Bootcamp

Day 1

Library - a bunch of code that someone else already wrote
openFrameworks - a library that helps you draw graphics and other creative code related tasks
C - invented in the 70s, one of the first programming languages
C++ - built off of C, an improvement on C that adds new concepts. A "type a" language.
Variable
- Allow you to save information in the computer's memory
- Must have a type
Parameter
- Functions can have parameters. Another word is "argument".
What can computers do?
- Math
- Remember stuff
- Control flow — Choose your own adventure stuff

How do I create a new openFrameworks project?
What are the different source files for?
- main.cpp
- ofApp.cpp
- ofApp.h
Coordinate systems start at the top left. (0, 0) is at the top left, and down is positive in Y.
How do I change the width and height?
- Open main.cpp, look for width/height
I get this error: "Expected ';' after expression"
- Almost every line in C++ ends with a semi-colon. This is an important piece of coding syntax. This is a way a computer knows the division between lines.
do i need to use spaces in between symbols? example: ofDrawLine(x+10,5,x+20,20); This is syntactically valid, but it is not the convention.
Does it matter what order I put lines of code?
- Absolutely, the order of lines is very important.
  - Background example
  - Variable example
How do I create a new function?
- add the "function header" to the .h file
- add a "function definition" to the .cpp file
What happens if i define a variable called x inside a function with a parameter called x?
very important use ofApp::

draw function
Coordinate system
ofDrawLine(x1, y1, x2, y2)
- x's come before y
ofBackground(r, g, b)
- each value ranges from 0-255
Painter's algorithm
- The order of the lines matters
Comments are a letter to yourself // This is a comment
- command + slash
ofDrawCircle(x, y, radius)
- radius, not diameter
ofDrawRectangle(x, y, width, height)
- width and height are (relative)
variables:
- binary can be used to represent numbers, letters, other types of data
- int x = 10;
  - A number that has no fractional component
- float x = 50;
  - A decimal number. 1.1, 3.14, -103345.2543
- char c = 'x';
  - a single letter
- bool b = true;
- types are fundamental to programming languages
mouseX / mouseY
custom functions
- double click on .h file
- add a new function under "public:"
  
  void drawLetterR()
parameters
- in .h file:
  - void drawLetterR(float x);
- in .cpp file: void drawLetterR(float x) { }
Always reduce redundancy

Exercise 1: Draw line from top left to bottom right
Exercise 2: Draw your name
- Coordinate systems?
- how do i change line width
- how do i use ofDrawCurve
- S's are hard ofPolyline curve;
  curve.arc(centre, radiusX, radiusY, startAngle, endAngle, arcResolution);
  curve.draw();
- you can use mathematical expressions in parameters
Exercise 3: Take the first letter of your name, and draw it twice on the screen
- make the computer do the math
  
  if this is our old line
  
  ofDrawLine(30, 30, 20, 500);
  
  then we can draw this new line
  
  ofDrawLine(200 + 30, 30, 200 + 20, 500)
  - we keep repeating the same number again and again
  - we can use a variable to store this number
  - we can move this code to a function
  - we can parameterize this function
Homework assignment:
- Rewrite drawLetter function so that it accepts 4 parameters:
  
  void drawLetter(int x, int y, int width, int height) { // ... }

Turn off autocomplete at the start
Color as 0-255 was called out by student, but needs to be reemphasized more clearly.
What happens if ofBackground comes after ofLine?
Overemphasis on XCode short cuts
"Little bit of addition" — not easy!
Don't show multi-cursor features
Lines of code are run top-down
don't introduce binary so early. i think that "you need to tell c++ what type of variable you want to store" is enough.
A program is a recipe.
More focus on syntax. Ex: variable declaration (doesn't need to be called x)
mental model of the execution thread
scope
returns are not motivated