Add SkMatrix44 constructor that allows user to control the initialization

method.  Preliminary results using Chromium's cc_perftests
show that we can avoid almost half of the default constructors from
redundantly/unnecessarily initializing the matrix to identity.

Review URL: https://codereview.appspot.com/6872056

git-svn-id: http://skia.googlecode.com/svn/trunk@6742 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 11 insertions, 0 deletions

diff --git a/include/utils/SkMatrix44.h b/include/utils/SkMatrix44.h
index af61a11c68..4789e7e209 100644
--- a/include/utils/SkMatrix44.h
+++ b/include/utils/SkMatrix44.h
@@ -103,6 +103,17 @@ struct SkVector4 {
 
 class SK_API SkMatrix44 {
 public:
+
+    enum Uninitialized_Constructor {
+        kUninitialized_Constructor
+    };
+    enum Identity_Constructor {
+        kIdentity_Constructor
+    };
+
+    SkMatrix44(Uninitialized_Constructor) { }
+    SkMatrix44(Identity_Constructor) { this->setIdentity(); }
+
     SkMatrix44() { this->setIdentity(); }
     SkMatrix44(const SkMatrix44&);
     SkMatrix44(const SkMatrix44& a, const SkMatrix44& b);