Check collision point polygon (#2685)

* Update raylib.h

* CheckCollisionPointPolygon()

* typo

src/rshapes.c

@@ -1631,6 +1631,28 @@ bool CheckCollisionPointTriangle(Vector2 point, Vector2 p1, Vector2 p2, Vector2
     return collision;
 }
 
+// Check if point is within a polygon described by array of vertices
+bool CheckCollisionPointPolygon(Vector2 point, Vector2* vertices, int verticesCount)
+{
+    // http://jeffreythompson.org/collision-detection/poly-point.php
+    
+    bool collision = false;
+    
+    if (verticesCount > 2)
+    {
+        for (int i = 0; i < verticesCount; i++)
+        {
+            Vector2 vc = vertices[i];
+            Vector2 vn = vertices[i + 1];
+            
+            if ((((vc.y >= point.y) && (vn.y < point.y)) || ((vc.y < point.y) && (vn.y >= point.y))) &&
+                 (point.x < ((vn.x - vc.x)*(point.y - vc.y)/(vn.y - vc.y) + vc.x))) collision = !collision;
+        }
+    }
+    
+    return collision;
+}
+
 // Check collision between two rectangles
 bool CheckCollisionRecs(Rectangle rec1, Rectangle rec2)
 {