Animation Piech, CS106A, Stanford University Our story so far - PowerPoint PPT Presentation

Animation Piech, CS106A, Stanford University

Our story so far… Piech, CS106A, Stanford University

Our story so far… Piech, CS106A, Stanford University

Learning Goals 1. Write animated programs 2. Center an object Piech, CS106A, Stanford University

You will be able to write Bouncing Ball Piech, CS106A, Stanford University

Learning Goals For Me 1. Speak slower Piech, CS106A, Stanford University

But First! private void run() { int x = 6 – 4 + 7 * 3; println(x); int y = (6 + 4 + 7) * 3; println(y); int z = 6 / 2 * 3; println(z); } Piech, CS106A, Stanford University

Move GRect Piech, CS106A, Stanford University

Animation Loop private void run() { // setup while(true) { // update world // pause pause(DELAY); } } Piech, CS106A, Stanford University

Animation Loop Make all the variables private void run() { you need. Add graphics // setup to the screen. while(true) { // update world // pause pause(DELAY); } } Piech, CS106A, Stanford University

Animation Loop private void run() { // setup The animation loop is a repetition of heartbeats while(true) { // update world // pause pause(DELAY); } } Piech, CS106A, Stanford University

Animation Loop private void run() { // setup while(true) { Each heart-beat, update // update world the world forward one frame // pause pause(DELAY); } } Piech, CS106A, Stanford University

Animation Loop private void run() { // setup while(true) { // update world If you don’t pause, // pause humans won’t be able pause(DELAY); to see it } } Piech, CS106A, Stanford University

Move To Center private void run() { // setup GRect r = new Grect(0, 250, 100, 100); r.setFilled(true); add(r); while(true) { // update world r.move(1, 0); // pause pause(DELAY); } } Piech, CS106A, Stanford University

Gravity Ball Piech, CS106A, Stanford University

Gravity Ball First heartbeat Velocity : how much the ball position changes each heartbeat Piech, CS106A, Stanford University

Gravity Ball First heartbeat vx vy The GOval move method takes in a change in x and a change in y Piech, CS106A, Stanford University

Gravity Ball Second heartbeat vx vy Piech, CS106A, Stanford University

Gravity Ball Third heartbeat vx vy Piech, CS106A, Stanford University

Gravity Ball What happens when we hit a wall? Piech, CS106A, Stanford University

Gravity Ball We have this velocity vx vy Piech, CS106A, Stanford University

Gravity Ball Our new velocity vx vy vy = vy * - DAMPING; Piech, CS106A, Stanford University

Gravity Ball Seventh Heartbeat vy vx vy = vy * - DAMPING; Piech, CS106A, Stanford University

Questions? Piech, CS106A, Stanford University

Gravity Ball Piech, CS106A, Stanford University

A Sticky Situation This is our new velocity The ball is above the bottom so we reverse its vy The ball is bellow the bottom so we reverse its vy Piech, CS106A, Stanford University

Centering Piech, CS106A, Stanford University

By Chris Piech, CS106A, Stanford University

Once upon a time… Piech, CS106A, Stanford University

x was looking for love… int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 x Piech, CS106A, Stanford University

x was looking for love… int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 x Piech, CS106A, Stanford University

x was looking for love… x was definitely int x = 5; looking for love if(lookingForLove()) { int y = 5; } println(x + y); 5 x Piech, CS106A, Stanford University

And met y int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 5 y x Piech, CS106A, Stanford University

And met y int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 Hi, I’m y 5 y x Piech, CS106A, Stanford University

“Wow!” Piech, CS106A, Stanford University

And met y int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 Wow 5 y x Piech, CS106A, Stanford University

And met y int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 We have so much 5 in common y x Piech, CS106A, Stanford University

And met y int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 We both have 5 value 5! y x Piech, CS106A, Stanford University

And met y int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 Maybe one day 5 we can… y x Piech, CS106A, Stanford University

And met y int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 println together? 5 y x Piech, CS106A, Stanford University

They got along int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 5 y x Piech, CS106A, Stanford University

It was a beautiful match… Piech, CS106A, Stanford University

But then tragedy struck. Piech, CS106A, Stanford University

Tragedy Struck int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 5 y x Piech, CS106A, Stanford University

Tragedy Struck int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 5 y x Piech, CS106A, Stanford University

Tragedy Struck int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 x Piech, CS106A, Stanford University

Noooooooooooooooo! Piech, CS106A, Stanford University

You see… Piech, CS106A, Stanford University

When a program exits the code block… int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 x Piech, CS106A, Stanford University

Where a variable was declared… int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 x Piech, CS106A, Stanford University

It gets deleted from memory! int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 x Piech, CS106A, Stanford University

Since y was declared inside the if int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 x Piech, CS106A, Stanford University

It gets deleted from memory here int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 x Piech, CS106A, Stanford University

And doesn’t exist here. int x = 5; if(lookingForLove()) { int y = 5; } println(x + y); 5 x Piech, CS106A, Stanford University

And doesn’t exist here. int x = 5; Error. Undefined if(lookingForLove()) { variable y. int y = 5; } println(x + y); 5 x Piech, CS106A, Stanford University

The End Piech, CS106A, Stanford University

Or is it? Piech, CS106A, Stanford University

Variables have a lifetime public void run(){ double v = 8; if ( condition ){ v = 4; … some code } … some other code } Piech, CS106A, Stanford University

Variables have a lifetime public void run(){ double v = 8; if ( condition ){ v = 4; … some code } … some other code } Piech, CS106A, Stanford University

Come to existence when declared public void run(){ double v = 8; Comes to life here if ( condition ){ v = 4; … some code 8 } v … some other code } Piech, CS106A, Stanford University

Live Until End of Code-Block public void run(){ double v = 8; if ( condition ){ This is the inner most code block in which it was v = 4; declared…. … some code 4 } v … some other code } Piech, CS106A, Stanford University

Variables have a lifetime public void run(){ double v = 8; if ( condition ){ Still alive here… v = 4; … some code 4 } v … some other code } Piech, CS106A, Stanford University

Live Until End of Code-Block public void run(){ double v = 8; if ( condition ){ v = 4; … some code 4 } v … some other code } It dies here (at the end of its code block) Piech, CS106A, Stanford University

Live Until End of Code-Block public void run(){ double v = 8; if ( condition ){ v = 4; … some code } … some other code } It dies here (at the end of its code block) Piech, CS106A, Stanford University

Chapter 2 Piech, CS106A, Stanford University

The programmer fixed her bug Piech, CS106A, Stanford University

x was looking for love… int x = 5; if(lookingForLove()) { int y = 5; println(x + y); } 5 x Piech, CS106A, Stanford University

x was looking for love… x was definitely int x = 5; looking for love if(lookingForLove()) { int y = 5; println(x + y); } 5 x Piech, CS106A, Stanford University

x met y int x = 5; if(lookingForLove()) { int y = 5; println(x + y); } 5 5 y x Piech, CS106A, Stanford University

Since they were both in scope… int x = 5; if(lookingForLove()) { int y = 5; println(x + y); } 5 5 y x Piech, CS106A, Stanford University

The story had a happy ending! Piech, CS106A, Stanford University