertical ? std::abs(verticalDelta) <= height : 0 <= verticalDelta && verticalDelta <= height;
+
+    return isValidPositionZ && IsInDist2d(cylinderOrigin, radius);
+}
+
+bool Position::IsInPolygon2D(Position const& polygonOrigin, std::span<Position const> vertices) const
+{
+    float testX = GetPositionX();
+    float testY = GetPositionY();
+
+    //this method uses the ray tracing algorithm to determine if the point is in the polygon
+    bool locatedInPolygon = false;
+
+    for (std::size_t vertex = 0; vertex < vertices.size(); ++vertex)
+    {
+        std::size_t nextVertex;
+
+        //repeat loop for all sets of points
+        if (vertex == (vertices.size() - 1))
+        {
+            //if i is the last vertex, let j be the first vertex
+            nextVertex = 0;
+        }
+        else
+        {
+            //for all-else, let j=(i+1)th vertex
+            nextVertex = vertex + 1;
+        }
+
+        float vertX_i = polygonOrigin.GetPositionX() + vertices[vertex].GetPositionX();
+        float vertY_i = polygonOrigin.GetPositionY() + vertices[vertex].GetPositionY();
+        float vertX_j = polygonOrigin.GetPositionX() + vertices[nextVertex].GetPositionX();
+        float vertY_j = polygonOrigin.GetPositionY() + vertices[nextVertex].GetPositionY();
+
+        // following statement checks if testPoint.Y is below Y-coord of i-th vertex
+        bool belowLowY = vertY_i > testY;
+        // following statement checks if testPoint.Y is below Y-coord of i+1-th vertex
+        bool belowHighY = vertY_j > testY;
+
+        /* following statement is true if testPoint.Y satisfies either (only one is possible)
+        -->(i).Y < testPoint.Y < (i+1).Y        OR
+        -->(i).Y > testPoint.Y > (i+1).Y
+
+        (Note)
+        Both of the conditions indicate that a point is located within the edges of the Y-th coordinate
+        of the (i)-th and the (i+1)- th vertices of the polygon. If neither of the above
+        conditions is satisfied, then it is assured that a semi-infinite horizontal line draw
+        to the right from the testpoint will NOT cross the line that connects vertices i and i+1
+        of the polygon
+        */
+        bool withinYsEdges = belowLowY != belowHighY;
+
+        if (withinYsEdges)
+        {
+            // this is the slope of the line that connects vertices i and i+1 of the polygon
+            float slopeOfLine = (vertX_j - vertX_i) / (vertY_j - vertY_i);
+
+            // this looks up the x-coord of a point lying on the above line, given its y-coord
+            float pointOnLine = (slopeOfLine * (testY - vertY_i)) + vertX_i;
+
+            //checks to see if x-coord of testPoint is smaller than the point on the line with the same y-coord
+            bool isLeftToLine = testX < pointOnLine;
+
+            if (isLeftToLine)
+            {
+                //this statement changes true to false (and vice-versa)
+                locatedInPolygon = !locatedInPolygon;
+            }//end if (isLeftToLine)
+        }//end if (withinYsEdges
+    }
+
+    return locatedInPolygon;
 }
 
 bool Position::HasInArc(float arc, Position const* obj, float border) const
diff --git a/src/server/game/Entities/Object/Position.h b/src/server/game/Entities/Object/Position.h
index 1bd11b69c88..ed4709dadf3 100644
--- a/src/server/game/Entities/Object/Position.h
+++ b/src/server/game/Entities/Object/Position.h
@@ -19,6 +19,7 @@
 #define Trinity_game_Position_h__
 
 #include "Define.h"
+#include <span>
 #include <string>
 #include <cmath>
 
@@ -138,16 +139,18 @@ public:
     float GetRelativeAngle(Position const* pos) const { return ToRelativeAngle(GetAbsoluteAngle(pos)); }
 
     constexpr bool IsInDist2d(float x, float y, float dist) const { return GetExactDist2dSq(x, y) < dist * dist; }
+    constexpr bool IsInDist2d(Position const& pos, float dist) const { return GetExactDist2dSq(pos) < dist * dist; }
     constexpr bool IsInDist2d(Position const* pos, float dist) const { return GetExactDist2dSq(pos) < dist * dist; }
 
     constexpr bool IsInDist(float x, float y, float z, float dist) const { return GetExactDistSq(x, y, z) < dist * dist; }
     constexpr bool IsInDist(Position const& pos, float dist) const { return GetExactDistSq(pos) < dist * dist; }
     constexpr bool IsInDist(Position const* pos, float dist) const { return GetExactDistSq(pos) < dist * dist; }
 
-    bool IsWithinBox(Position const& center, float xradius, float yradius, float zradius) const;
+    bool IsWithinBox(Position const& boxOrigin, float length, float width, float height) const;
 
-    // dist2d < radius && abs(dz) < height
-    bool IsWithinDoubleVerticalCylinder(Position const* center, float radius, float height) const;
+    bool IsWithinVerticalCylinder(Position const& cylinderOrigin, float radius, float height, bool isDoubleVertical = false) const;
+
+    bool IsInPolygon2D(Position const& polygonOrigin, std::span<Position const> vertices) const;
 
     bool HasInArc(float arcangle, Position const* pos, float border = 2.0f) const;
     bool HasInLine(Position const* pos, float objSize, float width) const;