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class Boid {
constructor(radius, color, x, y, direction, id, scene_width, scene_height) {
// Boid properties
this.radius = radius;
this.color = color;
this.x = x;
this.y = y;
this.direction = direction;
this.id = id;
// World properties
this.scene_width = scene_width;
this.scene_height = scene_height;
// Boid "dynamic" properties
this.rayLength = 40;
this.turnStepAmount = 20;
this.stepAmount = 4;
this.fieldOfView = 270;
this.boidBuffer = 20;
}
move(boids) {
// this.direction += Math.random() * (2 * this.turnStepAmount) - this.turnStepAmount
this.direction = this.findNextRay(boids);
var vector = this.findPoint(this.x, this.y, this.stepAmount, this.direction);
this.x = vector.x;
this.y = vector.y;
}
buildRays() {
let rays = new Array();
let rayInteval = 2;
let noOfSteps = this.fieldOfView / rayInteval;
for (let i = 0; i < noOfSteps / 2; i++) {
if (i != 0) {
rays.push(rayInteval * -i);
}
rays.push(rayInteval * i);
}
return rays;
}
findNextRay(boids) {
let rays = this.buildRays();
for (let i = 0; i < rays.length; i++) {
let tweakAngle = 0;
// if (Math.random() > 0.95) {
// tweakAngle = this.turnStepAmount * Math.random() - (this.turnStepAmount / 2);
// }
let rayAngle = tweakAngle + this.direction + rays[i];
if (i == 0 && this.detectBoid(rayAngle, boids)) {
continue;
}
if (this.detectBox(this.scene_width, this.scene_height, rayAngle)) {
continue;
}
return rayAngle;
}
console.log(this.x, this.y);
console.log('cannot find suitable ray');
}
detectBoid(direction, boids) {
for (let i = 0; i < boids.length; i++) {
// rule out ourselves
if (this.id == boids[i].id) {
continue;
}
let thisFututrePosition = this.findPoint(this.x, this.y, this.boidBuffer, direction);
let thisPath = {
x1: this.x,
y1: this.y,
x2: thisFututrePosition.x,
y2: thisFututrePosition.y
};
let boidFuturePosition = this.findPoint(boids[i].x, boids[i].y, boids[i].boidBuffer, boids[i].direction);
let boidPath = {
x1: boids[i].x,
y1: boids[i].y,
x2: boidFuturePosition.x,
y2: boidFuturePosition.y
};
let thisIntersectsBoid = this.pathsIntersect(
thisPath.x1, thisPath.y1, thisPath.x2, thisPath.y2, boidPath.x1, boidPath.y1, boidPath.x2, boidPath.y2
);
if (thisIntersectsBoid) {
return true;
}
}
return false;
}
pathsIntersect(x1, y1, x2, y2, x3, y3, x4, y4) {
// Check if none of the lines are of length 0
if ((x1 === x2 && y1 === y2) || (x3 === x4 && y3 === y4)) {
return false
}
let denominator = ((y4 - y3) * (x2 - x1) - (x4 - x3) * (y2 - y1))
// // Lines are parallel
// if (denominator === 0) {
// return false
// }
let ua = ((x4 - x3) * (y1 - y3) - (y4 - y3) * (x1 - x3)) / denominator
let ub = ((x2 - x1) * (y1 - y3) - (y2 - y1) * (x1 - x3)) / denominator
// is the intersection along the segments
if (ua < 0 || ua > 1 || ub < 0 || ub > 1) {
return false
}
// Return a object with the x and y coordinates of the intersection
let x = x1 + ua * (x2 - x1)
let y = y1 + ua * (y2 - y1)
return {
x,
y
}
}
detectBox(width, height, direction) {
let point = this.findPoint(this.x, this.y, this.rayLength, direction);
if (point.x - this.radius < 0 ||
point.y - this.radius < 0 ||
point.x + this.radius > width - 0 ||
point.y + this.radius > height - 0
) {
return true;
}
return false;
}
findPoint(x1, y1, length, angle) {
angle *= Math.PI / 180;
var x2 = x1 + length * Math.cos(angle),
y2 = y1 + length * Math.sin(angle);
return {
x: x2,
y: y2
};
}
draw(context) {
this.drawBoid(context);
this.drawRay(context, this.x, this.y, this.rayLength, this.direction);
}
drawBoid(context) {
context.beginPath();
context.fillStyle = "blue";
context.arc(this.x, this.y, this.radius, 0, 2 * Math.PI);
context.stroke();
context.restore();
}
drawRay(context, x, y, perceptionDistance, direction) {
let point = this.findPoint(x, y, perceptionDistance, direction);
context.lineWidth = 1;
context.beginPath();
context.moveTo(x, y);
context.lineTo(point.x, point.y);
context.stroke();
context.restore();
}
}
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