4 files changed, 30 insertions, 11 deletions
diff --git a/engines/composer/composer.cpp b/engines/composer/composer.cpp
index c63e07d9ee..e1ab6c9472 100644
--- a/engines/composer/composer.cpp
+++ b/engines/composer/composer.cpp
@@ -335,7 +335,7 @@ void ComposerEngine::loadLibrary(uint id) {
 
 	// add background sprite, if it exists
 	if (hasResource(ID_BMAP, 1000))
-		addSprite(1000, 0, 0xffff, Common::Point());
+		setBackground(1000);
 
 	// TODO: better CTBL logic
 	loadCTBL(1000, 100);
diff --git a/engines/composer/composer.h b/engines/composer/composer.h
index 95f262f1ec..55e3331faa 100644
--- a/engines/composer/composer.h
+++ b/engines/composer/composer.h
@@ -183,13 +183,14 @@ private:
 	void processAnimFrame();
 
 	bool spriteVisible(uint16 id, uint16 animId);
-	void addSprite(uint16 id, uint16 animId, uint16 zorder, const Common::Point &pos);
+	Sprite *addSprite(uint16 id, uint16 animId, uint16 zorder, const Common::Point &pos);
 	void removeSprite(uint16 id, uint16 animId);
 	const Sprite *getSpriteAtPos(const Common::Point &pos);
 	const Button *getButtonFor(const Sprite *sprite, const Common::Point &pos);
 
 	void redraw();
-	void loadCTBL(uint id, uint fadePercent);
+	void loadCTBL(uint16 id, uint fadePercent);
+	void setBackground(uint16 id);
 	void decompressBitmap(uint16 type, Common::SeekableReadStream *stream, byte *buffer, uint32 size, uint width, uint height);
 	bool initSprite(Sprite &sprite);
 	Common::SeekableReadStream *getStreamForSprite(uint16 id);
diff --git a/engines/composer/graphics.cpp b/engines/composer/graphics.cpp
index 65a12dd6a8..1b7c3bdfc9 100644
--- a/engines/composer/graphics.cpp
+++ b/engines/composer/graphics.cpp
@@ -369,7 +369,7 @@ bool ComposerEngine::spriteVisible(uint16 id, uint16 animId) {
 	return false;
 }
 
-void ComposerEngine::addSprite(uint16 id, uint16 animId, uint16 zorder, const Common::Point &pos) {
+Sprite *ComposerEngine::addSprite(uint16 id, uint16 animId, uint16 zorder, const Common::Point &pos) {
 	Sprite sprite;
 	bool foundSprite = false;
 
@@ -385,7 +385,7 @@ void ComposerEngine::addSprite(uint16 id, uint16 animId, uint16 zorder, const Co
 		if (i->_zorder == zorder) {
 			i->_animId = animId;
 			i->_pos = pos;
-			return;
+			return &(*i);
 		}
 
 		// otherwise, take a copy and remove it from the list
@@ -403,7 +403,7 @@ void ComposerEngine::addSprite(uint16 id, uint16 animId, uint16 zorder, const Co
 		sprite._id = id;
 		if (!initSprite(sprite)) {
 			warning("ignoring addSprite on invalid sprite %d", id);
-			return;
+			return NULL;
 		}
 	}
 
@@ -412,9 +412,11 @@ void ComposerEngine::addSprite(uint16 id, uint16 animId, uint16 zorder, const Co
 			continue;
 		// insert *before* this sprite
 		_sprites.insert(i, sprite);
-		return;
+		--i;
+		return &(*i);
 	}
 	_sprites.push_back(sprite);
+	return &_sprites.back();
 }
 
 void ComposerEngine::removeSprite(uint16 id, uint16 animId) {
@@ -453,7 +455,7 @@ void ComposerEngine::redraw() {
 	_needsUpdate = false;
 }
 
-void ComposerEngine::loadCTBL(uint id, uint fadePercent) {
+void ComposerEngine::loadCTBL(uint16 id, uint fadePercent) {
 	Common::SeekableReadStream *stream = getResource(ID_CTBL, id);
 
 	uint16 numEntries = stream->readUint16LE();
@@ -472,6 +474,22 @@ void ComposerEngine::loadCTBL(uint id, uint fadePercent) {
 	_system->getPaletteManager()->setPalette(buffer, 0, numEntries);
 }
 
+void ComposerEngine::setBackground(uint16 id) {
+	for (Common::List<Sprite>::iterator i = _sprites.begin(); i != _sprites.end(); i++) {
+		if (i->_id)
+			continue;
+		i->_surface.free();
+		i->_id = id;
+		initSprite(*i);
+		i->_id = 0;
+		return;
+	}
+
+	Sprite *background = addSprite(id, 0, 0xffff, Common::Point());
+	if (background)
+		background->_id = 0;
+}
+
 static void decompressSLWM(byte *buffer, Common::SeekableReadStream *stream) {
 	uint bitsLeft = 0;
 	uint16 lastBits;
diff --git a/engines/composer/scripting.cpp b/engines/composer/scripting.cpp
index ba1cdd7c74..f52ed3ea43 100644
--- a/engines/composer/scripting.cpp
+++ b/engines/composer/scripting.cpp
@@ -652,10 +652,10 @@ int16 ComposerEngine::scriptFuncCall(uint16 id, int16 param1, int16 param2, int1
 		_vars[param2] = _lastMousePos.y;
 		return 0;
 	case kFuncChangeBackground:
-		// TODO
-		warning("ignoring kFuncChangeBackground(%d)", param1);
+		debug(3, "kFuncChangeBackground(%d)", param1);
 		// TODO: return 1 if background existed, else 0
-		return 0;
+		setBackground(param1);
+		return 1;
 	case kFuncSetBackgroundColor:
 		// TODO
 		warning("ignoring kFuncSetBackgroundColor(%d)", param1);