scummvm/engines/mohawk/myst.cpp

/* 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/config-manager.h"
#include "common/debug-channels.h"
#include "common/system.h"
#include "common/translation.h"
#include "common/textconsole.h"

#include "mohawk/cursors.h"
#include "mohawk/myst.h"
#include "mohawk/myst_areas.h"
#include "mohawk/myst_graphics.h"
#include "mohawk/myst_scripts.h"
#include "mohawk/myst_state.h"
#include "mohawk/dialogs.h"
#include "mohawk/resource.h"
#include "mohawk/resource_cache.h"
#include "mohawk/sound.h"
#include "mohawk/video.h"

// The stacks
#include "mohawk/myst_stacks/channelwood.h"
#include "mohawk/myst_stacks/credits.h"
#include "mohawk/myst_stacks/demo.h"
#include "mohawk/myst_stacks/dni.h"
#include "mohawk/myst_stacks/intro.h"
#include "mohawk/myst_stacks/makingof.h"
#include "mohawk/myst_stacks/mechanical.h"
#include "mohawk/myst_stacks/myst.h"
#include "mohawk/myst_stacks/preview.h"
#include "mohawk/myst_stacks/selenitic.h"
#include "mohawk/myst_stacks/slides.h"
#include "mohawk/myst_stacks/stoneship.h"

namespace Mohawk {

MohawkEngine_Myst::MohawkEngine_Myst(OSystem *syst, const MohawkGameDescription *gamedesc) : MohawkEngine(syst, gamedesc) {
	DebugMan.addDebugChannel(kDebugVariable, "Variable", "Track Variable Accesses");
	DebugMan.addDebugChannel(kDebugSaveLoad, "SaveLoad", "Track Save/Load Function");
	DebugMan.addDebugChannel(kDebugView, "View", "Track Card File (VIEW) Parsing");
	DebugMan.addDebugChannel(kDebugHint, "Hint", "Track Cursor Hints (HINT) Parsing");
	DebugMan.addDebugChannel(kDebugResource, "Resource", "Track Resource (RLST) Parsing");
	DebugMan.addDebugChannel(kDebugINIT, "Init", "Track Card Init Script (INIT) Parsing");
	DebugMan.addDebugChannel(kDebugEXIT, "Exit", "Track Card Exit Script (EXIT) Parsing");
	DebugMan.addDebugChannel(kDebugScript, "Script", "Track Script Execution");
	DebugMan.addDebugChannel(kDebugHelp, "Help", "Track Help File (HELP) Parsing");
	DebugMan.addDebugChannel(kDebugCache, "Cache", "Track Resource Cache Accesses");

	_currentCursor = 0;
	_mainCursor = kDefaultMystCursor;
	_showResourceRects = false;
	_curCard = 0;
	_needsUpdate = false;
	_canSafelySaveLoad = false;
	_curResource = -1;
	_hoverResource = nullptr;

	_gfx = nullptr;
	_console = nullptr;
	_scriptParser = nullptr;
	_gameState = nullptr;
	_optionsDialog = nullptr;

	_prevStack = nullptr;
}

MohawkEngine_Myst::~MohawkEngine_Myst() {
	DebugMan.clearAllDebugChannels();

	delete _gfx;
	delete _console;
	delete _scriptParser;
	delete _gameState;
	delete _optionsDialog;
	delete _prevStack;
	delete _rnd;

	for (uint32 i = 0; i < _resources.size(); i++)
		delete _resources[i];
}

// Uses cached data objects in preference to disk access
Common::SeekableReadStream *MohawkEngine_Myst::getResource(uint32 tag, uint16 id) {
	Common::SeekableReadStream *ret = _cache.search(tag, id);

	if (ret)
		return ret;

	for (uint32 i = 0; i < _mhk.size(); i++)
		if (_mhk[i]->hasResource(tag, id)) {
			ret = _mhk[i]->getResource(tag, id);
			_cache.add(tag, id, ret);
			return ret;
		}

	error("Could not find a \'%s\' resource with ID %04x", tag2str(tag), id);
	return nullptr;
}

Common::Array<uint16> MohawkEngine_Myst::getResourceIDList(uint32 type) const {
	return _mhk[0]->getResourceIDList(type);
}

void MohawkEngine_Myst::cachePreload(uint32 tag, uint16 id) {
	if (!_cache.enabled)
		return;

	for (uint32 i = 0; i < _mhk.size(); i++) {
		// Check for MJMP in Myst ME
		if ((getFeatures() & GF_ME) && tag == ID_MSND && _mhk[i]->hasResource(ID_MJMP, id)) {
			Common::SeekableReadStream *tempData = _mhk[i]->getResource(ID_MJMP, id);
			uint16 msndId = tempData->readUint16LE();
			delete tempData;

			// We've found where the real MSND data is, so go get that
			tempData = _mhk[i]->getResource(tag, msndId);
			_cache.add(tag, id, tempData);
			delete tempData;
			return;
		}

		if (_mhk[i]->hasResource(tag, id)) {
			Common::SeekableReadStream *tempData = _mhk[i]->getResource(tag, id);
			_cache.add(tag, id, tempData);
			delete tempData;
			return;
		}
	}

	warning("cachePreload: Could not find a \'%s\' resource with ID %04x", tag2str(tag), id);
}

static const char *mystFiles[] = {
	"channel.dat",
	"credits.dat",
	"demo.dat",
	"dunny.dat",
	"intro.dat",
	"making.dat",
	"mechan.dat",
	"myst.dat",
	"selen.dat",
	"slides.dat",
	"sneak.dat",
	"stone.dat"
};

// Myst Hardcoded Movie Paths
// Mechanical Stack Movie "sstairs" referenced in executable, but not used?

