private void CalcPosition(ref move m, timepos last, ref timepos low, ref timepos high, ref double seek_time_delta)
{
// Need to increase next step search range
low = high;
high.time = last.time + seek_time_delta;
seek_time_delta += seek_time_delta;
if (high.time > m.move_t)
{
high.time = m.move_t;
}
high.position = calc_position(ref m, high.time);
}
// Find step using "false position" method
private timepos itersolve_find_step(ref move m, ref timepos low, ref timepos high, double target)
{
timepos best_guess = high;
low.position -= target;
high.position -= target;
if (high.position == 0)
{
// The high range was a perfect guess for the next step
return(best_guess);
}
int high_sign = Math.Sign(high.position);
if (high_sign == Math.Sign(low.position))
{
// The target is not in the low/high range - return low range
return(new timepos(low.time, target));
}
while (true)
{
double guess_time = (low.time * high.position - high.time * low.position) / (high.position - low.position);
if (Math.Abs(guess_time - best_guess.time) <= 0.000000001)
{
break;
}
best_guess.time = guess_time;
best_guess.position = calc_position(ref m, guess_time);
double guess_position = best_guess.position - target;
int guess_sign = Math.Sign(guess_position);
if (guess_sign == high_sign)
{
high.time = guess_time;
high.position = guess_position;
}
else
{
low.time = guess_time;
low.position = guess_position;
}
}
return(best_guess);
}
// Generate step times for a stepper during a move
public bool itersolve_gen_steps(ref move m)
{
stepcompress sc = this.sc;
double half_step = 0.5 * step_dist;
double mcu_freq = sc.get_mcu_freq();
timepos last = new timepos(0.0, commanded_pos), low = last, high = last;
double seek_time_delta = 0.000100;
bool sdir = sc.get_step_dir();
queue_append qa = sc.queue_append_start(m.print_time, 0.5);
bool ret;
while (true)
{
// Determine if next step is in forward or reverse direction
double dist = high.position - last.position;
if (Math.Abs(dist) < half_step)
{
if (high.time >= m.move_t)
{
// At end of move
break;
}
CalcPosition(ref m, last, ref low, ref high, ref seek_time_delta);
continue;
}
bool next_sdir = dist > 0.0;
if (next_sdir != sdir)
{
// Direction change
if (Math.Abs(dist) < half_step + .000000001)
{
// Only change direction if going past midway point
if (high.time >= m.move_t)
{
// At end of move
break;
}
CalcPosition(ref m, last, ref low, ref high, ref seek_time_delta);
continue;
}
if (last.time >= low.time && high.time > last.time)
{
// Must seek new low range to avoid re-finding previous time
high.time = (last.time + high.time) * .5;
high.position = calc_position(ref m, high.time);
continue;
}
ret = qa.append_set_next_step_dir(next_sdir);
if (ret)
{
return(ret);
}
sdir = next_sdir;
}
// Find step
double target = last.position + (sdir ? half_step : -half_step);
timepos next = itersolve_find_step(ref m, ref low, ref high, target);
// Add step at given time
ret = qa.append(next.time * mcu_freq);
if (ret)
{
return(ret);
}
seek_time_delta = next.time - last.time;
if (seek_time_delta < 0.000000001)
{
seek_time_delta = 0.000000001;
}
last.position = target + (sdir ? half_step : -half_step);
last.time = next.time;
low = next;
if (last.time >= high.time)
{
// The high range is no longer valid - recalculate it
if (high.time >= m.move_t)
{
// At end of move
break;
}
CalcPosition(ref m, last, ref low, ref high, ref seek_time_delta);
continue;
}
}
qa.queue_append_finish();
commanded_pos = last.position;
return(false);
}