crown-engine/engine/input/touch.h

/*
 * Copyright (c) 2012-2014 Daniele Bartolini and individual contributors.
 * License: https://github.com/taylor001/crown/blob/master/LICENSE
 */

#pragma once

#include "types.h"
#include "vector2.h"
#include <cstring> // mem*

namespace crown
{

/// Maximum number of pointers supported by Touch.
///
/// @ingroup Input
const uint32_t MAX_POINTER_IDS = 4;

/// Interface for accessing touch panel input device.
///
/// @ingroup Input
struct Touch
{
	Touch()
		: _last_pointer(0xFF)
	{
		memset(_last_state, 0, MAX_POINTER_IDS);
		memset(_current_state, 0, MAX_POINTER_IDS);
	}

	/// Returns whether the @a p pointer is pressed in the current frame.
	bool pointer_down(uint8_t p)
	{
		if (p >= MAX_POINTER_IDS) return false;
		return (~_last_state[p] & _current_state[p]) != 0;
	}

	/// Returns whether the @a p pointer is released in the current frame.
	bool pointer_up(uint8_t p)
	{
		if (p >= MAX_POINTER_IDS) return false;
		return (_last_state[p] & ~_current_state[p]) != 0;
	}

	/// Returns wheter any pointer is pressed in the current frame.
	bool any_down()
	{
		return pointer_down(_last_pointer);
	}

	/// Returns whether any pointer is released in the current frame.
	bool any_up()
	{
		return pointer_up(_last_pointer);
	}

	/// Returns the position of the pointer @a p in window space.
	/// @note
	/// Coordinates in window space have the origin at the
	/// upper-left corner of the window. +X extends from left
	/// to right and +Y extends from top to bottom.
	Vector2 pointer_xy(uint8_t p)
	{
		if (p >= MAX_POINTER_IDS) return vector2::ZERO;
		return Vector2(_x[p], _y[p]);
	}

	void set_position(uint8_t p, uint16_t x, uint16_t y)
	{
		if (p >= MAX_POINTER_IDS) return;
		_x[p] = x;
		_y[p] = y;
	}

	void set_metrics(uint16_t width, uint16_t height)
	{
		_width = width;
		_height = height;
	}

	void set_pointer_state(uint16_t x, uint16_t y, uint8_t p, bool state)
	{
		set_position(p, x, y);

		_last_pointer = p;
		_current_state[p] = state;
	}

	void update()
	{
		memcpy(_last_state, _current_state, MAX_POINTER_IDS);
	}

public:

	uint8_t _last_pointer;
	uint8_t _last_state[MAX_POINTER_IDS];
	uint8_t _current_state[MAX_POINTER_IDS];

	uint16_t _x[MAX_POINTER_IDS];
	uint16_t _y[MAX_POINTER_IDS];

	// Window size
	uint16_t _width;
	uint16_t _height;
};

} // namespace crown