public PointMass(float mass, Vec2 pos, Vec2 vel)
{
//parameterized constructor
this.mass = mass;
this.pos = pos;
this.vel = vel;
}
public static float Dot(Vec2 a, Vec2 b)
{
//calculates the Dot product of two vectors
float dotprod;
dotprod = (a.x * b.x) + (a.y * b.y);
return (float)dotprod;
}
protected bool collide(List<CollisionPair> collisions, CircleShell a, CircleShell b)
{
//for future use: will have conditionals here for the different shell types
float collision = a.radius + b.radius;
//calc current distance
Vec2 distance = new Vec2((b.position.x - a.position.x), (b.position.y - a.position.y));
//check if they overlap
float overlap = collision - distance.GetMag();
//if they overlap, create a new pair and add it to the list
if (overlap <= collision && overlap >= 0.0f)
{
CollisionPair cpair = new CollisionPair(a, b, (distance * overlap));
collisions.Add(cpair);
return true;
}
else
{
return false;
}
}
//each timestep, do this.
public override void Step(float dt)
{
Vec2 a = (1.0f/mass) * forceAccumulator;
Vec2 v = a * dt + vel;
pos = vel * dt + Pos;
vel = v;
forceAccumulator = new Vec2(); //zero out the force
}
public Circle(EWorld ew, Vec2 pos, Vec2 vel, float radius, float mass, Color color)
{
this.eworld = ew;
this.cshell = new CircleShell(pos, radius);
this.pm = new PhysicsWorld.PointMass(mass, pos, vel);
this.gobj = new GraphicsWorld.Circle(pos.x, pos.y, radius, color);
this.cshell.userData = this;
this.pm.userData = this;
eworld.Gworld.Add(this.gobj);
eworld.Cworld.Add(this.cshell);
eworld.Pworld.Add(this.pm);
}
public static Vec2 operator -(Vec2 a, Vec2 b)
{
//for subtracting 2 vectors
Vec2 newVector = new Vec2((a.x - b.x), (a.y - b.y));
return newVector;
}
public static Vec2 operator +(Vec2 a, Vec2 b)
{
//For adding 2 vectors
Vec2 newVector = new Vec2((a.x + b.x), (a.y + b.y));
return newVector;
}
public static Vec2 operator *(Vec2 v, float k)
{
//for multiplying 2 vectors
Vec2 newVector = new Vec2((v.x * k), (v.y * k));
return newVector;
}
//add the force vector to the current force
public void AddForce(Vec2 f)
{
forceAccumulator += f;
}
public PointMass(float mass)
{
this.mass = mass;
this.vel = new Vec2();
pos = new Vec2();
}
public CollisionPair(CollisionShell a, CollisionShell b, Vec2 force)
{
this.a = a;
this.b = b;
this.userData = force;
}
public CollisionShell(Vec2 pos)
{
this.position = pos;
}
public Object userData; //will be used in the future to help with encapsulation
#endregion Fields
#region Constructors
public CollisionShell(Vec2 pos, Object userData)
{
position = new Vec2(pos.x, pos.y);
this.userData = userData;
}
public CircleShell(Vec2 p, float r)
: base(p)
{
this.radius = r;
}
public CircleShell(Vec2 p, float r, Object userData)
: base(p, userData)
{
this.radius = r;
}