scummvm/common/events.h

/* 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.
 *
 * $URL$
 * $Id$
 *
 */

#ifndef COMMON_EVENTS_H
#define COMMON_EVENTS_H

#include "common/rect.h"
#include "common/system.h"
#include "common/noncopyable.h"

namespace Common {

/**
 * The types of events backends may generate.
 * @see Event
 *
 * @todo Merge EVENT_LBUTTONDOWN, EVENT_RBUTTONDOWN and EVENT_WHEELDOWN;
 *       likewise EVENT_LBUTTONUP, EVENT_RBUTTONUP, EVENT_WHEELUP.
 *       To do that, we just have to add a field to the Event which
 *       indicates which button was pressed.
 */
enum EventType {
	/** A key was pressed, details in Event::kbd. */
	EVENT_KEYDOWN = 1,
	/** A key was released, details in Event::kbd. */
	EVENT_KEYUP = 2,
	/** The mouse moved, details in Event::mouse. */
	EVENT_MOUSEMOVE = 3,
	EVENT_LBUTTONDOWN = 4,
	EVENT_LBUTTONUP = 5,
	EVENT_RBUTTONDOWN = 6,
	EVENT_RBUTTONUP = 7,
	EVENT_WHEELUP = 8,
	EVENT_WHEELDOWN = 9,

	EVENT_QUIT = 10,
	EVENT_SCREEN_CHANGED = 11,
	/**
	 * The backend requests the agi engine's predictive dialog to be shown.
	 * TODO: Fingolfin suggests that it would be of better value to expand
	 * on this notion by generalizing its use. For example the backend could
	 * use events to ask for the save game dialog or to pause the engine.
	 * An associated enumerated type can accomplish this.
	 **/
	EVENT_PREDICTIVE_DIALOG = 12
};

enum KeyCode {
	KEYCODE_INVALID     = 0,

	KEYCODE_BACKSPACE   = 8,
	KEYCODE_TAB         = 9,
	KEYCODE_CLEAR       = 12,
	KEYCODE_RETURN      = 13,
	KEYCODE_PAUSE       = 19,
	KEYCODE_ESCAPE      = 27,
	KEYCODE_SPACE       = 32,
	KEYCODE_EXCLAIM     = 33,
	KEYCODE_QUOTEDBL    = 34,
	KEYCODE_HASH        = 35,
	KEYCODE_DOLLAR      = 36,
	KEYCODE_AMPERSAND   = 38,
	KEYCODE_QUOTE       = 39,
	KEYCODE_LEFTPAREN   = 40,
	KEYCODE_RIGHTPAREN  = 41,
	KEYCODE_ASTERISK    = 42,
	KEYCODE_PLUS        = 43,
	KEYCODE_COMMA       = 44,
	KEYCODE_MINUS       = 45,
	KEYCODE_PERIOD      = 46,
	KEYCODE_SLASH       = 47,
	KEYCODE_0           = 48,
	KEYCODE_1           = 49,
	KEYCODE_2           = 50,
	KEYCODE_3           = 51,
	KEYCODE_4           = 52,
	KEYCODE_5           = 53,
	KEYCODE_6           = 54,
	KEYCODE_7           = 55,
	KEYCODE_8           = 56,
	KEYCODE_9           = 57,
	KEYCODE_COLON       = 58,
	KEYCODE_SEMICOLON   = 59,
	KEYCODE_LESS        = 60,
	KEYCODE_EQUALS      = 61,
	KEYCODE_GREATER     = 62,
	KEYCODE_QUESTION    = 63,
	KEYCODE_AT          = 64,

	KEYCODE_LEFTBRACKET = 91,
	KEYCODE_BACKSLASH   = 92,
	KEYCODE_RIGHTBRACKET= 93,
	KEYCODE_CARET       = 94,
	KEYCODE_UNDERSCORE  = 95,
	KEYCODE_BACKQUOTE   = 96,
	KEYCODE_a           = 97,
	KEYCODE_b           = 98,
	KEYCODE_c           = 99,
	KEYCODE_d           = 100,
	KEYCODE_e           = 101,
	KEYCODE_f           = 102,
	KEYCODE_g           = 103,
	KEYCODE_h           = 104,
	KEYCODE_i           = 105,
	KEYCODE_j           = 106,
	KEYCODE_k           = 107,
	KEYCODE_l           = 108,
	KEYCODE_m           = 109,
	KEYCODE_n           = 110,
	KEYCODE_o           = 111,
	KEYCODE_p           = 112,
	KEYCODE_q           = 113,
	KEYCODE_r           = 114,
	KEYCODE_s           = 115,
	KEYCODE_t           = 116,
	KEYCODE_u           = 117,
	KEYCODE_v           = 118,
	KEYCODE_w           = 119,
	KEYCODE_x           = 120,
	KEYCODE_y           = 121,
	KEYCODE_z           = 122,
	KEYCODE_DELETE      = 127,

