From 049affae6a545e114d8ee14671c1228a60fdd90a Mon Sep 17 00:00:00 2001
From: Benjamin Wiegand <ben@noreply.git.wiegand.pw>
Date: Tue, 10 Sep 2024 09:22:10 -0700
Subject: [PATCH] bounce duck at edge of screen so it doesn't fly off and
 expand the document

---
 www/cursor-thing.js | 39 +++++++++++++++++++++++++++++++--------
 1 file changed, 31 insertions(+), 8 deletions(-)

diff --git a/www/cursor-thing.js b/www/cursor-thing.js
index c1f1b38..b25fea4 100644
--- a/www/cursor-thing.js
+++ b/www/cursor-thing.js
@@ -29,6 +29,7 @@ const turnSpeedCoeff = .08; // coefficient of turning
 // other stuff
 let brake = false;
 const brakeDist = 70;
+const duckSize = 50;
 
 // animation
 let alt = false;
@@ -113,6 +114,26 @@ function update() {
     xPos += xVel * deltaT;
     yPos += yVel * deltaT;
 
+    // bounce duck at edge of screen
+    if (xPos > document.scrollingElement.scrollWidth - duckSize) {
+        xPos = document.scrollingElement.scrollWidth - duckSize;
+        angle = 2*Math.PI - angle;
+    } else if (xPos < 0) {
+        xPos = 0;
+        angle = 2*Math.PI - angle;
+    }
+    if (yPos > document.scrollingElement.scrollHeight - duckSize) {
+        yPos = document.scrollingElement.scrollHeight - duckSize;
+        angle = Math.PI - angle;
+    } else if (yPos < 0) {
+        yPos = 0;
+        angle = Math.PI - angle;
+    }
+
+    // limit angle again
+    if (angle > 2*Math.PI) angle -= 2*Math.PI;
+    else if (angle < 0) angle += 2*Math.PI;
+
     // console.log(`accel: ${accel}`);
     // console.log(`velocity: ${velocity} (${xVel}, ${yVel})`)
 
@@ -128,19 +149,19 @@ function update() {
     //     thing.style['background-color'] = '#ff0000';
     // }
 
-    let fuck = visualAngle + Math.PI/4;
-    if (fuck < Math.PI/2 || fuck > Math.PI * 2) {
+    let tAngle = visualAngle + Math.PI/4;
+    if (tAngle < Math.PI/2 || tAngle > Math.PI * 2) {
         // front-facing
-        thing.style['background-position-x'] = '100px';
-    } else if (fuck < Math.PI) {
+        thing.style['background-position-x'] = (2*duckSize) + 'px';
+    } else if (tAngle < Math.PI) {
         // left-facing
         thing.style['background-position-x'] = '0px';
-    } else if (fuck < Math.PI*3/2) {
+    } else if (tAngle < Math.PI*3/2) {
         // right-facing
-        thing.style['background-position-x'] = '150px';
+        thing.style['background-position-x'] = (3*duckSize) + 'px';
     } else {
         // back-facing
-        thing.style['background-position-x'] = '50px';
+        thing.style['background-position-x'] = duckSize + 'px';
     }
 
     if (thisUpdate - lastAlt > 70) {
@@ -149,13 +170,14 @@ function update() {
     }
     
     if (velocity > 50) {
-        thing.style['background-position-y'] = alt ? '50px' : '100px';
+        thing.style['background-position-y'] = (duckSize * (alt + 1)) + 'px';
     } else {
         thing.style['background-position-y'] = '0px';
     }
 
 }
 
+// scroll and mouse are separate so the cursor is followed when scrolled
 document.addEventListener('mousemove', e => {
     mouseX = e.clientX;
     mouseY = e.clientY;
@@ -167,6 +189,7 @@ document.addEventListener('scroll', e => {
     scrollY = el.scrollTop;
 });
 
+// kick-start duck
 let duck_start = false;
 function click_duck() {
     if (duck_start) return;