improved the alpha blending code, now works properly for nesting/redraw (changed meaning of WIDGET_CLEARBG a little bit for this)

svn-id: r4509

5 files changed, 137 insertions, 19 deletions

diff --git a/gui/dialog.cpp b/gui/dialog.cpp
index 9031e0e210..9942bcfa39 100644
--- a/gui/dialog.cpp
+++ b/gui/dialog.cpp
@@ -25,12 +25,52 @@
 #include "widget.h"
 #include "newgui.h"
 
+Dialog::~Dialog()
+{
+	teardownScreenBuf();
+}
+
+void Dialog::setupScreenBuf()
+{
+	// Create _screenBuf if it doesn't already exist
+	if (!_screenBuf)
+		_screenBuf = new byte[320*200];
+	
+	// Draw the fixed parts of the dialog: background and border.
+	_gui->blendArea(_x, _y, _w, _h, _gui->_bgcolor);
+	_gui->box(_x, _y, _w, _h);
+
+	// Draw a bgcolor rectangle for all widgets which have WIDGET_CLEARBG set. 
+	Widget *w = _firstWidget;
+	while (w) {
+		if (w->_flags & WIDGET_CLEARBG)
+			_gui->fillArea(_x + w->_x, _y + w->_y, w->_w, w->_h, _gui->_bgcolor);
+		// FIXME - should we also draw borders here if WIDGET_BORDER is set?
+		w = w->_next;
+	}
+	
+	// Finally blit this to _screenBuf
+	_gui->blitTo(_screenBuf, _x, _y, _w, _h); 
+}
+
+void Dialog::teardownScreenBuf()
+{
+	if (_screenBuf) {
+		delete [] _screenBuf;
+		_screenBuf = 0;
+	}
+}
+
 void Dialog::draw()
 {
 	Widget *w = _firstWidget;
 
-	_gui->fillArea(_x, _y, _w, _h, _gui->_bgcolor);
-	_gui->box(_x, _y, _w, _h);
+	if (_screenBuf) {
+		_gui->blitFrom(_screenBuf, _x, _y, _w, _h); 
+	} else {
+		_gui->fillArea(_x, _y, _w, _h, _gui->_bgcolor);
+		_gui->box(_x, _y, _w, _h);
+	}
 	_gui->setAreaDirty(_x, _y, _w, _h);
 
 	while (w) {
diff --git a/gui/dialog.h b/gui/dialog.h
index f91bc681a6..77eaf57738 100644
--- a/gui/dialog.h
+++ b/gui/dialog.h
@@ -43,11 +43,13 @@ protected:
 	int16	_x, _y;
 	uint16	_w, _h;
 	Widget	*_mouseWidget;
+	byte	*_screenBuf;
 
 public:
 	Dialog(NewGui *gui, int x, int y, int w, int h)
-		: _gui(gui), _firstWidget(0), _x(x), _y(y), _w(w), _h(h), _mouseWidget(0)
+		: _gui(gui), _firstWidget(0), _x(x), _y(y), _w(w), _h(h), _mouseWidget(0), _screenBuf(0)
 		{}
+	virtual ~Dialog();
 
 	virtual void draw();
 
@@ -58,6 +60,9 @@ public:
 	virtual void handleCommand(uint32 cmd);
 	
 	NewGui	*getGui()	{ return _gui; }
+	
+	void	setupScreenBuf();
+	void	teardownScreenBuf();
 
 protected:
 	Widget* findWidget(int x, int y); // Find the widget at pos x,y if any
diff --git a/gui/widget.cpp b/gui/widget.cpp
index 510eb8428b..bf45fb522f 100644
--- a/gui/widget.cpp
+++ b/gui/widget.cpp
@@ -43,8 +43,8 @@ void Widget::draw()
 	_x += _boss->_x;
 	_y += _boss->_y;
 
-	// Clear background
-	if (_flags & WIDGET_CLEARBG)
+	// Clear background (unless alpha blending is enabled)
+	if (_flags & WIDGET_CLEARBG && !_boss->_screenBuf)
 		gui->fillArea(_x, _y, _w, _h, gui->_bgcolor);
 
