qbsp: track original brushes, populate q2 leafbrushes accurately

include/qbsp/brush.hh

@@ -23,14 +23,20 @@
 
 #include <qbsp/winding.hh>
 #include <common/aabb.hh>
+#include <optional>
 
 struct brush_t
 {
-    //brush_t *original; // fixme-brushbsp: implement this
+    /**
+     * The brushes in the mapentity_t::brushes vector are considered originals. Brush fragments created during
+     * the BrushBSP will have this pointing back to the original brush in mapentity_t::brushes.
+     */
+    brush_t *original;
     aabb3d bounds;
     std::vector<face_t> faces;
     contentflags_t contents; /* BSP contents */
     short lmshift; /* lightmap scaling (qu/lightmap pixel), passed to the light util */
+    std::optional<uint32_t> outputnumber; /* only set for original brushes */
 
     void update_bounds();
 };

include/qbsp/qbsp.hh

@@ -307,7 +307,7 @@ struct node_t
 
     // information for leafs
     contentflags_t contents; // leaf nodes (0 for decision nodes)
-    // std::vector<brush_t *> original_brushes; // fixme-brushbsp: implement this
+    std::vector<brush_t *> original_brushes;
     std::vector<face_t *> markfaces; // leaf nodes only, point to node faces
     portal_t *portals;
     int visleafnum; // -1 = solid

qbsp/qbsp.cc

@@ -43,14 +43,6 @@ bool node_t::opaque() const
     return contents.is_sky(options.target_game) || contents.is_solid(options.target_game);
 }
 
-// a simple tree structure used for leaf brush
-// compression.
-struct leafbrush_entry_t
-{
-    uint32_t offset;
-    std::map<uint32_t, leafbrush_entry_t> entries;
-};
-
 // per-entity
 static struct
 {
@@ -58,36 +50,25 @@ static struct
     uint32_t total_leaf_brushes;
 } brush_state;
 
-// running total
-static uint32_t brush_offset;
-
-static void ExportBrushList_r(const mapentity_t *entity, node_t *node, const uint32_t &brush_offset)
+static void ExportBrushList_r(const mapentity_t *entity, node_t *node)
 {
     if (node->planenum == PLANENUM_LEAF) {
         if (node->contents.native) {
-            uint32_t b_id = brush_offset;
-            std::vector<uint32_t> brushes;
-
-            for (auto &b : entity->brushes) {
-                if (node->bounds.intersectWith(b.bounds)) {
-                    brushes.push_back(b_id);
-                }
-                b_id++;
-            }
-
-            if (brushes.size()) {
-                node->numleafbrushes = brushes.size();
+            if (node->original_brushes.size()) {
+                node->numleafbrushes = node->original_brushes.size();
                 brush_state.total_leaf_brushes += node->numleafbrushes;
                 node->firstleafbrush = map.bsp.dleafbrushes.size();
-                map.bsp.dleafbrushes.insert(map.bsp.dleafbrushes.end(), brushes.begin(), brushes.end());
+                for (auto &b : node->original_brushes) {
+                    map.bsp.dleafbrushes.push_back(b->outputnumber.value());
+                }
             }
         }
 
         return;
     }
 
-    ExportBrushList_r(entity, node->children[0], brush_offset);
-    ExportBrushList_r(entity, node->children[1], brush_offset);
+    ExportBrushList_r(entity, node->children[0]);
+    ExportBrushList_r(entity, node->children[1]);
 }
 
 /*
@@ -227,7 +208,7 @@ static std::vector<std::tuple<size_t, const face_t *>> AddBrushBevels(const brus
     return planes;
 }
 
-static void ExportBrushList(const mapentity_t *entity, node_t *node, uint32_t &brush_offset)
+static void ExportBrushList(mapentity_t *entity, node_t *node)
 {
     LogPrint(LOG_PROGRESS, "---- {} ----\n", __func__);
 
@@ -237,6 +218,8 @@ static void ExportBrushList(const mapentity_t *entity, node_t *node, uint32_t &b
         dbrush_t &brush = map.bsp.dbrushes.emplace_back(
             dbrush_t{static_cast<int32_t>(map.bsp.dbrushsides.size()), 0, b.contents.native});
 
