Refactor|BSP Builder: Began remodelling the space partitioning logic

Returning to this code after the enhancements made for Doomsday 1.10
it is clear that the high level design of this module was somewhat
compromised in the process.

Before going further with the extraction of the geometry generation
from the map renderer, it makes sense to clarify the implementation
once more.

doomsday/client/client.pro

@@ -224,10 +224,10 @@ DENG_HEADERS += \
     include/map/blockmap.h \
     include/map/blockmapvisual.h \
     include/map/bsp/bsptreenode.h \
-    include/map/bsp/hedgeinfo.h \
     include/map/bsp/hedgeintercept.h \
     include/map/bsp/hedgetip.h \
     include/map/bsp/lineinfo.h \
+    include/map/bsp/linesegment.h \
     include/map/bsp/partitioncost.h \
     include/map/bsp/partitioner.h \
     include/map/bsp/superblockmap.h \

doomsday/client/include/map/bsp/hedgeintercept.h

@@ -51,8 +51,9 @@ struct HEdgeIntercept
     // True if this intersection was on a self-referencing line.
     bool selfRef;
 
-    // Sector on each side of the vertex (along the partition),
-    // or NULL when that direction isn't OPEN.
+    /// Sector on each side of the vertex (along the partition), or @c 0 if that
+    /// direction is "closed" (i.e., the intercept point is along a map line that
+    /// has no Sector on the relevant side).
     Sector *before;
     Sector *after;
 
@@ -70,6 +71,37 @@ struct HEdgeIntercept
           after(other.after)
     {}
 
+    void merge(HEdgeIntercept const &other)
+    {
+        /*
+        LOG_TRACE("Merging intersections:");
+        debugPrint();
+        other.debugPrint();
+        */
+
+        if(selfRef && !other.selfRef)
+        {
+            if(before && other.before)
+                before = other.before;
+
+            if(after && other.after)
+                after = other.after;
+
+            selfRef = false;
+        }
+
+        if(!before && other.before)
+            before = other.before;
+
+        if(!after && other.after)
+            after = other.after;
+
+        /*
+        LOG_TRACE("Result:");
+        debugPrint();
+        */
+    }
+
 #ifdef DENG_DEBUG
     void debugPrint() const
     {

doomsday/client/include/map/bsp/lineinfo.h

@@ -47,7 +47,6 @@ struct LineInfo
     {
         Twosided   =        0x1, ///< Line is marked two-sided.
         ZeroLength =        0x2, ///< Zero length (line should be totally ignored).
-        SelfRef    =        0x4  ///< Sector is the same on both sides.
     };
     Q_DECLARE_FLAGS(Flags, Flag)
 
@@ -76,9 +75,6 @@ struct LineInfo
         if(line->hasFrontSections() && line->hasBackSections())
         {
             flags |= Twosided;
-
-            if(line->isSelfReferencing())
-                flags |= SelfRef;
         }
     }
 };

doomsday/client/include/map/bsp/hedgeinfo.h → doomsday/client/include/map/bsp/linesegment.h

@@ -1,4 +1,4 @@
-/** @file hedgeinfo.h BSP Builder half-edge info.
+/** @file map/bsp/linesegment.h BSP Builder Line Segment.
  *
  * Originally based on glBSP 2.24 (in turn, based on BSP 2.3)
  * @see http://sourceforge.net/projects/glbsp/
@@ -23,8 +23,8 @@
  * 02110-1301 USA</small>
  */
 
-#ifndef DENG_WORLD_MAP_BSP_HEDGEINFO
-#define DENG_WORLD_MAP_BSP_HEDGEINFO
+#ifndef DENG_WORLD_MAP_BSP_LINESEGMENT
+#define DENG_WORLD_MAP_BSP_LINESEGMENT
 
 #include <de/mathutil.h>
 #include <de/vector1.h>
@@ -38,12 +38,11 @@ namespace bsp {
 class SuperBlock;
 
 /**
- * Plain old data (POD) structure storing additional information about a
- * half-edge produced by BspBuilder.
+ * Models a finite line segment in the plane.
  *
  * @ingroup bsp
  */
-struct HEdgeInfo
+struct LineSegment
 {
     coord_t start[2];
     coord_t end[2];
@@ -59,22 +58,23 @@ struct HEdgeInfo
     HEdge *nextOnSide;
     HEdge *prevOnSide;
 
-    // The superblock that contains this half-edge, or NULL if the half-edge
-    // is no longer in any superblock (e.g. now in a leaf).
+    /// The superblock that contains this segment, or @c 0 if the segment is no
+    /// longer in any superblock (e.g., now in or being turned into a leaf edge).
     SuperBlock *bmapBlock;
 
-    /// Line side that this half-edge initially comes (otherwise @c 0 signifying a "mini-edge").
+    /// Line side that this line segment initially comes (otherwise @c 0 signifying
+    /// a "mini-segment").
     Line::Side *lineSide;
 
-    // Line side that this half-edge initially comes from. For "real" half-edges,
-    // this is just the same as @var line field. For "mini-edges", this is the
-    // the partition line side.
+    /// Line side that this line segment initially comes from. For "real" segments,
+    /// this is just the same as @var lineSide. For "mini-segments", this is the
+    /// the partition line side.
     Line::Side *sourceLineSide;
 
-    /// Map sector attributed to the half-edge. Can be @c 0 for "mini-edges".
+    /// Map sector attributed to the line segment. Can be @c 0 for "mini-segments".
     Sector *sector;
 
-    HEdgeInfo()
+    LineSegment()
         : pLength(0),
           pAngle(0),
           pPara(0),
@@ -92,7 +92,7 @@ struct HEdgeInfo
         V2d_Set(direction, 0, 0);
     }
 
-    HEdgeInfo(HEdgeInfo const &other)
+    LineSegment(LineSegment const &other)
         : pLength(other.pLength),
           pAngle(other.pAngle),
           pPara(other.pPara),
@@ -110,6 +110,25 @@ struct HEdgeInfo
         V2d_Copy(direction, other.direction);
     }
 
+    LineSegment &operator = (LineSegment const &other)
+    {
+        V2d_Copy(start, other.start);
+        V2d_Copy(end, other.end);
+        V2d_Copy(direction, other.direction);
+        pLength = other.pLength;
+        pAngle = other.pAngle;
+        pPara = other.pPara;
+        pPerp = other.pPerp;
+        pSlopeType = other.pSlopeType;
+        nextOnSide = other.nextOnSide;
+        prevOnSide = other.prevOnSide;
+        bmapBlock = other.bmapBlock;
+        lineSide = other.lineSide;
+        sourceLineSide = other.sourceLineSide;
+        sector = other.sector;
+        return *this;
+    }
+
     void initFromHEdge(HEdge const &hedge)
     {
         V2d_Set(start, hedge.fromOrigin().x, hedge.fromOrigin().y);
@@ -129,4 +148,4 @@ struct HEdgeInfo
 } // namespace bsp
 } // namespace de
 
-#endif // DENG_WORLD_MAP_BSP_HEDGEINFO
+#endif // DENG_WORLD_MAP_BSP_LINESEGMENT

doomsday/client/include/map/bsp/partitioncost.h

@@ -39,7 +39,7 @@ struct PartitionCost
 {
     enum Side
     {
-        Right = 0,
+        Right,
         Left
     };
 
@@ -67,7 +67,7 @@ struct PartitionCost
     inline PartitionCost &addHEdgeLeft(HEdge const &hedge)
     {
         if(hedge.hasLineSide()) realLeft += 1;
-        else                miniLeft += 1;
+        else                    miniLeft += 1;
         return *this;
     }