navigation mesh generation WIP

Ideas tried and failed:
- Using the Recast navigation library. Can't stop it from shrinking the mesh away from ledges, while still keeping it away from walls. This means narrow platforms are excluded. Invisible floors would also be missing.
- Generating from the floors of CONTENTS_EMPTY leaves. This works well for indoor areas but has polys extending past ledges. Using the intersection of empty and solid leaves had similar problems.

What's working now:
Generating the clipnodes for a hull as normal, but then cutting out all of the faces that face into the void. Many faces have to be cut. A lot of them start out inside the level then extend out into infinity outside the level. By cutting faces against each other there is a clear separation of inside and outside faces. To test if a face is facing inside the level, the contents of the BSP is checked for every point above the face (super slow). The spacing of this grid of checks has to be small or else tiny faces are excluded.

Currently the entire clipnode hull is being rendered as the mesh, and it replaces the usual hull 3 render for the world. Stripping faces that players can't walk on will make it look like a normal nav mesh.

.gitignore

@@ -6,3 +6,6 @@ msvc
 /release
 /imgui
 /qhull
+/imgui_177
+/imgui_178
+/merge

CMakeLists.txt

@@ -29,6 +29,7 @@ set(SOURCE_FILES
 	src/util/util.h			src/util/util.cpp
 	src/util/vectors.h		src/util/vectors.cpp
 	src/util/mat4x4.h		src/util/mat4x4.cpp
+	src/util/Polygon3D.h	src/util/Polygon3D.cpp
 
 	# OpenGL rendering
 	src/gl/shaders.h			src/gl/shaders.cpp
@@ -160,10 +161,12 @@ if(MSVC)
 
 	source_group("Header Files\\util" FILES		src/util/util.h
 												src/util/vectors.h
+												src/util/Polygon3D.h
 												src/util/mat4x4.h)
 
 	source_group("Source Files\\util" FILES		src/util/util.cpp
 												src/util/vectors.cpp
+												src/util/Polygon3D.cpp
 												src/util/mat4x4.cpp)
 
 	source_group("Header Files\\util\\lib" FILES	src/util/lodepng.h)

src/bsp/Bsp.cpp

@@ -250,7 +250,7 @@ void Bsp::getNodePlanes(int iNode, vector<int>& nodePlanes) {
 	}
 }
 
-vector<NodeVolumeCuts> Bsp::get_model_leaf_volume_cuts(int modelIdx, int hullIdx) {
+vector<NodeVolumeCuts> Bsp::get_model_leaf_volume_cuts(int modelIdx, int hullIdx, int16_t contents) {
 	vector<NodeVolumeCuts> modelVolumeCuts;
 
 	if (hullIdx >= 0 && hullIdx < MAX_MAP_HULLS)
@@ -271,14 +271,14 @@ vector<NodeVolumeCuts> Bsp::get_model_leaf_volume_cuts(int modelIdx, int hullIdx
 				get_node_leaf_cuts(nodeIdx, clipOrder, modelVolumeCuts);
 			}
 			else {
-				get_clipnode_leaf_cuts(nodeIdx, clipOrder, modelVolumeCuts);
+				get_clipnode_leaf_cuts(nodeIdx, clipOrder, modelVolumeCuts, contents);
 			}
 		}
 	}
 	return modelVolumeCuts;
 }
 
-void Bsp::get_clipnode_leaf_cuts(int iNode, vector<BSPPLANE>& clipOrder, vector<NodeVolumeCuts>& output) {
+void Bsp::get_clipnode_leaf_cuts(int iNode, vector<BSPPLANE>& clipOrder, vector<NodeVolumeCuts>& output, int16_t contents) {
 	BSPCLIPNODE& node = clipnodes[iNode];
 
 	if (node.iPlane < 0) {
@@ -294,9 +294,9 @@ void Bsp::get_clipnode_leaf_cuts(int iNode, vector<BSPPLANE>& clipOrder, vector<
 		clipOrder.push_back(plane);
 
 		if (node.iChildren[i] >= 0) {
-			get_clipnode_leaf_cuts(node.iChildren[i], clipOrder, output);
+			get_clipnode_leaf_cuts(node.iChildren[i], clipOrder, output, contents);
 		}
-		else if (node.iChildren[i] != CONTENTS_EMPTY) {
+		else if (node.iChildren[i] == contents) {
 			NodeVolumeCuts nodeVolumeCuts;
 			nodeVolumeCuts.nodeIdx = iNode;
 
@@ -327,7 +327,7 @@ void Bsp::get_node_leaf_cuts(int iNode, vector<BSPPLANE>& clipOrder, vector<Node
 		if (node.iChildren[i] >= 0) {
 			get_node_leaf_cuts(node.iChildren[i], clipOrder, output);
 		}
-		else if (leaves[~node.iChildren[i]].nContents != CONTENTS_EMPTY) {
+		else if (leaves[~node.iChildren[i]].nContents != CONTENTS_SOLID) {
 			NodeVolumeCuts nodeVolumeCuts;
 			nodeVolumeCuts.nodeIdx = iNode;
 

src/bsp/Bsp.h

@@ -10,6 +10,10 @@
 #include <set>
 #include "bsptypes.h"
 
+// largest coordinate allowed in map
+//#define MAX_COORD 131072
+#define MAX_COORD 32768
+
 struct membuf : std::streambuf
 {
 	membuf(char* begin, int len) {
@@ -107,8 +111,8 @@ class Bsp
 	bool is_node_hull_convex(int iNode);
 
 	// get cuts required to create bounding volumes for each solid leaf in the model
-	vector<NodeVolumeCuts> get_model_leaf_volume_cuts(int modelIdx, int hullIdx);
-	void get_clipnode_leaf_cuts(int iNode, vector<BSPPLANE>& clipOrder, vector<NodeVolumeCuts>& output);
+	vector<NodeVolumeCuts> get_model_leaf_volume_cuts(int modelIdx, int hullIdx, int16_t contents);
+	void get_clipnode_leaf_cuts(int iNode, vector<BSPPLANE>& clipOrder, vector<NodeVolumeCuts>& output, int16_t contents);
 	void get_node_leaf_cuts(int iNode, vector<BSPPLANE>& clipOrder, vector<NodeVolumeCuts>& output);
 
 	// this a cheat to recalculate plane normals after scaling a solid. Really I should get the plane
@@ -210,6 +214,8 @@ class Bsp
 
 	void update_lump_pointers();
 
+	void write_obj_file();
+
 private:
 	int remove_unused_lightmaps(bool* usedFaces);
 	int remove_unused_visdata(bool* usedLeaves, BSPLEAF* oldLeaves, int oldLeafCount); // called after removing unused leaves