Fixed grammer, Update Readme

Author: siddharthroy12

README.md

@@ -18,17 +18,28 @@
 </div>
 
 
-![Screenshot](./screenshots/screenshot1.png)
+![Screenshot](./screenshots/screenshot.png)
 
-Gravity sandbox is a simple gravity simulator based on Newton's law of universal
-gravitation.
+Gravity Sandbox is a fun toy/game where you can play with Newtonian Gravity. Place heavy objects in patterns and see interesting results.
 
-It's a web-based simulation so no need to install anything, just visit
+It's a web app so no need to install anything, just visit
 [the website](https://gravity-sandbox.netlify.app/) to play the game
 
 ## Controls
 
-- ![play/pause button](./screenshots/play-pause-btn.png) To play and pause
-- ![pan/place button](./screenshots/pan-place-btn.png) To Pan/Place Mode
-- ![clear button](./screenshots/clear-btn.png) To clear the canvas
-- Click on the body while in pan mode to follow
+On the left side, there are 5 buttons for Play/Pause, Place Mode, Pan Mode, Selection Mode, Clear All, and Load Presets.
+
+On the right side, the `Mass` and `Color` properties are for new bodies and `Speed` and `Gravity` are for simulation.
+
+## Shortcuts
+
+- Pause/Play: `space`
+- Place Mode: `p`
+- Pan Mode: `h`
+- Selection Mode: `s`
+- Clear `All: c`
+- Undo: `CTRL + Z`
+- Redo: `CTRL + Y`
+- Delete Selection: `delete`
+- New File: `CTRL + M`
+- Save File: `CTRL + S`

index.html

@@ -97,16 +97,15 @@
       <span class="close-btn">Close</span>
       <h2 style="text-align: center;">Gravity Sandbox</h2>
       <p>
-        Gravity Sandbox is a fun toy/game where you can play with Newtonian Gravity
-        by placing heavy objects in patterns and see intersting results.
+        Gravity Sandbox is a fun toy/game where you can play with Newtonian Gravity.
+        Place heavy objects in patterns and see interesting results.
       </p>
       <h3>Controls</h3>
       <p>
-        On the left side there are 5 buttons for Play/Pause, Place Mode, Pan Mode, Selection Mode,
-        Clear All, and Load Presets.
+        On the left side, there are 5 buttons for Play/Pause, Place Mode, Pan Mode, Selection Mode, Clear All, and Load Presets.
       </p>
       <p>
-        On the right side the <code>Mass</code> and <code>Color</code> properties are for
+        On the right side, the <code>Mass</code> and <code>Color</code> properties are for
         new bodies and <code>Speed</code> and <code>Gravity</code> are for simulation.
       </p>
       <h3>Shortcuts</h3>

screenshots/clear-btn.png

@@ -111,6 +111,7 @@ export default class Universe {
   }
 
   clear() {
+    this.undoHistory.push({type: "delete", bodies:this.bodies})
     this.bodies = [];
     this.previousPlacedCoords = {};
   }

screenshots/pan-place-btn.png

@@ -509,6 +509,7 @@ window.addEventListener('load', () => {
       switchMode("add");
     } else if (e.key === "c" || e.code === "C") {
       U.clear();
+      updateInfoBar();
     } else if (e.ctrlKey && (e.key === "z" || e.code === "Z")) {
       e.preventDefault();
       undo();