BREAKOUT Project - Help with collision detection

Processing Coding Questions
27

sorry / other timezone /

-a- your ( xy ± npx ) is a result of not having clean position for each rectangle.
so i want you again to check my above ( ready code ) for the “make” bricks

-b- for ball / rect collision are many ways,
basic should be a OVER RECT
a concept you need again and again with processing
like mouse over rect ( button )…
we make a boolean function:

boolean overRect(float mx, float my, int x, int y, int w, int h) {
  return ( mx > x && mx < x + w &&  my > y && my < y + h ) ;
}

this returns true if the POINT at ( mx,my )
is over a rect(x,y,w,h)

ha, but a ball is not a point, it has a radius, what we do?
the ball hits the rect actually “earlier” by br
so we just think that the rect is BIGGER by br ON ALL SIDES
with this a hit condition would be

circle(bx,by,2*br);
rect(rx,ry,rw,rh);
//  println( overRect(bx,by,rx,ry,rw,rh) );  // point thinking
println( overRect(bx,by,rx-br,ry-br,rw+2*br,rh+2*br) ); // ball radius >> bigger rect / thinking

all this works only if you NOT use rectMode(CENTER);

complete test code 
int rx=20, ry=30, rw=60, rh=40;
int bx, by, br=10;

void setup() {
  noFill();
}

void draw() {
  background(200, 200, 0);
  bx = mouseX;
  by=mouseY;
  circle(bx, by, 2*br);
  rect(rx, ry, rw, rh);
  //  println( overRect(bx,by,rx,ry,rw,rh) );  // point thinking
  println( overRect(bx, by, rx-br, ry-br, rw+2*br, rh+2*br) ); // ball radius >> bigger rect / thinking
}

boolean overRect(float mx, float my, int x, int y, int w, int h) {
  return ( mx > x && mx < x + w &&  my > y && my < y + h ) ;
}

-c-
but you want also a change of speed of the ball, depending on what side of the rect it hits?
a easy first way can be ( later make it shorter and also check on the rect edges hit… )


  for (int i=0; i < 50; i++) {
    if (blocks[i]==1) { 
      rect(rx[i], ry[i], rw, rh);
      if (  overRect(bx,by,rx[i]-br,ry[i]-br,rw+2*br,rh+2*br) ) {
        println("over block: "+i);
        blocks[i]=0; //_disable
        if ( by > ry[i] + rh )  ySpeed *= -1;  //     println("// ball come from bottom");
        if ( by < ry[i]      )  ySpeed *= -1;  //     println("// ball come from top");
        if ( bx < rx[i]      )  xSpeed *= -1;  //     println("// ball come from left");
        if ( bx > rx[i] + rw )  xSpeed *= -1;  //     println("// ball come from right");
      }
  }
}