// NOTE: cl1wg1.mov etc. found in the root directory in versions of Myst
// Original are duplicates of those in qtw/myst directory and thus not necessary.
// However, this *is* a problem for Myst ME Mac. Right now it will use the qtw/myst
// video, but this is most likely going to fail for the standalone Mac version.

// The following movies are not referenced in RLST or hardcoded into the executables.
// It is likely they are unused:
// qtw/mech/lwrgear2.mov + lwrgears.mov:	I have no idea what these are; perhaps replaced by an animated image in-game?
// qtw/myst/gar4wbf1.mov:	gar4wbf2.mov has two butterflies instead of one
// qtw/myst/libelev.mov:	libup.mov is basically the same with sound

Common::String MohawkEngine_Myst::wrapMovieFilename(const Common::String &movieName, uint16 stack) {
	Common::String prefix;

	switch (stack) {
	case kIntroStack:
		prefix = "intro/";
		break;
	case kChannelwoodStack:
		// The Windmill videos like to hide in a different folder
		if (movieName.contains("wmill"))
			prefix = "channel2/";
		else
			prefix = "channel/";
		break;
	case kDniStack:
		prefix = "dunny/";
		break;
	case kMechanicalStack:
		prefix = "mech/";
		break;
	case kMystStack:
		prefix = "myst/";
		break;
	case kSeleniticStack:
		prefix = "selen/";
		break;
	case kStoneshipStack:
		prefix = "stone/";
		break;
	default:
		// Masterpiece Edition Only Movies
		break;
	}

	return Common::String("qtw/") + prefix + movieName + ".mov";
}

Common::Error MohawkEngine_Myst::run() {
	MohawkEngine::run();

	_gfx = new MystGraphics(this);
	_console = new MystConsole(this);
	_gameState = new MystGameState(this, _saveFileMan);
	_optionsDialog = new MystOptionsDialog(this);
	_cursor = new MystCursorManager(this);
	_rnd = new Common::RandomSource("myst");

	// Cursor is visible by default
	_cursor->showCursor();

	// Load game from launcher/command line if requested
	if (ConfMan.hasKey("save_slot") && hasGameSaveSupport()) {
		int saveSlot = ConfMan.getInt("save_slot");
		if (!_gameState->load(saveSlot))
			error("Failed to load save game from slot %i", saveSlot);
	} else {
		// Start us on the first stack.
		if (getGameType() == GType_MAKINGOF)
			changeToStack(kMakingOfStack, 1, 0, 0);
		else if (getFeatures() & GF_DEMO)
			changeToStack(kDemoStack, 2000, 0, 0);
		else
			changeToStack(kIntroStack, 1, 0, 0);
	}

	// Load Help System (Masterpiece Edition Only)
	if (getFeatures() & GF_ME) {
		MohawkArchive *mhk = new MohawkArchive();
		if (!mhk->openFile("help.dat"))
			error("Could not load help.dat");
		_mhk.push_back(mhk);
	}

	// Test Load Function...
	loadHelp(10000);

	Common::Event event;
	while (!shouldQuit()) {
		// Update any background videos
		_needsUpdate = _video->updateMovies();
		_scriptParser->runPersistentScripts();

		while (pollEvent(event)) {
			switch (event.type) {
			case Common::EVENT_MOUSEMOVE: {
				_needsUpdate = true;
				bool mouseClicked = _system->getEventManager()->getButtonState() & 1;

				// Keep the same resource when dragging
				if (!mouseClicked) {
					checkCurrentResource();
				}
				if (_curResource >= 0 && _resources[_curResource]->isEnabled() && mouseClicked) {
					debug(2, "Sending mouse move event to resource %d", _curResource);
					_resources[_curResource]->handleMouseDrag();
				}
				break;
			}
			case Common::EVENT_LBUTTONUP:
				if (_curResource >= 0 && _resources[_curResource]->isEnabled()) {
					debug(2, "Sending mouse up event to resource %d", _curResource);
					_resources[_curResource]->handleMouseUp();
				}
				checkCurrentResource();
				break;
			case Common::EVENT_LBUTTONDOWN:
				if (_curResource >= 0 && _resources[_curResource]->isEnabled()) {
					debug(2, "Sending mouse up event to resource %d", _curResource);
					_resources[_curResource]->handleMouseDown();
				}
				break;
			case Common::EVENT_KEYDOWN:
				switch (event.kbd.keycode) {
				case Common::KEYCODE_d:
					if (event.kbd.flags & Common::KBD_CTRL) {
						_console->attach();
						_console->onFrame();
					}
					break;
				case Common::KEYCODE_SPACE:
					pauseGame();
					break;
				case Common::KEYCODE_F5:
					_needsPageDrop = false;
					_needsShowMap = false;
					_needsShowDemoMenu = false;
					_needsShowCredits = false;

