PX4-Autopilot/src/modules/ekf2/EKF/estimator_interface.cpp
Daniel Agar 5cb44a521c ekf2: estimator interface handle sample time with signed integers
- this prevents unsigned integer overflow if the timestamp is smaller
than the configured delay (mostly a simulation edge case)
2022-09-01 09:47:29 -04:00

649 lines
21 KiB
C++

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/**
* @file estimator_interface.cpp
* Definition of base class for attitude estimators
*
* @author Roman Bast <bapstroman@gmail.com>
* @author Paul Riseborough <p_riseborough@live.com.au>
* @author Siddharth B Purohit <siddharthbharatpurohit@gmail.com>
*/
#include "estimator_interface.h"
#include <mathlib/mathlib.h>
EstimatorInterface::~EstimatorInterface()
{
delete _gps_buffer;
delete _mag_buffer;
delete _baro_buffer;
delete _range_buffer;
delete _airspeed_buffer;
delete _flow_buffer;
delete _ext_vision_buffer;
delete _drag_buffer;
delete _auxvel_buffer;
}
// Accumulate imu data and store to buffer at desired rate
void EstimatorInterface::setIMUData(const imuSample &imu_sample)
{
// TODO: resolve misplaced responsibility
if (!_initialised) {
_initialised = init(imu_sample.time_us);
}
const float dt = math::constrain((imu_sample.time_us - _newest_high_rate_imu_sample.time_us) / 1e6f, 0.0001f, 0.02f);
if (_newest_high_rate_imu_sample.time_us > 0) {
_dt_imu_avg = 0.8f * _dt_imu_avg + 0.2f * dt;
}
_newest_high_rate_imu_sample = imu_sample;
_imu_updated = _imu_down_sampler.update(imu_sample);
// accumulate and down-sample imu data and push to the buffer when new downsampled data becomes available
if (_imu_updated) {
_imu_buffer.push(_imu_down_sampler.getDownSampledImuAndTriggerReset());
// get the oldest data from the buffer
_imu_sample_delayed = _imu_buffer.get_oldest();
// calculate the minimum interval between observations required to guarantee no loss of data
// this will occur if data is overwritten before its time stamp falls behind the fusion time horizon
_min_obs_interval_us = (imu_sample.time_us - _imu_sample_delayed.time_us) / (_obs_buffer_length - 1);
setDragData(imu_sample);
}
}
void EstimatorInterface::setMagData(const magSample &mag_sample)
{
if (!_initialised) {
return;
}
// Allocate the required buffer size if not previously done
if (_mag_buffer == nullptr) {
_mag_buffer = new RingBuffer<magSample>(_obs_buffer_length);
if (_mag_buffer == nullptr || !_mag_buffer->valid()) {
delete _mag_buffer;
_mag_buffer = nullptr;
printBufferAllocationFailed("mag");
return;
}
}
const int64_t time_us = mag_sample.time_us
- static_cast<int64_t>(_params.mag_delay_ms * 1000)
- static_cast<int64_t>(_dt_ekf_avg * 5e5f); // seconds to microseconds divided by 2
// limit data rate to prevent data being lost
if (time_us >= static_cast<int64_t>(_mag_buffer->get_newest().time_us + _min_obs_interval_us)) {
magSample mag_sample_new{mag_sample};
mag_sample_new.time_us = time_us;
_mag_buffer->push(mag_sample_new);
_time_last_mag_buffer_push = _newest_high_rate_imu_sample.time_us;
} else {
ECL_WARN("mag data too fast %" PRIi64 " < %" PRIu64 " + %d", time_us, _mag_buffer->get_newest().time_us, _min_obs_interval_us);
}
}
void EstimatorInterface::setGpsData(const gpsMessage &gps)
{
if (!_initialised) {
return;
}
// Allocate the required buffer size if not previously done
