Core/MMaps: Separate the path from the walls to prevent falling off the edges client-side and improve the behavior.

Thanks to Game2Mesh user in ownedcore.

src/server/game/Movement/PathGenerator.cpp

@@ -27,6 +27,8 @@
 #include "DetourCommon.h"
 #include "DetourNavMeshQuery.h"
 
+float PathGenerator::MinWallDistance = 2.5f;
+
 ////////////////// PathGenerator //////////////////
 PathGenerator::PathGenerator(const Unit* owner) :
     _type(PATHFIND_BLANK), _endPosition(G3D::Vector3::zero()),
@@ -131,6 +133,8 @@ bool PathGenerator::CalculatePath(float destX, float destY, float destZ, bool fo
         return false;
     }
 
+    SmoothPath(polyPickExt, resultHopCount, straightPath); // Separate the path from the walls
+
     for (uint32 i = 0; i < resultHopCount; ++i)
         _pathPoints.push_back(G3D::Vector3(-straightPath[i * 3 + 2], -straightPath[i * 3 + 0], straightPath[i * 3 + 1]));
 
@@ -157,4 +161,129 @@ void PathGenerator::CreateFilter()
 void PathGenerator::UpdateFilter()
 {
     
+}
+
+float PathGenerator::GetTriangleArea(float* verts, int nv)
+{
+    float area = 0;
+    for (int i = 0; i < nv - 1; i++)
+        area += verts[i * 3] * verts[i * 3 + 5] - verts[i * 3 + 3] * verts[i * 3 + 2];
+    area += verts[(nv - 1) * 3] * verts[2] - verts[0] * verts[(nv - 1) * 3 + 2];
+    return area * 0.5f;
+}
+
+bool PathGenerator::PointInPoly(float* pos, float* verts, int nv, float err)
+{
+    // Poly area
+    float area = abs(PathGenerator::GetTriangleArea(verts, nv));
+
+    // Calculate each area of the triangles
+    float testTri[9];
+    memcpy(testTri, pos, sizeof(float) * 3);
+    float area1 = 0;
+    for(int i = 0; i < nv - 1; ++i)
+    {
+        memcpy(&testTri[3], &verts[i * 3], sizeof(float) * 3);
+        memcpy(&testTri[6], &verts[i * 3 + 3], sizeof(float) * 3);
+        area1 += abs(PathGenerator::GetTriangleArea(testTri, 3));
+        if (area1 - err > area)
+            return false;
+    }
+
+    // Last one
+    memcpy(&testTri[3], verts, sizeof(float) * 3);
+    memcpy(&testTri[6], &verts[nv * 3 - 3] , sizeof(float) * 3);
+    area1 += abs(PathGenerator::GetTriangleArea(testTri, 3));
+
+    return abs(area1 - area) < err;
+}
+
+float PathGenerator::DistanceToWall(float* polyPickExt, float* pos, float* hitPos, float* hitNormal)
+{
+    float distanceToWall = 0;
+    dtPolyRef ref;
+    
+    dtStatus status = _navMeshQuery->findNearestPoly(pos, polyPickExt, &_filter, &ref, 0);
+    
+    if (!dtStatusSucceed(status) || ref == 0)
+        return -1;
+
+    const dtMeshTile* tile = 0;
+    const dtPoly* poly = 0;
+    if (dtStatusFailed(_navMesh->getTileAndPolyByRef(ref, &tile, &poly)))
+        return -1;
+
+    // Collect vertices.
+    float verts[DT_VERTS_PER_POLYGON * 3];
+    int nv = 0;
+    for (unsigned char i = 0; i < poly->vertCount; ++i)
+    {
+        dtVcopy(&verts[nv * 3], &tile->verts[poly->verts[i] * 3]);
+        nv++;
+    }		
+
+    bool inside = PathGenerator::PointInPoly(pos, verts, nv, 0.05f);
+    if (!inside)
+        return -1;
+
+    if (!dtStatusSucceed(_navMeshQuery->findDistanceToWall(ref, pos, 100.0f, &_filter, &distanceToWall, hitPos, hitNormal)))
+        return -1;
+
+    return distanceToWall;
+}
+
+void PathGenerator::SmoothPath(float* polyPickExt, int pathLength, float*& straightPath)
+{
+    float hitPos[3];
+    float hitNormal[3];
+    float testPos[3];
+    float distanceToWall = 0;
+    float up[]= { 0, 1, 0 };
+    float origDis = 0;
+
+    for (int i = 1; i < pathLength - 1; ++i)
+    {
+        dtPolyRef pt;
+        float* curPoi = &straightPath[i * 3];
+        distanceToWall = DistanceToWall(polyPickExt, curPoi, hitPos, hitNormal);
+
+        if (distanceToWall < PathGenerator::MinWallDistance && distanceToWall >= 0)
+        {
+            float vec[3];
+            dtVsub(vec, &straightPath[i * 3 - 3], &straightPath[i * 3]);
+            // If distanceToWall is 0 means the point is in the edge, so we can't get the hitpos.
+            if (distanceToWall == 0)
+            {
+                // Test the left side
+                dtVcross(testPos, vec, up);
+                dtVadd(testPos, testPos, curPoi);
+                float ft = PathGenerator::MinWallDistance / dtVdist(testPos, curPoi);
+                dtVlerp(testPos, curPoi, testPos, ft);
+                distanceToWall = DistanceToWall(polyPickExt, testPos, hitPos, hitNormal);
+                if (abs(PathGenerator::MinWallDistance - distanceToWall) > 0.1f)
+                {
+                    // Test the right side
+                    dtVcross(testPos, up, vec);
+                    dtVadd(testPos, testPos, curPoi);
+                    ft = PathGenerator::MinWallDistance / dtVdist(testPos, curPoi);
+                    dtVlerp(testPos, curPoi, testPos, ft);
+                    distanceToWall = DistanceToWall(polyPickExt, testPos, hitPos, hitNormal);
+                }
+
+                // If the test point is better than the orig point, replace it.
+                if (abs(distanceToWall - PathGenerator::MinWallDistance) < 0.1f)
+                    dtVcopy(curPoi, testPos);
+            }
+            else
+            {
+                // We get the hitpos with a ray
+                float ft = PathGenerator::MinWallDistance / distanceToWall;
+                dtVlerp(testPos, hitPos, curPoi, ft);
+                distanceToWall = DistanceToWall(polyPickExt, testPos, hitPos, hitNormal);
+
+                if (abs(distanceToWall - PathGenerator::MinWallDistance) < 0.1f)
+                    dtVcopy(curPoi, testPos);
+            }
+        }
+    }
 }