15 minutes, split into groups and share homework

two ways to approach animation:

1. animate a thing based on its previous position. we need the computer to remember; we need an attribute variable in the .h file.
2. there is a whole class of animations where the position (or color or whatever) is a calculation based on the current time. no variables needed!

store a circle's position in the .h file; two floats x and y. have it chase the mouse. ease towards the mouse. talk about multiplication, easing.

float ease = 0.9;
x = (x * ease) + (mouseX * (1-ease));

introduce cout << to peek inside ofGetElapsedTimef(). animate a circle moving across the screen.

// start with this
float y = ofGetElapsedTimef();
// evolve to this
float y = ofMap(sin(ofGetElapsedTimef(), -1, 1, 0, ofGetHeight()), 

ofDrawCircle(ofGetWidth() / 2, y, 10);

We aren't using sine as in trigonometry, but simply as a function that has an input and output (any number ➜ between -1 and 1). work your way up to using ofMap.

now map the the sine of elapsed time to colors, very simple, the background color.

float color = ofMap(sin(ofGetElapsedTimef()), -1, 1, 0, 255);
ofBackground(color);

with both of these in the same sketch, learn about phase. make these two sine of elapsed times oscillate at different rates.

ofGetElapsedTimef() and ofRandom(), two ways of getting a different number each frame. Introduce time before random as it more represents classical animation.

for context, show some algorists' work: Molnar, Nees, Mohr, Nake, computer pseudo-randomness kind of had a moment in these decades.

float x = ofRandom(ofGetWidth());
float y = ofRandom(ofGetHeight());
circle(x, y, 10);

think of random in 2 ways: directly visualizing random (the sketch above), or use random to affect a variable which in turn is visualized, so there is a layer of abstraction between you and random.

// random walker
x += ofRandom(-5, 5);
y += ofRandom(-5, 5);
circle(x, y, 2);

have fun with sin(ofGetElapsedTimef()), using map for position, colors.

what are some other ways you can layer abstraction between you and random?