if (_gps_buffer == nullptr) {
_gps_buffer = new RingBuffer<gpsSample>(_obs_buffer_length);
if (_gps_buffer == nullptr || !_gps_buffer->valid()) {
delete _gps_buffer;
_gps_buffer = nullptr;
printBufferAllocationFailed("GPS");
return;
}
}
const int64_t time_us = gps.time_usec
- static_cast<int64_t>(_params.gps_delay_ms * 1000)
- static_cast<int64_t>(_dt_ekf_avg * 5e5f); // seconds to microseconds divided by 2
if (time_us >= static_cast<int64_t>(_gps_buffer->get_newest().time_us + _min_obs_interval_us)) {
gpsSample gps_sample_new;
gps_sample_new.time_us = time_us;
gps_sample_new.vel = gps.vel_ned;
_gps_speed_valid = gps.vel_ned_valid;
gps_sample_new.sacc = gps.sacc;
gps_sample_new.hacc = gps.eph;
gps_sample_new.vacc = gps.epv;
gps_sample_new.hgt = (float)gps.alt * 1e-3f;
gps_sample_new.yaw = gps.yaw;
if (PX4_ISFINITE(gps.yaw_offset)) {
_gps_yaw_offset = gps.yaw_offset;
} else {
_gps_yaw_offset = 0.0f;
}
// Only calculate the relative position if the WGS-84 location of the origin is set
if (collect_gps(gps)) {
gps_sample_new.pos = _pos_ref.project((gps.lat / 1.0e7), (gps.lon / 1.0e7));
} else {
gps_sample_new.pos(0) = 0.0f;
gps_sample_new.pos(1) = 0.0f;
}
_gps_buffer->push(gps_sample_new);
_time_last_gps_buffer_push = _newest_high_rate_imu_sample.time_us;
if (PX4_ISFINITE(gps.yaw)) {
_time_last_gps_yaw_buffer_push = _newest_high_rate_imu_sample.time_us;
}
} else {
ECL_WARN("GPS data too fast %" PRIi64 " < %" PRIu64 " + %d", time_us, _gps_buffer->get_newest().time_us, _min_obs_interval_us);
}
}
void EstimatorInterface::setBaroData(const baroSample &baro_sample)
{
if (!_initialised) {
return;
}
// Allocate the required buffer size if not previously done
if (_baro_buffer == nullptr) {
_baro_buffer = new RingBuffer<baroSample>(_obs_buffer_length);
if (_baro_buffer == nullptr || !_baro_buffer->valid()) {
delete _baro_buffer;
_baro_buffer = nullptr;
printBufferAllocationFailed("baro");
return;
}
}
const int64_t time_us = baro_sample.time_us
- static_cast<int64_t>(_params.baro_delay_ms * 1000)
- static_cast<int64_t>(_dt_ekf_avg * 5e5f); // seconds to microseconds divided by 2
// limit data rate to prevent data being lost
if (time_us >= static_cast<int64_t>(_baro_buffer->get_newest().time_us + _min_obs_interval_us)) {
baroSample baro_sample_new;
baro_sample_new.time_us = time_us;
baro_sample_new.hgt = compensateBaroForDynamicPressure(baro_sample.hgt);
_baro_buffer->push(baro_sample_new);
_time_last_baro_buffer_push = _newest_high_rate_imu_sample.time_us;
} else {
ECL_WARN("baro data too fast %" PRIi64 " < %" PRIu64 " + %d", time_us, _baro_buffer->get_newest().time_us, _min_obs_interval_us);
}
}
void EstimatorInterface::setAirspeedData(const airspeedSample &airspeed_sample)
{
if (!_initialised) {
return;
}
// Allocate the required buffer size if not previously done
if (_airspeed_buffer == nullptr) {
_airspeed_buffer = new RingBuffer<airspeedSample>(_obs_buffer_length);
if (_airspeed_buffer == nullptr || !_airspeed_buffer->valid()) {
delete _airspeed_buffer;
_airspeed_buffer = nullptr;
printBufferAllocationFailed("airspeed");
return;
}
}
const int64_t time_us = airspeed_sample.time_us
- static_cast<int64_t>(_params.airspeed_delay_ms * 1000)
- static_cast<int64_t>(_dt_ekf_avg * 5e5f); // seconds to microseconds divided by 2
