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Index › Programming Questions & Help › Syntax Questions › really simple problem

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really simple problem (Read 297 times)

r4m3sh

really simple problem
Oct 6^th, 2008, 11:34pm

Hello,

I go in and out of using processing and as a result, sometimes have no Idea what is going on.

This is supposed to be a stupid-easy program that makes circles appear on the screen in a roygbiv fashion, however, the colors seem to change position when I add more than one.

this places the red circle where expected

void setup ()
{
size(1000, 200);
smooth();
background(0);
noStroke();

}

void draw()
{
float c = 60;

if (key=='a')

ellipse(50,150, c, c);
fill(255,0,0);

}

This code, however flip flops my expected outcome

void setup ()
{
size(1000, 200);
smooth();
background(0);
noStroke();

}

void draw()
{
float c = 60;

if (key=='a')

ellipse(50,150, c, c);
fill(255,0,0);

if (key=='s')

ellipse(120,150, c, c);
fill(230,100,0);

}

any help would be really appreciated, as I said, this is probably really simple.
I think I am doing something fundamentally wrong, but have no clue what exactly.

thanks

sojamo

Re: really simple problem
Reply #1 - Oct 7^th, 2008, 5:48am

i suspect you are missing the curly brackets in your if-statements. if an if-statement should only execute one line of code, the curly brackets are not required, but if there is more than 1 line to be executed in an if-statement, curly brackets are required. same goes for for-loops. reading through your code, i recommend to set the color before you draw a shape (same goes for lines). which would give you the following
Code:


void setup() {
  size(1000,200);
  smooth();  
  background(0);
  noStroke();
}
 
 
void draw() {
  // use background to 
  // overwrite what has been drawn
  // in the previous frame.
  background(0); 
  
  float c = 60;
  
  // the variable key stores
  // the last key that has been pressed. 
  // even if you release the key on 
  // your keyboard, the variable key 
  // will still contain the last 
  // key pressed.
  
  if (key=='a') {  
    fill(255,0,0);
    ellipse(50,150, c, c);  
  }
     
  if (key=='s') {
    fill(230,100,0);
    ellipse(120,150, c, c);  
  }
   
}

andreas schlegel / http://www.sojamo.de

r4m3sh YaBB Newbies Offline Posts: 2	Re: really simple problem Reply #2 - Oct 7^th, 2008, 7:34am thanks so much. I see what I was forgetting. very helpful. It has been too long, it is a shame how quickly my skills seem to rust

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