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Index › Programming Questions & Help › Programs › Star Making Help

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Star Making Help (Read 2352 times)

David_Benque

Star Making Help
Aug 17^th, 2005, 5:16pm

Hello,
this is my first processing script,
I would like to create images like this:
http://www.magueule.net/processing
(i made this in photoshop by layering outputs of the previous version of the script that was just saving a TIFF when you clicked)

the center of the star and the color are set by the mouse position,

Do you have any idea how i could make the whole image in Processing, clicking everytime I want to add a star (with a blending of the colors) to the background. and keep on going
I tried something but right now the program just gets stuck whenever I click

Thanks a lot

<code>

void setup() {

size(200,200);
rectMode(CENTER);

}

void draw()
{
background(255);
star(mouseX,mouseY);
}

void mousePressed()
{
// This part seems to be the problem
color c = color(mouseX,mouseY,width-mouseX);
loadPixels();
for (int i=0; i<width; i++){
for (int j=0; j<height; j++){
color pixel = get(i,j);
color newcolor = blend(pixel, c, BLEND);
set(i,j,newcolor);
updatePixels();
}
}

}

void star(int x, int y) {

noStroke();
fill(mouseX,mouseY,width-mouseX);
beginShape(POLYGON);
vertex(0,0);
vertex(width/4,0);
vertex(x,y);
vertex(0,0);
endShape();

beginShape(POLYGON);
vertex(width/2,0);
vertex(width*0.75,0);
vertex(mouseX,mouseY);
vertex(width/2,0);
endShape();

// Top right corner

beginShape(POLYGON);
vertex(width,0);
vertex(width,height/4);
vertex(x,y);
vertex(width,0);
endShape();

beginShape(POLYGON);
vertex(width,height/2);
vertex(width,height*0.75);
vertex(x,y);
vertex(width,height/2);
endShape();

// Bottom right corner

beginShape(POLYGON);
vertex(width*0.75,height);
vertex(width,height);
vertex(x,y);
vertex(width*0.75,height);
endShape();

beginShape(POLYGON);
vertex(width/4,height);
vertex(width/2,height);
vertex(x,y);
vertex(width/4,height);
endShape();

// Bottom left corner

beginShape(POLYGON);
vertex(0,height/4);
vertex(0,height/2);
vertex(x,y);
vertex(0,height/4);
endShape();

beginShape(POLYGON);
vertex(0,height*0.75);
vertex(0,height);
vertex(x,y);
vertex(0,height*0.75);
endShape();
}
</code>

« Last Edit: Aug 18^th, 2005, 12:46pm by David_Benque »

JohnG

Re: Star Making Help
Reply #1 - Aug 18^th, 2005, 1:55pm

The reason your code hangs is that you're calling updatePixels() for every single pixel on screen. move it to after the two for() loops.

However that won't fix the problem, because every frame you're clearing the screen with the background(255); call, that blank the sketch, so the blend will never be seen.

It shoudl be possible to achieve the result you want, but it might need the use of a PGraphics to draw the star to first, then blend that with the screen image.

David_Benque

Re: Star Making Help
Reply #2 - Aug 18^th, 2005, 3:08pm

Thanks a lot for the advice,
I moved updatePixels()
I guess now the whole mousepressed part isnt really doing much as I see no blending, but at least it doesn't get stuck
and also tried moving the background to the setup() but then it draws every single star the mouse makes

I was thinking if it would make sense to save a tiff when mouse is pressed and reimport that into the background but it sounds like a complicated way to do it.

anyways.. I'll search for that Pgraphics stuff you mentioned, is that in an older version of processing ?

JohnG Ex Member	Re: Star Making Help Reply #3 - Aug 18^th, 2005, 3:13pm PGraphics is current, just mostly undocumented. It can be used in the same way as saving the image, and re-loading it, just weithout having to save, and re-load things.

David_Benque YaBB Newbies Offline Posts: 5	Re: Star Making Help Reply #4 - Aug 18^th, 2005, 4:26pm PGraphics is current, just mostly undocumented is there no documentation at all ? If you have any clue where I could start searching please let me know Thanks a lot

JohnG

Re: Star Making Help
Reply #5 - Aug 18^th, 2005, 8:45pm

Well PGraphics is the same thing as to what you normally draw to.. e.g when you do "BeginShape(QUADS); vertex(...)" etc, that's actually (effectively) going to a PGraphics object, just one you're inside of...

So you can do something like this:
Code:


PGraphics3 foo;

void setup()
{
  size(200,200,P3D);
  foo=new PGraphics3(200,200,null);
  foo.defaults(); // <-- important!
}

void draw()
{
  background(0);
  foo.background(255);
  foo.stroke(0);
  foo.line(0,0,200,200);
  foo.updatePixels(); // just in case
  image(foo,100,0);
}

So you can prefix most drawing commands by the name of the PGraphics(2/3/GL) object, and they'll work on that, instead of the main screen, then just call image(thingy,x,y); and it'll copy the contents of the PGraphics object to screen.. so you could do blend(foo,0,0,width,height,BLEND); to blend the object and screen together.

David_Benque

Re: Star Making Help
Reply #6 - Aug 21^st, 2005, 5:00pm

Thanks again for sharing this knowledge

I tried to put your advice into the script, its not there yet but I'm trying stuff around...

A couple questions have showed up though

- in your example you're using P3D. I don't really need 3D for what I'm trying to do so I tried a PGraphics2 . Then it seems the line

foo=new PGraphics2(200,200,null);

creates a problem. I'm wondering what the null part refers to...

- Why do you have to give the statement
PGraphics3 foo;
before everything else, even the setup() ?

- I t doesn't seem possible to do something like

foo.star(mouseX,mouseY);

when I defined all the polygons in the star() function...

I'll also try and find answers to these questions ( they must sound really dumb )
anyways, I really apreciate your help

thanks

David_Benque

Re: Star Making Help
Reply #7 - Aug 21^st, 2005, 6:51pm

Some progress...

I did a little try with squares, if i get that to work, then i guess the stars or anything else will work..

so now its drawing a square on mousePressed, nice
but I've been trying the blending part and no way o get around it ...

<code>
PGraphics3 foo;
PGraphics3 IMG;

void setup() {

size(300,300,P3D);
foo = new PGraphics3 (300,300,null);
foo.defaults();
rectMode(CENTER);

IMG = new PGraphics3 (300,300,null);
IMG.defaults();
IMG.background(255);

}

void draw()
{

foo.noStroke();
foo.background(IMG);
foo.fill(mouseX,width-(mouseX+5),mouseY);
foo.rect(mouseX,mouseY,100,100);
image(foo,0,0);

}

void mousePressed()
{
IMG.set(0,0,foo);
IMG.blend(foo,0,0,0,0,BLEND);
IMG.updatePixels();

}

<\code>

ps: how do i display code properly ?

« Last Edit: Aug 21^st, 2005, 8:16pm by David_Benque »

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