Fix multiple issues with CSG module.

- Replaces BuildPoly with Build2DFaces, which creates faces as each
  pair of face intersections are processed, instead of trying to create
  them after all the intersections are processed. Ensures that faces are
  merged when possible, and removes degenerate triangles.

- Treats the child as inside the parent when faces are coplanar.

- General clean up of csg.h and csg.cpp.

modules/csg/csg.h

@@ -31,20 +31,21 @@
 #ifndef CSG_H
 #define CSG_H
 
+#include "core/list.h"
 #include "core/map.h"
 #include "core/math/aabb.h"
 #include "core/math/plane.h"
-#include "core/math/rect2.h"
 #include "core/math/transform.h"
+#include "core/math/vector2.h"
 #include "core/math/vector3.h"
 #include "core/oa_hash_map.h"
-
+#include "core/reference.h"
+#include "core/vector.h"
 #include "scene/resources/material.h"
 
 struct CSGBrush {
 
 	struct Face {
-
 		Vector3 vertices[3];
 		Vector2 uvs[3];
 		AABB aabb;
@@ -56,12 +57,11 @@ struct CSGBrush {
 	Vector<Face> faces;
 	Vector<Ref<Material> > materials;
 
-	void _regen_face_aabbs();
-	//create a brush from faces
+	inline void _regen_face_aabbs();
+
+	// Create a brush from faces.
 	void build_from_faces(const Vector<Vector3> &p_vertices, const Vector<Vector2> &p_uvs, const Vector<bool> &p_smooth, const Vector<Ref<Material> > &p_materials, const Vector<bool> &p_invert_faces);
 	void copy_from(const CSGBrush &p_brush, const Transform &p_xform);
-
-	void clear();
 };
 
 struct CSGBrushOperation {
@@ -70,12 +70,23 @@ struct CSGBrushOperation {
 		OPERATION_UNION,
 		OPERATION_INTERSECTION,
 		OPERATION_SUBSTRACTION,
-
 	};
 
+	void merge_brushes(Operation p_operation, const CSGBrush &p_brush_a, const CSGBrush &p_brush_b, CSGBrush &r_merged_brush, float p_vertex_snap);
+
 	struct MeshMerge {
 
-		struct BVH {
+		struct Face {
+			bool from_b;
+			bool inside;
+			int points[3];
+			Vector2 uvs[3];
+			bool smooth;
+			bool invert;
+			int material_idx;
+		};
+
+		struct FaceBVH {
 			int face;
 			int left;
 			int right;
@@ -84,32 +95,23 @@ struct CSGBrushOperation {
 			AABB aabb;
 		};
 
-		struct BVHCmpX {
-
-			bool operator()(const BVH *p_left, const BVH *p_right) const {
-
+		struct FaceBVHCmpX {
+			_FORCE_INLINE_ bool operator()(const FaceBVH *p_left, const FaceBVH *p_right) const {
 				return p_left->center.x < p_right->center.x;
 			}
 		};
 
-		struct BVHCmpY {
-
-			bool operator()(const BVH *p_left, const BVH *p_right) const {
-
+		struct FaceBVHCmpY {
+			_FORCE_INLINE_ bool operator()(const FaceBVH *p_left, const FaceBVH *p_right) const {
 				return p_left->center.y < p_right->center.y;
 			}
 		};
-		struct BVHCmpZ {
-
-			bool operator()(const BVH *p_left, const BVH *p_right) const {
-
+		struct FaceBVHCmpZ {
+			_FORCE_INLINE_ bool operator()(const FaceBVH *p_left, const FaceBVH *p_right) const {
 				return p_left->center.z < p_right->center.z;
 			}
 		};
 
-		int _bvh_count_intersections(BVH *bvhptr, int p_max_depth, int p_bvh_first, const Vector3 &p_begin, const Vector3 &p_end, int p_exclude) const;
-		int _create_bvh(BVH *p_bvh, BVH **p_bb, int p_from, int p_size, int p_depth, int &max_depth, int &max_alloc);
-
 		struct VertexKey {
 			int32_t x, y, z;
 			_FORCE_INLINE_ bool operator<(const VertexKey &p_key) const {
@@ -138,99 +140,59 @@ struct CSGBrushOperation {
 			}
 		};
 
