Introduction to programming - class 5
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Introduction to Programming Class 5 Paul Brebner
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Transcript of Introduction to programming - class 5
Introduction to ProgrammingClass 5
Paul Brebner
Exercises Revision
• Textbook– Page 42ff
– Example 4.6 to 4.13
– Then go back to fruit bowl problem
– Save your fruit bowl problem to work on later
– Monday Robot 2 Page 49
• How far did you get?– Who managed to get fruit bowl working?
– If you did keep working on it next time if you have time – try “surreal” version
Today Chapter 5 textbook – mouse
• Page 51ff// declare global variablesint anIntToRuleTheWorld = 1; // can be used anywhere
void setup() {// do stuff once onlyframeRate(60); // default frameRateprintln(anIntToRuleTheWorld++);
}void draw() {
// repeat foreverPrintln(“frame number “ + frameCount); // frameCount is global variable, incremented each time
draw runsprintln(anIntToRuleTheWorld++);
}
mouse
• mouseX and mouseY are global variables for current mouse position
• background(value) clears screen
• pmouseX and pmouseY – mouseX and mouseY in the previous frame
• dist(x1,y1,x2,y2) – length of line from (x1,y1) to (x2,y2)
dist(mouseX,mouseY,pmouseX,pmouseY) is speed of the mouse
Mouse button
• mousePressed global variable– Boolean so can only be true or false
– So don’t need the “==“
• if (mousePressed == true)println(“button!”)
else println(“no button”);
• if (mousePressed)println(“button!”)
else println(“no button”);
Mouse button – bugs“=“ (assignment) is legal but...
• if (mousePressed = true)
println(“button!”)
else println(“no button”);
• if (mousePressed = false)
println(“button!”)
else println(“no button”);
Mouse buttons
if (mousePressed){
If (mouseButton == LEFT)println(“Left button”);
else if (mouseButton == CENTER)println(“Center button”);
else if (mouseButton == RIGHT)println(“Right button”);
}else println(“NO button”);
Mouse buttons – same as
if (mousePressed)
If (mouseButton == LEFT)
println(“Left button”);
else if (mouseButton == CENTER)
println(“Center button”);
else if (mouseButton == RIGHT)
println(“Right button”);
else println(“NO button”);
Mouse buttons – same as
if (mousePressed)
If (mouseButton == LEFT)
println(“Left button”);
else if (mouseButton == CENTER)
println(“Center button”);
else if (mouseButton == RIGHT)
println(“Right button”);
else println(“NO button”);
Mouse buttons – same as
if (mousePressed && mouseButton == LEFT)
println("Left button");
else if (mousePressed && mouseButton == CENTER)
println("Center button");
else if (mousePressed && mouseButton == RIGHT)
println("Right button");
else println(“NO button”);
Mouse buttons – same as???Not sure – seems to be lag
if (mouseButton == LEFT)
println("Left button");
else if (mouseButton == CENTER)
println("Center button");
else if (mouseButton == RIGHT)
println("Right button");
else println(“NO button”);
switch statement – for lots of values
switch (mouseButton) // a variable{
case LEFT: println("Left Button"); break;case CENTER: println(“Center Button”); break;case RIGHT: println("Right Button"); break;default: println("No button"); break;// default matches if none of the other case values match (it’s a “catch all”)
}// case X is true if (mouseButton == X)// break exits the “block” (curly brackets) to here// don’t need the last break as exits automatically
Keys and text
• keyPressed – global boolean variable, true or false if key pressed or not
• key – global char variable remembers the last key typed (until a new key is hit)– Char is a single character ‘a’, ‘b’, ‘c’, ‘1’, ‘!’ etc
• “a” and a are not chars
– Some char values are not printable• Need to check if CODED as follows• if (key == CODED)
if (keyCode == LEFT) // check if left arrow pressed etc
• textSize(n) – sets font size (in pixels)• text(char, x, y) – draws char at (x,y) location
Exercises
• Examples 5-1 etc
– Don’t worry about easing and map examples
– Leave Example 5-16 and 5-17 (boundaries) until next time
