private Vector2 FleeFromPredator(Boid me)
{
if (me.ToString() == "BoidSimulation.Predator")
{
return(Vector2.Zero);
}
else
{
Vector2 FleeVel = Vector2.Zero;
int PredCnt = 0;
float percent = 0.01f;
List <Boid> boidList = SimWorld.GetInstance().GetBoidList();
foreach (Boid b in boidList)
{
if (b.ToString() == "BoidSimulation.Predator")
{
Vector2 diff = b.GetPosition() - me.GetPosition();
if (diff.Length() <= me.StayAwayRadius)
{
FleeVel -= diff;
PredCnt++;
}
}
}
if (PredCnt > 0)
{
FleeVel /= PredCnt;
return(FleeVel * percent);
}
return(Vector2.Zero);
}
}
//can we merge this with a general collision avoidance algorithm?
private Vector2 KeepApart(Boid me)
{
Vector2 KeepApartVel = Vector2.Zero;
List <Boid> boidList = SimWorld.GetInstance().GetBoidList();
foreach (Boid b in boidList)
{
if (me == b)
{
continue;
}
else
{
//test to see if we are smaller than a certain range (circle test)
Vector2 diff = b.GetPosition() - me.GetPosition();
if (diff.Length() <= me.Radius)
{
KeepApartVel -= diff;
}
}
}
return(KeepApartVel);
}
private Vector2 Flock(Boid me)
{
Vector2 CenterOfMassVel = Vector2.Zero;
Vector2 KeepApartVel = Vector2.Zero;
Vector2 MatchBoidVel = Vector2.Zero;
List <Boid> boidList = SimWorld.GetInstance().GetBoidList();
foreach (Boid b in boidList)
{
if (me == b)
{
continue;
}
else
{
//sum up the positions
CenterOfMassVel += b.GetPosition();
//sum up the velocities.
MatchBoidVel += b.GetVelocity();
//test to see if we are smaller than a certain range (circle test)
Vector2 diff = b.GetPosition() - me.GetPosition();
if (diff.Length() <= me.Radius)
{
KeepApartVel -= diff;
}
}
}
CenterOfMassVel /= boidList.Count - 1;
CenterOfMassVel *= 0.01f;
MatchBoidVel /= boidList.Count - 1;
MatchBoidVel *= me.Strength;
MatchBoidVel *= 0.01f;
Vector2 totalVel = (CenterOfMassVel + MatchBoidVel + KeepApartVel + FollowMouse(me)) * 0.001f;
totalVel += FleeFromPredator(me) * 0.05f;
totalVel += CollisionTest(me);
return(totalVel);
}
protected Vector2 CollisionTest(Boid me)
{
List <Plane> collisionList = SimWorld.GetInstance().GetCollisionList();
Vector4 pos = new Vector4(me.GetPosition(), 0.0f, 1.0f);
Vector3 avoidCollisionVel = Vector3.Zero;
foreach (Plane p in collisionList)
{
float distance = p.Dot(pos) / p.Normal.Length();
if (distance <= 5.0f)
{
avoidCollisionVel += p.Normal * (me.Radius - distance);
}
}
return(new Vector2(avoidCollisionVel.X, avoidCollisionVel.Y) * 0.001f);
}
public virtual bool DetectNearbyPredators()
{
if (this.ToString() == "BoidSimulation.Predator")
{
return(false);
}
List <Boid> boidList = SimWorld.GetInstance().GetBoidList();
foreach (Boid b in boidList)
{
if (b.ToString() == "BoidSimulation.Predator")
{
Vector2 diff = b.GetPosition() - this.GetPosition();
if (diff.Length() <= mStayAwayRadius)
{
return(true);
}
}
}
return(false);
}
/// <summary>
/// Load your graphics content. If loadAllContent is true, you should
/// load content from both ResourceManagementMode pools. Otherwise, just
/// load ResourceManagementMode.Manual content.
/// </summary>
/// <param name="loadAllContent">Which type of content to load.</param>
protected override void LoadContent()
{
//if (loadAllContent)
{
mSimWorldInstance = SimWorld.GetInstance();
mViewport = graphics.GraphicsDevice.Viewport;
//set up the collision detection planes
mSimWorldInstance.AddCollisionPlane(new Plane(new Vector3(1.0f, 0.0f, 0.0f), 0.0f));
mSimWorldInstance.AddCollisionPlane(new Plane(new Vector3(-1.0f, 0.0f, 0.0f), mViewport.Width));
mSimWorldInstance.AddCollisionPlane(new Plane(new Vector3(0.0f, 1.0f, 0.0f), 0.0f));
mSimWorldInstance.AddCollisionPlane(new Plane(new Vector3(0.0f, 1.0f, 0.0f), mViewport.Height));
//mouse cursor sprite.
mMouseCursor = content.Load <Texture2D>("Images/mouse");
//set up the boid sprites.
mSpriteBatch = new SpriteBatch(graphics.GraphicsDevice);
//create boids.
Random rand = new Random();
for (int i = 0; i < NUMBOIDS; ++i)
{
Boid newBoid = new Boid(rand.Next(mViewport.Width), rand.Next(mViewport.Height), new FlockStrategy());
newBoid.LoadGraphicAsset(content);
mSimWorldInstance.AddBoid(newBoid);
}
for (int j = 0; j < 10; ++j)
{
Predator newPredator = new Predator(rand.Next(mViewport.Width), rand.Next(mViewport.Height), new WanderStrategy());
newPredator.LoadGraphicAsset(content);
mSimWorldInstance.AddBoid(newPredator);
}
}
}