// limit data rate to prevent data being lost
if (time_us >= static_cast<int64_t>(_airspeed_buffer->get_newest().time_us + _min_obs_interval_us)) {
airspeedSample airspeed_sample_new{airspeed_sample};
airspeed_sample_new.time_us = time_us;
_airspeed_buffer->push(airspeed_sample_new);
} else {
ECL_WARN("airspeed data too fast %" PRIi64 " < %" PRIu64 " + %d", time_us, _airspeed_buffer->get_newest().time_us, _min_obs_interval_us);
}
}
void EstimatorInterface::setRangeData(const rangeSample &range_sample)
{
if (!_initialised) {
return;
}
// Allocate the required buffer size if not previously done
if (_range_buffer == nullptr) {
_range_buffer = new RingBuffer<rangeSample>(_obs_buffer_length);
if (_range_buffer == nullptr || !_range_buffer->valid()) {
delete _range_buffer;
_range_buffer = nullptr;
printBufferAllocationFailed("range");
return;
}
}
const int64_t time_us = range_sample.time_us
- static_cast<int64_t>(_params.range_delay_ms * 1000)
- static_cast<int64_t>(_dt_ekf_avg * 5e5f); // seconds to microseconds divided by 2
// limit data rate to prevent data being lost
if (time_us >= static_cast<int64_t>(_range_buffer->get_newest().time_us + _min_obs_interval_us)) {
rangeSample range_sample_new{range_sample};
range_sample_new.time_us = time_us;
_range_buffer->push(range_sample_new);
_time_last_range_buffer_push = _newest_high_rate_imu_sample.time_us;
} else {
ECL_WARN("range data too fast %" PRIi64 " < %" PRIu64 " + %d", time_us, _range_buffer->get_newest().time_us, _min_obs_interval_us);
}
}
void EstimatorInterface::setOpticalFlowData(const flowSample &flow)
{
if (!_initialised) {
return;
}
// Allocate the required buffer size if not previously done
if (_flow_buffer == nullptr) {
_flow_buffer = new RingBuffer<flowSample>(_imu_buffer_length);
if (_flow_buffer == nullptr || !_flow_buffer->valid()) {
delete _flow_buffer;
_flow_buffer = nullptr;
printBufferAllocationFailed("flow");
return;
}
}
const int64_t time_us = flow.time_us
- static_cast<int64_t>(_params.flow_delay_ms * 1000)
- static_cast<int64_t>(_dt_ekf_avg * 5e5f); // seconds to microseconds divided by 2
// limit data rate to prevent data being lost
if (time_us >= static_cast<int64_t>(_flow_buffer->get_newest().time_us + _min_obs_interval_us)) {
flowSample optflow_sample_new{flow};
optflow_sample_new.time_us = time_us;
_flow_buffer->push(optflow_sample_new);
} else {
ECL_WARN("optical flow data too fast %" PRIi64 " < %" PRIu64 " + %d", time_us, _flow_buffer->get_newest().time_us, _min_obs_interval_us);
}
}
// set attitude and position data derived from an external vision system
void EstimatorInterface::setExtVisionData(const extVisionSample &evdata)
{
if (!_initialised) {
return;
}
// Allocate the required buffer size if not previously done
if (_ext_vision_buffer == nullptr) {
_ext_vision_buffer = new RingBuffer<extVisionSample>(_obs_buffer_length);
if (_ext_vision_buffer == nullptr || !_ext_vision_buffer->valid()) {
delete _ext_vision_buffer;
_ext_vision_buffer = nullptr;
printBufferAllocationFailed("vision");
return;
}
}
// calculate the system time-stamp for the mid point of the integration period
const int64_t time_us = evdata.time_us
- static_cast<int64_t>(_params.ev_delay_ms * 1000)
- static_cast<int64_t>(_dt_ekf_avg * 5e5f); // seconds to microseconds divided by 2
