// image patterns based on "pattern" example by REAS
// showcases some of the new imaging functions and blend modes

int t0;
int delayT;
BImage brush,colFade,bgFade;

void setup() {
  size(500, 250);
  background(0);

  // create image to tint pixel buffer
  colFade=new BImage(1,1);
  colFade.set(0,0,0x01ff0000); // set pixel to red with minimal alpha (01)

  // create image to fade out to black, alpha again very low
  // use very low alpha value
  // the alpha value is stored in the highest byte (bits 24-31) of
  // a packed colour integer
  bgFade=new BImage(1,1);
  bgFade.set(0,0,0x02000000);

  brush=loadImage("brush.jpg");

  // fade out delay time 100ms
  delayT=100;
  t0=millis();
}

void loop() {
  if (millis()-t0>delayT) {
    // blend in black image every 1/10secs
    blend(bgFade,0,0,1,1,0,0,width,height,BLEND);
    t0=millis();
  }
  // tint image every frame
  blend(colFade,0,0,1,1,0,0,width,height,BLEND);
  // apply brush
  variableBrush(mouseX, mouseY, pmouseX, pmouseY);
}

// resize brush to current mouse speed
void variableBrush(int x, int y, int px, int py) {
  int speed = (abs(x-px) + abs(y-py))/2;
  blend(brush,0,0,brush.width,brush.height,x-speed,y-speed,x+speed,y+speed,ADD);
}