From 28795d481d33900f14bfc433d182dffc651abc6f Mon Sep 17 00:00:00 2001
From: Peter McGoron <code@mcgoron.com>
Date: Wed, 11 Oct 2023 13:03:47 +0000
Subject: [PATCH] comments

---
 scattering.js | 42 +++++++++++++++++++++++++++++++++++-------
 1 file changed, 35 insertions(+), 7 deletions(-)

diff --git a/scattering.js b/scattering.js
index 8730be1..0caae35 100644
--- a/scattering.js
+++ b/scattering.js
@@ -26,15 +26,38 @@
  *
  */
 
-let width = 800;
-let height = 600;
-let longestDiag = Math.sqrt(width**2 + height**2);
+/*****************************************
+ * Math
+ ****************************************/
 
 function sign(x) {
   if (x < 0) return -1;
   if (x >= 0) return 1;
 }
 
+function distance(x,y) {
+  return Math.sqrt(x**2 + y**2);
+}
+
+function veryClose(x, y) {
+  return Math.abs(x - y) < 0.001;
+}
+
+/*****************************************
+ * Parameters
+ ****************************************/
+
+let width = 800;
+let height = 600;
+
+/* Infinite lines are drawn with length = 2*longestDiag which will always
+ * cross the entire screen. */
+let longestDiag = distance(width, height);
+
+/*****************************************
+ * Object Classes
+ ****************************************/
+
 /* Basic infinite line class, useful for physics simulation */
 class InfiniteLine {
   constructor(x_0, y_0, angle) {
@@ -100,10 +123,6 @@ class PlaneWave extends InfiniteLine {
   }
 }
 
-function veryClose(x, y) {
-  return Math.abs(x - y) < 0.001;
-}
-
 class SimulationMouseHandler {
   constructor() {
     this.curWave = null;
@@ -113,21 +132,26 @@ class SimulationMouseHandler {
 
   handleMouse() {
     if (mouseIsPressed && !this.mouseDown) {
+      /* On mouseDown, make new plane wave and allow the user to edit it */
       this.mouseDown = true;
       this.curWave = new PlaneWave(mouseX, mouseY, this.oldAngle, 0.1);
     } else if (!mouseIsPressed) {
+      /* If mouse is released, return current wave if it exists */
       this.mouseDown = false;
       const curWave = this.curWave;
       this.curWave = null;
       return curWave;
     }
 
+    /* Change angle to where the mouse cursor is pointing */
     if (!veryClose(mouseX, this.curWave.x_0)  ||
         !veryClose(mouseY, this.curWave.y_0)) {
         this.oldAngle = Math.atan2(mouseY - this.curWave.y_0, mouseX - this.curWave.x_0);
         this.curWave.angle = this.oldAngle;
     }
 
+    /* TODO: make faster plane waves? */
+
     this.curWave.draw();
     this.curWave.drawArrow();
   }
@@ -154,6 +178,10 @@ class Simulation {
   }
 }
 
+/***************************
+ * Simulation wrapper
+ **************************/
+
 var sim;
 function setup() {
   frameRate(24);