// limit data rate to prevent data being lost
if (time_us >= static_cast<int64_t>(_ext_vision_buffer->get_newest().time_us + _min_obs_interval_us)) {
extVisionSample ev_sample_new{evdata};
ev_sample_new.time_us = time_us;
_ext_vision_buffer->push(ev_sample_new);
_time_last_ext_vision_buffer_push = _newest_high_rate_imu_sample.time_us;
} else {
ECL_WARN("EV data too fast %" PRIi64 " < %" PRIu64 " + %d", time_us, _ext_vision_buffer->get_newest().time_us, _min_obs_interval_us);
}
}
void EstimatorInterface::setAuxVelData(const auxVelSample &auxvel_sample)
{
if (!_initialised) {
return;
}
// Allocate the required buffer size if not previously done
if (_auxvel_buffer == nullptr) {
_auxvel_buffer = new RingBuffer<auxVelSample>(_obs_buffer_length);
if (_auxvel_buffer == nullptr || !_auxvel_buffer->valid()) {
delete _auxvel_buffer;
_auxvel_buffer = nullptr;
printBufferAllocationFailed("aux vel");
return;
}
}
const int64_t time_us = auxvel_sample.time_us
- static_cast<int64_t>(_params.auxvel_delay_ms * 1000)
- static_cast<int64_t>(_dt_ekf_avg * 5e5f); // seconds to microseconds divided by 2
// limit data rate to prevent data being lost
if (time_us >= static_cast<int64_t>(_auxvel_buffer->get_newest().time_us + _min_obs_interval_us)) {
auxVelSample auxvel_sample_new{auxvel_sample};
auxvel_sample_new.time_us = time_us;
_auxvel_buffer->push(auxvel_sample_new);
} else {
ECL_WARN("aux velocity data too fast %" PRIi64 " < %" PRIu64 " + %d", time_us, _auxvel_buffer->get_newest().time_us, _min_obs_interval_us);
}
}
void EstimatorInterface::setDragData(const imuSample &imu)
{
// down-sample the drag specific force data by accumulating and calculating the mean when
// sufficient samples have been collected
if ((_params.fusion_mode & SensorFusionMask::USE_DRAG)) {
// Allocate the required buffer size if not previously done
if (_drag_buffer == nullptr) {
_drag_buffer = new RingBuffer<dragSample>(_obs_buffer_length);
if (_drag_buffer == nullptr || !_drag_buffer->valid()) {
delete _drag_buffer;
_drag_buffer = nullptr;
printBufferAllocationFailed("drag");
return;
}
}
_drag_sample_count++;
// note acceleration is accumulated as a delta velocity
_drag_down_sampled.accelXY(0) += imu.delta_vel(0);
_drag_down_sampled.accelXY(1) += imu.delta_vel(1);
_drag_down_sampled.time_us += imu.time_us;
_drag_sample_time_dt += imu.delta_vel_dt;
// calculate the downsample ratio for drag specific force data
uint8_t min_sample_ratio = (uint8_t) ceilf((float)_imu_buffer_length / _obs_buffer_length);
if (min_sample_ratio < 5) {
min_sample_ratio = 5;
}
// calculate and store means from accumulated values
if (_drag_sample_count >= min_sample_ratio) {
// note conversion from accumulated delta velocity to acceleration
_drag_down_sampled.accelXY(0) /= _drag_sample_time_dt;
_drag_down_sampled.accelXY(1) /= _drag_sample_time_dt;
_drag_down_sampled.time_us /= _drag_sample_count;
// write to buffer
_drag_buffer->push(_drag_down_sampled);
// reset accumulators
_drag_sample_count = 0;
_drag_down_sampled.accelXY.zero();
_drag_down_sampled.time_us = 0;
_drag_sample_time_dt = 0.0f;
}
}
}
bool EstimatorInterface::initialise_interface(uint64_t timestamp)
{
// find the maximum time delay the buffers are required to handle
