[OpenTK] Do not raise *Frame events when time = 0

Affects issue #40

diff --git a/Source/OpenTK/GameWindow.cs b/Source/OpenTK/GameWindow.cs
index e342923..8012eba 100644 (file)
--- a/Source/OpenTK/GameWindow.cs
+++ b/Source/OpenTK/GameWindow.cs
@@ -469,7 +469,7 @@ namespace OpenTK
 
         bool RaiseUpdateFrame(double time)
         {
-            if (time >= TargetUpdatePeriod)
+            if (time > 0 && time >= TargetUpdatePeriod)
             {
                 update_args.Time = time;
                 OnUpdateFrameInternal(update_args);
@@ -481,7 +481,7 @@ namespace OpenTK
 
         bool RaiseRenderFrame(double time)
         {
-            if (time >= TargetRenderPeriod)
+            if (time > 0 && time >= TargetRenderPeriod)
             {
                 render_args.Time = time;
                 OnRenderFrameInternal(render_args);