portapack-mayhem/firmware/application/touch.hpp

239 lines
5.0 KiB
C++

/*
* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
*
* This file is part of PortaPack.
*
* 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, 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; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifndef __TOUCH_H__
#define __TOUCH_H__
#include <cstdint>
#include <cstddef>
#include <algorithm>
#include <array>
#include <functional>
#include "debounce.hpp"
#include "ui.hpp"
namespace touch {
using sample_t = uint16_t;
constexpr sample_t sample_max = 1023;
constexpr sample_t touch_threshold = sample_max * 0.5f;
struct Samples {
sample_t xp;
sample_t xn;
sample_t yp;
sample_t yn;
constexpr Samples(
) : Samples { 0 }
{
}
constexpr Samples(
uint32_t v
) : xp { static_cast<sample_t>(v) },
xn { static_cast<sample_t>(v) },
yp { static_cast<sample_t>(v) },
yn { static_cast<sample_t>(v) }
{
}
constexpr Samples(
uint32_t xp,
uint32_t xn,
uint32_t yp,
uint32_t yn
) : xp { static_cast<sample_t>(xp) },
xn { static_cast<sample_t>(xn) },
yp { static_cast<sample_t>(yp) },
yn { static_cast<sample_t>(yn) }
{
}
Samples& operator +=(const Samples& r) {
xp += r.xp;
xn += r.xn;
yp += r.yp;
yn += r.yn;
return *this;
}
Samples operator/(const unsigned int r) const {
return {
static_cast<sample_t>(xp / r),
static_cast<sample_t>(xn / r),
static_cast<sample_t>(yp / r),
static_cast<sample_t>(yn / r)
};
}
Samples operator>>(const size_t n) const {
return {
static_cast<sample_t>(xp >> n),
static_cast<sample_t>(xn >> n),
static_cast<sample_t>(yp >> n),
static_cast<sample_t>(yn >> n)
};
}
};
struct Frame {
Samples pressure { };
Samples x { };
Samples y { };
bool touch { false };
};
template<size_t N>
class Filter {
public:
constexpr Filter(
) : history(),
history_history { 0 },
accumulator { 0 },
n { 0 }
{
}
void reset() {
history.fill(0);
history_history = 0;
accumulator = 0;
n = 0;
}
void feed(const sample_t value) {
accumulator = accumulator + value - history[n];
history[n] = value;
n = (n + 1) % history.size();
history_history = (history_history << 1) | 1U;
}
uint32_t value() const {
return accumulator / N;
}
bool stable(const uint32_t bound) const {
if( history_valid() ) {
const auto minmax = std::minmax_element(history.cbegin(), history.cend());
const auto min = *minmax.first;
const auto max = *minmax.second;
const uint32_t delta = max - min;
return (delta < bound);
} else {
return false;
}
}
private:
static constexpr uint32_t history_history_mask { (1U << N) - 1 };
std::array<sample_t, N> history;
uint32_t history_history;
uint32_t accumulator;
size_t n;
bool history_valid() const {
return (history_history & history_history_mask) == history_history_mask;
}
};
class Manager {
public:
std::function<void(ui::TouchEvent)> on_event;
void feed(const Frame frame);
private:
enum State {
NoTouch,
TouchDetected,
};
static float cmx;
static float cmy;
static constexpr uint32_t width_pixels = 240;
static constexpr uint32_t height_pixels = 320;
static constexpr float r_touch_threshold = 0x1000;
static constexpr size_t touch_count_threshold { 4 };
static constexpr uint32_t touch_stable_bound { 4 };
static constexpr float calib_x_low = 0.15f;
static constexpr float calib_x_high = 0.93f;
static constexpr float calib_x_range = calib_x_high - calib_x_low;
static constexpr float calib_y_low = 0.05f;
static constexpr float calib_y_high = 0.84f;
static constexpr float calib_y_range = calib_y_high - calib_y_low;
// Ensure filter length is equal or less than touch_count_threshold,
// or coordinates from the last touch will be in the initial averages.
Filter<touch_count_threshold> filter_x;
Filter<touch_count_threshold> filter_y;
//Debounce touch_debounce;
State state { State::NoTouch };
bool point_stable() const {
return filter_x.stable(touch_stable_bound)
&& filter_y.stable(touch_stable_bound);
}
ui::Point filtered_point() const {
return {
static_cast<ui::Coord>(filter_x.value()),
static_cast<ui::Coord>(filter_y.value())
};
}
ui::Point raw_point() const ;
void touch_started() {
fire_event(ui::TouchEvent::Type::Start);
}
void touch_moved() {
fire_event(ui::TouchEvent::Type::Move);
}
void touch_ended() {
fire_event(ui::TouchEvent::Type::End);
}
void fire_event(ui::TouchEvent::Type type) {
if( on_event ) {
on_event({ filtered_point(), type, raw_point() });
}
}
};
} /* namespace touch */
#endif/*__TOUCH_H__*/