From 9a85db4a91aadd3104e7d9735e1140b6d20da75c Mon Sep 17 00:00:00 2001
From: coder0xff <coder0xff@gmail.com>
Date: Mon, 23 Feb 2015 01:09:39 -0500
Subject: [PATCH 1/3] Update ellipse.coffee

An improved (and untested) implementation for containsPoint
---
 app/lib/world/ellipse.coffee | 55 ++++++++----------------------------
 1 file changed, 11 insertions(+), 44 deletions(-)

diff --git a/app/lib/world/ellipse.coffee b/app/lib/world/ellipse.coffee
index 6aaf88057..a3ed537f0 100644
--- a/app/lib/world/ellipse.coffee
+++ b/app/lib/world/ellipse.coffee
@@ -50,50 +50,17 @@ class Ellipse
     if shape.isEllipse then @distanceSquaredToEllipse shape else @distanceSquaredToRectangle shape
 
   containsPoint: (p, withRotation=true) ->
-    [a, b] = [@width / 2, @height / 2]
-    [h, k] = [@x, @y]
-    [x, y] = [p.x, p.y]
-    x2 = Math.pow(x, 2)
-    a2 = Math.pow(a, 2)
-    a4 = Math.pow(a, 4)
-    b2 = Math.pow(b, 2)
-    b4 = Math.pow(b, 4)
-    h2 = Math.pow(h, 2)
-    k2 = Math.pow(k, 2)
-    if withRotation and @rotation
-      sint = Math.sin(@rotation)
-      sin2t = Math.sin(2 * @rotation)
-      cost = Math.cos(@rotation)
-      cos2t = Math.cos(2 * @rotation)
-      numeratorLeft = (-a2 * h * sin2t) + (a2 * k * cos2t) + (a2 * k) + (a2 * x * sin2t)
-      numeratorMiddle = Math.SQRT2 * Math.sqrt((a4 * b2 * cos2t) + (a4 * b2) - (a2 * b4 * cos2t) + (a2 * b4) - (2 * a2 * b2 * h2) + (4 * a2 * b2 * h * x) - (2 * a2 * b2 * x2))
-      numeratorRight = (b2 * h * sin2t) - (b2 * k * cos2t) + (b2 * k) - (b2 * x * sin2t)
-      denominator = (a2 * cos2t) + a2 - (b2 * cos2t) + b2
-      solution1 = (numeratorLeft - numeratorMiddle + numeratorRight) / denominator
-      solution2 = (numeratorLeft + numeratorMiddle + numeratorRight) / denominator
-      if (not isNaN solution1) and (not isNaN solution2)
-        [bigSolution, littleSolution] = if solution1 > solution2 then [solution1, solution2] else [solution2, solution1]
-        if y > littleSolution and y < bigSolution
-          return true
-        else
-          return false
-      else
-        return false
-    else
-      numeratorLeft = a2 * k
-      numeratorRight = Math.sqrt((a4 * b2) - (a2 * b2 * h2) + (2 * a2 * b2 * h * x) - (a2 * b2 * x2))
-      denominator = a2
-      solution1 = (numeratorLeft + numeratorRight) / denominator
-      solution2 = (numeratorLeft - numeratorRight) / denominator
-      if (not isNaN solution1) and (not isNaN solution2)
-        [bigSolution, littleSolution] = if solution1 > solution2 then [solution1, solution2] else [solution2, solution1]
-        if y > littleSolution and y < bigSolution
-          return true
-        else
-          return false
-      else
-        return false
-    false
+    # "ellipse space" is the cartesian space
+    # where the ellipse becomes the unit
+    # circle centered at (0, 0)
+    [x, y] = [p.x - @x, p.y - @y] # translate point into ellipse space
+    if withRotation and @rotation # optionally rotate point into ellipse space
+      c = Math.cos(@rotation)
+      s = Math.sin(@rotation)
+      [x, y] = [x*c + y*s, y*c + x*s]
+    x = x / @width # scale point into ellipse space
+    y = y / @height
+    x*x + y*y <= 1 #if the resulting point falls on/in the unit circle at 0, 0
 
   intersectsLineSegment: (p1, p2) ->
     [px1, py1, px2, py2] = [p1.x, p1.y, p2.x, p2.y]

From 55e43c247f689a96d5940a4ad8fdfdbf5dad147f Mon Sep 17 00:00:00 2001
From: coder0xff <coder0xff@gmail.com>
Date: Mon, 23 Feb 2015 01:14:21 -0500
Subject: [PATCH 2/3] Update ellipse.coffee

Copy/pasted wrong version of containsPoint!
---
 app/lib/world/ellipse.coffee | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/lib/world/ellipse.coffee b/app/lib/world/ellipse.coffee
index a3ed537f0..2a45b04ba 100644
--- a/app/lib/world/ellipse.coffee
+++ b/app/lib/world/ellipse.coffee
@@ -57,7 +57,7 @@ class Ellipse
     if withRotation and @rotation # optionally rotate point into ellipse space
       c = Math.cos(@rotation)
       s = Math.sin(@rotation)
-      [x, y] = [x*c + y*s, y*c + x*s]
+      [x, y] = [x*c - y*s, y*c + x*s]
     x = x / @width # scale point into ellipse space
     y = y / @height
     x*x + y*y <= 1 #if the resulting point falls on/in the unit circle at 0, 0

From 9dbecd213b9d258f9050a443db75d7124f96201b Mon Sep 17 00:00:00 2001
From: coder0xff <coder0xff@gmail.com>
Date: Sat, 14 Mar 2015 01:26:13 -0400
Subject: [PATCH 3/3] Update ellipse.coffee

Fix to pass unit tests
---
 app/lib/world/ellipse.coffee | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/app/lib/world/ellipse.coffee b/app/lib/world/ellipse.coffee
index 2a45b04ba..686b44b46 100644
--- a/app/lib/world/ellipse.coffee
+++ b/app/lib/world/ellipse.coffee
@@ -57,11 +57,12 @@ class Ellipse
     if withRotation and @rotation # optionally rotate point into ellipse space
       c = Math.cos(@rotation)
       s = Math.sin(@rotation)
-      [x, y] = [x*c - y*s, y*c + x*s]
-    x = x / @width # scale point into ellipse space
-    y = y / @height
+      [x, y] = [x*c + y*s, y*c - x*s]
+    x = x / @width * 2 # scale point into ellipse space
+    y = y / @height * 2
     x*x + y*y <= 1 #if the resulting point falls on/in the unit circle at 0, 0
 
+
   intersectsLineSegment: (p1, p2) ->
     [px1, py1, px2, py2] = [p1.x, p1.y, p2.x, p2.y]
     m = (py1 - py2) / (px1 - px2)