This example is for Processing 3+. If you have a previous version, use the examples included with your software. If you see any errors or have suggestions, please let us know.

Texture Sphere by Gillian Ramsay

Rewritten by Gillian Ramsay to better display the poles. Previous version by Mike 'Flux' Chang (and cleaned up by Aaron Koblin). Original based on code by Toxi.

A 3D textured sphere with simple rotation control.


int ptsW, ptsH;

PImage img;

int numPointsW;
int numPointsH_2pi; 
int numPointsH;

float[] coorX;
float[] coorY;
float[] coorZ;
float[] multXZ;

void setup() {
  size(640, 360, P3D);
  background(0);
  noStroke();
  img=loadImage("world32k.jpg");
  ptsW=30;
  ptsH=30;
  // Parameters below are the number of vertices around the width and height
  initializeSphere(ptsW, ptsH);
}

// Use arrow keys to change detail settings
void keyPressed() {
  if (keyCode == ENTER) saveFrame();
  if (keyCode == UP) ptsH++;
  if (keyCode == DOWN) ptsH--;
  if (keyCode == LEFT) ptsW--;
  if (keyCode == RIGHT) ptsW++;
  if (ptsW == 0) ptsW = 1;
  if (ptsH == 0) ptsH = 2;
  // Parameters below are the number of vertices around the width and height
  initializeSphere(ptsW, ptsH);
}

void draw() {
  background(0);
  camera(width/2+map(mouseX, 0, width, -2*width, 2*width), 
         height/2+map(mouseY, 0, height, -height, height),
         height/2/tan(PI*30.0 / 180.0), 
         width, height/2.0, 0, 
         0, 1, 0);
    
  pushMatrix();
  translate(width/2, height/2, 0);  
  textureSphere(200, 200, 200, img);
  popMatrix();
}

void initializeSphere(int numPtsW, int numPtsH_2pi) {

  // The number of points around the width and height
  numPointsW=numPtsW+1;
  numPointsH_2pi=numPtsH_2pi;  // How many actual pts around the sphere (not just from top to bottom)
  numPointsH=ceil((float)numPointsH_2pi/2)+1;  // How many pts from top to bottom (abs(....) b/c of the possibility of an odd numPointsH_2pi)

  coorX=new float[numPointsW];   // All the x-coor in a horizontal circle radius 1
  coorY=new float[numPointsH];   // All the y-coor in a vertical circle radius 1
  coorZ=new float[numPointsW];   // All the z-coor in a horizontal circle radius 1
  multXZ=new float[numPointsH];  // The radius of each horizontal circle (that you will multiply with coorX and coorZ)

  for (int i=0; i<numPointsW ;i++) {  // For all the points around the width
    float thetaW=i*2*PI/(numPointsW-1);
    coorX[i]=sin(thetaW);
    coorZ[i]=cos(thetaW);
  }
  
  for (int i=0; i<numPointsH; i++) {  // For all points from top to bottom
    if (int(numPointsH_2pi/2) != (float)numPointsH_2pi/2 && i==numPointsH-1) {  // If the numPointsH_2pi is odd and it is at the last pt
      float thetaH=(i-1)*2*PI/(numPointsH_2pi);
      coorY[i]=cos(PI+thetaH); 
      multXZ[i]=0;
    } 
    else {
      //The numPointsH_2pi and 2 below allows there to be a flat bottom if the numPointsH is odd
      float thetaH=i*2*PI/(numPointsH_2pi);

      //PI+ below makes the top always the point instead of the bottom.
      coorY[i]=cos(PI+thetaH); 
      multXZ[i]=sin(thetaH);
    }
  }
}

void textureSphere(float rx, float ry, float rz, PImage t) { 
  // These are so we can map certain parts of the image on to the shape 
  float changeU=t.width/(float)(numPointsW-1); 
  float changeV=t.height/(float)(numPointsH-1); 
  float u=0;  // Width variable for the texture
  float v=0;  // Height variable for the texture

  beginShape(TRIANGLE_STRIP);
  texture(t);
  for (int i=0; i<(numPointsH-1); i++) {  // For all the rings but top and bottom
    // Goes into the array here instead of loop to save time
    float coory=coorY[i];
    float cooryPlus=coorY[i+1];

    float multxz=multXZ[i];
    float multxzPlus=multXZ[i+1];

    for (int j=0; j<numPointsW; j++) { // For all the pts in the ring
      normal(-coorX[j]*multxz, -coory, -coorZ[j]*multxz);
      vertex(coorX[j]*multxz*rx, coory*ry, coorZ[j]*multxz*rz, u, v);
      normal(-coorX[j]*multxzPlus, -cooryPlus, -coorZ[j]*multxzPlus);
      vertex(coorX[j]*multxzPlus*rx, cooryPlus*ry, coorZ[j]*multxzPlus*rz, u, v+changeV);
      u+=changeU;
    }
    v+=changeV;
    u=0;
  }
  endShape();
}