Stop bullets getting stuck in walls. See comment for details.

src/bullet.cpp

@@ -10,10 +10,31 @@ Bullet::Bullet(ph::vec3f pos, ph::vec3f vel) {
 	initialize(mass, inertia, state);
 
 	body->setGravity(btVector3(0,0,0));
+
+	// If we move further than this in a given timestep, use continuous
+	// collision detection.
 	body->setCcdMotionThreshold(0.2);
-	body->setCcdSweptSphereRadius(0.2);
+
+	// CCD sweeps a sphere along the path the body will take, then checks
+	// whether it collides with anything. This is the radius of that sphere.
+	// If it's too big, the bullet can get stuck in walls. I assume this
+	// happens because the bullet is stopped before the sweep-sphere
+	// collides, hence the bullet itself is not at that point colliding, so
+	// no collision resolution happens. I don't understand why .15 would be
+	// too big, given that the actual collision shape has a radius of .2,
+	// but when I tried this at .15, they did sometimes get stuck.
+	body->setCcdSweptSphereRadius(0.1);
 }
 
+void Bullet::update() {
+	ph::vec3f vel = body->getLinearVelocity();
+	printf("%f, %f, %f\n", vel.x, vel.y, vel.z);
+
+	btTransform trans;
+	body->getMotionState()->getWorldTransform(trans);
+	ph::vec3f pos = trans.getOrigin();
+	printf("%f, %f, %f\n", pos.x, pos.y, pos.z);
+}
 
 
 

src/bullet.h

@@ -8,6 +8,8 @@ class Bullet : public Entity {
 	typedef Entity super;
 
 	Bullet(ph::vec3f pos, ph::vec3f vel);
+
+	void update();
 };
 
 #endif

src/world.cpp

@@ -23,8 +23,6 @@ World::World() {
 	groundBody = new btRigidBody(construct);
 
 	G::physics->addRigidBody(groundBody);
-
-	addEntity(new Bullet(ph::vec3f(0, 2, 2), ph::vec3f(0,0,0)));
 }
 
 World::~World () {
@@ -52,6 +50,10 @@ void World::update() {
 	rotate += 1.0f;
 
 	printf("%d\n", gNumClampedCcdMotions);
+
+	foreach(Entity *e, entities) {
+		e->update();
+	}
 }
 
 void World::addEntity(Entity *ent) {