-		OAHashMap<VertexKey, int, VertexKeyHash> snap_cache;
-
 		Vector<Vector3> points;
-
-		struct Face {
-			bool from_b;
-			bool inside;
-			int points[3];
-			Vector2 uvs[3];
-			bool smooth;
-			bool invert;
-			int material_idx;
-		};
-
 		Vector<Face> faces;
-
 		Map<Ref<Material>, int> materials;
-
 		Map<Vector3, int> vertex_map;
-		void add_face(const Vector3 &p_a, const Vector3 &p_b, const Vector3 &p_c, const Vector2 &p_uv_a, const Vector2 &p_uv_b, const Vector2 &p_uv_c, bool p_smooth, bool p_invert, const Ref<Material> &p_material, bool p_from_b);
-		//		void add_face(const Vector3 &p_a, const Vector3 &p_b, const Vector3 &p_c, bool p_from_b);
-
+		OAHashMap<VertexKey, int, VertexKeyHash> snap_cache;
 		float vertex_snap;
+
+		inline void _add_distance(List<real_t> &r_intersectionsA, List<real_t> &r_intersectionsB, bool p_from_B, real_t p_distance) const;
+		inline bool _bvh_inside(FaceBVH *facebvhptr, int p_max_depth, int p_bvh_first, int p_face_idx) const;
+		inline int _create_bvh(FaceBVH *facebvhptr, FaceBVH **facebvhptrptr, int p_from, int p_size, int p_depth, int &r_max_depth, int &r_max_alloc);
+
+		void add_face(const Vector3 p_points[3], const Vector2 p_uvs[3], bool p_smooth, bool p_invert, const Ref<Material> &p_material, bool p_from_b);
 		void mark_inside_faces();
 	};
 
-	struct BuildPoly {
+	struct Build2DFaces {
 
-		Plane plane;
-		Transform to_poly;
-		Transform to_world;
-		int face_index;
-
-		struct Point {
+		struct Vertex2D {
 			Vector2 point;
 			Vector2 uv;
 		};
 
-		Vector<Point> points;
-
-		struct Edge {
-			bool outer;
-			int points[2];
-			Edge() {
-				outer = false;
-			}
+		struct Face2D {
+			int vertex_idx[3];
 		};
 
-		Vector<Edge> edges;
-		Ref<Material> material;
-		bool smooth;
-		bool invert;
-
-		int base_edges; //edges from original triangle, even if split
-
-		void _clip_segment(const CSGBrush *p_brush, int p_face, const Vector2 *segment, MeshMerge &mesh_merge, bool p_for_B);
-
-		void create(const CSGBrush *p_brush, int p_face, MeshMerge &mesh_merge, bool p_for_B);
-		void clip(const CSGBrush *p_brush, int p_face, MeshMerge &mesh_merge, bool p_for_B);
-	};
-
-	struct PolyPoints {
-
-		Vector<int> points;
-
-		Vector<Vector<int> > holes;
-	};
-
-	struct EdgeSort {
-		int edge;
-		int prev_point;
-		int edge_point;
-		float angle;
-		bool operator<(const EdgeSort &p_edge) const { return angle < p_edge.angle; }
+		Vector<Vertex2D> vertices;
+		Vector<Face2D> faces;
+		Plane plane;
+		Transform to_2D;
+		Transform to_3D;
+		float vertex_snap2;
+
+		inline int _get_point_idx(const Vector2 &p_point);
+		inline int _add_vertex(const Vertex2D &p_vertex);
+		inline void _add_vertex_idx_sorted(Vector<int> &r_vertex_indices, int p_new_vertex_index);
+		inline void _merge_faces(const Vector<int> &p_segment_indices);
+		inline void _find_edge_intersections(const Vector2 p_segment_points[2], Vector<int> &r_segment_indices);
+		inline int _insert_point(const Vector2 &p_point);
+
+		void insert(const CSGBrush &p_brush, int p_brush_face);
+		void addFacesToMesh(MeshMerge &r_mesh_merge, bool p_smooth, bool p_invert, const Ref<Material> &p_material, bool p_from_b);
+
+		Build2DFaces() {}
+		Build2DFaces(const CSGBrush &p_brush, int p_brush_face, float p_vertex_snap2);
 	};
 
-	struct CallbackData {
-		const CSGBrush *A;
-		const CSGBrush *B;
-		int face_a;
-		CSGBrushOperation *self;
-		Map<int, BuildPoly> build_polys_A;
-		Map<int, BuildPoly> build_polys_B;
+	struct Build2DFaceCollection {
+		Map<int, Build2DFaces> build2DFacesA;
+		Map<int, Build2DFaces> build2DFacesB;
 	};
 
-	void _add_poly_points(const BuildPoly &p_poly, int p_edge, int p_from_point, int p_to_point, const Vector<Vector<int> > &vertex_process, Vector<bool> &edge_process, Vector<PolyPoints> &r_poly);
-	void _add_poly_outline(const BuildPoly &p_poly, int p_from_point, int p_to_point, const Vector<Vector<int> > &vertex_process, Vector<int> &r_outline);
-	void _merge_poly(MeshMerge &mesh, int p_face_idx, const BuildPoly &p_poly, bool p_from_b);
-
-	void _collision_callback(const CSGBrush *A, int p_face_a, Map<int, BuildPoly> &build_polys_a, const CSGBrush *B, int p_face_b, Map<int, BuildPoly> &build_polys_b, MeshMerge &mesh_merge);
-
-	static void _collision_callbacks(void *ud, int p_face_b);
-	void merge_brushes(Operation p_operation, const CSGBrush &p_A, const CSGBrush &p_B, CSGBrush &result, float p_snap = 0.001);
+	void update_faces(const CSGBrush &p_brush_a, const int p_face_idx_a, const CSGBrush &p_brush_b, const int p_face_idx_b, Build2DFaceCollection &p_collection, float p_vertex_snap);
 };
 
 #endif // CSG_H