quakeforge/include/QF/input/binding.h

/*
	binding.h

	Input Mapping Table management

	Copyright (C) 2001 Zephaniah E. Hull <warp@babylon.d2dc.net>
	Copyright (C) 2021 Bill Currie <bill@taniwha.org>

	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:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

*/

#ifndef __QF_input_binding_h
#define __QF_input_binding_h

#ifndef __QFCC__

/*** Recipe for converting an axis to a floating point value.

	Recipes apply only to absolute axes.

	\a deadzone applies only to balanced axes, thus it doubles as a flag
	for balanced (>= 0) or unbalanced (< 0).

	\a curve is applied after the input has been converted
*/
typedef struct in_recipe_s {
	int         minzone;	///< Size of deadzone near axis minimum
	int         maxzone;	///< Size of deadzone near axis maximum
	int         deadzone;	///< Size of deadzone near axis center (balanced)
	float       curve;		///< Power factor for absolute axes
} in_recipe_t;

typedef enum {
	ina_set,		///< write the axis value to the destination
	ina_accumulate,	///< add the axis value to the destination
} in_axis_mode;

/*** Logical axis.

	Logical axes are the inputs defined by the game on which axis inputs
	(usually "physical" axes) can act. Depending on the mode, the physical
	axis value is either written as-is, or added to the existing value. It is
	the responsibility of the code using the axis to clear the value for
	accumulated inputs.
*/
typedef struct in_axis_s {
	float       value;		///< converted value of the axis
	in_axis_mode mode;		///< method used for updating the destination
} in_axis_t;

/*** Current state of the logical button.

	Captures the current state and any transitions during the last frame.
	Not all combinations are valid (inb_edge_up|inb_down and inb_edge_down
	(no inb_down) are not valid states), but inb_edge_up|inb_edge_down )with
	or without inb_down) is valid as it represents a double transition during
	the frame.
*/
typedef enum {
	inb_down      = 1<<0,	///< button is held
	inb_edge_down = 1<<1,	///< button pressed this frame
	inb_edge_up   = 1<<2,	///< button released this frame
} in_button_state;

/*** Logical button.

	Logical buttons are the inputs defined by the game on which button inputs
	(usually "physical" buttons) can act. Up to two button inputs can be
	bound to a logical button. The logical button acts as an or gate where
	either input will put the logical button in the pressed state, and both
	inputs must be inactive for the logical button to be released.
*/
typedef struct in_button_s {
	int         down[2];    ///< button ids holding this button down
	int         state;      ///< in_button_state
	const char *name;
	const char *description;
} in_button_t;

typedef struct in_axisbinding_s {
	in_recipe_t *recipe;
	in_axis_t   *axis;
} in_axisbinding_t;

typedef enum {
	inb_button,
	inb_command,
} in_button_type;

typedef struct in_buttonbinding_s {
	in_button_type type;
	union {
		struct {
			int         bind_id;	///< for button multi-press support
			in_button_t *button;
		};
		char       *command;
	};
} in_buttonbinding_t;

/*** Represent the button's activity in the last frame as a float.

	The detected activity is:
		steady off (up)
		steady on (down)
		off to on (up to down) transition
		on to off )down to up) transition
		pulse on (off-on-off or up-down-up)
		pulse off (on-off-on or down-up-down)
	Any additional transitions are treated as a pulse appropriate for the
	final state of the button.

	\param button	Pointer to the button being tested.
	\return			Float value between 0 (off/up) and 1 (on/down)
	\note			The edge transitions are cleared, so for each frame, this
					is a one-shot function (ie, it is NOT idempotent).
*/
GNU89INLINE inline float IN_ButtonState (in_button_t *button);

/*** Test whether a button has been pressed in the last frame.

	Both steady-state on, and brief clicks are detected.

	\return			True if the button is currently held or was pulsed on
					in the last frame.
	\note			The edge transitions are cleared, so for each frame, this
					is a one-shot function (ie, it is NOT idempotent).
*/
GNU89INLINE inline int IN_ButtonPressed (in_button_t *button);

/*** Test whether a button was released in the last frame.

	Valid only if the button is still released. A pulsed off does not
	count as being released as the button is still held.

	\return			True if the button is currently released and the release
					was in the last frame.
	\note			The edge transitions are cleared, so for each frame, this
					is a one-shot function (ie, it is NOT idempotent).
*/
GNU89INLINE inline int IN_ButtonReleased (in_button_t *button);

#ifndef IMPLEMENT_INPUT_Funcs
GNU89INLINE inline
#else
VISIBLE
#endif
float
IN_ButtonState (in_button_t *button)
{
	static const float state_values[8] = {
		// held down for the entire frame
		[inb_down] = 1,
		// released this frame
		[inb_edge_up] = 0,	// instant falloff
		// pressed this frame
		[inb_edge_down|inb_down] = 0.5,
		// pressed and released this frame
		[inb_edge_down|inb_edge_up] = 0.25,
		// released and pressed this frame
		[inb_edge_down|inb_edge_up|inb_down] = 0.75,
	};
	int         state = button->state;
	button->state &= inb_down;	// clear edges, preserve pressed
	return state_values[state & (inb_down|inb_edge_down|inb_edge_up)];
}

#ifndef IMPLEMENT_INPUT_Funcs
GNU89INLINE inline
#else
VISIBLE
#endif
int
IN_ButtonPressed (in_button_t *button)
{
	int         state = button->state;
	button->state &= inb_down;	// clear edges, preserve pressed
	// catch even press and release that occurs between frames
	return (state & (inb_down | inb_edge_down)) != 0;
}

#ifndef IMPLEMENT_INPUT_Funcs
GNU89INLINE inline
#else
VISIBLE
#endif
int
IN_ButtonReleased (in_button_t *button)
{
	int         state = button->state;
	button->state &= inb_down;	// clear edges, preserve pressed
	// catch only full release (a pulsed on does count as a release)
	return (state & (inb_down | inb_edge_up)) == inb_edge_up;
}

void IN_ButtonAction (in_button_t *buttin, int id, int pressed);

int IN_RegisterButton (in_button_t *button);
int IN_RegisterAxis (in_axis_t *axis, const char *name,
					 const char *description);
in_button_t *IN_FindButton (const char *name);

#endif

#endif//__QF_input_binding_h