From 7d71713bea2268c5154b60947ab447028f510d76 Mon Sep 17 00:00:00 2001
From: Irlan <->
Date: Thu, 19 Apr 2018 19:42:37 -0300
Subject: [PATCH] store hull features on the stack

---
 include/bounce/collision/shapes/qhull.h | 25 ++++++++++++--
 src/bounce/collision/shapes/qhull.cpp   | 46 +++----------------------
 2 files changed, 28 insertions(+), 43 deletions(-)

diff --git a/include/bounce/collision/shapes/qhull.h b/include/bounce/collision/shapes/qhull.h
index d71b7cf..c17738a 100644
--- a/include/bounce/collision/shapes/qhull.h
+++ b/include/bounce/collision/shapes/qhull.h
@@ -21,10 +21,31 @@
 
 #include <bounce/collision/shapes/hull.h>
 
+// The maximum number of vertices that a hull can have.
+#define B3_MAX_HULL_VERTICES (256)
+
+// The maximum number of half-edges a hull can have.
+#define B3_MAX_HULL_EDGES (256)
+
+// The maximum number of faces and planes a hull can have.
+#define B3_MAX_HULL_FACES (256)
+
+// This hull can be constructed from an array of points.
 struct b3QHull : public b3Hull
 {
-	b3QHull();
-	~b3QHull();
+	b3Vec3 hullVertices[B3_MAX_HULL_VERTICES];
+	b3HalfEdge hullEdges[B3_MAX_HULL_EDGES];
+	b3Face hullFaces[B3_MAX_HULL_FACES];
+	b3Plane hullPlanes[B3_MAX_HULL_FACES];
+
+	//
+	b3QHull()
+	{
+		vertices = hullVertices;
+		edges = hullEdges;
+		faces = hullFaces;
+		planes = hullPlanes;
+	}
 
 	// Create a convex hull from an array of points.
 	// If the points define a degenerate polyhedron the hull is not overwritten.
diff --git a/src/bounce/collision/shapes/qhull.cpp b/src/bounce/collision/shapes/qhull.cpp
index 1ad4083..ed9b2f8 100644
--- a/src/bounce/collision/shapes/qhull.cpp
+++ b/src/bounce/collision/shapes/qhull.cpp
@@ -19,14 +19,6 @@
 #include <bounce/collision/shapes/qhull.h>
 #include <bounce/quickhull/qh_hull.h>
 
-// Euler's formula
-// V - E + F = 2
-//#define B3_MAX_HULL_VERTICES 87
-//#define B3_MAX_HULL_EDGES (3 * B3_MAX_HULL_VERTICES - 6)
-//#define B3_MAX_HULL_FACES (2 * B3_MAX_HULL_VERTICES - 4)
-
-#define B3_MAX_HULL_FEATURES 256
-
 #define B3_NULL_HULL_FEATURE 0xFF
 
 //
@@ -61,26 +53,6 @@ struct b3PointerMap
 	b3StackArray<b3PointerIndex, N> m_entries;
 };
 
-b3QHull::b3QHull()
-{
-	centroid.SetZero();
-	vertexCount = 0;
-	vertices = NULL;
-	edgeCount = 0;
-	edges = NULL;
-	faceCount = 0;
-	faces = NULL;
-	planes = NULL;
-}
-
-b3QHull::~b3QHull()
-{
-	b3Free(vertices);
-	b3Free(edges);
-	b3Free(faces);
-	b3Free(planes);
-}
-
 //
 static b3Vec3 b3ComputeCentroid(b3QHull* hull)
 {
@@ -151,7 +123,7 @@ static b3Vec3 b3ComputeCentroid(b3QHull* hull)
 void b3QHull::Set(const b3Vec3* points, u32 count)
 {
 	// Copy points into local buffer, remove coincident points.
-	b3StackArray<b3Vec3, B3_MAX_HULL_FEATURES> ps;
+	b3StackArray<b3Vec3, B3_MAX_HULL_VERTICES> ps;
 	for (u32 i = 0; i < count; ++i)
 	{
 		b3Vec3 p = points[i];
@@ -209,27 +181,19 @@ void b3QHull::Set(const b3Vec3* points, u32 count)
 		face = face->next;
 	}
 
-	if (V > B3_MAX_HULL_FEATURES || E > B3_MAX_HULL_FEATURES || F > B3_MAX_HULL_FEATURES)
+	if (V > B3_MAX_HULL_VERTICES || E > B3_MAX_HULL_EDGES || F > B3_MAX_HULL_FACES)
 	{
 		b3Free(qh_memory);
 		return; 
 	}
 
-	b3Free(vertices);
-	b3Free(edges);
-	b3Free(faces);
-	b3Free(planes);
-
+	// Convert the constructed hull into a run-time hull.
 	vertexCount = 0;
-	vertices = (b3Vec3*)b3Alloc(V * sizeof(b3Vec3));
 	edgeCount = 0;
-	edges = (b3HalfEdge*)b3Alloc(E * sizeof(b3HalfEdge));
 	faceCount = 0;
-	faces = (b3Face*)b3Alloc(F * sizeof(b3Face));
-	planes = (b3Plane*)b3Alloc(F * sizeof(b3Plane));
 
-	b3PointerMap<B3_MAX_HULL_FEATURES> vertexMap;
-	b3PointerMap<B3_MAX_HULL_FEATURES> edgeMap;
+	b3PointerMap<B3_MAX_HULL_VERTICES> vertexMap;
+	b3PointerMap<B3_MAX_HULL_EDGES> edgeMap;
 
 	face = faceList.head;
 	while (face)