Bug 1276066 - Add Union with "components" member to math classes to enable array access to members. r=bas

- Adding an array member to access the components of vector, size,
  and matrix classes reduces the code needed when passing all of the
  members to functions.

MozReview-Commit-ID: A6XL7y3zwsV

--HG--
extra : rebase_source : 77fb1b9784ae1213530cff7f42563e0afc8859e3

gfx/2d/BasePoint.h

@@ -22,7 +22,12 @@ namespace gfx {
  */
 template <class T, class Sub, class Coord = T>
 struct BasePoint {
-  T x, y;
+  union {
+    struct {
+      T x, y;
+    };
+    T components[2];
+  };
 
   // Constructors
   MOZ_CONSTEXPR BasePoint() : x(0), y(0) {}

gfx/2d/BasePoint3D.h

@@ -18,7 +18,12 @@ namespace gfx {
  */
 template <class T, class Sub>
 struct BasePoint3D {
-  T x, y, z;
+  union {
+    struct {
+      T x, y, z;
+    };
+    T components[3];
+  };
 
   // Constructors
   BasePoint3D() : x(0), y(0), z(0) {}

gfx/2d/BasePoint4D.h

@@ -18,7 +18,12 @@ namespace gfx {
  */
 template <class T, class Sub>
 struct BasePoint4D {
-  T x, y, z, w;
+  union {
+    struct {
+      T x, y, z, w;
+    };
+    T components[4];
+  };
 
   // Constructors
   BasePoint4D() : x(0), y(0), z(0), w(0) {}

gfx/2d/BaseSize.h

@@ -18,7 +18,12 @@ namespace gfx {
  */
 template <class T, class Sub>
 struct BaseSize {
-  T width, height;
+  union {
+    struct {
+      T width, height;
+    };
+    T components[2];
+  };
 
   // Constructors
   MOZ_CONSTEXPR BaseSize() : width(0), height(0) {}

gfx/2d/Matrix.h

@@ -37,9 +37,14 @@ public:
     , _21(a21), _22(a22)
     , _31(a31), _32(a32)
   {}
-  Float _11, _12;
-  Float _21, _22;
-  Float _31, _32;
+  union {
+    struct {
+      Float _11, _12;
+      Float _21, _22;
+      Float _31, _32;
+    };
+    Float components[6];
+  };
 
   MOZ_ALWAYS_INLINE Matrix Copy() const
   {
@@ -461,10 +466,15 @@ public:
     memcpy(this, &aOther, sizeof(*this));
   }
 
-  Float _11, _12, _13, _14;
-  Float _21, _22, _23, _24;
-  Float _31, _32, _33, _34;
-  Float _41, _42, _43, _44;
+  union {
+    struct {
+      Float _11, _12, _13, _14;
+      Float _21, _22, _23, _24;
+      Float _31, _32, _33, _34;
+      Float _41, _42, _43, _44;
+    };
+    Float components[16];
+  };
 
   friend std::ostream& operator<<(std::ostream& aStream, const Matrix4x4Typed& aMatrix)
   {
@@ -1618,11 +1628,16 @@ public:
     return *this;
   }
 
-  Float _11, _12, _13, _14;
-  Float _21, _22, _23, _24;
-  Float _31, _32, _33, _34;
-  Float _41, _42, _43, _44;
-  Float _51, _52, _53, _54;
+  union {
+    struct {
+      Float _11, _12, _13, _14;
+      Float _21, _22, _23, _24;
+      Float _31, _32, _33, _34;
+      Float _41, _42, _43, _44;
+      Float _51, _52, _53, _54;
+    };
+    Float components[20];
+  };
 };
 
 } // namespace gfx