	// Numeric keypad
	KEYCODE_KP0         = 256,
	KEYCODE_KP1         = 257,
	KEYCODE_KP2         = 258,
	KEYCODE_KP3         = 259,
	KEYCODE_KP4         = 260,
	KEYCODE_KP5         = 261,
	KEYCODE_KP6         = 262,
	KEYCODE_KP7         = 263,
	KEYCODE_KP8         = 264,
	KEYCODE_KP9         = 265,
	KEYCODE_KP_PERIOD   = 266,
	KEYCODE_KP_DIVIDE   = 267,
	KEYCODE_KP_MULTIPLY = 268,
	KEYCODE_KP_MINUS    = 269,
	KEYCODE_KP_PLUS     = 270,
	KEYCODE_KP_ENTER    = 271,
	KEYCODE_KP_EQUALS   = 272,

	// Arrows + Home/End pad
	KEYCODE_UP          = 273,
	KEYCODE_DOWN        = 274,
	KEYCODE_RIGHT       = 275,
	KEYCODE_LEFT        = 276,
	KEYCODE_INSERT      = 277,
	KEYCODE_HOME        = 278,
	KEYCODE_END         = 279,
	KEYCODE_PAGEUP      = 280,
	KEYCODE_PAGEDOWN    = 281,

	// Function keys
	KEYCODE_F1          = 282,
	KEYCODE_F2          = 283,
	KEYCODE_F3          = 284,
	KEYCODE_F4          = 285,
	KEYCODE_F5          = 286,
	KEYCODE_F6          = 287,
	KEYCODE_F7          = 288,
	KEYCODE_F8          = 289,
	KEYCODE_F9          = 290,
	KEYCODE_F10         = 291,
	KEYCODE_F11         = 292,
	KEYCODE_F12         = 293,
	KEYCODE_F13         = 294,
	KEYCODE_F14         = 295,
	KEYCODE_F15         = 296,

	// Key state modifier keys
	KEYCODE_NUMLOCK     = 300,
	KEYCODE_CAPSLOCK    = 301,
	KEYCODE_SCROLLOCK   = 302,
	KEYCODE_RSHIFT      = 303,
	KEYCODE_LSHIFT      = 304,
	KEYCODE_RCTRL       = 305,
	KEYCODE_LCTRL       = 306,
	KEYCODE_RALT        = 307,
	KEYCODE_LALT        = 308,
	KEYCODE_RMETA       = 309,
	KEYCODE_LMETA       = 310,
	KEYCODE_LSUPER      = 311,      // Left "Windows" key
	KEYCODE_RSUPER      = 312,      // Right "Windows" key
	KEYCODE_MODE        = 313,      // "Alt Gr" key
	KEYCODE_COMPOSE     = 314,      // Multi-key compose key

	// Miscellaneous function keys 
	KEYCODE_HELP        = 315,
	KEYCODE_PRINT       = 316,
	KEYCODE_SYSREQ      = 317,
	KEYCODE_BREAK       = 318,
	KEYCODE_MENU        = 319,
	KEYCODE_POWER       = 320,      // Power Macintosh power key
	KEYCODE_EURO        = 321,      // Some european keyboards
	KEYCODE_UNDO        = 322       // Atari keyboard has Undo
};

/**
 * List of certan special and some fake 'ascii' values used in keyboard events.
 * The values for the function keys listed here are based on what certain SCUMM
 * games expect in their scripts.
 * @todo Get rid of the function key values, and instead enforce that engines use
 * the keycode value to handle these.
 */
enum {
	ASCII_BACKSPACE     = 8,
	ASCII_TAB           = 9,
	ASCII_RETURN        = 13,
	ASCII_ESCAPE        = 27,
	ASCII_SPACE         = 32,

	ASCII_F1            = 315,
	ASCII_F2            = 316,
	ASCII_F3            = 317,
	ASCII_F4            = 318,
	ASCII_F5            = 319,
	ASCII_F6            = 320,
	ASCII_F7            = 321,
	ASCII_F8            = 322,
	ASCII_F9            = 323,
	ASCII_F10           = 324,
	ASCII_F11           = 325,
	ASCII_F12           = 326
};

