257 lines
8.0 KiB
C
257 lines
8.0 KiB
C
// Trapezoidal velocity movement queue
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//
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// Copyright (C) 2018-2021 Kevin O'Connor <kevin@koconnor.net>
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//
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// This file may be distributed under the terms of the GNU GPLv3 license.
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#include <math.h> // sqrt
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#include <stddef.h> // offsetof
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#include <stdlib.h> // malloc
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#include <string.h> // memset
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#include "compiler.h" // unlikely
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#include "trapq.h" // move_get_coord
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// Allocate a new 'move' object
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struct move *
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move_alloc(void)
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{
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struct move *m = malloc(sizeof(*m));
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memset(m, 0, sizeof(*m));
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return m;
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}
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// Return the distance moved given a time in a move
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inline double
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move_get_distance(struct move *m, double move_time)
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{
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return (m->start_v + m->half_accel * move_time) * move_time;
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}
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// Return the XYZ coordinates given a time in a move
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inline struct coord
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move_get_coord(struct move *m, double move_time)
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{
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double move_dist = move_get_distance(m, move_time);
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return (struct coord) {
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.x = m->start_pos.x + m->axes_r.x * move_dist,
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.y = m->start_pos.y + m->axes_r.y * move_dist,
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.z = m->start_pos.z + m->axes_r.z * move_dist };
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}
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#define NEVER_TIME 9999999999999999.9
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// Allocate a new 'trapq' object
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struct trapq * __visible
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trapq_alloc(void)
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{
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struct trapq *tq = malloc(sizeof(*tq));
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memset(tq, 0, sizeof(*tq));
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list_init(&tq->moves);
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list_init(&tq->history);
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struct move *head_sentinel = move_alloc(), *tail_sentinel = move_alloc();
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tail_sentinel->print_time = tail_sentinel->move_t = NEVER_TIME;
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list_add_head(&head_sentinel->node, &tq->moves);
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list_add_tail(&tail_sentinel->node, &tq->moves);
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return tq;
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}
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// Free memory associated with a 'trapq' object
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void __visible
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trapq_free(struct trapq *tq)
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{
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while (!list_empty(&tq->moves)) {
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struct move *m = list_first_entry(&tq->moves, struct move, node);
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list_del(&m->node);
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free(m);
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}
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while (!list_empty(&tq->history)) {
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struct move *m = list_first_entry(&tq->history, struct move, node);
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list_del(&m->node);
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free(m);
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}
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free(tq);
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}
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// Update the list sentinels
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void
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trapq_check_sentinels(struct trapq *tq)
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{
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struct move *tail_sentinel = list_last_entry(&tq->moves, struct move, node);
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if (tail_sentinel->print_time)
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// Already up to date
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return;
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struct move *m = list_prev_entry(tail_sentinel, node);
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struct move *head_sentinel = list_first_entry(&tq->moves, struct move,node);
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if (m == head_sentinel) {
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// No moves at all on this list
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tail_sentinel->print_time = NEVER_TIME;
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return;
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}
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tail_sentinel->print_time = m->print_time + m->move_t;
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tail_sentinel->start_pos = move_get_coord(m, m->move_t);
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}
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#define MAX_NULL_MOVE 1.0
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// Add a move to the trapezoid velocity queue
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void
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trapq_add_move(struct trapq *tq, struct move *m)
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{
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struct move *tail_sentinel = list_last_entry(&tq->moves, struct move, node);
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struct move *prev = list_prev_entry(tail_sentinel, node);
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if (prev->print_time + prev->move_t < m->print_time) {
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// Add a null move to fill time gap
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struct move *null_move = move_alloc();
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null_move->start_pos = m->start_pos;
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if (!prev->print_time && m->print_time > MAX_NULL_MOVE)
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// Limit the first null move to improve numerical stability
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null_move->print_time = m->print_time - MAX_NULL_MOVE;
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else
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null_move->print_time = prev->print_time + prev->move_t;
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null_move->move_t = m->print_time - null_move->print_time;
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list_add_before(&null_move->node, &tail_sentinel->node);
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}
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list_add_before(&m->node, &tail_sentinel->node);
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tail_sentinel->print_time = 0.;
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}
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// Fill and add a move to the trapezoid velocity queue
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void __visible
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trapq_append(struct trapq *tq, double print_time
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, double accel_t, double cruise_t, double decel_t
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, double start_pos_x, double start_pos_y, double start_pos_z
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, double axes_r_x, double axes_r_y, double axes_r_z
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, double start_v, double cruise_v, double accel)
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{
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struct coord start_pos = { .x=start_pos_x, .y=start_pos_y, .z=start_pos_z };
