Comments on: Exercise 5-6: Fading Squares

By: Leo T Nozawa

Leo T Nozawa — Fri, 12 Aug 2011 02:05:00 +0000

Kit, if u’re using ints try using this:

if(rec == 0) rec = 1;
if(rec1 == 0) rec1 = 1;
if(rec2 == 0) rec2 = 1;
if(rec3 == 0) rec3 = 1;

Can’t make work with constrain using int too…

By: riko

riko — Thu, 18 Feb 2010 23:06:12 +0000

Hi!

A differente solution, but I don’t know if it’s better or not to do this.

float brightA = 0;
float brightB = 0;
float brightC = 0;
float brightD = 0;

void setup () {
size(200,200);
}
void draw(){
background(0);
stroke(255);
line(0,100,200,100);
line(100,0,100,200);
if(mouseX >100 && mouseY >100) {
brightA = 255;
}else{
brightA = brightA – 1;
}
if(mouseX > 100 && mouseY <100){
brightB = 255;
}else{
brightB = brightB – 1;
}
if(mouseX <100 && mouseY <100) {
brightC = 255;
}else{
brightC = brightC – 1;
}
if(mouseX 100){
brightD = 255;
}else{
brightD = brightD – 1;
}

fill(brightA);
rect(100,100,100,100);
fill(brightB);
rect(100,0,100,100);
fill(brightC);
rect(0,0,100,100);
fill(brightD);
rect(0,100,100,100);

brightA = constrain (brightA,0,255);
brightB = constrain (brightB,0,255);
brightC = constrain (brightC,0,255);
brightD = constrain (brightD,0,255);

}

By: Daniel Shiffman

Daniel Shiffman — Sun, 31 Jan 2010 01:47:43 +0000

No, floats can absolutely be negative. Processing just constrains the values for you when you pass in a float for brightness into the fill() function and this doesn’t happen with an int.

It’s probably best to use constrain() in all cases just to be safe.

By: Dave

Dave — Sat, 30 Jan 2010 17:18:36 +0000

Does that mean float values can’t go into negatives? (that would explain why there is no constrain code in the answer?)

By: admin

admin — Mon, 27 Jul 2009 15:35:45 +0000

When you use integers, Processing will read negative numbers as strange colors. So you must make sure you constrain the values to between 0 and 255.

  // All rectangles always fade
  bright0 = constrain(bright0 - 1,0,255);
  bright1 = constrain(bright1 - 1,0,255);
  bright2 = constrain(bright2 - 1,0,255);
  bright3 = constrain(bright3 - 1,0,255);

By: Kit

Kit — Mon, 27 Jul 2009 13:32:46 +0000

I can’t work out exactly why this won’t work if the brightness variables are int rather than float.