I don't understand how to fill a simple polygon in 3D. Here is some code that I thought would work but I've fiddled with it quite a lot and I just can't seem to fill my beloved circle shapes. Do I have to use a texture or what?

While I am at it..can somebody explain how to put a fog/semi-transparent colored flat surface up in 3D?

Thanks to all in advance! Her is the code:

// import processing.opengl.*;
// 3D circle on Sphere class
class sCircle{
float oangle, theta, phi;
sCircle(float _theta, float _phi, float _oangle){
oangle=_oangle%PI;
theta=_theta%PI;
phi=_phi*TWO_PI;
};
sCircle(float centx, float centy, float centz, float ex, float ey, float ez){
float normc=sqrt(centx*centx+centy*centy+centz*centz);
float norme=sqrt(ex*ex+ey*ey+ez*ez);
theta=acos(centz/normc);
phi=atan(centy/centx);
oangle=acos((centx*ex+centy*ey+centz*ez)/(normc*norme));
};
void setAngles(float _theta, float _phi, float _oangle){
oangle=_oangle%PI;
theta=_theta%PI;
phi=_phi*TWO_PI;
};
void setPoints(float centx, float centy, float centz, float ex, float ey, float ez){
float normc=sqrt(centx*centx+centy*centy+centz*centz);
float norme=sqrt(ex*ex+ey*ey+ez*ez);
theta=acos(centz/normc);
phi=atan(centy/centx);
oangle=acos((centx*ex+centy*ey+centz*ez)/(normc*norme));
};
// a simple drawing function using THE MATRIX to orient our circle
void drawCircle(float rScale, int rd, int gr, int bl){
float rad=sin(oangle);
float py=cos(oangle);
float dangle=TWO_PI/250;
float angle=0;
float px,pz;
pushMatrix();
scale(rScale);
rotateZ(phi);
rotateX(theta);
stroke(rd,gr,bl);
fill(rd,gr,bl,255); // ????? WHy doesn't this work?
beginShape(POLYGON);
for(int i=0;i<250;i++){
px=rad*cos(angle);
pz=rad*sin(angle);
vertex(px,py,pz);
angle+=dangle;
};
endShape();
popMatrix();
};
};

// set up a circle
sCircle aCircle;

// get ready to rock
void setup(){
size(800,800,P3D);
background(0);
aCircle=new sCircle(0,0,0);
framerate(3);
}
// let her rip
void draw(){
background(20);
translate(0.5*width,0.5*height,0.25*(width+height));
lights();
ambientLight(200,200,200);

aCircle.setPoints(random(1,10), random(-10,10),random(-10,10),random(-10,10),random(-10,10),random(-10,10));
aCircle.drawCircle(100,(int) random(128,255),(int) random(128,255),(int) random(128,255));

};