GOB: Move the background saving into its own class BackBuffer

engines/gob/aniobject.cpp

@@ -28,23 +28,20 @@
 namespace Gob {
 
 ANIObject::ANIObject(const ANIFile &ani) : _ani(&ani), _cmp(0),
-	_visible(false), _paused(false), _mode(kModeContinuous),
-	_x(0), _y(0), _background(0), _drawn(false) {
+	_visible(false), _paused(false), _mode(kModeContinuous), _x(0), _y(0) {
 
 	setAnimation(0);
 	setPosition();
 }
 
 ANIObject::ANIObject(const CMPFile &cmp) : _ani(0), _cmp(&cmp),
-	_visible(false), _paused(false), _mode(kModeContinuous),
-	_x(0), _y(0), _background(0), _drawn(false) {
+	_visible(false), _paused(false), _mode(kModeContinuous), _x(0), _y(0) {
 
 	setAnimation(0);
 	setPosition();
 }
 
 ANIObject::~ANIObject() {
-	delete _background;
 }
 
 void ANIObject::setVisible(bool visible) {
@@ -188,46 +185,36 @@ bool ANIObject::draw(Surface &dest, int16 &left, int16 &top,
 bool ANIObject::drawCMP(Surface &dest, int16 &left, int16 &top,
                                        int16 &right, int16 &bottom) {
 
-	if (!_background) {
+	if (!hasBuffer()) {
 		uint16 width, height;
 
 		_cmp->getMaxSize(width, height);
 
-		_background = new Surface(width, height, dest.getBPP());
+		resizeBuffer(width, height);
 	}
 
-	const uint16 cR = _cmp->getWidth (_animation) - 1;
-	const uint16 cB = _cmp->getHeight(_animation) - 1;
+	left   = _x;
+	top    = _y;
+	right  = _x + _cmp->getWidth (_animation) - 1;
+	bottom = _y + _cmp->getHeight(_animation) - 1;
 
-	_backgroundLeft   = CLIP<int16>(   + _x, 0, dest.getWidth () - 1);
-	_backgroundTop    = CLIP<int16>(   + _y, 0, dest.getHeight() - 1);
-	_backgroundRight  = CLIP<int16>(cR + _x, 0, dest.getWidth () - 1);
-	_backgroundBottom = CLIP<int16>(cB + _y, 0, dest.getHeight() - 1);
-
-	_background->blit(dest, _backgroundLeft , _backgroundTop,
-	                        _backgroundRight, _backgroundBottom, 0, 0);
+	if (!saveScreen(dest, left, top, right, bottom))
+		return false;
 
 	_cmp->draw(dest, _animation, _x, _y, 0);
 
-	_drawn = true;
-
-	left   = _backgroundLeft;
-	top    = _backgroundTop;
-	right  = _backgroundRight;
-	bottom = _backgroundBottom;
-
 	return true;
 }
 
 bool ANIObject::drawANI(Surface &dest, int16 &left, int16 &top,
                                        int16 &right, int16 &bottom) {
 
-	if (!_background) {
+	if (!hasBuffer()) {
 		uint16 width, height;
 
 		_ani->getMaxSize(width, height);
 
-		_background = new Surface(width, height, dest.getBPP());
+		resizeBuffer(width, height);
 	}
 
 	const ANIFile::Animation &animation = _ani->getAnimationInfo(_animation);
@@ -236,45 +223,23 @@ bool ANIObject::drawANI(Surface &dest, int16 &left, int16 &top,
 
 	const ANIFile::FrameArea &area = animation.frameAreas[_frame];
 
-	_backgroundLeft   = CLIP<int16>(area.left   + _x, 0, dest.getWidth () - 1);
-	_backgroundTop    = CLIP<int16>(area.top    + _y, 0, dest.getHeight() - 1);
-	_backgroundRight  = CLIP<int16>(area.right  + _x, 0, dest.getWidth () - 1);
-	_backgroundBottom = CLIP<int16>(area.bottom + _y, 0, dest.getHeight() - 1);
+	left   = _x + area.left;
+	top    = _y + area.top;
+	right  = _x + area.right;
+	bottom = _y + area.bottom;
 
-	_background->blit(dest, _backgroundLeft , _backgroundTop,
-	                        _backgroundRight, _backgroundBottom, 0, 0);
+	if (!saveScreen(dest, left, top, right, bottom))
+		return false;
 
 	_ani->draw(dest, _animation, _frame, _x, _y);
 
-	_drawn = true;
-
-	left   = _backgroundLeft;
-	top    = _backgroundTop;
-	right  = _backgroundRight;
-	bottom = _backgroundBottom;
-
 	return true;
 }
 
 bool ANIObject::clear(Surface &dest, int16 &left, int16 &top,
                                      int16 &right, int16 &bottom) {
 
-	if (!_drawn)
-		return false;
-
-	const int16 bgRight  = _backgroundRight  - _backgroundLeft;
-	const int16 bgBottom = _backgroundBottom - _backgroundTop;
-
-	dest.blit(*_background, 0, 0, bgRight, bgBottom, _backgroundLeft, _backgroundTop);
-
-	_drawn = false;
-
-	left   = _backgroundLeft;
-	top    = _backgroundTop;
-	right  = _backgroundRight;
-	bottom = _backgroundBottom;
-
-	return true;
+	return restoreScreen(dest, left, top, right, bottom);
 }
 
 void ANIObject::advance() {

engines/gob/aniobject.h

@@ -25,6 +25,8 @@
 
 #include "common/system.h"
 
