Hi everyone!
I found some awesome demos while trying to figure out what I could do for my assignment. I miserably tried to manipulate code for hours…thinking I could simply look at a flocking code and other notes and synthesize a predator from which the boids would flee from. But, a challenge it was and a challenge it has remained. View a screen capture of everything here.
Here are some awesome demos:
Particles with Attraction and Repulsion Forces
I managed to integrate my ball into the flocking code found on processing (see below), but I couldn’t figure out how to code such that the flock would flee from the ball as well. So, I just pretended that this was a game and the user’s purpose was to avoid the flock with the mouse.
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float xPos; float yPos; float xSpeed; float ySpeed; float diam = 50; float easing = 0.10; Flock flock; void setup() { size(640, 360); xPos = random(diam/2, width-diam/2); yPos = random(diam/2, height-diam/2); xSpeed = random(-5.0, 5.0); ySpeed = random(-5.0, 5.0); flock = new Flock(); // Add an initial set of boids into the system for (int i = 0; i < 150; i++) { flock.addBoid(new Boid(width/2,height/2)); } } void draw() { background(0); noStroke(); drawBall(xPos, yPos, diam); float targetX = mouseX; // target of ellipse X direction float dx = targetX - xPos; xPos += dx * easing; float targetY = mouseY; // target of ellipse Y direction float dy = targetY - yPos; yPos += dy * easing; xPos = updateBallX(xPos, xSpeed); yPos = updateBallY(yPos, ySpeed); checkBounds(); flock.run(); } void drawBall(float x_, float y_, float s_) { float x = x_; float y = y_; float s = s_; ellipse(x, y, s, s); } float updateBallX(float x_, float xs_) { float xpos = x_; float xspeed = xs_; xpos = xpos + xspeed; return xpos; } float updateBallY(float y_, float ys_) { float ypos = y_; float yspeed = ys_; ypos = ypos + yspeed; return ypos; } void checkBounds() { if(xPos > width-diam/2 || xPos < diam/2) { xSpeed = xSpeed * -1; } if(yPos > height-diam/2 || yPos < diam/2 ) { ySpeed = ySpeed * -1; } } void mousePressed() { flock.addBoid(new Boid(mouseX,mouseY)); } // The Flock (a list of Boid objects) class Flock { ArrayList<Boid> boids; // An ArrayList for all the boids Flock() { boids = new ArrayList<Boid>(); // Initialize the ArrayList } void run() { for (Boid b : boids) { b.run(boids); // Passing the entire list of boids to each boid individually } } void addBoid(Boid b) { boids.add(b); } } // The Boid class class Boid { PVector location; PVector velocity; PVector acceleration; float r; float maxforce; // Maximum steering force float maxspeed; // Maximum speed Boid(float x, float y) { acceleration = new PVector(0, 0); // This is a new PVector method not yet implemented in JS // velocity = PVector.random2D(); // Leaving the code temporarily this way so that this example runs in JS float angle = random(TWO_PI); velocity = new PVector(cos(angle), sin(angle)); location = new PVector(x, y); r = 2.0; maxspeed = 2; maxforce = 0.03; } void run(ArrayList<Boid> boids) { flock(boids); update(); borders(); render(); } void applyForce(PVector force) { // We could add mass here if we want A = F / M acceleration.add(force); } // We accumulate a new acceleration each time based on three rules void flock(ArrayList<Boid> boids) { PVector sep = separate(boids); // Separation PVector ali = align(boids); // Alignment PVector coh = cohesion(boids); // Cohesion // Arbitrarily weight these forces sep.mult(1.5); ali.mult(1.0); coh.mult(1.0); // Add the force vectors to acceleration applyForce(sep); applyForce(ali); applyForce(coh); } // Method to update location void update() { // Update velocity velocity.add(acceleration); // Limit speed velocity.limit(maxspeed); location.add(velocity); // Reset accelertion to 0 each cycle acceleration.mult(0); } // A method that calculates and applies a steering force towards a target // STEER = DESIRED MINUS VELOCITY PVector seek(PVector target) { PVector desired = PVector.sub(target, location); // A vector pointing from the location to the target // Scale to maximum speed desired.normalize(); desired.mult(maxspeed); // Above two lines of code below could be condensed with new PVector setMag() method // Not using this method until Processing.js catches up // desired.setMag(maxspeed); // Steering = Desired minus Velocity PVector steer = PVector.sub(desired, velocity); steer.limit(maxforce); // Limit to maximum steering force return steer; } void render() { // Draw a triangle rotated in the direction of velocity float theta = velocity.heading2D() + radians(90); // heading2D() above is now heading() but leaving old syntax until Processing.js catches up fill(200, 100); stroke(255); pushMatrix(); translate(location.x, location.y); rotate(theta); beginShape(TRIANGLES); vertex(0, -r*2); vertex(-r, r*2); vertex(r, r*2); endShape(); popMatrix(); } // Wraparound void borders() { if (location.x < -r) location.x = width+r; if (location.y < -r) location.y = height+r; if (location.x > width+r) location.x = -r; if (location.y > height+r) location.y = -r; } // Separation // Method checks for nearby boids and steers away PVector separate (ArrayList<Boid> boids) { float desiredseparation = 25.0f; PVector steer = new PVector(0, 0, 0); int count = 0; // For every boid in the system, check if it's too close for (Boid other : boids) { float d = PVector.dist(location, other.location); // If the distance is greater than 0 and less than an arbitrary amount (0 when you are yourself) if ((d > 0) && (d < desiredseparation)) { // Calculate vector pointing away from neighbor PVector diff = PVector.sub(location, other.location); diff.normalize(); diff.div(d); // Weight by distance steer.add(diff); count++; // Keep track of how many } } // Average -- divide by how many if (count > 0) { steer.div((float)count); } // As long as the vector is greater than 0 if (steer.mag() > 0) { // First two lines of code below could be condensed with new PVector setMag() method // Not using this method until Processing.js catches up // steer.setMag(maxspeed); // Implement Reynolds: Steering = Desired - Velocity steer.normalize(); steer.mult(maxspeed); steer.sub(velocity); steer.limit(maxforce); } return steer; } // Alignment // For every nearby boid in the system, calculate the average velocity PVector align (ArrayList<Boid> boids) { float neighbordist = 50; PVector sum = new PVector(0, 0); int count = 0; for (Boid other : boids) { float d = PVector.dist(location, other.location); if ((d > 0) && (d < neighbordist)) { sum.add(other.velocity); count++; } } if (count > 0) { sum.div((float)count); // First two lines of code below could be condensed with new PVector setMag() method // Not using this method until Processing.js catches up // sum.setMag(maxspeed); // Implement Reynolds: Steering = Desired - Velocity sum.normalize(); sum.mult(maxspeed); PVector steer = PVector.sub(sum, velocity); steer.limit(maxforce); return steer; } else { return new PVector(0, 0); } } // Cohesion // For the average location (i.e. center) of all nearby boids, calculate steering vector towards that location PVector cohesion (ArrayList<Boid> boids){ float neighbordist = 50; PVector sum = new PVector(0, 0); // Start with empty vector to accumulate all locations int count = 0; for (Boid other : boids) { float d = PVector.dist(location, other.location); if ((d > 0) && (d < neighbordist)) { sum.add(other.location); // Add location count++; } } if (count > 0) { sum.div(count); return seek(sum); // Steer towards the location } else { return new PVector(0, 0); } } } |
Ideally, one would create another function that tells the flock to avoid the x and y position of the ball (plus its diameter I assume) at any times.
Furthermore, I changed the class’s original multi-ball animation script by adding some color coding (see below). I just wrote another function and incorporated it.
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float xPos; float yPos; float xPos2; float yPos2; float xSpeed; float ySpeed; float xSpeed2; float ySpeed2; float diam = 50; float easing = 0.05; void setup() { size(500, 400); //background(133, 227, 252); xPos = random(diam/2, width-diam/2); yPos = random(diam/2, height-diam/2); xPos2 = random(diam/2, width-diam/2); yPos2 = random(diam/2, height-diam/2); xSpeed = random(-5.0, 5.0); ySpeed = random(-5.0, 5.0); xSpeed2 = random(-5.0, 5.0); ySpeed2 = random(-5.0, 5.0); } void draw(){ background(0); noStroke(); drawBall(xPos, yPos, diam); // gonna need to give some arguments drawBall(xPos2, yPos2, diam); xPos = updateBallX(xPos, xSpeed); yPos = updateBallY(yPos, ySpeed); xPos2 = updateBallX(xPos2, xSpeed2); yPos2 = updateBallY(yPos2, ySpeed2); float targetX = xPos; float dx = targetX - xPos; xPos += dx * easing; float targetY = yPos; float dy = targetY - yPos; yPos += dy * easing; float targetX2 = xPos2; float dx2 = targetX2 - xPos2; xPos2 += dx2 * easing; float targetY2 = yPos2; float dy2 = targetY2 - yPos2; yPos2 += dy2 * easing; checkBounds(); checkBounds2(); vroom(); } void drawBall(float x_, float y_, float s_) { float x = x_; float y = y_; float s = s_; ellipse(x, y, s, s); } float updateBallX(float x_, float xs_) { float xpos = x_; float xspeed = xs_; xpos = xpos + xspeed; return xpos; } float updateBallY(float y_, float ys_) { float ypos = y_; float yspeed = ys_; ypos = ypos + yspeed; return ypos; } void checkBounds() { if(xPos > width-diam/2 || xPos < diam/2) { xSpeed = xSpeed * -1; } if(yPos > height-diam/2 || yPos < diam/2) { ySpeed = ySpeed * -1; } } void checkBounds2() { if (xPos2 > width-diam/2 || xPos2 < diam/2) { xSpeed2 = xSpeed2*-1; } if (yPos2 > height-diam/2 || yPos2 < diam/2) { ySpeed2 = ySpeed2*-1; } } void vroom() { if (xPos >= xPos2 || yPos >= yPos2) { fill(#7512A0); println("x: " + xPos); println("y: " + yPos); } else if (xPos < xPos2 || yPos < yPos2){ fill(255); } } |