From 81caa72aed6ad8f653aabb191b099ec3d544bf2b Mon Sep 17 00:00:00 2001
From: Fbenas <philbeansburton@gmail.com>
Date: Wed, 14 Oct 2020 00:48:34 +0100
Subject: Add future collision detection... ish

---
 resources/js/boid.js | 81 ++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 62 insertions(+), 19 deletions(-)

(limited to 'resources/js/boid.js')

diff --git a/resources/js/boid.js b/resources/js/boid.js
index a15022a..a3aefea 100644
--- a/resources/js/boid.js
+++ b/resources/js/boid.js
@@ -14,27 +14,34 @@ class Boid {
         this.scene_height = scene_height;
 
         // Boid "dynamic" properties
-        this.rayLength = 40;
+        this.rayLength = 60;
+        this.wallBuffer = 40;
         this.turnStepAmount = 20;
-        this.stepAmount = 4;
-        this.fieldOfView = 270;
+        this.stepAmount = 2;
+        this.fieldOfView = 180;
         this.boidBuffer = 20;
     }
 
     move(boids) {
         // this.direction += Math.random() * (2 * this.turnStepAmount) - this.turnStepAmount
+        let direction = this.findNextRay(boids);
 
-        this.direction = this.findNextRay(boids);
+        if (!direction) {
+            return false;
+        }
+        this.direction = direction;
 
         var vector = this.findPoint(this.x, this.y, this.stepAmount, this.direction);
         this.x = vector.x;
         this.y = vector.y;
+
+        return true;
     }
 
     buildRays() {
         let rays = new Array();
 
-        let rayInteval = 2;
+        let rayInteval = 5;
         let noOfSteps = this.fieldOfView / rayInteval;
         let is_clockwise = Math.random() >= 0.5;
 
@@ -61,27 +68,33 @@ class Boid {
     findNextRay(boids) {
         let rays = this.buildRays();
 
+        let collision = false;
         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];
+            let rayAngle = this.direction + rays[i];
 
             // Check against all other boids
             if (this.detectBoids(rayAngle, boids)) {
+                if (i == 0) {
+                    collision = true;
+                }
                 continue;
             }
 
             // Check against scene boundaries
             if (this.detectBox(this.scene_width, this.scene_height, rayAngle)) {
+                if (i == 0) {
+                    collision = true;
+                }
                 continue;
             }
 
             return rayAngle;
         }
 
+        if (!collision) {
+            return this.direction;
+        }
+
         console.log('cannot find suitable ray');
         return false;
     }
@@ -112,9 +125,16 @@ class Boid {
 
         if (intersect) {
             console.log('boids intersect detected');
+            return true;
         }
 
-        return intersect;
+        return this.willBoidsIntersect(boid, direction);
+    }
+
+    willBoidsIntersect(boid, direction) {
+        let future_position = this.findPoint(this.x, this.y, this.rayLength, direction);
+
+        return this.lineIntersectsCircle(this.x, future_position.x, this.y, future_position.y, boid.radius * 2, boid.x, boid.y);
     }
 
     boidsIntersect(boid) {
@@ -145,13 +165,36 @@ class Boid {
         if (!x4 || !y4) {
             return false;
         }
-        console.log('intersecting circles');
+
         return {
             x: x4,
             y: y4
         };
     }
 
+    lineIntersectsCircle(x1, x2, y1, y2, r, rx, ry) {
+        // first r is at 0,0 so we must first move the line the same distance
+        // Normalize points
+        x1 -= rx;
+        y1 -= ry;
+        x2 -= rx;
+        y2 -= ry;
+
+        let dx = x2 - x1;
+        let dy = y2 - y1;
+
+        let dr = Math.sqrt(Math.pow(dx, 2) + Math.pow(dy, 2));
+        let dd = (x1 * y2) - (x2 * y1);
+
+        let di = (Math.pow(r, 2) * Math.pow(dr, 2)) - Math.pow(dd, 2);
+
+        if (di < 0) {
+            return false;
+        } else {
+            return true;
+        }
+    }
+
     distanceBetweenPoints(x1, x2, y1, y2) {
         let dx = Math.abs(x1 - x2);
         let dy = Math.abs(y1 - y2);
@@ -219,7 +262,7 @@ class Boid {
     }
 
     detectBox(width, height, direction) {
-        let point = this.findPoint(this.x, this.y, this.rayLength, direction);
+        let point = this.findPoint(this.x, this.y, this.wallBuffer, direction);
 
         if (point.x - this.radius < 0 ||
             point.y - this.radius < 0 ||
@@ -235,18 +278,18 @@ class Boid {
     findPoint(x1, y1, length, angle) {
         angle *= Math.PI / 180;
 
-        var x2 = x1 + length * Math.cos(angle),
-            y2 = y1 + length * Math.sin(angle);
+        let x2 = x1 + length * Math.cos(angle); // must be rad
+        let y2 = y1 + length * Math.sin(angle); // must be radrayLength
 
         return {
-            x: x2,
-            y: y2
+            x: parseFloat((Number(x2).toFixed(2))),
+            y: parseFloat(Number(y2).toFixed(2))
         };
     }
 
     draw(context) {
         this.drawBoid(context);
-        // this.drawRay(context, this.x, this.y, this.rayLength, this.direction);
+        this.drawRay(context, this.x, this.y, this.rayLength, this.direction);
     }
 
     drawBoid(context) {
-- 
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