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Title	Bouncing off Walls & Explanation
ID	4537725537484800
Created	12 years ago, 1389375708314
Updated	12 years ago, 1389495087348
Code	// This made top of the the hotlist! Glad I could help! I hope you learn something here. // I just added a spin-off where you can bounce off of diagonal edges on the corners. I explained those too. You can look at that at https://www.khanacademy.org/cs/diagonals-added/5208416272252928 // use the arrow keys to move and bounce. // maybe I'll make a game out of this sometime. 0r you could if you want, it's not complicated. // I explained each step below. You can custumize it. // if any of these are true, the ball is accelerated in that direction. var up = false; var down = false; var left = false; var right = false; // position of the ball in x,y coordinates var x = 200; var y = 200; //speed of the ball var speedDown = 0; var speedRight = 0; // if an arrow key is pressed, the variable for that direction is true var keyPressed = function() { if (keyCode === UP) { up = true; } if (keyCode === DOWN) { down = true; } if (keyCode === LEFT) { left = true; } if (keyCode === RIGHT) { right = true; } }; // when the arrowkey is released, the variable is false var keyReleased = function() { if (keyCode === UP) { up = false; } if (keyCode === DOWN) { down = false; } if (keyCode === LEFT) { left = false; } if (keyCode === RIGHT) { right = false; } }; // the built-in draw function repeats at 30 frames per second. When I started programming, I didn't realize that "draw" was a special command. I was pretty confused for while. Hope that helps. var draw = function() { //the background is drawn. You can give smiley a mustache or something. stroke(94, 255, 0); background(59, 59, 59); fill(58, 80, 92); rect(20,20,360,360); noStroke(); fill(51, 63, 84); ellipse(200,180,250,300); fill(58, 80, 92); ellipse(200,150,310,250); fill(51, 63, 84); ellipse(120,100,50,75); ellipse(280,100,50,75); // the ball is drawn at x and y positions fill(43, 235, 5); ellipse(x,y,20,20); // if a direction variable is true, the ball is accelerated in that direction. This might mean that the ball is slowed in the opposite direction. Change the 0.5 up or down for a higher or lower acceleration. if (up) {speedDown -= 0.5;} if (down) {speedDown += 0.5;} if (left) {speedRight -= 0.5;} if (right) {speedRight += 0.5;} // the x and y positions change to the left right, up or down, according to the speed in each direction. a speed of speedRight = -5 will send the ball five spaces to the left every drawing cycle. x += speedRight; y += speedDown; // every cycle, the speed is automatically brought down to 99%. This slows the ball to eventually stop. If you delete these lines, then the ball won't slow down until you push in opposite direction. That's kind of fun. Shorthand suggested by karnik.tanav. speedDown = 0.99; speedRight = 0.99; // if the ball (x and y coordinates) is too far to one side, the ball will reverse direction, or bounce off the wall. Try turning the -1 into a -1.5, this will the ball a speed boost everytime it hits a wall. if (x < 30 \|\| x > 370) { speedRight = speedRight-1; } if (y < 30 \|\| y > 370) { speedDown = speedDown-1; } // because of a glitch, if you hit a wall slowly you can go through it. I could have fixed this, but instead I decided to state the obvious for you. If you are too much farther to the edge of the screen than the wall, then the text will pop up. if (x < 8 \|\| x > 392 \|\| y < 8 \|\| y > 392) { fill(247, 255, 0); textSize(20); text("dude, you just melted through a wall",45,200); } };
Folds
Fork	false
Key	ag5zfmtoYW4tYWNhZGVteXIXCxIKU2NyYXRjaHBhZBiAgID2mOGHCAw
Votes	184
Spin-Offs	49
Type	PJS
Width	400
Height	400
User Flagged	false
Origin Scratchpad	null
Hidden From Hotlist	false
Restricted Posting	false
By Child	false
Author Nick	jacobstratford
Author Name	jacobstratford
Author ID	kaid_617431448224202153702173
Author Profile Access	COACH

Archive Data

Added	10 months ago, 1739363248963
Updated	10 months ago, 1739363257129
Source Deleted	unknown