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Index › Programming Questions & Help › Syntax Questions › Texture 2d not working
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Texture 2d not working? (Read 404 times)
ilazarte
Texture 2d not working?
Jan 4th, 2009, 12:48am  
I'm generating a texture with PGraphics and create an image using PGraphics.get();
Then I try to texture() a shape using the created image.  It doesn't work!

Can someone glance at the source code to see what's going on here?

live demo:
http://www.ivanlazarte.com/processing/ref/polygon_tex_2d/applet/

code:
PImage tex1;
color cred = color(255,0,0,255);

void setup() {
 size(500,300,P2D);
 smooth();
 textures();
}

void draw() {
 background(0);
 translate(mouseX,mouseY);
 image(tex1,0,0);
   
 stroke(cred);
 strokeWeight(2);
 
 textureMode(IMAGE);
 beginShape();
 texture(tex1);
 vertex(0, 00);
 vertex(75, 0);
 vertex(75, 75);
 vertex(0, 75);
 endShape(CLOSE);
}

void textures() {
 PGraphics tex1g = createGraphics(150,150,JAVA2D);
 tex1g.beginDraw();
 tex2(tex1g);
 tex1 = tex1g.get();
 tex1g.endDraw();
}

void tex2(PGraphics g) {
 for (int y = 0; y < g.height; y+=10) {
   for (int x = 0; x < g.width; x+=10) {
     g.ellipse(x,y,10,10);
   }
 }
}
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WombatNation
Re: Texture 2d not working?
Reply #1 - Jan 4th, 2009, 8:16am  
You have to specify the mapping of the texture onto the polygon in the calls to vertex(). For example,

 textureMode(NORMALIZED);
 beginShape();
 texture(tex1);
 vertex(0, 0, 0, 0);
 vertex(75, 0, 1, 0);
 vertex(75, 75, 1, 1);
 vertex(0, 75, 0, 1);
 endShape(CLOSE);

I set the texture mode to NORMALIZED to simplify the mapping.

Check out the last paragraph of the description for vertex() for more info.

http://processing.org/reference/vertex_.html

Change the third vertex() call to something like

 vertex(75, 75, 0.3, 0.3);

to get a better sense of how the mapping works.
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ilazarte
Re: Texture 2d not working?
Reply #2 - Jan 4th, 2009, 6:18pm  
How did I miss that?? Thanks Wombat.  I'm reading up on this uv coordinate stuff now.  Thanks again!
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ilazarte
Re: Texture 2d not working?
Reply #3 - Jan 5th, 2009, 7:02am  
If I understand correctly, bezier and curve-based shapes don't allow for texturing?  I'm trying to make it look like a curve is "cut" out of a pattern.  I guess the alternative are quads or strips to emulate curvy shapes?
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fjen
Re: Texture 2d not working?
Reply #4 - Jan 5th, 2009, 8:58am  
you can use bezierPoint() to access the points on the bezier curve and set vertices.

F
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ilazarte
Re: Texture 2d not working?
Reply #5 - Jan 6th, 2009, 5:19am  
Thanks fjen!

For fellow beginners, I've put together a working sample:
http://www.ivanlazarte.com/processing/test/bezier_point_tex/applet/

Quote:
/**
Try commenting/uncommenting textureMode.
By default the texture will warp to the curve.
*/

PImage tex;
int steps = 5;
int slen = 10;

void setup() {
  size(500,300,P2D);
  tex = loadImage("tex.jpg");
}

void draw() {
  background(127);
  translate(mouseX,mouseY);
  //textureMode(IMAGE);
  beginShape();
  texture(tex);
  vertex(0,0,0,0);
  int steps = 50;
  for (int i = 0; i <= steps; i++) {
    float t = i / float(steps);
    float x = bezierPoint(0,100,100,0,t);
    float y = bezierPoint(0,0,100,100,t);
    vertex(x,y,x,y);
  }
  endShape();
}
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