 	// Draw border
@@ -94,7 +94,7 @@ void StaticTextWidget::drawWidget(bool hilite)
 ButtonWidget::ButtonWidget(Dialog *boss, int x, int y, int w, int h, const char *label, uint32 cmd, uint8 hotkey)
 	: StaticTextWidget(boss, x, y, w, h, label), _cmd(cmd), _hotkey(hotkey)
 {
-	_flags = WIDGET_ENABLED | WIDGET_BORDER /* | WIDGET_CLEARBG */ ;
+	_flags = WIDGET_ENABLED | WIDGET_BORDER | WIDGET_CLEARBG ;
 	_type = kButtonWidget;
 }
 
@@ -148,7 +148,7 @@ void CheckboxWidget::drawWidget(bool hilite)
 	if (_state)
 		gui->drawBitmap(checked_img, _x + 3, _y + 3, gui->_textcolor);
 	else
-		gui->fillArea(_x + 3, _y + 3, 8, 8, gui->_bgcolor);
+		gui->fillArea(_x + 2, _y + 2, 10, 10, gui->_bgcolor);
 	
 	// Finally draw the label
 	gui->drawString(_text, _x + 20, _y + 3, _w, gui->_textcolor);
@@ -159,7 +159,7 @@ void CheckboxWidget::drawWidget(bool hilite)
 SliderWidget::SliderWidget(Dialog *boss, int x, int y, int w, int h, const char *label, uint32 cmd, uint8 hotkey)
 	: ButtonWidget(boss, x, y, w, h, label, cmd, hotkey), _value(0), _old_value(1)
 {
-	_flags = WIDGET_ENABLED | WIDGET_TRACK_MOUSE;
+	_flags = WIDGET_ENABLED | WIDGET_TRACK_MOUSE | WIDGET_CLEARBG;
 	_type = kSliderWidget;
 }
 
diff --git a/newgui.cpp b/newgui.cpp
index 6f5d6153ea..b16f3fbc83 100644
--- a/newgui.cpp
+++ b/newgui.cpp
@@ -95,8 +95,9 @@ void ClearBlendCache(byte *palette, int weight) {
  * - ...
  */
 
-NewGui::NewGui(Scumm *s) : _s(s), _need_redraw(false), _pauseDialog(0),
-	_saveLoadDialog(0), _aboutDialog(0), _optionsDialog(0)
+NewGui::NewGui(Scumm *s) : _s(s), _use_alpha_blending(true),
+	_need_redraw(false),_prepare_for_gui(true),
+	_pauseDialog(0), _saveLoadDialog(0), _aboutDialog(0), _optionsDialog(0)
 {	
 }
 
@@ -109,7 +110,6 @@ void NewGui::pauseDialog()
 
 void NewGui::saveloadDialog()
 {
-	ClearBlendCache(_s->_currentPalette, 128);
 	if (!_saveLoadDialog)
 		_saveLoadDialog = new SaveLoadDialog(this);
 	openDialog(_saveLoadDialog);
@@ -133,11 +133,19 @@ void NewGui::loop()
 {
 	Dialog *activeDialog = _dialogStack.top();
 	
+	if (_prepare_for_gui) {
+		ClearBlendCache(_s->_currentPalette, 128);
+		saveState();
+		if (_use_alpha_blending)
+			activeDialog->setupScreenBuf();
+		_prepare_for_gui = false;
+	}
+	
 	if (_need_redraw) {
 		activeDialog->draw();
-		saveState();
 		_need_redraw = false;
 	}
+	
 	_s->animateCursor();
 	_s->getKeyInput(0);
 	if (_s->_mouseButStat & MBS_LEFT_CLICK) {		
@@ -194,17 +202,31 @@ void NewGui::restoreState()
 
 void NewGui::openDialog(Dialog *dialog)
 {
+	if (_dialogStack.empty())
+		_prepare_for_gui = true;
+	else if (_use_alpha_blending)
+		dialog->setupScreenBuf();
+
 	_dialogStack.push(dialog);
 	_need_redraw = true;
 }
 
 void NewGui::closeTopDialog()
 {
+	// Don't do anything if no dialog is open
+	if (_dialogStack.empty())
+		return;
+	
+	// Tear down its screenBuf
+	if (_use_alpha_blending)
+		_dialogStack.top()->teardownScreenBuf();
+	
+	// Remove the dialog from the stack
 	_dialogStack.pop();
 	if (_dialogStack.empty())
 		restoreState();
 	else
-		_dialogStack.top()->draw();
+		_need_redraw = true;
 }
 
