Address warnings and review feedback

- Resolve mixed-signs warnings where feasible
- Introduce new vector3::ReciprocalSafe() method to compute 1.0 / vector without introducing NaNs
- Fix initialization order warning in CollisionContact.h

src/collider/BVHTree.cpp

@@ -44,9 +44,9 @@ void SingleBVHTreeBase::Build(const AABBd &bounds, AABBd *objAabbs, uint32_t num
 	m_nodes.reserve(2 * numObjs + 1);
 
 	// compute a remapping term to express object positions with highest precision using single floating point
-	// use the average of the bounding volue to remap into [-1 .. 1] space
+	// use the average of the bounding volume to remap into [-1 .. 1] space
 	m_boundsCenter = (bounds.max + bounds.min) * 0.5;
-	vector3d inv_scale = 1.0 / (bounds.max - m_boundsCenter);
+	vector3d inv_scale = (bounds.max - m_boundsCenter).ReciprocalSafe();
 	m_inv_scale_factor = (inv_scale.x + inv_scale.y + inv_scale.z) / 3.0;
 
 	// Build a vector of sort keys for individual nodes (position within system)
@@ -324,7 +324,7 @@ float BinnedAreaBVHTree::FindPivot(SortKey *keys, uint32_t numKeys, const AABBd
 		bins[bin_idx].bounds.Update(objAabbs[keys[i].index]);
 	}
 
-	constexpr size_t NUM_PLANES = NUM_BINS - 1;
+	constexpr int NUM_PLANES = NUM_BINS - 1;
 
 	float planeCost[NUM_PLANES];
 	float bestCost = FLT_MAX;

src/collider/CollisionContact.h

@@ -23,9 +23,9 @@ struct CollisionContact {
 		distance(0),
 		timestep(0),
 		triIdx(-1),
+		geomFlag(0),
 		userData1(nullptr),
-		userData2(nullptr),
-		geomFlag(0)
+		userData2(nullptr)
 	{}
 
 	// ctor for collision with terrain

src/collider/Geom.cpp

@@ -71,7 +71,7 @@ void Geom::CollideSphere(Sphere &sphere, void (*callback)(CollisionContact *)) c
 std::vector<CollisionContact> Geom::Collide(Geom *b) const
 {
 	PROFILE_SCOPED()
-	int max_contacts = MAX_CONTACTS;
+	size_t max_contacts = MAX_CONTACTS;
 	matrix4x4d transTo;
 
 	std::vector<CollisionContact> contacts;
@@ -108,7 +108,7 @@ static AABBd rotateAaabb(const AABBd &a, const matrix4x4d transA)
  * Intersect this Geom's edge BVH tree with geom b's triangle BVH tree.
  * Generate collision contacts.
  */
-void Geom::CollideEdgesWithTrisOf(std::vector<CollisionContact> &contacts, int maxContacts, const Geom *b, const matrix4x4d &transTo) const
+void Geom::CollideEdgesWithTrisOf(std::vector<CollisionContact> &contacts, size_t maxContacts, const Geom *b, const matrix4x4d &transTo) const
 {
 	PROFILE_SCOPED()
 	struct stackobj {
@@ -197,7 +197,7 @@ void Geom::CollideEdgeTris(std::vector<CollisionContact> &contacts, const matrix
 	isect.triIdx = -1;
 
 	isect_buf.clear();
-	b->GetGeomTree()->GetTriTree()->TraceRay(v1, 1.0 / dir, edge.len, isect_buf, triNode);
+	b->GetGeomTree()->GetTriTree()->TraceRay(v1, dir.ReciprocalSafe(), edge.len, isect_buf, triNode);
 
 	// TODO
 	// This is subtly dependent on overwriting intersections with the last triangle to be processed
@@ -211,7 +211,7 @@ void Geom::CollideEdgeTris(std::vector<CollisionContact> &contacts, const matrix
 		return;
 
 	// in world coords
-	CollisionContact contact;
+	CollisionContact contact = {};
 	contact.pos = b->GetTransform() * (v1 + dir * double(isect.dist));
 	contact.normal = vector3d(b->m_geomtree->GetTriNormal(isect.triIdx));
 	contact.normal = b->GetTransform().ApplyRotationOnly(contact.normal);

src/collider/Geom.h

@@ -37,7 +37,7 @@ class Geom {
 
 private:
 	// Note: these functions could easily be made static and extracted into a separate collision system
-	void CollideEdgesWithTrisOf(std::vector<CollisionContact> &contacts, int maxContacts, const Geom *b, const matrix4x4d &transTo) const;
+	void CollideEdgesWithTrisOf(std::vector<CollisionContact> &contacts, size_t maxContacts, const Geom *b, const matrix4x4d &transTo) const;
 	void CollideEdgeTris(std::vector<CollisionContact> &contacts, const matrix4x4d &transToB, const Geom *b, uint32_t edgeIdx, uint32_t triIdx, std::vector<uint32_t> &isect_buf) const;
 
 	// double-buffer position so we can keep previous position

src/collider/GeomTree.cpp

@@ -227,7 +227,7 @@ GeomTree::GeomTree(Serializer::Reader &rd)
 void GeomTree::TraceRay(const vector3f &start, const vector3f &dir, isect_t *isect) const
 {
 	std::vector<uint32_t> tri_isect;
-	m_triTree->TraceRay(vector3d(start), vector3d(1.f / dir), FLT_MAX, tri_isect);
+	m_triTree->TraceRay(vector3d(start), vector3d(dir).ReciprocalSafe(), FLT_MAX, tri_isect);
 
 	for (uint32_t triIdx : tri_isect) {
 		RayTriIntersect(1, start, &dir, triIdx * 3, isect);

src/vector3.h

@@ -150,6 +150,15 @@ class alignas(sizeof(T)) vector3 {
 		}
 	}
 
+	// Compute the reciprocal of the vector (1.0 / v), avoiding division by zero
+	vector3 ReciprocalSafe() const
+	{
+		return vector3(
+			x == 0.0 ? 0.0 : 1.0 / x,
+			y == 0.0 ? 0.0 : 1.0 / y,
+			z == 0.0 ? 0.0 : 1.0 / z);
+	}
+
 	void Print() const { printf("v(%f,%f,%f)\n", x, y, z); }
 
 	/* Rotate this vector about point o, in axis defined by v. */