// it's reasonable to assume that aux velocity device has low delay. TODO: check the delay only if the aux device is used
float max_time_delay_ms = math::max((float)_params.sensor_interval_max_ms, _params.auxvel_delay_ms);
// using baro
if (_params.baro_ctrl > 0) {
max_time_delay_ms = math::max(_params.baro_delay_ms, max_time_delay_ms);
}
// using airspeed
if (_params.arsp_thr > FLT_EPSILON) {
max_time_delay_ms = math::max(_params.airspeed_delay_ms, max_time_delay_ms);
}
// mag mode
if (_params.mag_fusion_type != MagFuseType::NONE) {
max_time_delay_ms = math::max(_params.mag_delay_ms, max_time_delay_ms);
}
// using range finder
if ((_params.rng_ctrl != RngCtrl::DISABLED)) {
max_time_delay_ms = math::max(_params.range_delay_ms, max_time_delay_ms);
}
if (_params.gnss_ctrl > 0) {
max_time_delay_ms = math::max(_params.gps_delay_ms, max_time_delay_ms);
}
if (_params.fusion_mode & SensorFusionMask::USE_OPT_FLOW) {
max_time_delay_ms = math::max(_params.flow_delay_ms, max_time_delay_ms);
}
if (_params.fusion_mode & (SensorFusionMask::USE_EXT_VIS_POS | SensorFusionMask::USE_EXT_VIS_YAW | SensorFusionMask::USE_EXT_VIS_VEL)) {
max_time_delay_ms = math::max(_params.ev_delay_ms, max_time_delay_ms);
}
const float filter_update_period_ms = _params.filter_update_interval_us / 1000.f;
// calculate the IMU buffer length required to accomodate the maximum delay with some allowance for jitter
_imu_buffer_length = ceilf(max_time_delay_ms / filter_update_period_ms);
// set the observation buffer length to handle the minimum time of arrival between observations in combination
// with the worst case delay from current time to ekf fusion time
// allow for worst case 50% extension of the ekf fusion time horizon delay due to timing jitter
const float ekf_delay_ms = max_time_delay_ms * 1.5f;
_obs_buffer_length = roundf(ekf_delay_ms / filter_update_period_ms);
// limit to be no longer than the IMU buffer (we can't process data faster than the EKF prediction rate)
_obs_buffer_length = math::min(_obs_buffer_length, _imu_buffer_length);
ECL_DEBUG("EKF max time delay %.1f ms, OBS length %d\n", (double)ekf_delay_ms, _obs_buffer_length);
if (!_imu_buffer.allocate(_imu_buffer_length) || !_output_buffer.allocate(_imu_buffer_length)
|| !_output_vert_buffer.allocate(_imu_buffer_length)) {
printBufferAllocationFailed("IMU and output");
return false;
}
_imu_sample_delayed.time_us = timestamp;
_imu_sample_delayed.delta_vel_clipping[0] = false;
_imu_sample_delayed.delta_vel_clipping[1] = false;
_imu_sample_delayed.delta_vel_clipping[2] = false;
_fault_status.value = 0;
return true;
}
bool EstimatorInterface::isOnlyActiveSourceOfHorizontalAiding(const bool aiding_flag) const
{
return aiding_flag && !isOtherSourceOfHorizontalAidingThan(aiding_flag);
}
bool EstimatorInterface::isOtherSourceOfHorizontalAidingThan(const bool aiding_flag) const
{
const int nb_sources = getNumberOfActiveHorizontalAidingSources();
return aiding_flag ? nb_sources > 1 : nb_sources > 0;
}
int EstimatorInterface::getNumberOfActiveHorizontalAidingSources() const
{
return int(_control_status.flags.gps)
+ int(_control_status.flags.opt_flow)
+ int(_control_status.flags.ev_pos)
+ int(_control_status.flags.ev_vel)
// Combined airspeed and sideslip fusion allows sustained wind relative dead reckoning
// and so is treated as a single aiding source.
