Question

i have several circles drawn programmatically on the screen . I then work out the distance between the finger click’s x and y coordinates with each of the circle’s x and y coordinates.

Which ever distance is less than any of the circle’s radius is the circle that was clicked on. Quite simple really. However im finding that ive got a lot of repeated code and i feel that i can clean up the code but im not sure what the best way to do it at the moment.

any help is appreciated.

float diffx = touch.x - bass.pos.x;
float diffy = touch.y - bass.pos.y;
float dist = sqrt(diffx*diffx + diffy*diffy);
if(dist < bass.radius){

    if(recordingInfo.isRecording){
        //do some stuff related to this button unique

    }
    //play some sound
}

diffx = touch.x - treble.pos.x;
diffy = touch.y - treble.pos.y;
dist = sqrt(diffx*diffx + diffy*diffy);

if(dist < treble.radius){
    if(recordingInfo.isRecording){
        //do something related to this button
    }
    //play some sound
}

diffx = touch.x - hihat.pos.x;
diffy = touch.y - hihat.pos.y;
dist = sqrt(diffx*diffx + diffy*diffy);

if(dist < hihat.radius){
    if(recordingInfo.isRecording){

        //do shayt related to this button

    }
    //play this sound
}

diffx = touch.x - bassTwo.pos.x;
diffy = touch.y - bassTwo.pos.y;
dist = sqrt(diffx*diffx + diffy*diffy);

if(dist < bassTwo.radius){
    if(recordingInfo.isRecording){
        //do some crap regarding this indivudal button

    }
    //play another sound
}

diffx = touch.x - kick.pos.x;
diffy = touch.y - kick.pos.y;
dist = sqrt(diffx*diffx + diffy*diffy);

if(dist < kick.radius){
    if(recordingInfo.isRecording){
      //do some funky stuff related to this button
    }
    //play some sound
}

diffx = touch.x - snare.pos.x;
diffy = touch.y - snare.pos.y;
dist = sqrt(diffx*diffx + diffy*diffy);

if(dist < snare.radius){
    if(recordingInfo.isRecording){
        //
    }
    //play some sound
}

diffx = touch.x - recordButton.pos.x;
diffy = touch.y - recordButton.pos.y;
dist = sqrt(diffx*diffx + diffy*diffy);

if(dist < recordButton.radius){
    //and do some funky stuff audio visual styff gere
}    

diffx = touch.x - play.pos.x;
diffy = touch.y - play.pos.y;
dist = sqrt(diffx*diffx + diffy*diffy);
     //code execution if this circle button is hit
}    

or is this fine? i place all of this code in the touchDown method

Answer 1

The repeated code is:

diffx = touch.x - recordButton.pos.x;
diffy = touch.y - recordButton.pos.y;
dist = sqrt(diffx*diffx + diffy*diffy);

Any time code appears more than once you should consider putting it in a function:

float distance(vec touch, vec button_center) {
    float diffx = touch.x - bass.pos.x;
    float diffy = touch.y - bass.pos.y;
    float dist = sqrt(diffx*diffx + diffy*diffy);
    return dist;
}

if(distance(touch,bass.pos) < bass.radius){
   ...
}
if(distance(touch, treble.pos) < treble.radius){
   ...
}
if(distance(touch,hihat.pos) < hihat.radius){
   ...
}

Of course, you’re also repeating that check to see if a button has been hit:

bool is_hit(Button b,vec touch) {
    return distance(b.pos,touch) < b.radius;
}

if(is_hit(bass,touch)) {}
if(is_hit(treble,touch)) {}
...

This is a very simple method of handling events and it’s hard to reduce the repetition further without changing the program’s architecture. If you want something a little more flexible you might want to look into how GUI frameworks handle events. The Cocoa documentation on the events might be a good example to look at: Cocoa Event-Handling Guide