					_canSafelySaveLoad = true;
					runDialog(*_optionsDialog);
					if (_optionsDialog->getLoadSlot() >= 0)
						loadGameState(_optionsDialog->getLoadSlot());
					_canSafelySaveLoad = false;

					if (_needsPageDrop) {
						dropPage();
						_needsPageDrop = false;
					}

					if (_needsShowMap) {
						_scriptParser->showMap();
						_needsShowMap = false;
					}

					if (_needsShowDemoMenu) {
						changeToStack(kDemoStack, 2002, 0, 0);
						_needsShowDemoMenu = false;
					}

					if (_needsShowCredits) {
						_cursor->hideCursor();
						changeToStack(kCreditsStack, 10000, 0, 0);
						_needsShowCredits = false;
					}
					break;
				default:
					break;
				}
				break;
			default:
				break;
			}
		}

		if (_needsUpdate) {
			_system->updateScreen();
			_needsUpdate = false;
		}

		// Cut down on CPU usage
		_system->delayMillis(10);
	}

	return Common::kNoError;
}

bool MohawkEngine_Myst::pollEvent(Common::Event &event) {
	// Saving / Loading is allowed from the GMM only when the main event loop is running
	_canSafelySaveLoad = true;
	bool eventReturned =  _eventMan->pollEvent(event);
	_canSafelySaveLoad = false;

	return eventReturned;
}

bool MohawkEngine_Myst::skippableWait(uint32 duration) {
	uint32 end = _system->getMillis() + duration;
	bool skipped = false;

	while (_system->getMillis() < end && !skipped) {
		Common::Event event;
		while (_system->getEventManager()->pollEvent(event)) {
			switch (event.type) {
			case Common::EVENT_LBUTTONUP:
				skipped = true;
				break;
			case Common::EVENT_KEYDOWN:
				switch (event.kbd.keycode) {
				case Common::KEYCODE_SPACE:
					pauseGame();
					break;
				case Common::KEYCODE_ESCAPE:
					skipped = true;
					break;
				default:
					break;
			}
			default:
				break;
			}
		}

		// Cut down on CPU usage
		_system->delayMillis(10);
	}

	return skipped;
}

void MohawkEngine_Myst::changeToStack(uint16 stack, uint16 card, uint16 linkSrcSound, uint16 linkDstSound) {
	debug(2, "changeToStack(%d)", stack);

	_curStack = stack;

	// Fill screen with black and empty cursor
	_cursor->setCursor(0);
	_currentCursor = 0;

	if (getFeatures() & GF_ME)
		_system->fillScreen(_system->getScreenFormat().RGBToColor(0, 0, 0));
	else
		_gfx->clearScreenPalette();

	_system->updateScreen();

	_sound->stopSound();
	_sound->stopBackgroundMyst();
	_video->stopVideos();
	if (linkSrcSound)
		_sound->playSoundBlocking(linkSrcSound);

	// Delete the previous stack and move the current stack to the previous one
	// There's probably a better way to do this, but the script classes shouldn't
	// take up much memory.
	delete _prevStack;
	_prevStack = _scriptParser;

	switch (_curStack) {
	case kChannelwoodStack:
		_gameState->_globals.currentAge = 4;
		_scriptParser = new MystStacks::Channelwood(this);
		break;
	case kCreditsStack:
		_scriptParser = new MystStacks::Credits(this);
		break;
	case kDemoStack:
		_gameState->_globals.currentAge = 0;
		_scriptParser = new MystStacks::Demo(this);
		break;
	case kDniStack:
		_gameState->_globals.currentAge = 6;
		_scriptParser = new MystStacks::Dni(this);
		break;
	case kIntroStack:
		_scriptParser = new MystStacks::Intro(this);
		break;
	case kMakingOfStack:
		_scriptParser = new MystStacks::MakingOf(this);
		break;
	case kMechanicalStack:
		_gameState->_globals.currentAge = 3;
		_scriptParser = new MystStacks::Mechanical(this);
		break;
	case kMystStack:
		_gameState->_globals.currentAge = 2;
		_scriptParser = new MystStacks::Myst(this);
		break;
	case kDemoPreviewStack:
		_scriptParser = new MystStacks::Preview(this);
		break;
	case kSeleniticStack:
		_gameState->_globals.currentAge = 0;
		_scriptParser = new MystStacks::Selenitic(this);
		break;
	case kDemoSlidesStack:
		_gameState->_globals.currentAge = 1;
		_scriptParser = new MystStacks::Slides(this);
		break;
	case kStoneshipStack:
		_gameState->_globals.currentAge = 1;
		_scriptParser = new MystStacks::Stoneship(this);
		break;
	default:
		error("Unknown Myst stack");
	}

	// If the array is empty, add a new one. Otherwise, delete the first
	// entry which is the stack file (the second, if there, is the help file).
	if (_mhk.empty())
		_mhk.push_back(new MohawkArchive());
	else {
		delete _mhk[0];
		_mhk[0] = new MohawkArchive();
	}

	if (!_mhk[0]->openFile(mystFiles[_curStack]))
		error("Could not open %s", mystFiles[_curStack]);

	_runExitScript = false;

