simplepad.hh

/*

MIT License

Copyright (c) 2022 PCSX-Redux authors

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
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furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

*/

#pragma once

#include <EASTL/functional.h>
#include <stdint.h>

namespace psyqo {

/**
 * @brief A simple class to access the pads.
 *
 * @details This class is meant to be used as a singleton, probably in
 * the `Application` derived class. It is a simple thunk to the BIOS'
 * PAD interface, and has the same caveats, namely that it should be
 * initialized prior using the BIOS' memory card functions, and that
 * polling will alternate between the two pads at each frame when two
 * pads are connected, which can introduce input lags. This class
 * will not be able to be used if the kernel is taken over. See the
 * `Kernel` namespace for more information.
 */

class SimplePad {
  public:
    enum Pad { Pad1, Pad2 };

    enum Button {
        Select = 0,
        L3 = 1,
        R3 = 2,
        Start = 3,
        Up = 4,
        Right = 5,
        Down = 6,
        Left = 7,
        L2 = 8,
        R2 = 9,
        L1 = 10,
        R1 = 11,
        Triangle = 12,
        Circle = 13,
        Cross = 14,
        Square = 15,
    };

    struct Event {
        enum { PadConnected, PadDisconnected, ButtonPressed, ButtonReleased } type;
        Pad pad;
        Button button;
    };

    /**
     * @brief Initializes the pads.
     *
     * @details This will initialize the pads polling by calling the BIOS'
     * interface. This means this method cannot be called from the `prepare`
     * method of the `Application` class, but rather from the `start` method
     * of the root `Scene` object. Also, there can be interference with
     * the BIOS' memory card functions, so this method is explicit to be
     * called in the right order.
     */
    void initialize();

    /**
     * @brief Sets the event callback function.
     *
     * @details The event callback will be called for each pad-related event,
     * such as pad connection / disconnection, or button press / release.
     * The callback will only be called between frames.
     *
     * Scenes that are calling `setOnEvent` during their `start` method should
     * call `setOnEvent` again in their `teardown` method with the `nullptr`
     * value in order to unregister the event callback cleanly.
     *
     * Only one callback can be registered at a time, so setting a new
     * callback will simply remove the previous one.
     *
     * Careful about what is called from the callback: pushing or popping scenes
     * might call into `setOnEvent` as a result, and could end up corrupting
     * memory as a result of the callback being deleted while being executed.
     */
    void setOnEvent(eastl::function<void(Event)>&& callback) { m_callback = eastl::move(callback); }

    /**
     * @brief Returns the state of a pad.
     *
     * @details Returns the state of a pad. The state is a boolean value
     * that is `true` if the pad is connected, and `false` otherwise.
     *
     * @param pad The pad to query.
     * @return A boolean value indicating whether the pad is connected.
     */
    bool isPadConnected(Pad pad) const { return (m_padData[pad][0] & 0xff) == 0; }

    /**
     * @brief Returns the state of a button.
     *
     * @details Returns the state of a button. The state is a boolean value
     * that is `true` if the button is pressed, and `false` otherwise.
     *
     * @param pad The pad to query.
     * @param button The button to query.
     * @return A boolean value indicating whether the button is pressed.
     */
    bool isButtonPressed(Pad pad, Button button) const { return (m_padData[pad][1] & (1 << button)) == 0; }

  private:
    void processChanges(Pad pad);

    uint16_t m_padData[2][0x11];
    eastl::function<void(Event)> m_callback;
    bool m_connected[2] = {false, false};
    uint16_t m_buttons[2] = {0xffff, 0xffff};
};

}  // namespace psyqo