decompile: add a simplifed --decompile-geomonly mode

bsputil/bsputil.cc

@@ -529,7 +529,8 @@ main(int argc, char **argv)
     printf("---- bsputil / ericw-tools " stringify(ERICWTOOLS_VERSION) " ----\n");
     if (argc == 1) {
         printf("usage: bsputil [--extract-entities] [--extract-textures] [--convert bsp29|bsp2|bsp2rmq|q2bsp] [--check] [--modelinfo]\n"
-               "[--check] [--compare otherbsp] [--findfaces x y z nx ny nz] [--settexinfo facenum texinfonum] [--decompile] bspfile\n");
+               "[--check] [--compare otherbsp] [--findfaces x y z nx ny nz] [--settexinfo facenum texinfonum]\n"
+               "[--decompile] [--decompile-geomonly] bspfile\n");
         exit(1);
     }
 
@@ -676,7 +677,9 @@ main(int argc, char **argv)
             WriteBSPFile(source, &bspdata);
 
             return 0;
-        } else if (!strcmp(argv[i], "--decompile")) {
+        } else if (!strcmp(argv[i], "--decompile") || !strcmp(argv[i], "--decompile-geomonly")) {
+            const bool geomOnly = !strcmp(argv[i], "--decompile-geomonly");
+
             StripExtension(source);
             DefaultExtension(source, "-decompile.map");
             printf("-> writing %s... ", source);
@@ -685,7 +688,10 @@ main(int argc, char **argv)
             if (!f)
                 Error("couldn't open %s for writing\n", source);
 
-            DecompileBSP(bsp, f);
+            decomp_options options;
+            options.geometryOnly = geomOnly;
+
+            DecompileBSP(bsp, options, f);
 
             fclose(f);
             return 0;

bsputil/decompile.cpp

@@ -632,6 +632,26 @@ DecompileLeaf(const std::vector<decomp_plane_t>* planestack, const mbsp_t *bsp,
     result->push_back({*planestack, leaf});
 }
 
+static std::string
+DecompileLeafTaskGeometryOnly(const mbsp_t *bsp, const leaf_decompile_task& task)
+{
+    const mleaf_t *leaf = task.leaf;
+
+    fmt::memory_buffer file;
+    fmt::format_to(file, "{{\n");
+    for (const auto& side : task.allPlanes) {
+        PrintPlanePoints(bsp, side, file);
+
+        // print a default face
+        fmt::format_to(file, " {} ", DefaultTextureForContents(leaf->contents).c_str());
+        WriteNullTexdef(bsp, file);
+        fmt::format_to(file, "\n");
+    }
+    fmt::format_to(file, "}}\n");
+
+    return fmt::to_string(file);
+}
+
 static std::string
 DecompileLeafTask(const mbsp_t *bsp, const leaf_decompile_task& task)
 {
@@ -767,7 +787,7 @@ AddMapBoundsToStack(std::vector<decomp_plane_t>* planestack, const mbsp_t *bsp,
 }
 
 static void
-DecompileEntity(const mbsp_t *bsp, FILE* file, const entdict_t& dict, bool isWorld)
+DecompileEntity(const mbsp_t *bsp, const decomp_options& options, FILE* file, const entdict_t& dict, bool isWorld)
 {
     // we use -1 to indicate it's not a brush model
     int modelNum = -1;
@@ -811,7 +831,11 @@ DecompileEntity(const mbsp_t *bsp, FILE* file, const entdict_t& dict, bool isWor
         std::vector<std::string> leafStrings;
         leafStrings.resize(tasks.size());
         tbb::parallel_for(static_cast<size_t>(0), tasks.size(), [&](const size_t i) {
-            leafStrings[i] = DecompileLeafTask(bsp, tasks[i]);
+            if (options.geometryOnly) {
+                leafStrings[i] = DecompileLeafTaskGeometryOnly(bsp, tasks[i]);
+            } else {
+                leafStrings[i] = DecompileLeafTask(bsp, tasks[i]);
+            }
         });
 
         // finally print out the leafs
@@ -824,12 +848,12 @@ DecompileEntity(const mbsp_t *bsp, FILE* file, const entdict_t& dict, bool isWor
 }
 
 void
-DecompileBSP(const mbsp_t *bsp, FILE* file)
+DecompileBSP(const mbsp_t *bsp, const decomp_options& options, FILE* file)
 {
     auto entdicts = EntData_Parse(bsp->dentdata);
 
     for (size_t i = 0; i < entdicts.size(); ++i) {
         // entity 0 is implicitly worldspawn (model 0)
-        DecompileEntity(bsp, file, entdicts[i], i == 0);
+        DecompileEntity(bsp, options, file, entdicts[i], i == 0);
     }
 }

bsputil/decompile.h

@@ -5,4 +5,14 @@
 struct mbsp_t;
 struct bsp2_dnode_t;
 
-void DecompileBSP(const mbsp_t *bsp, FILE* file);
+struct decomp_options {
+    /**
+     * If true, use a simplified algorithm that just dumps the planes bounding each leaf,
+     * without attempting to reconstruct faces or discard redundant planes.
+     *
+     * For debugging (there's not much that can go wrong).
+     */
+    bool geometryOnly = false;
+};
+
+void DecompileBSP(const mbsp_t *bsp, const decomp_options& options, FILE* file);