133 lines
4.5 KiB
C
133 lines
4.5 KiB
C
/* Copyright 2022 Daniel Kao <daniel.m.kao@gmail.com>
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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 of the License, or
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* (at your option) 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. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <string.h>
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#include "pointing_device_gestures.h"
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#include "timer.h"
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#ifdef POINTING_DEVICE_GESTURES_CURSOR_GLIDE_ENABLE
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# ifdef POINTING_DEVICE_MOTION_PIN
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# error POINTING_DEVICE_MOTION_PIN not supported when using inertial cursor. Need repeated calls to get_report() to generate glide events.
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# endif
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static void cursor_glide_stop(cursor_glide_context_t* glide) {
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memset(&glide->status, 0, sizeof(glide->status));
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}
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static cursor_glide_t cursor_glide(cursor_glide_context_t* glide) {
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cursor_glide_status_t* status = &glide->status;
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cursor_glide_t report;
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int32_t p;
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int32_t x, y;
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if (status->v0 == 0) {
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report.dx = 0;
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report.dy = 0;
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report.valid = false;
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cursor_glide_stop(glide);
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goto exit;
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}
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status->counter++;
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/* Calculate current 1D position */
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p = status->v0 * status->counter - (int32_t)glide->config.coef * status->counter * status->counter / 2;
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/*
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* Translate to x & y axes
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* Done this way instead of applying friction to each axis separately, so we don't end up with the shorter axis stuck at 0 towards the end of diagonal movements.
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*/
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x = (int32_t)(p * status->dx0 / status->v0);
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y = (int32_t)(p * status->dy0 / status->v0);
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report.dx = (mouse_xy_report_t)(x - status->x);
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report.dy = (mouse_xy_report_t)(y - status->y);
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report.valid = true;
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if (report.dx <= 1 && report.dx >= -1 && report.dy <= 1 && report.dy >= -1) {
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/* Stop gliding once speed is low enough */
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cursor_glide_stop(glide);
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goto exit;
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}
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status->x = x;
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status->y = y;
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status->timer = timer_read();
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exit:
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return report;
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}
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cursor_glide_t cursor_glide_check(cursor_glide_context_t* glide) {
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cursor_glide_t invalid_report = {0, 0, false};
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cursor_glide_status_t* status = &glide->status;
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if (status->z || (status->dx0 == 0 && status->dy0 == 0) || timer_elapsed(status->timer) < glide->config.interval) {
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return invalid_report;
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} else {
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return cursor_glide(glide);
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}
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}
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static inline uint16_t sqrt32(uint32_t x) {
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uint32_t l, m, h;
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if (x == 0) {
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return 0;
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} else if (x > (UINT16_MAX >> 2)) {
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/* Safe upper bound to avoid integer overflow with m * m */
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h = UINT16_MAX;
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} else {
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/* Upper bound based on closest log2 */
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h = (1 << (((__builtin_clzl(1) - __builtin_clzl(x) + 1) + 1) >> 1));
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}
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/* Lower bound based on closest log2 */
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l = (1 << ((__builtin_clzl(1) - __builtin_clzl(x)) >> 1));
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/* Binary search to find integer square root */
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while (l != h - 1) {
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m = (l + h) / 2;
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if (m * m <= x) {
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l = m;
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} else {
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h = m;
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}
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}
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return l;
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}
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cursor_glide_t cursor_glide_start(cursor_glide_context_t* glide) {
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cursor_glide_t invalid_report = {0, 0, false};
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cursor_glide_status_t* status = &glide->status;
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status->timer = timer_read();
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status->counter = 0;
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status->v0 = (status->dx0 == 0 && status->dy0 == 0) ? 0.0 : sqrt32(((int32_t)status->dx0 * 256 * status->dx0 * 256) + ((int32_t)status->dy0 * 256 * status->dy0 * 256)); // skip trigonometry if not needed, calculate distance in Q8
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status->x = 0;
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status->y = 0;
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status->z = 0;
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if (status->v0 < ((uint32_t)glide->config.trigger_px * 256)) { /* Q8 comparison */
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/* Not enough velocity to be worth gliding, abort */
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cursor_glide_stop(glide);
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return invalid_report;
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}
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return cursor_glide(glide);
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}
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void cursor_glide_update(cursor_glide_context_t* glide, mouse_xy_report_t dx, mouse_xy_report_t dy, uint16_t z) {
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cursor_glide_status_t* status = &glide->status;
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status->dx0 = dx;
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status->dy0 = dy;
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status->z = z;
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}
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#endif
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