	// Clear the resource cache and the image cache
	_cache.clear();
	_gfx->clearCache();

	if (getFeatures() & GF_ME) {
		// Play Flyby Entry Movie on Masterpiece Edition.
		const char *flyby = nullptr;

		switch (_curStack) {
		case kSeleniticStack:
			flyby = "selenitic flyby";
			break;
		case kStoneshipStack:
			flyby = "stoneship flyby";
			break;
		// Myst Flyby Movie not used in Original Masterpiece Edition Engine
		// We play it when first arriving on Myst, and if the user has chosen so.
		case kMystStack:
			if (ConfMan.getBool("playmystflyby") && card == 4134)
				flyby = "myst flyby";
			break;
		case kMechanicalStack:
			flyby = "mech age flyby";
			break;
		case kChannelwoodStack:
			flyby = "channelwood flyby";
			break;
		default:
			break;
		}

		if (flyby)
			_video->playMovieBlockingCentered(wrapMovieFilename(flyby, kMasterpieceOnly));
	}

	changeToCard(card, kTransitionCopy);

	if (linkDstSound)
		_sound->playSoundBlocking(linkDstSound);
}

uint16 MohawkEngine_Myst::getCardBackgroundId() {
	uint16 imageToDraw = 0;

	if (_view.conditionalImages.size() == 0)
		imageToDraw = _view.mainImage;
	else {
		for (uint16 i = 0; i < _view.conditionalImages.size(); i++) {
			uint16 varValue = _scriptParser->getVar(_view.conditionalImages[i].var);
			if (varValue < _view.conditionalImages[i].values.size())
				imageToDraw = _view.conditionalImages[i].values[varValue];
		}
	}

	return imageToDraw;
}

void MohawkEngine_Myst::drawCardBackground() {
	_gfx->copyImageToBackBuffer(getCardBackgroundId(), Common::Rect(0, 0, 544, 332));
}

void MohawkEngine_Myst::changeToCard(uint16 card, TransitionType transition) {
	debug(2, "changeToCard(%d)", card);

	_scriptParser->disablePersistentScripts();

	_video->stopVideos();

	// Run exit script from last card (if present)
	if (_runExitScript)
		runExitScript();

	_runExitScript = true;

	unloadCard();

	// Clear the resource cache and image cache
	_cache.clear();
	_gfx->clearCache();

	_curCard = card;

	// Load a bunch of stuff
	loadCard();
	loadResources();
	loadCursorHints();

	// Handle images
	drawCardBackground();

	// Handle sound
	applySoundBlock(_view.soundBlock);

	if (_view.flags & kMystZipDestination)
		_gameState->addZipDest(_curStack, card);

	// Run the entrance script (if present)
	runInitScript();

	// Update the images of each area too
	drawResourceImages();

	for (uint16 i = 0; i < _resources.size(); i++)
		_resources[i]->handleCardChange();

	// The demo resets the cursor at each card change except when in the library
	if (getFeatures() & GF_DEMO
			&& _gameState->_globals.currentAge != 2) {
		_cursor->setDefaultCursor();
	}

	// Make sure the screen is updated
	if (transition != kNoTransition) {
		if (_gameState->_globals.transitions) {
			_gfx->runTransition(transition, Common::Rect(544, 333), 10, 0);
		} else {
			_gfx->copyBackBufferToScreen(Common::Rect(544, 333));
			_system->updateScreen();
			_needsUpdate = false;
		}
	}

	// Make sure we have the right cursor showing
	_hoverResource = nullptr;
	_curResource = -1;
	checkCurrentResource();

	// Debug: Show resource rects
	if (_showResourceRects)
		drawResourceRects();
}

void MohawkEngine_Myst::drawResourceRects() {
	for (uint16 i = 0; i < _resources.size(); i++) {
		_resources[i]->getRect().debugPrint(0);
		_resources[i]->drawBoundingRect();
	}

	_system->updateScreen();
}

void MohawkEngine_Myst::checkCurrentResource() {
	// See what resource we're over
	bool foundResource = false;
	const Common::Point &mouse = _system->getEventManager()->getMousePos();

	// Tell previous resource the mouse is no longer hovering it
	if (_hoverResource && !_hoverResource->contains(mouse)) {
		_hoverResource->handleMouseLeave();
		_hoverResource = nullptr;
	}

	for (uint16 i = 0; i < _resources.size(); i++)
		if (_resources[i]->contains(mouse)) {
			if (_hoverResource != _resources[i] && _resources[i]->type == kMystAreaHover) {
				_hoverResource = static_cast<MystAreaHover *>(_resources[i]);
				_hoverResource->handleMouseEnter();
			}

			if (!foundResource && _resources[i]->canBecomeActive()) {
				_curResource = i;
				foundResource = true;
			}
		}

	// Set the resource to none if we're not over any
	if (!foundResource)
		_curResource = -1;

	checkCursorHints();
}

MystArea *MohawkEngine_Myst::updateCurrentResource() {
	checkCurrentResource();

	if (_curResource >= 0)
		return _resources[_curResource];
	else
		return nullptr;
}

void MohawkEngine_Myst::loadCard() {
	debugC(kDebugView, "Loading Card View: %d", _curCard);

