Hello, I am trying to make a flying, somewhat glowing bird that will somehow react to a mouse click or keyboard. I don't really know how to apply either of these. Also, I wanted to add an image in the background, but where exactly in the code to I put the code for the image??
I'm very confused about this!
Here is what I have:

float ang = 0, ang2 = 0, ang3 = 0, ang4 = 0;
float px = 0, py = 0, pz = 0;
float flapSpeed = 0.2;

void setup(){
 size(640, 360, P3D);
 noStroke();
}

void draw(){
 background(0);
 lights();

 // Flight
 px = sin(radians(ang3)) * 170;
 py = cos(radians(ang3)) * 300;
 pz = sin(radians(ang4)) * 500;
 translate(width/2 + px, height/2 + py, -700+pz);
 rotateX(sin(radians(ang2)) * 120);
 rotateY(sin(radians(ang2)) * 50);
 rotateZ(sin(radians(ang2)) * 65);
 
 // Body
 fill(153);
 box(20, 100, 20);

 
 // Left wing
 fill(204);
 pushMatrix();
 rotateY(sin(radians(ang)) * -20);
 rect(-75, -50, 75, 100);
 popMatrix();

 // Right wing
 pushMatrix();
 rotateY(sin(radians(ang)) * 20);
 rect(0, -50, 75, 100);
 popMatrix();

 // Wing flap
 ang += flapSpeed;
 if (ang > 3) {
   flapSpeed *= -1;
 }
 if (ang < -3) {
   flapSpeed *= -1;
 }

 // Increment angles
 ang2 += 0.01;
 ang3 += 2.0;
 ang4 += 0.75;
}


...Just a basic bird. But I would like to change the background to an image and make the bird react somehow to the mouse. I am making this to go with "blackbird" the song.
If I could get help or suggestions, that would be absolutely wonderful!
thankyou!