add square:contains() function

2 files changed, 61 insertions, 7 deletions

diff --git a/city/geometry-test.lua b/city/geometry-test.lua
index 3fedae6..f85bec0 100644
--- a/city/geometry-test.lua
+++ b/city/geometry-test.lua
@@ -40,14 +40,56 @@ test(
 test(
    'create square object',
    function()
-      local s = geom.square(geom.point(0, 0), 1)
-      assert(s.center.x == 0)
-      assert(s.center.y == 0)
+      local s = geom.square(geom.point(2, 5), 1)
+      assert(s.center.x == 2)
+      assert(s.center.y == 5)
       assert(s.span == 1)
 
-      assert(s.x.min == -0.5)
-      assert(s.x.max ==  0.5)
-      assert(s.y.min == -0.5)
-      assert(s.y.max ==  0.5)
+      assert(s.x.min ==  1.5)
+      assert(s.x.max ==  2.5)
+      assert(s.y.min ==  4.5)
+      assert(s.y.max ==  5.5)
+   end
+)
+
+test(
+   'check if point is in square',
+   function()
+      local center = geom.point(1, 1)
+      local square = geom.square(center, 2)
+
+      local interior_points = {
+	 geom.point(1, 1),
+	 geom.point(2, 2),
+	 geom.point(2, 0.1),
+	 geom.point(0.1, 0.1),
+      }
+      for _, point in ipairs(interior_points) do
+	 assert(
+	    square:contains(point),
+	    string.format(
+	       'point (%0.2f, %0.2f) was incorrectly outside!',
+	       point.x, point.y
+	    )
+	 )
+      end
+
+      local exterior_points = {
+	 geom.point(0, 0),
+	 geom.point(10, 10),
+	 geom.point(0, 1),
+	 geom.point(1, 0),
+	 geom.point(-2, 1),
+	 geom.point(1, -2),
+      }
+      for _, point in ipairs(exterior_points) do
+	 assert(
+	    not square:contains(point),
+	    string.format(
+	       'point (%0.2f, %0.2f) was incorrectly inside!',
+	       point.x, point.y
+	    )
+	 )
+      end
    end
 )
diff --git a/city/geometry.lua b/city/geometry.lua
index a775213..1632393 100644
--- a/city/geometry.lua
+++ b/city/geometry.lua
@@ -46,6 +46,18 @@ geom.square = class{
    end,
 
    axis_range = function(c, r) return {min=c-r, max=c+r} end,
+
+   contains = function(self, point)
+      local x_overlap =
+	 (point.x > self.x.min) and (point.x <= self.x.max)
+      local y_overlap =
+	 (point.y > self.y.min) and (point.y <= self.y.max)
+
+      if x_overlap and y_overlap then
+	 return true
+      end
+      return false
+   end
 }
 
 return geom