	Common::SeekableReadStream *viewStream = getResource(ID_VIEW, _curCard);

	// Card Flags
	_view.flags = viewStream->readUint16LE();
	debugC(kDebugView, "Flags: 0x%04X", _view.flags);

	// The Image Block (Reminiscent of Riven PLST resources)
	uint16 conditionalImageCount = viewStream->readUint16LE();
	debugC(kDebugView, "Conditional Image Count: %d", conditionalImageCount);
	if (conditionalImageCount != 0) {
		for (uint16 i = 0; i < conditionalImageCount; i++) {
			MystCondition conditionalImage;

			debugC(kDebugView, "\tImage %d:", i);
			conditionalImage.var = viewStream->readUint16LE();
			debugC(kDebugView, "\t\tVar: %d", conditionalImage.var);
			uint16 numStates = viewStream->readUint16LE();
			debugC(kDebugView, "\t\tNumber of States: %d", numStates);
			for (uint16 j = 0; j < numStates; j++) {
				conditionalImage.values.push_back(viewStream->readUint16LE());
				debugC(kDebugView, "\t\tState %d -> Value %d", j, conditionalImage.values[j]);
			}

			_view.conditionalImages.push_back(conditionalImage);
		}
		_view.mainImage = 0;
	} else {
		_view.mainImage = viewStream->readUint16LE();
		debugC(kDebugView, "Main Image: %d", _view.mainImage);
	}

	// The Sound Block (Reminiscent of Riven SLST resources)
	_view.soundBlock = readSoundBlock(viewStream);

	// Resources that scripts can call upon
	uint16 scriptResCount = viewStream->readUint16LE();
	debugC(kDebugView, "Script Resource Count: %d", scriptResCount);
	for (uint16 i = 0; i < scriptResCount; i++) {
		MystView::ScriptResource scriptResource;

		debugC(kDebugView, "\tResource %d:", i);
		scriptResource.type = (MystView::ScriptResourceType) viewStream->readUint16LE();
		debugC(kDebugView, "\t\t Type: %d", scriptResource.type);

		switch (scriptResource.type) {
		case MystView::kResourceImage:
			debugC(kDebugView, "\t\t\t\t= Image");
			break;
		case MystView::kResourceSound:
			debugC(kDebugView, "\t\t\t\t= Sound");
			break;
		case MystView::kResourceSwitch:
			debugC(kDebugView, "\t\t\t\t= Resource Switch");
			break;
		case MystView::kResourceImageNoCache:
			debugC(kDebugView, "\t\t\t\t= Image - Caching disabled");
			break;
		case MystView::kResourceSoundNoCache:
			debugC(kDebugView, "\t\t\t\t= Sound - Caching disabled");
			break;
		default:
			debugC(kDebugView, "\t\t\t\t= Unknown");
			warning("Unknown script resource type '%d' in card '%d'", scriptResource.type, _curCard);
			break;
		}

		if (scriptResource.type == MystView::kResourceSwitch) {
			scriptResource.switchVar = viewStream->readUint16LE();
			debugC(kDebugView, "\t\t Var: %d", scriptResource.switchVar);
			uint16 count = viewStream->readUint16LE();
			debugC(kDebugView, "\t\t Resource List Count: %d", count);
			scriptResource.switchResourceType = (MystView::ScriptResourceType) viewStream->readUint16LE();
			debugC(kDebugView, "\t\t u0: %d", scriptResource.switchResourceType);

			for (uint16 j = 0; j < count; j++) {
				scriptResource.switchResourceIds.push_back(viewStream->readSint16LE());
				debugC(kDebugView, "\t\t Resource List %d: %d", j, scriptResource.switchResourceIds[j]);
			}
		} else {
			scriptResource.id = viewStream->readUint16LE();
			debugC(kDebugView, "\t\t Id: %d", scriptResource.id);
		}

		_view.scriptResources.push_back(scriptResource);
	}

	// Identifiers for other resources. 0 if non existent. There is always an RLST.
	_view.rlst = viewStream->readUint16LE();
	if (!_view.rlst)
		error("RLST Index missing");

	_view.hint = viewStream->readUint16LE();
	_view.init = viewStream->readUint16LE();
	_view.exit = viewStream->readUint16LE();

	delete viewStream;

	// Precache Card Resources
	uint32 cacheImageType;
	if (getFeatures() & GF_ME)
		cacheImageType = ID_PICT;
	else
		cacheImageType = ID_WDIB;

	// Precache Image Block data
	if (_view.conditionalImages.size() != 0) {
		for (uint16 i = 0; i < _view.conditionalImages.size(); i++) {
			uint16 value = _scriptParser->getVar(_view.conditionalImages[i].var);
			cachePreload(cacheImageType, _view.conditionalImages[i].values[value]);
		}
	} else {
		cachePreload(cacheImageType, _view.mainImage);
	}

	// Precache Sound Block data
	if (_view.soundBlock.sound > 0)
		cachePreload(ID_MSND, _view.soundBlock.sound);
	else if (_view.soundBlock.sound == kMystSoundActionConditional) {
		uint16 value = _scriptParser->getVar(_view.soundBlock.soundVar);
		if (_view.soundBlock.soundList[value].action > 0) {
			cachePreload(ID_MSND, _view.soundBlock.soundList[value].action);
		}
	}