+        b.outputnumber = { static_cast<uint32_t>(map.bsp.dbrushes.size()) };
+
         auto bevels = AddBrushBevels(b);
 
         for (auto &plane : bevels) {
@@ -249,9 +232,7 @@ static void ExportBrushList(const mapentity_t *entity, node_t *node, uint32_t &b
         brush_state.total_brushes++;
     }
 
-    ExportBrushList_r(entity, node, brush_offset);
-
-    brush_offset += brush_state.total_brushes;
+    ExportBrushList_r(entity, node);
 
     LogPrint(LOG_STAT, "     {:8} total brushes\n", brush_state.total_brushes);
     LogPrint(LOG_STAT, "     {:8} total brush sides\n", brush_state.total_brush_sides);
@@ -645,7 +626,7 @@ static void ProcessEntity(mapentity_t *entity, const int hullnum)
         firstface = MakeFaceEdges(entity, nodes);
 
         if (options.target_game->id == GAME_QUAKE_II) {
-            ExportBrushList(entity, nodes, brush_offset);
+            ExportBrushList(entity, nodes);
         }
 
         ExportDrawNodes(entity, nodes, firstface);

qbsp/solidbsp.cc

@@ -631,8 +631,7 @@ static twosided<std::optional<brush_t>> SplitBrush(const brush_t &brush, const q
 
     for (int i = 0; i < 2; i++) {
         result[i] = { brush_t{} };
-        // fixme-brushbsp: set original pointer
-        //b[i]->original = brush->original;
+        result[i]->original = brush.original;
         // fixme-brushbsp: add a brush_t copy constructor to make sure we get all fields
         result[i]->contents = brush.contents;
         result[i]->lmshift = brush.lmshift;
@@ -785,6 +784,10 @@ static void CreateLeaf(const std::vector<brush_t> &brushes, node_t *leafnode)
     for (auto &brush : brushes) {
         leafnode->contents = MergeContents(leafnode->contents, brush.contents);
     }
+    for (auto &brush : brushes) {
+        Q_assert(brush.original != nullptr);
+        leafnode->original_brushes.push_back(brush.original);
+    }
 
     if (leafnode->contents.extended & CFLAGS_ILLUSIONARY_VISBLOCKER) {
         c_illusionary_visblocker++;
@@ -828,7 +831,7 @@ PartitionBrushes
 Called in parallel.
 ==================
 */
-static void PartitionBrushes(std::vector<brush_t> &brushes, node_t *node)
+static void PartitionBrushes(std::vector<brush_t> brushes, node_t *node)
 {
     face_t *split = SelectPartition(brushes);
 
@@ -890,8 +893,8 @@ static void PartitionBrushes(std::vector<brush_t> &brushes, node_t *node)
     g.run([&]() { PartitionBrushes(backlist, node->children[1]); });
     g.wait();
 #else
-    PartitionBrushes(frontlist, node->children[0]);
-    PartitionBrushes(backlist, node->children[1]);
+    PartitionBrushes(std::move(frontlist), node->children[0]);
+    PartitionBrushes(std::move(backlist), node->children[1]);
 #endif
 }
 
@@ -943,7 +946,14 @@ node_t *SolidBSP(mapentity_t *entity, bool midsplit)
     // count map surfaces; this is used when deciding to switch between midsplit and the expensive partitioning
     mapbrushes = entity->brushes.size();
 
-    PartitionBrushes(entity->brushes, headnode);
+    // set the original pointers
+    std::vector<brush_t> brushcopies;
+    for (brush_t &original : entity->brushes) {
+        brush_t copy = original;
+        copy.original = &original;
+        brushcopies.push_back(std::move(copy));
+    }
+    PartitionBrushes(std::move(brushcopies), headnode);
 
     LogPrint(LOG_STAT, "     {:8} split nodes\n", splitnodes.load());
     LogPrint(LOG_STAT, "     {:8} solid leafs\n", c_solid.load());