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Index › Programming Questions & Help › Syntax Questions › Basic 3D

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Basic 3D (Read 542 times)

Terry_Bell

Basic 3D
Feb 10^th, 2010, 11:34am

I haven't used 3D in processing yet.

I wanted to create an effect where each draw loop moves towards a vanishing point in the center of the screen.

A rectangle drawn in this sketch would give the impression of a tunnel, stretching off to the middle of the screen.

Not quite sure how to describe this.

I have looked for a 3D tutorial but to no avail.

Thanks,
TB

Quark

Re: Basic 3D
Reply #1 - Feb 10^th, 2010, 11:57am

This might help get you started

Code:

void setup(){
  size(420,320, P3D);
}

void draw(){
  background(0);
  stroke(255);
  strokeWeight(1);
  translate(width/2,height/2);
  for(int i = 0; i < 10; i++){
    // a rectangleDraw 
    line(-200, -200, -i*60,  200, -200, -i*60);
    line( 200, -200, -i*60,  200,  200, -i*60);
    line( 200,  200, -i*60, -200,  200, -i*60);
    line(-200,  200, -i*60, -200, -200, -i*60);
  }
}

Also look at line() reference.

The size of the rectangles are determined through perspective.

Terry_Bell

Re: Basic 3D
Reply #2 - Feb 10^th, 2010, 1:46pm

Thanks - i'll look at the perspective command.

Ultimately I wanted to create something like this, though that actually works. This is the best representation I could come up with with my limited processing knowledge.

So as time progresses, what a person drew gradually moves off into the distance.

Code:


PImage screenShot;
int x = 0;
int y = 0;
int imgWidth;
int imgHeight;
int i = 0;
int increment = 1;

void setup(){
  size(640,480);
  background(0);
  noFill();
  stroke(255);
  imgWidth = width;
  imgHeight = height;

}

void draw(){

  line(mouseX,mouseY,pmouseX,pmouseY);
  if(i%20==0){
    println("HERE");
    x += increment;
    y += increment;
    imgWidth -= 2*increment;
    imgHeight -= 2*increment;
    save("screenShot.tif");
    screenShot = loadImage("screenShot.tif");
    image(screenShot, x, y, imgWidth, imgHeight);

  }
  i++;
}

Quark

Re: Basic 3D
Reply #3 - Feb 11^th, 2010, 1:02am

Forget the perspective command for now.

You have a working program but it is slow because you are saving the image to a file (on disc) and then retrieve it. To speed this up you might consider creating your own images using createImage() to store the intermediate image (rather than disc).

That is a possible 2D solution but you might eventually consider a 3D solution. The following code is messy and has issues but is probably easier to understand than the logic than a full blown solution. Try it out.

Code:

int count = 0;
int x = 0;
int y = 0;

ArrayList xp = new ArrayList();
ArrayList yp = new ArrayList();

void setup(){
  size(640,480, P3D); 
  background(0);  
  noFill();
  stroke(255);
  strokeWeight(2);
}

void draw(){
  background(0);
  int sx,ex,sy,ey;
  float z = 0;
  xp.add(mouseX);
  yp.add(mouseY); 
  if(xp.size() > 1){
    for(int i = xp.size()-1 ; i > 0 ; i--){
	sx = (Integer) xp.get(i);
	ex = (Integer) xp.get(i-1);
	sy = (Integer) yp.get(i);
	ey = (Integer) yp.get(i-1);
	line(sx,sy,z,ex,ey,z-10);
	z -= 10;
    }
  }
  count++;
}

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