CGrectContainPoints & Touches queries

Question

Im getting straight to the point. I have static coordinates stored as array and i want to compare this coordinates with user touch.

//touch handling
 UITouch *touch = [[event allTouches] anyObject];
 CGPoint touchPoint = [touch locationInView:touch.view];
//comparing touches
 if (CGRectContainsPoint((CGRectMake(x1, y1, w, h)) , touchPoint)) {
  // do something
            // this is where i got stuck coz i got 2 more sets of x & y. (x2-y2 & x3-y3)

but right now im stuck here coz i dont know how to structure my codes and i want to compare 3 save location touches to user touches so that when they hit the right spot points/score will be added but when they hit the wrong spot life will be deducted. Thanks.

Answer 1

Hi,

If you had points stored like this . . .

CGPoint p1 = CGPointMake(100,100);
CGPoint p2 = CGPointMake(200,200);

try something like this :

// Get the location of the user's touch
UITouch *touch = [[event allTouches] anyObject];
CGPoint touchPoint = [touch locationInView:touch.view];

float maxDistance = 10;

// Is it in the right place?
if (distanceBetween(touchPoint, p1) < maxDistance)
  NSLog(@"touched point 1");
else
if (distanceBetween(touchPoint, p2) < maxDistance)
  NSLog(@"touched point 2");

where distanceBetween is a function that looks something like (some maths)

// Distance between two CGPoints
float distanceBetween(CGPoint p1, CGPoint p2) {
  float dx = p1.x-p2.x;
  float dy = p1.y-p2.y;
  return sqrt( dx*dx + dy*dy);
}

Hope that helps,

Sam