mirror of
https://github.com/portapack-mayhem/mayhem-firmware.git
synced 2024-12-13 19:54:39 +00:00
120 lines
3.3 KiB
C++
120 lines
3.3 KiB
C++
/*
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* Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
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*
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* This file is part of PortaPack.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#include "touch.hpp"
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namespace touch {
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struct Metrics {
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const float x;
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const float y;
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const float r;
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};
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static Metrics calculate_metrics(const Frame& frame) {
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/* TODO: Yikes! M0 doesn't have floating point, so this code is
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* expensive! On the other hand, it seems to be working well (and
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* fast *enough*?), so maybe leave it alone at least for now.
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*/
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const auto x_max = frame.x.xp;
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const auto x_min = frame.x.xn;
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const auto x_range = x_max - x_min;
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const auto x_position = (frame.x.yp + frame.x.yn) / 2;
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const float x_norm = float(x_position - x_min) / x_range;
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const auto y_max = frame.y.yn;
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const auto y_min = frame.y.yp;
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const auto y_range = y_max - y_min;
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const auto y_position = (frame.y.xp + frame.y.xn) / 2;
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const float y_norm = float(y_position - y_min) / y_range;
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const auto z_max = frame.pressure.yp;
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const auto z_min = frame.pressure.xn;
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const auto z_range = z_max - z_min;
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const auto z1_position = frame.pressure.xp;
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const float z1_norm = float(z1_position - z_min) / z_range;
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const auto z2_position = frame.pressure.yn;
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const float z2_norm = float(z2_position - z_min) / z_range;
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const float r_x_plate = 330.0f;
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//const float r_y_plate = 600.0f;
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const float r_touch = r_x_plate * x_norm * (z2_norm / z1_norm - 1.0f);
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return {
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.x = x_norm,
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.y = y_norm,
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.r = r_touch,
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};
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}
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void Manager::feed(const Frame& frame) {
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// touch_debounce.feed(touch_raw);
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const auto touch_raw = frame.touch;
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//const auto touch_stable = touch_debounce.state();
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const auto touch_stable = frame.touch;
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bool touch_pressure = false;
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// Only feed coordinate averaging if there's a touch.
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// TODO: Separate threshold to gate coordinates for filtering?
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if( touch_raw ) {
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const auto metrics = calculate_metrics(frame);
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// TODO: Add touch pressure hysteresis?
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touch_pressure = (metrics.r < r_touch_threshold);
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if( touch_pressure ) {
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const float x = width_pixels * (metrics.x - calib_x_low) / calib_x_range;
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filter_x.feed(x);
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const float y = height_pixels * (calib_y_high - metrics.y) / calib_y_range;
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filter_y.feed(y);
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}
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} else {
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filter_x.reset();
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filter_y.reset();
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}
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switch(state) {
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case State::NoTouch:
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if( touch_stable && touch_pressure ) {
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if( point_stable() ) {
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state = State::TouchDetected;
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touch_started();
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}
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}
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break;
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case State::TouchDetected:
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if( touch_stable && touch_pressure ) {
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touch_moved();
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} else {
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state = State::NoTouch;
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touch_ended();
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}
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break;
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default:
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state = State::NoTouch;
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break;
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}
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}
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} /* namespace touch */
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