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    <p>Instead of testing against a box you can of course test against any shape that you wish.</p> <p>I initially posted you can use an NSBezierPath, but appearantly that ins't available on the iPhone kit, only on Macs. Instead, on the iPhone you can use CGPath.</p> <p>Create a new path by using <code>CGPathCreateMutable()</code> which returns a <code>const CGPath *</code> (also known as <code>CHPathRef</code><br> Then use <code>CGPathAddRect</code> or <code>CGPathAddLines</code> to create our path.<br> <code>CGPathContainsPoint</code> will test if your point was in the shape.</p> <p>Alternatively, you can create a customer function that (since you use triangles) just does a simple calculation to check whether your point is inside the triangle shape. Bit of math should do the trick (though when you rotate the shape it'll be slightly more complicated. I write slightly, as you can then just rotate the touch point relative to the shape's origin and do the hit detection)</p> <p>For a triangle:</p> <pre><code> C /\ /__\ A B point of touch is P </code></pre> <p>With the following algorithm you should be able to find the touch:</p> <pre><code>/* first test against a box, for performance */ if( P.y &gt; C.y || P.y &lt; A.y || P.x &lt; A.x || P.X &gt; B.x ) return false; // false if P falls outside "the box" /* then check if its within the shape */ /* split the triangle into 2 parts, around the axle of point C */ if( P.x &lt; C.x ) // if the x value of point P is on the left of point C if( P.y &gt; ((C.y -A.y) / (C.x - A.x)) * P.x ) return false; // the point is above the triangle's side AC else // if the x value of point P is greater than or equal to point C if( P.y &gt; C.y - ((C.y - B.y) / ( B.x - C.x )) * ( P.x - C.x ) ) return false; // the point is above the triangle's side BC return true; // the point must be in the triangle, so return true. </code></pre> <p>The above is dry coded, but should be correct.</p> <p>The above only works against a triangle in the shape as I drew it (where C.x is between A.x and B.x, and A and B are on the same height, but below C). Of course you can modify this to test against any shape, however, you have to weigh this against just using the available <code>CGPath</code>.</p> <p>If you don't get it, or if it's faulty, let me know!</p>
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