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◆ main openmsx / src / input / ArkanoidPad.cc
4.5 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
e8555c89 Andy McCall 1 
#include "ArkanoidPad.hh"
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#include "Event.hh"
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#include "MSXEventDistributor.hh"
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#include "StateChange.hh"
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#include "StateChangeDistributor.hh"
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#include "serialize.hh"
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#include "serialize_meta.hh"
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#include <algorithm>
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// Implemented mostly according to the info here: http://www.msx.org/forumtopic7661.html
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// This is absolutely not accurate, but good enough to make the pad work in the
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// Arkanoid games.
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// The hardware works with a 556 dual timer that's unemulated here, it requires
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// short delays at each shift, and a long delay at latching. Too short delays
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// will cause garbage reads, and too long delays at shifting will eventually
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// cause the shift register bits to return to 0.
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namespace openmsx {
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static constexpr int POS_MIN = 55; // measured by hap
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static constexpr int POS_MAX = 325; // measured by hap
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static constexpr int POS_CENTER = 236; // approx. middle used by games
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static constexpr int SCALE = 2;
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ArkanoidPad::ArkanoidPad(MSXEventDistributor& eventDistributor_,
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                         StateChangeDistributor& stateChangeDistributor_)
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	: eventDistributor(eventDistributor_)
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	, stateChangeDistributor(stateChangeDistributor_)
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	, dialPos(POS_CENTER)
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{
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}
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ArkanoidPad::~ArkanoidPad()
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{
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	if (isPluggedIn()) {
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		ArkanoidPad::unplugHelper(EmuTime::dummy());
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	}
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}
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// Pluggable
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zstring_view ArkanoidPad::getName() const
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{
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	return "arkanoidpad";
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}
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zstring_view ArkanoidPad::getDescription() const
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{
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	return "Arkanoid pad";
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}
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void ArkanoidPad::plugHelper(Connector& /*connector*/, EmuTime /*time*/)
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{
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	eventDistributor.registerEventListener(*this);
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	stateChangeDistributor.registerListener(*this);
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}
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void ArkanoidPad::unplugHelper(EmuTime /*time*/)
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{
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	stateChangeDistributor.unregisterListener(*this);
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	eventDistributor.unregisterEventListener(*this);
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}
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// JoystickDevice
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uint8_t ArkanoidPad::read(EmuTime /*time*/)
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{
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	return buttonStatus | ((shiftReg & 0x100) >> 8);
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}
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void ArkanoidPad::write(uint8_t value, EmuTime /*time*/)
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{
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	uint8_t diff = lastValue ^ value;
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	lastValue = value;
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	if (diff & value & 0x4) {
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		// pin 8 from low to high: copy dial position into shift reg
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		shiftReg = dialPos;
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	}
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	if (diff & value & 0x1) {
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		// pin 6 from low to high: shift the shift reg
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		shiftReg = (shiftReg << 1) | (shiftReg & 1); // bit 0's value is 'shifted in'
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	}
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}
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// MSXEventListener
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void ArkanoidPad::signalMSXEvent(const Event& event,
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                                 EmuTime time) noexcept
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{
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	visit(overloaded{
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		[&](const MouseMotionEvent& e) {
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			int newPos = std::min(POS_MAX,
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					std::max(POS_MIN,
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						dialPos + e.getX() / SCALE));
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			int delta = newPos - dialPos;
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			if (delta != 0) {
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				stateChangeDistributor.distributeNew<ArkanoidState>(
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					time, delta, false, false);
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			}
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		},
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		[&](const MouseButtonDownEvent& /*e*/) {
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			// any button will press the Arkanoid Pad button
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			if (buttonStatus & 2) {
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				stateChangeDistributor.distributeNew<ArkanoidState>(
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					time, 0, true, false);
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			}
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		},
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		[&](const MouseButtonUpEvent& /*e*/) {
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			// any button will unpress the Arkanoid Pad button
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			if (!(buttonStatus & 2)) {
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				stateChangeDistributor.distributeNew<ArkanoidState>(
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					time, 0, false, true);
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			}
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		},
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		[](const EventBase&) { /*ignore */}
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	}, event);
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}
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// StateChangeListener
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void ArkanoidPad::signalStateChange(const StateChange& event)
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{
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	const auto* as = std::get_if<ArkanoidState>(&event);
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	if (!as) return;
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	dialPos += as->getDelta();
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	if (as->getPress())   buttonStatus &= ~2;
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	if (as->getRelease()) buttonStatus |=  2;
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}
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void ArkanoidPad::stopReplay(EmuTime time) noexcept
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{
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	// TODO Get actual mouse button(s) state. Is it worth the trouble?
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	int delta = POS_CENTER - dialPos;
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	bool release = (buttonStatus & 2) == 0;
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	if ((delta != 0) || release) {
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		stateChangeDistributor.distributeNew<ArkanoidState>(
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			time, delta, false, release);
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	}
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}
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// version 1: Initial version, the variables dialPos and buttonStatus were not
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//            serialized.
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// version 2: Also serialize the above variables, this is required for
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//            record/replay, see comment in Keyboard.cc for more details.
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template<typename Archive>
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void ArkanoidPad::serialize(Archive& ar, unsigned version)
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{
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	ar.serialize("shiftreg",  shiftReg,
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	             "lastValue", lastValue);
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	if (ar.versionAtLeast(version, 2)) {
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		ar.serialize("dialpos",      dialPos,
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		             "buttonStatus", buttonStatus);
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	}
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	if constexpr (Archive::IS_LOADER) {
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		if (isPluggedIn()) {
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			plugHelper(*getConnector(), EmuTime::dummy());
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		}
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	}
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}
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INSTANTIATE_SERIALIZE_METHODS(ArkanoidPad);
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REGISTER_POLYMORPHIC_INITIALIZER(Pluggable, ArkanoidPad, "ArkanoidPad");
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} // namespace openmsx