Flipping runes.pde

PImage img1, img2, img3, img4, img5, img6, img7, img8, img;
float i = 0;
static final color BG = -4;
    
void setup()
{
    size(1000,1000,P3D);
    img1 = loadImage("assembly (1).png");
    img2 = loadImage("assembly (2).png");
    img3 = loadImage("assembly (3).png");
    img4 = loadImage("assembly (4).png");
    img5 = loadImage("assembly (5).png");
    img6 = loadImage("assembly (6).png");
    img7 = loadImage("assembly (7).png");
    img8 = loadImage("assembly (8).png");
                            
    int picheight = 300,picwidth = 300;
    
    img1.resize(picheight, picwidth);
    img2.resize(picheight, picwidth);
    img3.resize(picheight, picwidth);
    img4.resize(picheight, picwidth);
    img5.resize(picheight, picwidth);
    img6.resize(picheight, picwidth);
    img7.resize(picheight, picwidth);
    img8.resize(picheight, picwidth);

}

void draw(){
    background(BG);

if (frameCount <= 5){
img = img1;
} else if (frameCount <= 13){
img = img2;
} else if (frameCount <= 21){
img = img3;
} else if (frameCount <= 29){
img = img4;
} else if (frameCount <= 37){
img = img5;
} else if (frameCount <= 45){
img = img6;
} else if (frameCount <= 53){
img = img7;
} else if (frameCount <= 61){
img = img8;
} else if (frameCount <= 77){
img = img1;
} 

    pushMatrix();
    // Move the coordinate system to the center of the screen
    translate(width/2.0, height/2.0);
    // Rotate the coordinate system a bit more each frame    
 if (frameCount > 2) {
    rotateY(i); 
 }
    // Draw the image in the center
    image(img,-img.width/2.0, -img.height/2.0);
    popMatrix();
 //   saveFrame("frame####");
    saveTransparentCanvas(BG, "img");
    i = i+(PI/8);
}

void saveTransparentCanvas(final color bg, final String name) {
  final PImage canvas = get(0,0,height,width);
  canvas.format = ARGB;
 
  final color p[] = canvas.pixels, bgt = bg & ~#000000;
  for (int i = 0; i != p.length; ++i)  if (p[i] == bg)  p[i] = bgt;
 
  canvas.updatePixels();
  canvas.save("Frame"+frameCount+".png");
}