* Update the snow flakes only once per frame. This fixes the problem of faster snow flakes if there are more then one screens.

* Disable snow effect if there is an active full screen effect as it causes some problems. E.g. in desktop grid the snow flakes are painted several times and by that look terrible.
CCBUG: 176489

svn path=/trunk/KDE/kdebase/workspace/; revision=890836

effects/snow.cpp

@@ -50,6 +50,7 @@ SnowEffect::SnowEffect()
     , mShader( 0 )
     , mInited( false )
     , mUseShader( true )
+    , hasSnown( false )
     {
     srandom( std::time( NULL ) );
     nextFlakeMillis = 0;
@@ -81,7 +82,7 @@ void SnowEffect::reconfigure( ReconfigureFlags )
 
 void SnowEffect::prePaintScreen( ScreenPrePaintData& data, int time )
     {
-    if ( active )
+    if ( active && effects->activeFullScreenEffect() == NULL )
         {
             // if number of active snowflakes is smaller than maximum number
             // create a random new snowflake
@@ -101,6 +102,7 @@ void SnowEffect::prePaintScreen( ScreenPrePaintData& data, int time )
                 nextFlakeMillis = next;
                 }
         data.mask |= PAINT_SCREEN_TRANSFORMED;
+        hasSnown = false;
         }
     effects->prePaintScreen( data, time );
     }
@@ -116,6 +118,8 @@ void SnowEffect::paintScreen( int mask, QRegion region, ScreenPaintData& data )
 
 void SnowEffect::snowing( QRegion& region )
     {
+    if( effects->activeFullScreenEffect() != NULL )
+        return;
     if(! texture ) loadTexture();
     if( texture )
         {
@@ -136,10 +140,14 @@ void SnowEffect::snowing( QRegion& region )
         for (int i=0; i<flakes.count(); i++)
             {
             SnowFlake& flake = flakes[i];
-            if( flake.addFrame() == 0 )
+            if( !hasSnown )
                 {
-                flakes.removeAt( i-- );
-                continue;
+                // only update during first paint in one frame
+                if( flake.addFrame() == 0 )
+                    {
+                    flakes.removeAt( i-- );
+                    continue;
+                    }
                 }
 
             if( mUseShader )
@@ -156,7 +164,11 @@ void SnowEffect::snowing( QRegion& region )
                 }
             else
                 {
-                flake.updateSpeedAndRotation();
+                if( !hasSnown )
+                    {
+                    // only update during first paint in one frame
+                    flake.updateSpeedAndRotation();
+                    }
                 // no shader
                 // save the matrix
                 glPushMatrix();
@@ -186,6 +198,7 @@ void SnowEffect::snowing( QRegion& region )
         glDisable( GL_BLEND );
         texture->unbind();
         glPopAttrib();
+        hasSnown = true;
         }
     }
 

effects/snow.h

@@ -98,6 +98,7 @@ class SnowEffect
         bool mInited;
         bool mUseShader;
         QRegion repaintRegion;
+        bool hasSnown;
     };
 
 } // namespace