fix mesh size, decouple mesh topology from geometry, add polygon triangulation to make mass calculation O(n) in memory

include/bounce/collision/shapes/mesh.h

@@ -22,6 +22,43 @@
 #include <bounce/common/geometry.h>
 #include <bounce/collision/trees/static_tree.h>
 
+// A triangle in indexed form.
+struct b3Triangle
+{
+	// Does nothing for performance.
+	b3Triangle() { }
+
+	// Set this triangle from three vertices.
+	b3Triangle(u32 _v1, u32 _v2, u32 _v3)
+	{
+		v1 = _v1;
+		v2 = _v2;
+		v3 = _v3;
+	}
+
+	// Set this triangle from three vertices.
+	void Set(u32 _v1, u32 _v2, u32 _v3)
+	{
+		v1 = _v1;
+		v2 = _v2;
+		v3 = _v3;
+	}
+
+	// Test if this triangle contains a given vertex.
+	bool TestVertex(u32 v) const
+	{
+		return v == v1 || v == v2 || v == v3;
+	}
+
+	// Test if this triangle contains two vertices.
+	bool TestEdge(u32 _v1, u32 _v2) const
+	{
+		return TestVertex(_v1) && TestVertex(_v2);
+	}
+
+	u32 v1, v2, v3;
+};
+
 struct b3Mesh 
 {
 	u32 vertexCount;
@@ -102,13 +139,12 @@ inline b3AABB3 b3Mesh::GetTriangleAABB(u32 index) const
 
 inline u32 b3Mesh::GetSize() const
 {
-	u32 memory = 0;
-	memory += sizeof(b3Mesh);
-	memory += sizeof(b3Vec3) * vertexCount;
-	memory += sizeof(b3Triangle) * triangleCount;
-	memory += sizeof(b3Plane) * triangleCount;
-	memory += sizeof(b3StaticTree);
-	return memory;
+	u32 size = 0;
+	size += sizeof(b3Mesh);
+	size += sizeof(b3Vec3) * vertexCount;
+	size += sizeof(b3Triangle) * triangleCount;
+	size += tree.GetSize();
+	return size;
 }
 
 #endif

include/bounce/collision/trees/static_tree.h

@@ -57,6 +57,8 @@ public:
 
 	// Draw this tree.
 	void Draw(b3Draw* draw) const;
+
+	u32 GetSize() const;
 private :
 	// A node in a static tree.
 	struct b3Node
@@ -198,4 +200,12 @@ inline void b3StaticTree::RayCast(T* callback, const b3RayCastInput& input) cons
 	}
 }
 
+inline u32 b3StaticTree::GetSize() const
+{
+	u32 size = 0;
+	size += sizeof(b3StaticTree);
+	size += m_nodeCount * sizeof(b3Node);
+	return size;
+}
+
 #endif

include/bounce/common/geometry.h

@@ -22,43 +22,6 @@
 #include <bounce/common/math/math.h>
 #include <bounce/common/math/transform.h>
 
-// A triangle in indexed form.
-struct b3Triangle
-{
-	// Does nothing for performance.
-	b3Triangle() { }
-
-	// Set this triangle from three vertices.
-	b3Triangle(u32 _v1, u32 _v2, u32 _v3) 
-	{
-		v1 = _v1;
-		v2 = _v2;
-		v3 = _v3;
-	}
-	
-	// Set this triangle from three vertices.
-	void Set(u32 _v1, u32 _v2, u32 _v3)
-	{
-		v1 = _v1;
-		v2 = _v2;
-		v3 = _v3;
-	}
-
-	// Test if this triangle contains a given vertex.
-	bool TestVertex(u32 v) const
-	{
-		return v == v1 || v == v2 || v == v3;
-	}
-
-	// Test if this triangle contains two vertices.
-	bool TestEdge(u32 _v1, u32 _v2) const
-	{
-		return TestVertex(_v1) && TestVertex(_v2);
-	}
-
-	u32 v1, v2, v3;
-};
-
 // A plane in constant normal form.
 // dot(n, p) - d = 0.
 struct b3Plane

src/bounce/dynamics/shapes/hull_shape.cpp

@@ -39,41 +39,6 @@ void b3HullShape::Swap(const b3HullShape& other)
 
 void b3HullShape::ComputeMass(b3MassData* massData, float32 density) const
 {
-	// Build triangles for hull
-	b3StackArray<b3Triangle, 256> triangles;
-	
-	// Use a small buffer for polygons.
-	u32 polygon[B3_MAX_HULL_FEATURES];
-	u32 vCount = 0;
-
-	// Convert polygons to triangles
-	for (u32 i = 0; i < m_hull->faceCount; ++i)
-	{
-		// Build convex polygon for loop
-		const b3Face* face = m_hull->GetFace(i);
-		const b3HalfEdge* begin = m_hull->GetEdge(face->edge);
-		const b3HalfEdge* edge = begin;
-		do
-		{
-			polygon[vCount++] = u32(edge->origin);
-			edge = m_hull->GetEdge(edge->next);
-		} while (edge != begin);
-		
-		// Triangulate convex polygon
-		B3_ASSERT(vCount > 2);
-		for (u32 j = 1; j < vCount - 1; ++j)
-		{
-			b3Triangle triangle;
-			triangle.v1 = polygon[0];
-			triangle.v2 = polygon[j];
-			triangle.v3 = polygon[j + 1];
-			triangles.PushBack(triangle);
-		}
-
-		vCount = 0;
-	}
-	vCount = 0;
-
 	// Compute mass data
 	b3Vec3 center(0.0f, 0.0f, 0.0f);
 	float32 volume = 0.0f;
@@ -92,13 +57,25 @@ void b3HullShape::ComputeMass(b3MassData* massData, float32 density) const
 	b3Vec3 diag(0.0f, 0.0f, 0.0f);
 	b3Vec3 offDiag(0.0f, 0.0f, 0.0f);
 
