Art, Randomness, and Functions

Size: px

Start display at page:

Download "Art, Randomness, and Functions"

Alexandrina Jennings
6 years ago
Views:

1 Art, Randomness, and Functions

2 Midterm Step up your game!

3 Common Issues

4 Essays Final stage! Read your peer reviews on CrowdGrader Vote your reviews as helpful or unhelpful This affects other people's grades, so take it seriously Not a vote on whether you agree with the review Votes due by Thursday before class

5 Creativity Creativity in Processing Homework 7 Due next Tuesday at 5pm Get a programming partner Go crazy!

6 Creativity Examples

7 Why pair programming? Having a partner gives you a helper Many people find computers more fun when working with others Learning to work with computers is similar to learning a foreign language lots of new words, codes easier to learn if you have to converse in the language Working with a partner develops teamwork skills Real-life programming is almost always done in teams Employers are looking for team players

8 Processing as Art

9 If we generate it with Processing, is it art? Piet Mondrian ( ) Jackson Pollock ( ) Josef Albers ( )

have aesthetic sensibilities? Piet Mondrian (1872-1944) http://en.

10 Computer Art True computer art would be art created by a computer, not just art created by a person using a computer Could computers have aesthetic sensibilities? Piet Mondrian ( ) ndrian Cubist Could we generate this in Processing?

11 A little easier...

12 Colored Squares What does random(...) do?

13 Random Numbers Random numbers are really random number sequences No matter how many numbers you know in the sequence, you can't predict the next one Non-random: 2, 4, 6, 8, 10,... Computers can't actually be random, they are completely predictable But they can produce sequences that pass all the tests of randomness Pseudo-random numbers (everyone just drops the pseudo-) In Processing: random(<smallest number>, <largest number>) Get back a number (unpredictable) between the two limits, including end points To generate a random number between 0 and 255, write random(0, 255) To generate a random number between 0 and 1, write random(0, 1)

14 lerpcolor() The function lerpcolor() Generates intermediate colors between two colors You give it two colors Gold and purple It finds mixes between those colors Also give it a fraction (like.33 or.66) between 0 and 1 specifies the mix ratio

15 lerpcolor() lerp is short for linear interpolation

16 Remember how colors work... Colors are sets of Red Green Blue values from 0 to

17 Mixing Colors Colors are sets of Red Green Blue values from 0 to Halfway color (0.5 mix)

18 Review: Crazy Rectangles Remember: System variables mousex mousey pmousex pmousey width height framecount

19 Arty Version

20 Alternate Arty Version

21 The jumping ball...

22 The jumping ball... A. Ball moves across, jumping back to left edge and changing color as soon as it touches the right edge. B. Ball moves across as one color until it moves off the right edge then changes color and moves back in from the left edge C. Ball moves across until half way off the right edge (showing just half a circle) then changes color and jumps to the left side D. Ball moves across then disappears and doesn't come back.

23 Pointilism (and other image manipulation)

24 Tints, Transparency, more...

25 Jackson Pollock Abstract expressionist

JacksonPollock.org http://jacksonpollock.

26 JacksonPollock.org org/ Miltos Manetas 2003 Created Feb 2014

27 Pollock in Processing

28 Repeating with Variation

29 for loops We've seen this before! Functions We've used functions, defined a few like draw() ourselves Let's review for loops quickly

30 Repetition Repeating commands is powerful Lightbot 2.0 used recursion Symbolic Lightbot used a prefix number function calls itself 4:Step means do Step Step Step Step Processing uses a for loop

31 Parts of a for loop Here are the parts of a for loop (all are required) parens for keyword starting value test increment for (int i = 0; i < 16; i++) { // stuff to be repeated ellipse( *i, 100, 15, 15); } braces Result: we get 16 copies of the ellipse Pac-Man pills!

32 What does this code display? A. Lots of little pills going off the left and right side of the screen B. Rows of little pills repeating with every mouse click C. A row of little pills that change color with every mouse click D. Pulsing images of circles changing colors and growing every frame

33 Functions

34 Processing Reference tml

35 Instructions formed from simpler actions Check out this screenshot It is partway through an instruction... it's beacon is lit, but the tile is still blue To the programmer the instruction is one step (monolithic) To the agent each instruction is a series of steps An instruction abstracts these steps

36 Abstracting Collecting the operations together and giving them a name is functional abstraction The group of operations performs some function but we ignore the details Only need to refer to the name we gave it This is AMAZINGLY powerful Why? We can forget about the operations Only thing about what function they do We'll talk more about this...

37 Example: Abstracting your morning Get dressed Dress bottom half Put on socks Put on pants Dress top half Put on shirt

38 Functions abstract by packaging computation F1() packages actions (e.g. process a riser )

39 The Function becomes a Concept Because F1() processes a riser, you can think of the task as: Process a riser F1 Move to next riser Process a riser F1 Move to next riser Process a riser F1 With F1() as a concept, we simplified the programming to 9 steps instead of 21 steps

40 Calling functions What happens if we comment out the second call?

42 Functions Here is the form of a function definition <return type> <name> ( <param list> ) { <body> } Example: void draw_box(int x_pos, int y_pos) { rect(x_pos, y_pos, 20, 20); } color pinkish() { return color(255, 200, 180); }

43 Return types Functions that do something but do not return a value Use void as <return type> Functions that return a value must specify the type void draw_box(int x_pos, int y_pos) { rect(x_pos, y_pos, 20, 20); } color pinkish() { return color(255, 200, 180); }

44 Parameters Parameters are the values used as input to the function Functions don't have to use parameters Still need parentheses even if no parameters Type of each parameter must be given void draw_box(int x_pos, int y_pos) { rect(x_pos, y_pos, 20, 20); } color pinkish() { return color(255, 200, 180); }

45 More on Parameters Parameters Customize each function call to a specific situation They are the input to the function Terminology: Parameters are the names of the values used inside the function body Arguments are the values from outside to be used for each of the parameters

46 Arguments become Parameters If the definition has n parameters The call needs n arguments The parameters and arguments correspond

47 Return A function returns its value with the return statement Value following the return is the result Function is done when it reaches return or the end of the body void draw_box(int x_pos, int y_pos) { rect(x_pos, y_pos, 20, 20); } color pinkish() { return color(255, 200, 180); }

48 End

What can we do with Processing? Let s check. Natural Language and Dialogue Systems Lab Guest Image. Remember how colors work.

MIDTERM REVIEW: THURSDAY I KNOW WHAT I WANT TO REVIEW. BUT ALSO I WOULD LIKE YOU TO TELL ME WHAT YOU MOST NEED TO GO OVER FOR MIDTERM. BY EMAIL AFTER TODAY S CLASS. What can we do with Processing? Let