Hi everyone.


I'm trying create a stack of planes and then map a distinct image as texture on each of them. This is intended to recreate 3D from anatomic 2D slices.

Anyhow, when I assign the texture to the plane, the alpha channel seems to be available only on one side of the plane.

Does anyone knows how I could get alpha to work on both sides?

Code:

import processing.opengl.*;

PImage[] images_ar, masks_ar;
int bodyDef;

void setup()
{

size(320, 240, OPENGL);

framerate(25);

colorMode(HSB, 100);

rectMode(CENTER);

noStroke();


bodyDef = 165 / 5;

images_ar = new PImage[bodyDef];

masks_ar = new PImage[bodyDef];

String index;

for (int i = 0; i < bodyDef; i++) {
  

index = str(i*5);
  

index = (i*5 < 99) ? "0" + index : index;
  

index = (i*5 < 9) ? "0" + index : index;
   

images_ar[i] = loadImage("PD1" + index + ".JPG");
 
}

for (int i = 0; i < images_ar.length; i++) {
  

PImage sliceImage = images_ar[i];
  

PImage tmpImage = new PImage(256, 256);
  

sliceImage.loadPixels();
  

tmpImage.loadPixels();
  

for (int j = 0; j < sliceImage.pixels.length; j++) {
    


int pix = sliceImage.pixels[j];
    


if (brightness(pix) > 1) {
	



tmpImage.pixels[j] = pix;
  


}
    


else {
	



tmpImage.pixels[j] = color(0, 0, 0, 0);
  


}
	

}
  

sliceImage.updatePixels();
  

masks_ar[i] = tmpImage;
  
}
}

void draw() 
{

background(15, 5, 5);
    
    
float hw = images_ar[0].width / 2 / 100;
    
float hh = images_ar[0].height / 2 / 100;
    
float stepY = 0.045;
    
float z;
    
rotateX(-PI/2);
    
//fill(255, 20); 
    
translate(0, 0, -1);

for (int i = 0; i < bodyDef; i++) {
  

PImage img = images_ar[i];
  

img.mask(masks_ar[i]);
  

textureMode(NORMALIZED);


beginShape(QUADS);


texture(img);


z = i * stepY;

    
vertex(-hw, -hh, +z, 0, 1);


vertex(+hw, -hh, +z, 1, 1);


vertex(+hw, +hh, +z, 1, 0);


vertex(-hw, +hh, +z, 0, 0);


endShape();
 
}
}

 

Thanx, geek fellows.



MrBlaise.

It worked all right!
I figured out there's a lot of threads about this particular issue.
I have no idea what z-near and z-far mean.

Thanx a lot.


MrBL