Added very basic support for backgrounds larger than screen:

- background surfaces are now reallocated for every location
- screen is copied according to _scrollX/Y position

svn-id: r28538

2 files changed, 11 insertions, 2 deletions

diff --git a/engines/parallaction/graphics.cpp b/engines/parallaction/graphics.cpp
index 2e7d79c37c..95e36cbd69 100644
--- a/engines/parallaction/graphics.cpp
+++ b/engines/parallaction/graphics.cpp
@@ -280,7 +280,7 @@ void Gfx::setHalfbriteMode(bool enable) {
 }
 
 void Gfx::updateScreen() {
-	g_system->copyRectToScreen((const byte*)_buffers[kBitFront]->pixels, _vm->_screenWidth, 0, 0, _vm->_screenWidth, _vm->_screenHeight);
+	g_system->copyRectToScreen((const byte*)_buffers[kBitFront]->pixels, _buffers[kBitFront]->pitch, _screenX, _screenY, _vm->_screenWidth, _vm->_screenHeight);
 	g_system->updateScreen();
 	return;
 }
@@ -695,6 +695,10 @@ void Gfx::restoreBackground(const Common::Rect& r) {
 
 void Gfx::setBackground(Graphics::Surface *surface) {
 	_buffers[kBit2] = surface;
+
+	_buffers[kBitFront]->create(surface->w, surface->h, 1);
+	_buffers[kBitBack]->create(surface->w, surface->h, 1);
+
 	copyScreen(kBit2, kBitBack);
 }
 
@@ -778,13 +782,15 @@ Gfx::Gfx(Parallaction* vm) :
 	_buffers[kBitFront]->create(_vm->_screenWidth, _vm->_screenHeight, 1);
 	_buffers[kBitBack] = new Graphics::Surface;
 	_buffers[kBitBack]->create(_vm->_screenWidth, _vm->_screenHeight, 1);
-
 	_buffers[kBit2] = 0;
 
 	_depthMask = 0;
 
 	setPalette(_palette);
 
+	_screenX = 0;
+	_screenY = 0;
+
 	_bgLayers[0] = _bgLayers[1] = _bgLayers[2] = _bgLayers[3] = 0;
 
 	memset(_palettefx, 0, sizeof(_palettefx));
diff --git a/engines/parallaction/graphics.h b/engines/parallaction/graphics.h
index a830b9b2c9..5125e09b04 100644
--- a/engines/parallaction/graphics.h
+++ b/engines/parallaction/graphics.h
@@ -241,6 +241,9 @@ public:
 	PaletteFxRange		_palettefx[6];
 	Palette				_palette;
 
+	uint				_screenX;		// scrolling position
+	uint				_screenY;
+
 protected:
 	Parallaction*		_vm;
 	Graphics::Surface	*_buffers[NUM_BUFFERS];