	// Precache Script Resources
	for (uint16 i = 0; i < _view.scriptResources.size(); i++) {
		MystView::ScriptResourceType type;
		int16 id;
		if (_view.scriptResources[i].type == MystView::kResourceSwitch) {
			type = _view.scriptResources[i].switchResourceType;
			uint16 value = _scriptParser->getVar(_view.scriptResources[i].switchVar);
			id = _view.scriptResources[i].switchResourceIds[value];
		} else {
			type = _view.scriptResources[i].type;
			id = _view.scriptResources[i].id;
		}

		if (id < 0) continue;

		switch (type) {
		case MystView::kResourceImage:
			cachePreload(cacheImageType, id);
			break;
		case MystView::kResourceSound:
			cachePreload(ID_MSND, id);
			break;
		default:
			// The other resource types should not be cached
			break;
		}
	}
}

void MohawkEngine_Myst::unloadCard() {
	_view.conditionalImages.clear();
	_view.soundBlock.soundList.clear();
	_view.scriptResources.clear();
}

void MohawkEngine_Myst::runInitScript() {
	if (!_view.init) {
		debugC(kDebugINIT, "No INIT Present");
		return;
	}

	debugC(kDebugINIT, "Running INIT script");

	Common::SeekableReadStream *initStream = getResource(ID_INIT, _view.init);
	MystScript script = _scriptParser->readScript(initStream, kMystScriptInit);
	delete initStream;

	_scriptParser->runScript(script);
}

void MohawkEngine_Myst::runExitScript() {
	if (!_view.exit) {
		debugC(kDebugEXIT, "No EXIT Present");
		return;
	}

	debugC(kDebugEXIT, "Running EXIT script");

	Common::SeekableReadStream *exitStream = getResource(ID_EXIT, _view.exit);
	MystScript script = _scriptParser->readScript(exitStream, kMystScriptExit);
	delete exitStream;

	_scriptParser->runScript(script);
}

void MohawkEngine_Myst::loadHelp(uint16 id) {
	// The original version did not have the help system
	if (!(getFeatures() & GF_ME))
		return;

	// TODO: Help File contains 5 cards i.e. VIEW, RLST, etc.
	//       in addition to HELP resources.
	//       These are Ids 9930 to 9934
	//       Need to deal with loading and displaying these..
	//       Current engine structure only supports display of
	//       card from primary stack MHK

	debugC(kDebugHelp, "Loading Help System Data");

	Common::SeekableReadStream *helpStream = getResource(ID_HELP, id);

	uint16 count = helpStream->readUint16LE();
	uint16 *u0 = new uint16[count];
	Common::String helpText;

	debugC(kDebugHelp, "\tcount: %d", count);

	for (uint16 i = 0; i < count; i++) {
		u0[i] = helpStream->readUint16LE();
		debugC(kDebugHelp, "\tu0[%d]: %d", i, u0[i]);
	}

	// TODO: Previous values i.e. u0[0] to u0[count - 2]
	// appear to be resource ids in the help.dat file..
	if (u0[count - 1] != count)
		warning("loadHelp(): last u0 value is not equal to count");

	do {
		helpText += helpStream->readByte();
	} while (helpText.lastChar() != 0);
	helpText.deleteLastChar();

	debugC(kDebugHelp, "\thelpText: \"%s\"", helpText.c_str());

	delete[] u0;

	delete helpStream;
}

void MohawkEngine_Myst::loadCursorHints() {
	_cursorHints.clear();

	if (!_view.hint) {
		debugC(kDebugHint, "No HINT Present");
		return;
	}

	debugC(kDebugHint, "Loading Cursor Hints:");

	Common::SeekableReadStream *hintStream = getResource(ID_HINT, _curCard);
	uint16 cursorHintCount = hintStream->readUint16LE();
	debugC(kDebugHint, "Cursor Hint Count: %d", cursorHintCount);

	for (uint16 i = 0; i < cursorHintCount; i++) {
		MystCursorHint hint;

		debugC(kDebugHint, "Cursor Hint %d:", i);
		hint.id = hintStream->readUint16LE();
		debugC(kDebugHint, "\tId: %d", hint.id);
		hint.cursor = hintStream->readSint16LE();
		debugC(kDebugHint, "\tCursor: %d", hint.cursor);

		if (hint.cursor == -1) {
			debugC(kDebugHint, "\tConditional Cursor Hints:");
			hint.variableHint.var = hintStream->readUint16LE();
			debugC(kDebugHint, "\tVar: %d", hint.variableHint.var);
			uint16 numStates = hintStream->readUint16LE();
			debugC(kDebugHint, "\tNumber of States: %d", numStates);
			for (uint16 j = 0; j < numStates; j++) {
				hint.variableHint.values.push_back(hintStream->readUint16LE());
				debugC(kDebugHint, "\t\t State %d: Cursor %d", j, hint.variableHint.values[j]);
			}
		} else {
			hint.variableHint.var = 0;
		}

