Allows one mousemove event per N ticks.

Review URL: http://codereview.chromium.org/4592001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@65266 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 22 insertions, 0 deletions

diff --git a/o3d/core/cross/client.cc b/o3d/core/cross/client.cc
index c9f9066..a4160df 100644
--- a/o3d/core/cross/client.cc
+++ b/o3d/core/cross/client.cc
@@ -85,6 +85,15 @@ namespace o3d {
 static const float kContinuousModeMinDrawPerSecond = 15;
 // TODO(zhurunz) Tuning this value.
 
+// We don't want to handle too much MOUSEMOVE events for perf reasons.
+// This is used for limiting one MOUSEMOVE event per N ticks.
+//
+// Notes:
+// Don't limit MOUSEMOVE event on new texture since that don't always come.
+// Don't limit MOUSEMOVE event on rendering since RENDERMODE_ON_DEMAND might
+// depends on MOUSEMOVE first.
+static const int kTicksPerMouseMoveEvent = 4;
+
 // Client constructor.  Creates the default root node for the scenegraph
 Client::Client(ServiceLocator* service_locator)
     : service_locator_(service_locator),
@@ -103,6 +112,7 @@ Client::Client(ServiceLocator* service_locator)
       event_manager_(),
       is_ticking_(false),
       last_tick_time_(0),
+      tick_count_(0),
       root_(NULL),
 #ifdef OS_WIN
       calls_(0),
@@ -238,6 +248,7 @@ bool Client::Tick() {
   }
 
   is_ticking_ = false;
+  tick_count_++;
   return message_check_ok;
 }
 
@@ -470,6 +481,14 @@ void Client::ClearEventCallback(String type_name) {
 }
 
 void Client::AddEventToQueue(const Event& event) {
+  // Limit one MOUSEMOVE event per N ticks.
+  if (event.type() == Event::TYPE_MOUSEMOVE) {
+    if (tick_count_ <= kTicksPerMouseMoveEvent) {
+      return;
+    } else {
+      tick_count_ = 0;
+    }
+  }
   event_manager_.AddEventToQueue(event);
 }
 
diff --git a/o3d/core/cross/client.h b/o3d/core/cross/client.h
index 4affeb2..eebc586 100644
--- a/o3d/core/cross/client.h
+++ b/o3d/core/cross/client.h
@@ -520,6 +520,9 @@ class Client {
   // Time used for tick and message processing.
   float last_tick_time_;
 
+  // Number of ticks since last reset.
+  int tick_count_;
+
   // Reference to global transform graph root for Client.
   Transform::Ref root_;