LAB: Implement the scroll buffer of doScrollWipe() and doScrollBounce()

This was left out from previous refactoring. Also, simplify
doScrollBounce()

3 files changed, 25 insertions, 30 deletions

diff --git a/engines/lab/anim.cpp b/engines/lab/anim.cpp
index 9444a8f9bc..5f469d8188 100644
--- a/engines/lab/anim.cpp
+++ b/engines/lab/anim.cpp
@@ -58,10 +58,7 @@ Anim::Anim(LabEngine *vm) : _vm(vm) {
 	_diffFile = nullptr;
 	_diffFileStart = 0;
 	_size = 0;
-	_rawDiffBM._bytesPerRow = 0;
-	_rawDiffBM._drawOnScreen = false;
-	for (int i = 0; i < 16; i++)
-		_rawDiffBM._planes[i] = nullptr;
+	_scrollScreenBuffer = nullptr;
 	_waitForEffect = false;
 	_stopPlayingEnd = false;
 	_sampleSpeed = 0;
@@ -73,6 +70,11 @@ Anim::Anim(LabEngine *vm) : _vm(vm) {
 		_diffPalette[i] = 0;
 }
 
+Anim::~Anim() {
+	delete[] _vm->_anim->_scrollScreenBuffer;
+	_vm->_anim->_scrollScreenBuffer = nullptr;
+}
+
 void Anim::diffNextFrame(bool onlyDiffData) {
 	if (_lastBlockHeader == 65535)
 		// Already done.
@@ -143,9 +145,15 @@ void Anim::diffNextFrame(bool onlyDiffData) {
 			break;
 
 		case 10:
-			if (onlyDiffData)
-				warning("Boom");
-			_diffFile->read(disp->_planes[_curBit], _size);
+			if (onlyDiffData) {
+				if (_curBit > 0)
+					error("diffNextFrame: attempt to read screen to non-zero plane (%d)", _curBit);
+				delete[] _scrollScreenBuffer;
+				_scrollScreenBuffer = new byte[_headerdata._width * _headerdata._height];
+				_diffFile->read(_scrollScreenBuffer, _size);
+			} else {
+				_diffFile->read(disp->_planes[_curBit], _size);
+			}
 			_curBit++;
 			break;
 
@@ -325,8 +333,8 @@ void Anim::readDiff(Common::File *diffFile, bool playOnce, bool onlyDiffData) {
 
 	assert(_numChunks < 16);
 
-	for (int i = 0; i < 8; i++)
-		_rawDiffBM._planes[i] = nullptr;
+	delete[] _scrollScreenBuffer;
+	_scrollScreenBuffer = nullptr;
 
 	if (_headerdata._fps)
 		_delayMicros = 1000 / _headerdata._fps;
diff --git a/engines/lab/anim.h b/engines/lab/anim.h
index 563f2816ad..db2e23e9b5 100644
--- a/engines/lab/anim.h
+++ b/engines/lab/anim.h
@@ -74,13 +74,14 @@ private:
 
 public:
 	Anim(LabEngine *vm);
+	virtual ~Anim();
 
 	DIFFHeader _headerdata;
 	char _diffPalette[256 * 3];
 	bool _waitForEffect; // Wait for each sound effect to finish before continuing.
 	bool _doBlack;       // Black the screen before new picture
 	bool _noPalChange;   // Don't change the palette.
-	BitMap _rawDiffBM;
+	byte *_scrollScreenBuffer;
 
 	/**
 	 * Reads in a DIFF file.
diff --git a/engines/lab/dispman.cpp b/engines/lab/dispman.cpp
index 2e133500e8..cbf7575ff2 100644
--- a/engines/lab/dispman.cpp
+++ b/engines/lab/dispman.cpp
@@ -704,7 +704,7 @@ void DisplayMan::doScrollWipe(const Common::String filename) {
 
 	readPict(filename, true, true);
 	setPalette(_vm->_anim->_diffPalette, 256);
-	byte *mem = _vm->_anim->_rawDiffBM._planes[0];
+	byte *mem = _vm->_anim->_scrollScreenBuffer;
 
 	_vm->updateMusicAndEvents();
 	uint16 by = _vm->_utils->vgaScaleX(3);
@@ -744,42 +744,28 @@ void DisplayMan::doScrollWipe(const Common::String filename) {
 }
 
 void DisplayMan::doScrollBounce() {
-	const uint16 *newby, *newby1;
-
-	const uint16 newbyd[5] = {5, 4, 3, 2, 1}, newby1d[8] = {3, 3, 2, 2, 2, 1, 1, 1};
-	const uint16 newbyw[5] = {10, 8, 6, 4, 2}, newby1w[8] = {6, 6, 4, 4, 4, 2, 2, 2};
-
-	if (_vm->getPlatform() != Common::kPlatformWindows) {
-		newby = newbyd;
-		newby1 = newby1d;
-	} else {
-		newby = newbyw;
-		newby1 = newby1w;
-	}
+	const uint16 offsets[8] = { 3, 3, 2, 2, 2, 1, 1, 1 };
+	const int multiplier = (_vm->_isHiRes) ? 2 : 1;
 
 	_vm->_event->mouseHide();
 	int width = _vm->_utils->vgaScaleX(320);
 	int height = _vm->_utils->vgaScaleY(149) + _vm->_utils->svgaCord(2);
-	byte *mem = _vm->_anim->_rawDiffBM._planes[0];
+	byte *mem = _vm->_anim->_scrollScreenBuffer;
 
 	_vm->updateMusicAndEvents();
 	int startLine = _vm->_anim->_headerdata._height - height - 1;
 
 	for (int i = 0; i < 5; i++) {
 		_vm->updateMusicAndEvents();
-		startLine -= newby[i];
+		startLine -= (5 - i) * multiplier;
 		copyPage(width, height, 0, startLine, mem);
-
-		screenUpdate();
 		_vm->waitTOF();
 	}
 
 	for (int i = 8; i > 0; i--) {
 		_vm->updateMusicAndEvents();
-		startLine += newby1[i - 1];
+		startLine += offsets[i - 1] * multiplier;
 		copyPage(width, height, 0, startLine, mem);
-
-		screenUpdate();
 		_vm->waitTOF();
 	}