Buffer layered sprites under SDL

This improves framerate and allows transparent overlay for complex
sprites. Two copies of the buffer are kept, one at full opacity,
one with variable opactiy, to reduce calls to setAlpha.

Reviewed-by: Bertram

1 files changed, 26 insertions, 8 deletions

diff --git a/src/animatedsprite.cpp b/src/animatedsprite.cpp
index bc595f79..3e4104a9 100644
--- a/src/animatedsprite.cpp
+++ b/src/animatedsprite.cpp
@@ -70,18 +70,22 @@ AnimatedSprite::~AnimatedSprite()
     mSprite->decRef();
 }
 
-void AnimatedSprite::reset()
+bool AnimatedSprite::reset()
 {
+    bool ret = mFrameIndex !=0 || mFrameTime != 0 || mLastTime != 0;
+
     mFrameIndex = 0;
     mFrameTime = 0;
     mLastTime = 0;
+
+    return ret;
 }
 
-void AnimatedSprite::play(SpriteAction spriteAction)
+bool AnimatedSprite::play(SpriteAction spriteAction)
 {
     Action *action = mSprite->getAction(spriteAction);
     if (!action)
-        return;
+        return false;
 
     mAction = action;
     Animation *animation = mAction->getAnimation(mDirection);
@@ -92,10 +96,14 @@ void AnimatedSprite::play(SpriteAction spriteAction)
         mFrame = mAnimation->getFrame(0);
 
         reset();
+
+        return true;
     }
+
+    return false;
 }
 
-void AnimatedSprite::update(int time)
+bool AnimatedSprite::update(int time)
 {
     // Avoid freaking out at first frame or when tick_time overflows
     if (time < mLastTime || mLastTime == 0)
@@ -103,16 +111,22 @@ void AnimatedSprite::update(int time)
 
     // If not enough time has passed yet, do nothing
     if (time <= mLastTime || !mAnimation)
-        return;
+        return false;
 
     unsigned int dt = time - mLastTime;
     mLastTime = time;
 
+    Animation *animation = mAnimation;
+    Frame *frame = mFrame;
+
     if (!updateCurrentAnimation(dt))
     {
         // Animation finished, reset to default
         play(ACTION_STAND);
     }
+
+    // Make sure something actually changed
+    return animation != mAnimation || frame != mFrame;
 }
 
 bool AnimatedSprite::updateCurrentAnimation(unsigned int time)
@@ -159,14 +173,14 @@ bool AnimatedSprite::draw(Graphics *graphics, int posX, int posY) const
                                posY + mFrame->offsetY);
 }
 
-void AnimatedSprite::setDirection(SpriteDirection direction)
+bool AnimatedSprite::setDirection(SpriteDirection direction)
 {
     if (mDirection != direction)
     {
         mDirection = direction;
 
         if (!mAction)
-            return;
+            return false;
 
         Animation *animation = mAction->getAnimation(mDirection);
 
@@ -176,7 +190,11 @@ void AnimatedSprite::setDirection(SpriteDirection direction)
             mFrame = mAnimation->getFrame(0);
             reset();
         }
+
+        return true;
     }
+
+    return false;
 }
 
 int AnimatedSprite::getWidth() const
@@ -195,7 +213,7 @@ int AnimatedSprite::getHeight() const
         return 0;
 }
 
-Image* AnimatedSprite::getImage() const
+const Image* AnimatedSprite::getImage() const
 {
     return mFrame ? mFrame->image : 0;
 }