		_cursorHints.push_back(hint);
	}

	delete hintStream;
}

void MohawkEngine_Myst::setMainCursor(uint16 cursor) {
	_currentCursor = _mainCursor = cursor;
	_cursor->setCursor(_currentCursor);
}

void MohawkEngine_Myst::checkCursorHints() {
	if (!_view.hint) {
		// Default to the main cursor when no hints are present
		if (_currentCursor != _mainCursor) {
			_currentCursor = _mainCursor;
			_cursor->setCursor(_currentCursor);
		}
		return;
	}

	// Check all the cursor hints to see if we're in a hotspot that contains a hint.
	for (uint16 i = 0; i < _cursorHints.size(); i++)
		if (_cursorHints[i].id == _curResource && _resources[_cursorHints[i].id]->isEnabled()) {
			if (_cursorHints[i].cursor == -1) {
				uint16 var_value = _scriptParser->getVar(_cursorHints[i].variableHint.var);

				if (var_value >= _cursorHints[i].variableHint.values.size())
					warning("Variable %d Out of Range in variable HINT Resource %d", _cursorHints[i].variableHint.var, i);
				else {
					_currentCursor = _cursorHints[i].variableHint.values[var_value];
					if (_currentCursor == 0)
						_currentCursor = _mainCursor;
					_cursor->setCursor(_currentCursor);
				}
			} else if (_currentCursor != _cursorHints[i].cursor) {
				if (_cursorHints[i].cursor == 0)
					_currentCursor = _mainCursor;
				else
					_currentCursor = _cursorHints[i].cursor;

				_cursor->setCursor(_currentCursor);
			}
			return;
		}

	if (_currentCursor != _mainCursor) {
		_currentCursor = _mainCursor;
		_cursor->setCursor(_currentCursor);
	}
}

void MohawkEngine_Myst::setResourceEnabled(uint16 resourceId, bool enable) {
	if (resourceId < _resources.size()) {
		_resources[resourceId]->setEnabled(enable);
	} else
		warning("Attempt to change unknown resource enable state");
}

void MohawkEngine_Myst::drawResourceImages() {
	for (uint16 i = 0; i < _resources.size(); i++)
		if (_resources[i]->isDrawSubimages())
			_resources[i]->drawDataToScreen();
}

void MohawkEngine_Myst::redrawResource(MystAreaImageSwitch *resource, bool update) {
	resource->drawConditionalDataToScreen(_scriptParser->getVar(resource->getImageSwitchVar()), update);
}

void MohawkEngine_Myst::redrawArea(uint16 var, bool update) {
	for (uint16 i = 0; i < _resources.size(); i++)
		if (_resources[i]->type == kMystAreaImageSwitch && _resources[i]->getImageSwitchVar() == var)
			redrawResource(static_cast<MystAreaImageSwitch *>(_resources[i]), update);
}

MystArea *MohawkEngine_Myst::loadResource(Common::SeekableReadStream *rlstStream, MystArea *parent) {
	MystArea *resource = nullptr;
	ResourceType type = static_cast<ResourceType>(rlstStream->readUint16LE());

	debugC(kDebugResource, "\tType: %d", type);
	debugC(kDebugResource, "\tSub_Record: %d", (parent == nullptr) ? 0 : 1);

	switch (type) {
	case kMystAreaAction:
		resource =  new MystAreaAction(this, rlstStream, parent);
		break;
	case kMystAreaVideo:
		resource =  new MystAreaVideo(this, rlstStream, parent);
		break;
	case kMystAreaActionSwitch:
		resource =  new MystAreaActionSwitch(this, rlstStream, parent);
		break;
	case kMystAreaImageSwitch:
		resource =  new MystAreaImageSwitch(this, rlstStream, parent);
		break;
	case kMystAreaSlider:
		resource =  new MystAreaSlider(this, rlstStream, parent);
		break;
	case kMystAreaDrag:
		resource =  new MystAreaDrag(this, rlstStream, parent);
		break;
	case kMystVideoInfo:
		resource =  new MystVideoInfo(this, rlstStream, parent);
		break;
	case kMystAreaHover:
		resource =  new MystAreaHover(this, rlstStream, parent);
		break;
	default:
		resource = new MystArea(this, rlstStream, parent);
		break;
	}

	resource->type = type;

	return resource;
}

void MohawkEngine_Myst::loadResources() {
	for (uint32 i = 0; i < _resources.size(); i++)
		delete _resources[i];

	_resources.clear();

	if (!_view.rlst) {
		debugC(kDebugResource, "No RLST present");
		return;
	}

	Common::SeekableReadStream *rlstStream = getResource(ID_RLST, _view.rlst);
	uint16 resourceCount = rlstStream->readUint16LE();
	debugC(kDebugResource, "RLST Resource Count: %d", resourceCount);

	for (uint16 i = 0; i < resourceCount; i++) {
		debugC(kDebugResource, "Resource #%d:", i);
		_resources.push_back(loadResource(rlstStream, nullptr));
	}

	delete rlstStream;
}

Common::Error MohawkEngine_Myst::loadGameState(int slot) {
	if (_gameState->load(slot))
		return Common::kNoError;

	return Common::kUnknownError;
}

Common::Error MohawkEngine_Myst::saveGameState(int slot, const Common::String &desc) {
	return _gameState->save(slot, desc) ? Common::kNoError : Common::kUnknownError;
}

bool MohawkEngine_Myst::hasGameSaveSupport() const {
	return !(getFeatures() & GF_DEMO) && getGameType() != GType_MAKINGOF;
}

bool MohawkEngine_Myst::canLoadGameStateCurrently() {
	// No loading in the demo/makingof
	return _canSafelySaveLoad && hasGameSaveSupport();
}

bool MohawkEngine_Myst::canSaveGameStateCurrently() {
	if (!_canSafelySaveLoad) {
		return false;
	}

