From last time…

• Introduced the Project Proposal – due in 1 week!

• Talked about Design Thinking!

• Office Hours will be before class: MW 4th Period

CAP 3032

Libraries

A Simple Sketch

size(500,500); background(255); ellipse(250,250,50,50);

How does the computer!know what all this is?

The Core Library• The IDE automatically imports the Core Library!

• What is in the Core Library?!

• http://processing.org/reference!

• http://processing.org/reference/libraries/!

• Why not import all libraries, all the time?

Functions

A function is a block of code!

We can “call a function”:!

functionName(argument1, argument2);

But we can also define functions…

Defining a Function

returnType functionName( argumentList ) { // some code goes here }

the arguments we can pass in

the type of value we expect to be ‘returned’

the arguments we can pass inthe type of value we expect to be ‘returned’

1. Function Name: a logical name!

2. Input: the type of values we can pass in!

3. Output: the type of returned (“void” signifies that we do not expect returned value)

returnType functionName( argumentList ) { // some code goes here }

size(500,500);

What is its name?!

What arguments do we pass in?!

What type of arguments are these?!

Does it return anything?!

What is the return type?

size

width & height

nope!

void

integers

size(500,500);

void size(int newWidth, int newHeight) { sketchWindow.width = newWidth; sketchWindow.height = newHeight; }

int x = multiply(3,2);

What is its name?!

What arguments do we pass in?!

What type of arguments are these?!

Does it return anything?!

What is the return type?

multiply

values to multiply

yes!

int

integers

int x = multiply(3,2);

int multiply(int value1, int value2) { int result = value1 * value2; return result; }

OR { return value1 * value2; }

CAP 3032

Dynamic Sketches

Static Mode

size(500,500); background(255); ellipse(250,250,50,50); !

Play

Start

Finish

Active Modevoid setup() { // some code here } !

void draw() { // other code here }

void setup( )• Is called 1 time after you run the sketch!

• First line is always size()

• Other functions:!

! background()

! smooth()

! colorMode() or rectMode()

void draw( )

• Is called 30 times per second after setup()

• This is what was call our “Draw Loop”

CAP 3032

The Sketch “Flow”

your sketch

Import the Core Library

Look for and run: setup()

Execute: draw()…!30 fps, forever!

CAP 3032

Interaction!!Mouse Position!& Event Listeners

1. Mouse Position• Mouse Position Variables: these global variables

are calculated for us by Processing!

• They are updated at 30fps (each draw loop)!

• Current mouse location: mouseX, mouseY!

• Previous mouse location: pmouseX, pmouseY

Demo!Mouse Position

mousePressed()

• Define the event listener function mousePressed()

• Anytime the mouse is clicked, it will run the body of code you defined

keyPressed()

• Define the event listener function keyPressed()

• Anytime a key is clicked, it will run the body of code you defined

Demo!Event Listeners

Active Template

A generic active sketch template would define each of the following functions:!void setup() {} void draw() {} void mousePressed() {} void keyPressed() {}

The Nature of Code!Shiffman, Daniel!!

Generative Art!Pearson, Matt

Visualizing Data!Fry, Ben

For next time…• Read Shiffman, p. 45–58 (Variables)!

• Quiz on Friday!

! - Last 20 minutes of class!

! - Shiffman, p. 3–42 (Pixels, Processing, & Interaction)!

• Continue developing your Project Proposals