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struct coord axes_r = { .x=axes_r_x, .y=axes_r_y, .z=axes_r_z };
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if (accel_t) {
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struct move *m = move_alloc();
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m->print_time = print_time;
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m->move_t = accel_t;
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m->start_v = start_v;
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m->half_accel = .5 * accel;
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m->start_pos = start_pos;
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m->axes_r = axes_r;
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trapq_add_move(tq, m);
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print_time += accel_t;
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start_pos = move_get_coord(m, accel_t);
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}
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if (cruise_t) {
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struct move *m = move_alloc();
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m->print_time = print_time;
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m->move_t = cruise_t;
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m->start_v = cruise_v;
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m->half_accel = 0.;
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m->start_pos = start_pos;
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m->axes_r = axes_r;
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trapq_add_move(tq, m);
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print_time += cruise_t;
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start_pos = move_get_coord(m, cruise_t);
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}
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if (decel_t) {
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struct move *m = move_alloc();
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m->print_time = print_time;
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m->move_t = decel_t;
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m->start_v = cruise_v;
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m->half_accel = -.5 * accel;
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m->start_pos = start_pos;
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m->axes_r = axes_r;
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trapq_add_move(tq, m);
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}
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}
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// Expire any moves older than `print_time` from the trapezoid velocity queue
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void __visible
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trapq_finalize_moves(struct trapq *tq, double print_time
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, double clear_history_time)
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{
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struct move *head_sentinel = list_first_entry(&tq->moves, struct move,node);
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struct move *tail_sentinel = list_last_entry(&tq->moves, struct move, node);
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// Move expired moves from main "moves" list to "history" list
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for (;;) {
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struct move *m = list_next_entry(head_sentinel, node);
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if (m == tail_sentinel) {
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tail_sentinel->print_time = NEVER_TIME;
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break;
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}
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if (m->print_time + m->move_t > print_time)
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break;
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list_del(&m->node);
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if (m->start_v || m->half_accel)
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list_add_head(&m->node, &tq->history);
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else
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free(m);
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}
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// Free old moves from history list
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if (list_empty(&tq->history))
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return;
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struct move *latest = list_first_entry(&tq->history, struct move, node);
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for (;;) {
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struct move *m = list_last_entry(&tq->history, struct move, node);
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if (m == latest || m->print_time + m->move_t > clear_history_time)
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break;
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list_del(&m->node);
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free(m);
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}
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}
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// Note a position change in the trapq history
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void __visible
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trapq_set_position(struct trapq *tq, double print_time
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, double pos_x, double pos_y, double pos_z)
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{
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// Flush all moves from trapq
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trapq_finalize_moves(tq, NEVER_TIME, 0);
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// Prune any moves in the trapq history that were interrupted
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while (!list_empty(&tq->history)) {
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struct move *m = list_first_entry(&tq->history, struct move, node);
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if (m->print_time < print_time) {
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if (m->print_time + m->move_t > print_time)
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m->move_t = print_time - m->print_time;
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break;
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}
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list_del(&m->node);
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free(m);
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}
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// Add a marker to the trapq history
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struct move *m = move_alloc();
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m->print_time = print_time;
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m->start_pos.x = pos_x;
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m->start_pos.y = pos_y;
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m->start_pos.z = pos_z;
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list_add_head(&m->node, &tq->history);
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}
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// Return history of movement queue
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int __visible
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trapq_extract_old(struct trapq *tq, struct pull_move *p, int max
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, double start_time, double end_time)
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{
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int res = 0;
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struct move *m;
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list_for_each_entry(m, &tq->history, node) {
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if (start_time >= m->print_time + m->move_t || res >= max)
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break;
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if (end_time <= m->print_time)
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continue;
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p->print_time = m->print_time;
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p->move_t = m->move_t;
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p->start_v = m->start_v;
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p->accel = 2. * m->half_accel;
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p->start_x = m->start_pos.x;
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p->start_y = m->start_pos.y;
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p->start_z = m->start_pos.z;
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p->x_r = m->axes_r.x;
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p->y_r = m->axes_r.y;
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p->z_r = m->axes_r.z;
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p++;
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res++;
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}
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return res;
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}
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