	// There's a limited number of stacks the game can save in
	switch (_curStack) {
	case kChannelwoodStack:
	case kDniStack:
	case kMechanicalStack:
	case kMystStack:
	case kSeleniticStack:
	case kStoneshipStack:
		return true;
	}

	return false;
}

void MohawkEngine_Myst::dropPage() {
	uint16 page = _gameState->_globals.heldPage;
	bool whitePage = page == 13;
	bool bluePage = page - 1 < 6;
	bool redPage = page - 7 < 6;

	// Play drop page sound
	_sound->replaceSoundMyst(800);

	// Drop page
	_gameState->_globals.heldPage = 0;

	// Redraw page area
	if (whitePage && _gameState->_globals.currentAge == 2) {
		redrawArea(41);
	} else if (bluePage) {
		if (page == 6) {
			if (_gameState->_globals.currentAge == 2)
				redrawArea(24);
		} else {
			redrawArea(103);
		}
	} else if (redPage) {
		if (page == 12) {
			if (_gameState->_globals.currentAge == 2)
				redrawArea(25);
		} else if (page == 10) {
			if (_gameState->_globals.currentAge == 1)
				redrawArea(35);
		} else {
			redrawArea(102);
		}
	}

	setMainCursor(kDefaultMystCursor);
	checkCursorHints();
}

MystSoundBlock MohawkEngine_Myst::readSoundBlock(Common::ReadStream *stream) const {
	MystSoundBlock soundBlock;
	soundBlock.sound = stream->readSint16LE();
	debugCN(kDebugView, "Sound Control: %d = ", soundBlock.sound);

	if (soundBlock.sound > 0) {
		debugC(kDebugView, "Play new Sound, change volume");
		debugC(kDebugView, "\tSound: %d", soundBlock.sound);
		soundBlock.soundVolume = stream->readUint16LE();
		debugC(kDebugView, "\tVolume: %d", soundBlock.soundVolume);
	} else if (soundBlock.sound == kMystSoundActionContinue)
		debugC(kDebugView, "Continue current sound");
	else if (soundBlock.sound == kMystSoundActionChangeVolume) {
		debugC(kDebugView, "Continue current sound, change volume");
		soundBlock.soundVolume = stream->readUint16LE();
		debugC(kDebugView, "\tVolume: %d", soundBlock.soundVolume);
	} else if (soundBlock.sound == kMystSoundActionStop) {
		debugC(kDebugView, "Stop sound");
	} else if (soundBlock.sound == kMystSoundActionConditional) {
		debugC(kDebugView, "Conditional sound list");
		soundBlock.soundVar = stream->readUint16LE();
		debugC(kDebugView, "\tVar: %d", soundBlock.soundVar);
		uint16 soundCount = stream->readUint16LE();
		debugC(kDebugView, "\tCount: %d", soundCount);

		for (uint16 i = 0; i < soundCount; i++) {
			MystSoundBlock::SoundItem sound;

			sound.action = stream->readSint16LE();
			debugC(kDebugView, "\t\tCondition %d: Action %d", i, sound.action);
			if (sound.action == kMystSoundActionChangeVolume || sound.action >= 0) {
				sound.volume = stream->readUint16LE();
				debugC(kDebugView, "\t\tCondition %d: Volume %d", i, sound.volume);
			}

			soundBlock.soundList.push_back(sound);
		}
	} else {
		debugC(kDebugView, "Unknown");
		warning("Unknown sound control value '%d' in card '%d'", soundBlock.sound, _curCard);
	}

	return soundBlock;
}

void MohawkEngine_Myst::applySoundBlock(const MystSoundBlock &block) {
	int16 soundAction = 0;
	uint16 soundActionVolume = 0;

	if (block.sound == kMystSoundActionConditional) {
		uint16 soundVarValue = _scriptParser->getVar(block.soundVar);
		if (soundVarValue >= block.soundList.size())
			warning("Conditional sound variable outside range");
		else {
			soundAction = block.soundList[soundVarValue].action;
			soundActionVolume = block.soundList[soundVarValue].volume;
		}
	} else {
		soundAction = block.sound;
		soundActionVolume = block.soundVolume;
	}

	if (soundAction == kMystSoundActionContinue)
		debug(2, "Continuing with current sound");
	else if (soundAction == kMystSoundActionChangeVolume) {
		debug(2, "Continuing with current sound, changing volume");
		_sound->changeBackgroundVolumeMyst(soundActionVolume);
	} else if (soundAction == kMystSoundActionStop) {
		debug(2, "Stopping sound");
		_sound->stopBackgroundMyst();
	} else if (soundAction > 0) {
		debug(2, "Playing new sound %d", soundAction);
		_sound->replaceBackgroundMyst(soundAction, soundActionVolume);
	} else {
		error("Unknown sound action %d", soundAction);
	}
}

} // End of namespace Mohawk