From b94b24ab0d7411cb7f26f2e671ba7ed7d6e99e41 Mon Sep 17 00:00:00 2001
From: Anthony Wang
Date: Mon, 29 Jan 2024 13:52:22 -0500
Subject: Spread circles out evenly across path, move stuff to separate file

---
 script.js | 54 ++++++++++++++++++++++++++++++------------------------
 1 file changed, 30 insertions(+), 24 deletions(-)

(limited to 'script.js')

diff --git a/script.js b/script.js
index d40711a..6cfcd78 100644
--- a/script.js
+++ b/script.js
@@ -6,14 +6,15 @@ document.querySelectorAll("svg").forEach(function(svg) {
 	svg.outerHTML = req.responseText
 })
 
-let rad = 10 // Stroke width
+let rad = 10 // Stroke radius
 let size = 200 // SVG width and height
 let A = [] // Objects
 let cnt = 0
 document.querySelectorAll("svg").forEach(function(svg) {
 	// Move objects so they aren't overlapping
-	svg.style.left = 1.5 * size * cnt++ + "px"
-	svg.style.top = "50px"
+	svg.style.left = 1.5 * size * (cnt % 2) + "px"
+	svg.style.top = 1.5 * size * Math.floor(cnt / 2) + "px"
+	cnt++
 	let a = {
 		id: svg.id, // Unique ID
 		p: [], // Collision circles
@@ -25,8 +26,9 @@ document.querySelectorAll("svg").forEach(function(svg) {
 	}
 	svg.querySelectorAll("path").forEach(function(path) {
 		// Get circles on path for collision checking
-		for (let i = 0; i < path.getTotalLength(); i += 5) {
-			const p = path.getPointAtLength(i)
+		let num = Math.floor(path.getTotalLength() / 5)
+		for (let i = 0; i <= num; i++) {
+			const p = path.getPointAtLength(i / num * path.getTotalLength())
 			a.cm.x += p.x
 			a.cm.y += p.y
 			a.p.push(p)
@@ -34,7 +36,7 @@ document.querySelectorAll("svg").forEach(function(svg) {
 			/* let circle = document.createElementNS("http://www.w3.org/2000/svg", "circle")
 			circle.setAttribute("cx", p.x)
 			circle.setAttribute("cy", p.y)
-			circle.setAttribute("r", rad)
+			circle.setAttribute("r", 10)
 			circle.setAttribute("fill", "red")
 			svg.appendChild(circle) */
 		}
@@ -119,24 +121,31 @@ function wallCollide(a, k, d) {
 
 // Collision of object a with object b
 function objectsCollide(a, b) {
-	if (ds(a, b) < size * size) {
+	if (ds(a, b) < 2 * (size + 2 * rad) ** 2) {
 		// Objects are close
 		let c = {x: 0, y: 0, cnt: 0}
 		let n = {x: 0, y: 0}
+		// Slight performance optimization?
+		// Only consider points close to other object
+		let aa = []
+		let bb = []
 		for (const p of a.p.map(x => rot(a, x))) {
-			// p is close to object b
-			if (ds(p, b) < size * size) {
-				for (const q of b.p.map(x => rot(b, x))) {
-					const d = ds(p, q)
-					if (d < 4 * rad * rad) {
-						// Collision!
-						// These calculations are a bit sketchy but I guess they work?
-						c.x += p.x + q.x
-						c.y += p.y + q.y
-						c.cnt++
-						n.x += (p.x - q.x) / d
-						n.y += (p.y - q.y) / d
-					}
+			if (ds(p, b) < 2 * (size + 2 * rad) ** 2) aa.push(p)
+		}
+		for (const p of b.p.map(x => rot(b, x))) {
+			if (ds(p, a) < 2 * (size + 2 * rad) ** 2) bb.push(p)
+		}
+		for (const p of aa) {
+			for (const q of bb) {
+				const d = ds(p, q)
+				if (d < (2 * rad) ** 2) {
+					// Collision!
+					// These calculations are a bit sketchy but I guess they work?
+					c.x += p.x + q.x
+					c.y += p.y + q.y
+					c.cnt++
+					n.x += (p.x - q.x) / d
+					n.y += (p.y - q.y) / d
 				}
 			}
 		}
@@ -152,6 +161,7 @@ function objectsCollide(a, b) {
 	}
 }
 
+// Move stuff, check collisions, and render
 function tick() {
 	// Move each object one step
 	for (let a of A) {
@@ -162,7 +172,6 @@ function tick() {
 		if (Math.abs(a.vy) > 0.001) a.vy -= 0.001 * Math.sign(a.vy)
 		if (Math.abs(a.w) > 0.00001) a.w -= 0.00001 * Math.sign(a.w)
 	}
-
 	// Check wall collisions
 	for (let a of A) {
 		wallCollide(a, 0, 0)
@@ -170,14 +179,12 @@ function tick() {
 		wallCollide(a, 0, 1)
 		wallCollide(a, window.innerHeight, 1)
 	}
-
 	// Check collisions between objects
 	for (let i = 0; i < A.length; i++) {
 		for (let j = i + 1; j < A.length; j++) {
 			objectsCollide(A[i], A[j])
 		}
 	}
-
 	// Render every 10ms
 	cnt++
 	if (cnt == 10) {
@@ -198,7 +205,6 @@ function updatev(event) {
 		a.vx += 100 * (a.x - event.clientX) / d
 		a.vy += 100 * (a.y - event.clientY) / d
 	}
-
 	// Display spreading out circles
 	let circle = document.createElement("div")
 	circle.style.width = circle.style.height = "10px"
-- 
cgit v1.2.3-70-g09d2