I am trying to construct a rotatable tetrahedron with textured surfaces. I first successfully converted the RGB cube into a tetrahedron with filled surfaces. When I then applied textures only three of the four faces would complete and even they became fractured/distorted on rotation. The problem goes away completely in OpenGL but I prefer not to use that because the JOGL applet launcher often gets stuck.

I've searched the site for clues but I'm uncertain how to accurately describe this phenomenon, so I'm not surprised to come up empty. Any suggestions are welcome.

Here's the sketch:
http://www.leadershipforcollaborationandinnovation.com/imagetestP3D/index.html


Here's the code:


PImage organization;  
PImage contribution;  
PImage collaboration;  
PImage visualization;  

float rotx = PI/4;
float roty = PI/4;

void setup()
{
 size(450, 450, P3D);
 stroke(180, 180, 180);
 
 organization = loadImage("organizationlead.gif");  
 contribution = loadImage("contributionimplement.gif");
 collaboration = loadImage("collaborationlead.gif");
 visualization = loadImage("visualizationlead.gif");  
 

   
}

void draw()                                              
{

 background(252, 252, 229);
                             
 
 translate(width/2, height/2, 0);                        
 
 rotateX(rotx);                                          
 rotateY(roty);                                            

 pushMatrix();
 
 scale(50);
 
 textureMode(IMAGE);                                                      
   
     beginShape(TRIANGLES);
 texture(organization);
  vertex(0,  2,  3, 161,   0);     /*purple apex*/
  vertex(3, -2, -0, 323, 280);      /*green apex?*/
  vertex(0, 2,  -3,   0, 280);         /*blue apex*/
 endShape();
 
beginShape(TRIANGLES);
 texture(contribution);
 vertex(3, -2, 0, 161, 0);      /*green apex*/
 vertex(-3, -2, 0, 323, 280);      /*orange apex*/
 vertex( 0, 2, -3, 0, 280);    /*blue apex*/
endShape();

beginShape(TRIANGLES);
 texture(collaboration);
 vertex(0,  2,  3, 161, 0);      /*purple apex*/      
 vertex(-3, -2, 0, 0, 280);     /*orange apex*/
 vertex( 0, 2, -3, 323, 280);     /*blue apex*/
endShape();

beginShape(TRIANGLES);
 texture(visualization);
 vertex(0,  2,  3, 161, 0);      /*purple apex*/
 vertex(3, -2, 0, 0, 280);        /*green apex?*/
 vertex(-3, -2, 0, 323, 280);        /* orange apex?*/
endShape();
 
   popMatrix();
}

void mouseDragged() {                                
 float rate = 0.01;
 rotx += (pmouseY-mouseY) * rate;    
 roty += (mouseX-pmouseX) * rate;
}

fjen.

I tried your suggestion and the same phenomenon occurred.

Whatever the z distance and depending on the rotation, two or three of the four triangular faces are complete and in appropriate positions. Then, at another rotation, an interior view of one triangle strangely intersects an exterior view of another.

There is always one face missing and it is always the same one. I've checked the dimensions of the missing image and it is the same as the others. I've altered the sequence of Shapes in the Matrix and still the same face is missing! But . . . .  all faces appear at all rotations when I use fill rather than texture or when I use OpenGL !

No, I hadn't tried this and I was unaware of the hint() function in general. As it turned out it was hint(ENABLE_DEPTH_SORT) which solved the problem! Thanks for pointing me in that direction.