/**
 * Keyboard modifier flags, used for Event::kbd::flags.
 */
enum {
	KBD_CTRL  = 1 << 0,
	KBD_ALT   = 1 << 1,
	KBD_SHIFT = 1 << 2
};

/**
 * Keyboard status, as used in the Event struct.
 */
struct KeyState {
	/**
	 * Abstract key code (will be the same for any given key regardless
	 * of modifiers being held at the same time.
	 * For example, this is the same for both 'A' and Shift-'A'.
	 * @todo Document which values are to be used for non-ASCII keys
	 * like F1-F10. For now, let's just say that our primary backend
	 * is the SDL one, and it uses the values SDL uses... so until
	 * we fix this, your best bet is to get a copy of SDL_keysym.h
	 * and look at that, if you want to find out a key code.
	 */
	KeyCode keycode;
	/**
	 * ASCII-value of the pressed key (if any).
	 * This depends on modifiers, i.e. pressing the 'A' key results in
	 * different values here depending on the status of shift, alt and
	 * caps lock.
	 */
	uint16 ascii;
	/**
	 * Status of the modifier keys. Bits are set in this for each
	 * pressed modifier
	 * @see KBD_CTRL, KBD_ALT, KBD_SHIFT
	 */
	byte flags;
	
	KeyState() { reset(); }
	void reset() {
		keycode = KEYCODE_INVALID;
		ascii = flags = 0;
	}
};

/**
 * Data structure for an event. A pointer to an instance of Event
 * can be passed to pollEvent.
 * @todo Rework/document this structure. It should be made 100% clear which
 *       field is valid for which event type.
 *       Implementation wise, we might want to use the classic
 *       union-of-structs trick. It goes roughly like this:
 *       struct BasicEvent {
 *       	EventType type;
 *       };
 *       struct MouseMovedEvent : BasicEvent {
 *       	Common::Point pos;
 *       };
 *       struct MouseButtonEvent : MouseMovedEvent {
 *       	int button;
 *       };
 *       struct KeyEvent : BasicEvent {
 *       	...
 *       };
 *       ...
 *       union Event {
 *          EventType type;
 *       	MouseMovedEvent mouse;
 *       	MouseButtonEvent button;
 *       	KeyEvent key;
 *       	...
 *       };
 */
struct Event {
	/** The type of the event. */
	EventType type;
	/** Flag to indicate if the event is real or synthetic. E.g. keyboard
	  * repeat events are synthetic.
	  */
	bool synthetic;
	/**
	  * Keyboard data; only valid for keyboard events (EVENT_KEYDOWN and
	  * EVENT_KEYUP). For all other event types, content is undefined.
	  */
	KeyState kbd;
	/**
	 * The mouse coordinates, in virtual screen coordinates. Only valid
	 * for mouse events.
	 * Virtual screen coordinates means: the coordinate system of the
	 * screen area as defined by the most recent call to initSize().
	 */
	Common::Point mouse;
};


/**
 * The EventManager provides user input events to the client code.
 * In addition, it keeps track of the state of various input devices,
 * like keys, mouse position and buttons.
 */
class EventManager : NonCopyable {
public:
	EventManager() {}
	virtual ~EventManager() {}
	
	enum {
		LBUTTON = 1 << 0,
		RBUTTON = 1 << 1
	};

	/**
	 * Get the next event in the event queue.
	 * @param event	point to an Event struct, which will be filled with the event data.
	 * @return true if an event was retrieved.
	 */
	virtual bool pollEvent(Common::Event &event) = 0;


	/** Return the current key state */
	virtual Common::Point getMousePos() const = 0;
	
	/**
	 * Return a bitmask with the button states:
	 * - bit 0: left button up=1, down=0
	 * - bit 1: right button up=1, down=0
	 */
	virtual int getButtonState() const = 0;
	
	/** Get a bitmask with the current modifier state */
	virtual int getModifierState() const = 0;

	/**
	 * Should the application terminate? Set to true if we
	 * received an EVENT_QUIT.
	 */
	virtual int shouldQuit() const = 0;
	
	// Optional: check whether a given key is currently pressed ????
	//virtual bool isKeyPressed(int keycode) = 0;

	// TODO: Keyboard repeat support?
	
	// TODO: Consider removing OSystem::getScreenChangeID and
	// replacing it by a generic getScreenChangeID method here
};

} // End of namespace Common

#endif