+#include "gob/backbuffer.h"
+
 namespace Gob {
 
 class ANIFile;
@@ -32,7 +34,7 @@ class CMPFile;
 class Surface;
 
 /** An ANI object, controlling an animation within an ANI file. */
-class ANIObject {
+class ANIObject : public BackBuffer {
 public:
 	enum Mode {
 		kModeContinuous, ///< Play the animation continuously.
@@ -118,13 +120,6 @@ private:
 	int16 _x; ///< The current X position.
 	int16 _y; ///< The current Y position.
 
-	Surface *_background; ///< The saved background.
-	bool _drawn;          ///< Was the animation drawn?
-
-	int16 _backgroundLeft;   ///< The left position of the saved background.
-	int16 _backgroundTop;    ///< The top of the saved background.
-	int16 _backgroundRight;  ///< The right position of the saved background.
-	int16 _backgroundBottom; ///< The bottom position of the saved background.
 
 	bool drawCMP(Surface &dest, int16 &left, int16 &top, int16 &right, int16 &bottom);
 	bool drawANI(Surface &dest, int16 &left, int16 &top, int16 &right, int16 &bottom);

engines/gob/backbuffer.cpp

@@ -0,0 +1,100 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#include "common/util.h"
+
+#include "gob/backbuffer.h"
+#include "gob/surface.h"
+
+namespace Gob {
+
+BackBuffer::BackBuffer() : _background(0), _saved(false) {
+}
+
+BackBuffer::~BackBuffer() {
+	delete _background;
+}
+
+bool BackBuffer::hasBuffer() const {
+	return _background != 0;
+}
+
+bool BackBuffer::hasSavedBackground() const {
+	return _saved;
+}
+
+void BackBuffer::trashBuffer() {
+	_saved = false;
+}
+
+void BackBuffer::resizeBuffer(uint16 width, uint16 height) {
+	trashBuffer();
+
+	if (_background && (_background->getWidth() == width) && (_background->getHeight() == height))
+		return;
+
+	delete _background;
+
+	_background = new Surface(width, height, 1);
+}
+
+bool BackBuffer::saveScreen(const Surface &dest, int16 &left, int16 &top, int16 &right, int16 &bottom) {
+	if (!_background)
+		return false;
+
+	const int16 width  = MIN<int16>(right  - left + 1, _background->getWidth ());
+	const int16 height = MIN<int16>(bottom - top  + 1, _background->getHeight());
+	if ((width <= 0) || (height <= 0))
+		return false;
+
+	right  = left + width  - 1;
+	bottom = top  + height - 1;
+
+	_saveLeft   = left;
+	_saveTop    = top;
+	_saveRight  = right;
+	_saveBottom = bottom;
+
+	_background->blit(dest, _saveLeft, _saveTop, _saveRight, _saveBottom, 0, 0);
+
+	_saved = true;
+
+	return true;
+}
+
+bool BackBuffer::restoreScreen(Surface &dest, int16 &left, int16 &top, int16 &right, int16 &bottom) {
+	if (!_saved)
+		return false;
+
+	left   = _saveLeft;
+	top    = _saveTop;
+	right  = _saveRight;
+	bottom = _saveBottom;
+
+	dest.blit(*_background, 0, 0, right - left, bottom - top, left, top);
+
+	_saved = false;
+
+	return true;
+}
+
+} // End of namespace Gob

engines/gob/backbuffer.h

@@ -0,0 +1,59 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef GOB_BACKBUFFER_H
+#define GOB_BACKBUFFER_H
+
+#include "common/system.h"
+
+namespace Gob {
+
+class Surface;
+
+class BackBuffer {
+public:
+	BackBuffer();
+	~BackBuffer();
+
+protected:
+	void trashBuffer();
+	void resizeBuffer(uint16 width, uint16 height);
+
+	bool saveScreen   (const Surface &dest, int16 &left, int16 &top, int16 &right, int16 &bottom);
+	bool restoreScreen(      Surface &dest, int16 &left, int16 &top, int16 &right, int16 &bottom);
+
+	bool hasBuffer() const;
+	bool hasSavedBackground() const;
+
+private:
+	Surface *_background; ///< The saved background.
+	bool _saved;          ///< Was the background saved?
+
+	int16 _saveLeft;   ///< The left position of the saved background.
+	int16 _saveTop;    ///< The top of the saved background.
+	int16 _saveRight;  ///< The right position of the saved background.
+	int16 _saveBottom; ///< The bottom position of the saved background.
+};
+
+} // End of namespace Gob
+
+#endif // GOB_BACKBUFFER_H

engines/gob/module.mk

@@ -3,6 +3,7 @@ MODULE := engines/gob
 MODULE_OBJS := \
 	anifile.o \
 	aniobject.o \
+	backbuffer.o \
 	cheater.o \
 	cheater_geisha.o \
 	cmpfile.o \