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Index › Programming Questions & Help › Syntax Questions › Noob question about pushMatrix/popMatrix
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Noob question about pushMatrix/popMatrix (Read 1114 times)
Phattee
Noob question about pushMatrix/popMatrix
Apr 14th, 2009, 10:05am  
PFont font;
String s = "VERTIGO";
float angle;

void setup() {
 size(100, 100);
 font = loadFont("AgencyFB-Reg-48.vlw");
 textFont(font, 24);
 fill(0);
}

void draw() {
 background(204);
 angle = angle + 0.02;
 pushMatrix();
 translate(33, 50);
 scale((cos(angle/4.0) + 1.2) * 2.0);
 rotate(angle);
 text(s, 0, 0);
 popMatrix();
}

Hello, the preceding code is from page 330 of the Processing book. What's the point of including pushMatrix and popMatrix in this example? I don't notice any difference when I run the code without pushMatrix and popMatrix. Is it just good form? Or is it in case the code gets more complex later on?
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PhiLho 
Re: Noob question about pushMatrix/popMatrix
Reply #1 - Apr 14th, 2009, 11:21am  
Phattee wrote on Apr 14th, 2009, 10:05am:
Or is it in case the code gets more complex later on

Exactly! Eg. if you need to do other independent transformations on another shape.
draw() resets the matrix when exiting, so indeed, the example isn't very meaningful.
Try adding a rect(0, 0, 10, 10); after popMatrix() to see a difference.
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FranciscoGargallo
Re: Noob question about pushMatrix/popMatrix
Reply #2 - Apr 14th, 2009, 1:15pm  
I think the case is that in your code you are not using 3D animation,

to do this change add OPENGL or P3D in the size window.

size(100,100,OPENGL);

note you have to import the opengl library if you did not.

import processing.opengl.*;

hope this helps!

blessings!
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