+ int(_control_status.flags.fuse_aspd && _control_status.flags.fuse_beta);
}
bool EstimatorInterface::isHorizontalAidingActive() const
{
return getNumberOfActiveHorizontalAidingSources() > 0;
}
bool EstimatorInterface::isOtherSourceOfVerticalPositionAidingThan(const bool aiding_flag) const
{
const int nb_sources = getNumberOfActiveVerticalPositionAidingSources();
return aiding_flag ? nb_sources > 1 : nb_sources > 0;
}
bool EstimatorInterface::isVerticalPositionAidingActive() const
{
return getNumberOfActiveVerticalPositionAidingSources() > 0;
}
bool EstimatorInterface::isOnlyActiveSourceOfVerticalPositionAiding(const bool aiding_flag) const
{
return aiding_flag && !isOtherSourceOfVerticalPositionAidingThan(aiding_flag);
}
int EstimatorInterface::getNumberOfActiveVerticalPositionAidingSources() const
{
return int(_control_status.flags.gps_hgt)
+ int(_control_status.flags.baro_hgt)
+ int(_control_status.flags.rng_hgt)
+ int(_control_status.flags.ev_hgt);
}
bool EstimatorInterface::isVerticalVelocityAidingActive() const
{
return getNumberOfActiveVerticalVelocityAidingSources() > 0;
}
int EstimatorInterface::getNumberOfActiveVerticalVelocityAidingSources() const
{
return int(_control_status.flags.gps)
+ int(_control_status.flags.ev_vel);
}
void EstimatorInterface::printBufferAllocationFailed(const char *buffer_name)
{
if (buffer_name) {
ECL_ERR("%s buffer allocation failed", buffer_name);
}
}
void EstimatorInterface::print_status()
{
printf("IMU average dt: %.6f seconds\n", (double)_dt_imu_avg);
printf("EKF average dt: %.6f seconds\n", (double)_dt_ekf_avg);
printf("IMU buffer: %d (%d Bytes)\n", _imu_buffer.get_length(), _imu_buffer.get_total_size());
printf("minimum observation interval %d us\n", _min_obs_interval_us);
if (_gps_buffer) {
printf("gps buffer: %d/%d (%d Bytes)\n", _gps_buffer->entries(), _gps_buffer->get_length(), _gps_buffer->get_total_size());
}
if (_mag_buffer) {
printf("mag buffer: %d/%d (%d Bytes)\n", _mag_buffer->entries(), _mag_buffer->get_length(), _mag_buffer->get_total_size());
}
if (_baro_buffer) {
printf("baro buffer: %d/%d (%d Bytes)\n", _baro_buffer->entries(), _baro_buffer->get_length(), _baro_buffer->get_total_size());
}
if (_range_buffer) {
printf("range buffer: %d/%d (%d Bytes)\n", _range_buffer->entries(), _range_buffer->get_length(), _range_buffer->get_total_size());
}
if (_airspeed_buffer) {
printf("airspeed buffer: %d/%d (%d Bytes)\n", _airspeed_buffer->entries(), _airspeed_buffer->get_length(), _airspeed_buffer->get_total_size());
}
if (_flow_buffer) {
printf("flow buffer: %d/%d (%d Bytes)\n", _flow_buffer->entries(), _flow_buffer->get_length(), _flow_buffer->get_total_size());
}
if (_ext_vision_buffer) {
printf("vision buffer: %d/%d (%d Bytes)\n", _ext_vision_buffer->entries(), _ext_vision_buffer->get_length(), _ext_vision_buffer->get_total_size());
}
if (_drag_buffer) {
printf("drag buffer: %d/%d (%d Bytes)\n", _drag_buffer->entries(), _drag_buffer->get_length(), _drag_buffer->get_total_size());
}
printf("output buffer: %d/%d (%d Bytes)\n", _output_buffer.entries(), _output_buffer.get_length(), _output_buffer.get_total_size());
printf("output vert buffer: %d/%d (%d Bytes)\n", _output_vert_buffer.entries(), _output_vert_buffer.get_length(), _output_vert_buffer.get_total_size());
}