 #pragma mark -
@@ -298,6 +320,20 @@ void NewGui::line(int x, int y, int x2, int y2, byte color)
 	}
 }
 
+void NewGui::blendArea(int x, int y, int w, int h, byte color)
+{
+	byte *ptr = getBasePtr(x, y);
+	if (ptr == NULL)
+		return;
+
+	while (h--) {
+		for (int i = 0; i < w; i++) {
+			ptr[i] = Blend(ptr[i], color, _s->_currentPalette);
+		}
+		ptr += 320;
+	}
+}
+
 void NewGui::fillArea(int x, int y, int w, int h, byte color)
 {
 	byte *ptr = getBasePtr(x, y);
@@ -306,10 +342,8 @@ void NewGui::fillArea(int x, int y, int w, int h, byte color)
 
 	while (h--) {
 		for (int i = 0; i < w; i++) {
-			int srcc = ptr[i];
-			ptr[i] = Blend(srcc, color, _s->_currentPalette);
+			ptr[i] = color;
 		}
-			//ptr[i] = color;
 		ptr += 320;
 	}
 }
@@ -392,3 +426,36 @@ void NewGui::drawBitmap(uint32 bitmap[8], int x, int y, byte color)
 		ptr += 320;
 	}
 }
+
+void NewGui::blitTo(byte buffer[320*200], int x, int y, int w, int h)
+{
+	byte *dstPtr = buffer + x + y*320;
+	byte *srcPtr = getBasePtr(x, y);
+	if (srcPtr == NULL)
+		return;
+
+	while (h--) {
+		for (int i = 0; i < w; i++) {
+			*dstPtr++ = *srcPtr++;
+		}
+		dstPtr += 320 - w;
+		srcPtr += 320 - w;
+	}
+}
+
+void NewGui::blitFrom(byte buffer[320*200], int x, int y, int w, int h)
+{
+	byte *srcPtr = buffer + x + y*320;
+	byte *dstPtr = getBasePtr(x, y);
+	if (dstPtr == NULL)
+		return;
+
+	while (h--) {
+		for (int i = 0; i < w; i++) {
+			*dstPtr++ = *srcPtr++;
+		}
+		dstPtr += 320 - w;
+		srcPtr += 320 - w;
+	}
+}
+
diff --git a/newgui.h b/newgui.h
index da405c9639..a7707abb00 100644
--- a/newgui.h
+++ b/newgui.h
@@ -63,7 +63,9 @@ public:
 
 protected:
 	Scumm		*_s;
+	bool		_use_alpha_blending;
 	bool		_need_redraw;
+	bool		_prepare_for_gui;
 	DialogStack	_dialogStack;
 	
 	Dialog		*_pauseDialog;
@@ -94,12 +96,16 @@ public:
 	// Drawing
 	byte *getBasePtr(int x, int y);
 	void box(int x, int y, int width, int height);
-    void line(int x, int y, int x2, int y2, byte color);
-    void fillArea(int x, int y, int w, int h, byte color);
-    void setAreaDirty(int x, int y, int w, int h);
+	void line(int x, int y, int x2, int y2, byte color);
+	void blendArea(int x, int y, int w, int h, byte color);
+	void fillArea(int x, int y, int w, int h, byte color);
+	void setAreaDirty(int x, int y, int w, int h);
 	void drawChar(const char c, int x, int y);
 	void drawString(const char *str, int x, int y, int w, byte color);
+
 	void drawBitmap(uint32 bitmap[8], int x, int y, byte color);
+	void blitTo(byte buffer[320*200], int x, int y, int w, int h);
+	void blitFrom(byte buffer[320*200], int x, int y, int w, int h);
 
 	// Query a string from the resources
 	const char *queryResString(int stringno);