Possibly fixed goto() by changing safety margin

TODO: More testing

Closes #326

src/object/task/taskgoto.cpp

@@ -37,7 +37,12 @@
 
 const float FLY_DIST_GROUND = 80.0f;    // minimum distance to remain on the ground
 const float FLY_DEF_HEIGHT  = 50.0f;    // default flying height
-const float BM_DIM_STEP     = 5.0f;
+
+// Settings that define goto() accuracy:
+const float BM_DIM_STEP     = 5.0f;     // Size of one pixel on the bitmap. Setting 5 means that 5x5 square (in game units) will be represented by 1 px on the bitmap. Decreasing this value will make a bigger bitmap, and may increase accuracy. TODO: Check how it actually impacts goto() accuracy
+const float BEAM_ACCURACY   = 5.0f;    // higher value = more accurate, but slower
+const float SAFETY_MARGIN   = 0.5f;     // Smallest distance between two objects. Smaller = less "no route to destination", but higher probability of collisions between objects.
+// Changing SAFETY_MARGIN (old value was 4.0f) seems to have fixed many issues with goto(). TODO: maybe we could make it even smaller? Did changing it introduce any new bugs?
 
 
 
@@ -1739,7 +1744,7 @@ Error CTaskGoto::BeamSearch(const Math::Vector &start, const Math::Vector &goal,
     m_bmStep ++;
 
     len = Math::DistanceProjected(start, goal);
-    step = len/5.0f;
+    step = len/BEAM_ACCURACY;
     if ( step < BM_DIM_STEP*2.1f )  step = BM_DIM_STEP*2.1f;
     if ( step > 20.0f            )  step = 20.0f;
     nbIter = 200;  // in order not to lower the framerate
@@ -1969,7 +1974,7 @@ void CTaskGoto::BitmapObject()
             }
 
             if ( type == OBJECT_PARA )  oRadius -= 2.0f;
-            BitmapSetCircle(oPos, oRadius+iRadius+4.0f);
+            BitmapSetCircle(oPos, oRadius+iRadius+SAFETY_MARGIN);
         }
     }
 }