-	for (u32 i = 0; i < triangles.Count(); ++i)
+	// Triangulate convex polygons
+	for (u32 i = 0; i < m_hull->faceCount; ++i)
 	{
-		const b3Triangle* triangle = triangles.Get(i);
+		const b3Face* face = m_hull->GetFace(i);
+		const b3HalfEdge* begin = m_hull->GetEdge(face->edge);
 		
-		b3Vec3 v2 = m_hull->GetVertex(triangle->v1);
-		b3Vec3 v3 = m_hull->GetVertex(triangle->v2);
-		b3Vec3 v4 = m_hull->GetVertex(triangle->v3);
+		const b3HalfEdge* edge = m_hull->GetEdge(begin->next);
+		do
+		{
+			u32 i1 = begin->origin;
+			u32 i2 = edge->origin;
+			const b3HalfEdge* next = m_hull->GetEdge(edge->next);
+			u32 i3 = next->origin;
+
+			b3Vec3 v2 = m_hull->vertices[i1];
+			b3Vec3 v3 = m_hull->vertices[i2];
+			b3Vec3 v4 = m_hull->vertices[i3];
+			
+			//
 			b3Vec3 tetraCenter = inv4 * (v1 + v2 + v3 + v4);
 
 			b3Vec3 e1 = v2 - v1;
@@ -127,6 +104,9 @@ void b3HullShape::ComputeMass(b3MassData* massData, float32 density) const
 						e1[j1] * e3[j2] + e2[j1] * e1[j2] + e3[j1] * e2[j2] +
 						e1[j1] * e1[j2] * 2.0f + e2[j1] * e2[j2] * 2.0f + e3[j1] * e3[j2] * 2.0f);
 			}
+			
+			edge = next;
+		} while (m_hull->GetEdge(edge->next) != begin);
 	}
 
 	B3_ASSERT(volume > 0.0f);

src/testbed/framework/debug_draw.cpp

@@ -467,39 +467,52 @@ struct DrawShapes
 	void DrawHull(const b3HullShape* s, const b3Transform& xf)
 	{
 		const b3Hull* hull = s->m_hull;
+
 		for (u32 i = 0; i < hull->faceCount; ++i)
 		{
-			b3Vec3 n = xf.rotation * hull->planes[i].normal;
-			
-			glBegin(GL_POLYGON);
-			glNormal3f(n.x, n.y, n.z);
-
 			const b3Face* face = hull->GetFace(i);
 			const b3HalfEdge* begin = hull->GetEdge(face->edge);
-			const b3HalfEdge* edge = begin;
+
+			b3Vec3 n = xf.rotation * hull->planes[i].normal;
+
+			const b3HalfEdge* edge = hull->GetEdge(begin->next);
 			do
 			{
-				b3Vec3 v = xf * hull->GetVertex(edge->origin);
+				u32 i1 = begin->origin;
+				u32 i2 = edge->origin;
+				const b3HalfEdge* next = hull->GetEdge(edge->next);
+				u32 i3 = next->origin;
 
-				glVertex3f(v.x, v.y, v.z);
+				b3Vec3 v1 = xf * hull->vertices[i1];
+				b3Vec3 v2 = xf * hull->vertices[i2];
+				b3Vec3 v3 = xf * hull->vertices[i3];
 
-				edge = hull->GetEdge(edge->next);
-			} while (edge != begin);
+				glBegin(GL_TRIANGLES);
+				glNormal3f(n.x, n.y, n.z);
+
+				glVertex3f(v1.x, v1.y, v1.z);
+				glVertex3f(v2.x, v2.y, v2.z);
+				glVertex3f(v3.x, v3.y, v3.z);
 
 				glEnd();
+
+				edge = next;
+			} while (hull->GetEdge(edge->next) != begin);
+
 		}
 	}
 
 	void DrawMesh(const b3MeshShape* s, const b3Transform& xf)
 	{
 		const b3Mesh* mesh = s->m_mesh;
+		
 		for (u32 i = 0; i < mesh->triangleCount; ++i)
 		{
-			const b3Triangle* triangle = mesh->triangles + i;
+			const b3Triangle* t = mesh->triangles + i;
 
-			b3Vec3 v1 = xf * mesh->vertices[triangle->v1];
-			b3Vec3 v2 = xf * mesh->vertices[triangle->v2];
-			b3Vec3 v3 = xf * mesh->vertices[triangle->v3];
+			b3Vec3 v1 = xf * mesh->vertices[t->v1];
+			b3Vec3 v2 = xf * mesh->vertices[t->v2];
+			b3Vec3 v3 = xf * mesh->vertices[t->v3];
 
 			b3Vec3 n = b3Cross(v2 - v1, v3 - v1);
 			n.Normalize();