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Mujoco_WASM/src/engine/engine_sensor.c
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Yuval Tassa b9900db00e Extract memory allocation functions and core utilities
PiperOrigin-RevId: 801745499
Change-Id: Iaf05c3430769d3115743d8ab020d13148cb2eb59
2025-09-01 03:38:25 -07:00

1507 lines
50 KiB
C

// Copyright 2021 DeepMind Technologies Limited
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "engine/engine_sensor.h"
#include <stddef.h>
#include <mujoco/mjdata.h>
#include <mujoco/mjmodel.h>
#include <mujoco/mjplugin.h>
#include <mujoco/mjsan.h> // IWYU pragma: keep
#include "engine/engine_callback.h"
#include "engine/engine_collision_sdf.h"
#include "engine/engine_core_smooth.h"
#include "engine/engine_core_util.h"
#include "engine/engine_crossplatform.h"
#include "engine/engine_memory.h"
#include "engine/engine_plugin.h"
#include "engine/engine_ray.h"
#include "engine/engine_sort.h"
#include "engine/engine_support.h"
#include "engine/engine_util_blas.h"
#include "engine/engine_util_errmem.h"
#include "engine/engine_util_misc.h"
#include "engine/engine_util_spatial.h"
//-------------------------------- utility ---------------------------------------------------------
typedef struct {
mjtNum criterion; // criterion for partial sort
int id; // index in d->contact
int flip; // 0: don't flip the normal, 1: flip the normal
} ContactInfo;
// define ContactSelect: find the k smallest elements of a ContactInfo array
static int ContactInfoCompare(const ContactInfo* a, const ContactInfo* b, void* context) {
if (a->criterion < b->criterion) return -1;
if (a->criterion > b->criterion) return 1;
if (a->id < b->id) return -1;
if (a->id > b->id) return 1;
return 0;
}
mjPARTIAL_SORT(ContactSelect, ContactInfo, ContactInfoCompare)
// apply cutoff after each stage
static void apply_cutoff(const mjModel* m, mjData* d, mjtStage stage) {
// process sensors matching stage and having positive cutoff
for (int i=0; i < m->nsensor; i++) {
if (m->sensor_needstage[i] == stage && m->sensor_cutoff[i] > 0) {
// skip fromto sensors
if (m->sensor_type[i] == mjSENS_GEOMFROMTO) {
continue;
}
// get sensor info
int adr = m->sensor_adr[i];
int dim = m->sensor_dim[i];
mjtNum cutoff = m->sensor_cutoff[i];
// process all dimensions
for (int j=0; j < dim; j++) {
// real: apply on both sides
if (m->sensor_datatype[i] == mjDATATYPE_REAL) {
d->sensordata[adr+j] = mju_clip(d->sensordata[adr+j], -cutoff, cutoff);
}
// positive: apply on positive side only
else if (m->sensor_datatype[i] == mjDATATYPE_POSITIVE) {
d->sensordata[adr+j] = mju_min(cutoff, d->sensordata[adr+j]);
}
}
}
}
}
// get xpos and xmat pointers to an object in mjData
static void get_xpos_xmat(const mjData* d, mjtObj type, int id, int sensor_id,
mjtNum **xpos, mjtNum **xmat) {
switch (type) {
case mjOBJ_XBODY:
*xpos = d->xpos + 3*id;
*xmat = d->xmat + 9*id;
break;
case mjOBJ_BODY:
*xpos = d->xipos + 3*id;
*xmat = d->ximat + 9*id;
break;
case mjOBJ_GEOM:
*xpos = d->geom_xpos + 3*id;
*xmat = d->geom_xmat + 9*id;
break;
case mjOBJ_SITE:
*xpos = d->site_xpos + 3*id;
*xmat = d->site_xmat + 9*id;
break;
case mjOBJ_CAMERA:
*xpos = d->cam_xpos + 3*id;
*xmat = d->cam_xmat + 9*id;
break;
default:
mjERROR("invalid object type in sensor %d", sensor_id);
}
}
// get global quaternion of an object in mjData
static void get_xquat(const mjModel* m, const mjData* d, mjtObj type, int id, int sensor_id,
mjtNum *quat) {
switch (type) {
case mjOBJ_XBODY:
mju_copy4(quat, d->xquat+4*id);
break;
case mjOBJ_BODY:
mju_mulQuat(quat, d->xquat+4*id, m->body_iquat+4*id);
break;
case mjOBJ_GEOM:
mju_mulQuat(quat, d->xquat+4*m->geom_bodyid[id], m->geom_quat+4*id);
break;
case mjOBJ_SITE:
mju_mulQuat(quat, d->xquat+4*m->site_bodyid[id], m->site_quat+4*id);
break;
case mjOBJ_CAMERA:
mju_mulQuat(quat, d->xquat+4*m->cam_bodyid[id], m->cam_quat+4*id);
break;
default:
mjERROR("invalid object type in sensor %d", sensor_id);
}
}
static void cam_project(mjtNum sensordata[2], const mjtNum target_xpos[3],
const mjtNum cam_xpos[3], const mjtNum cam_xmat[9],
const int cam_res[2], mjtNum cam_fovy,
const float cam_intrinsic[4], const float cam_sensorsize[2]) {
mjtNum fx, fy;
// translation matrix (4x4)
mjtNum translation[4][4] = {0};
translation[0][0] = 1;
translation[1][1] = 1;
translation[2][2] = 1;
translation[3][3] = 1;
translation[0][3] = -cam_xpos[0];
translation[1][3] = -cam_xpos[1];
translation[2][3] = -cam_xpos[2];
// rotation matrix (4x4)
mjtNum rotation[4][4] = {0};
rotation[0][0] = 1;
rotation[1][1] = 1;
rotation[2][2] = 1;
rotation[3][3] = 1;
for (int i=0; i < 3; i++) {
for (int j=0; j < 3; j++) {
rotation[i][j] = cam_xmat[j*3+i];
}
}
// focal transformation matrix (3x4)
if (cam_sensorsize[0] && cam_sensorsize[1]) {
fx = cam_intrinsic[0] / cam_sensorsize[0] * cam_res[0];
fy = cam_intrinsic[1] / cam_sensorsize[1] * cam_res[1];
} else {
fx = fy = .5 / mju_tan(cam_fovy * mjPI / 360.) * cam_res[1];
}
mjtNum focal[3][4] = {0};
focal[0][0] = -fx;
focal[1][1] = fy;
focal[2][2] = 1.0;
// image matrix (3x3)
mjtNum image[3][3] = {0};
image[0][0] = 1;
image[1][1] = 1;
image[2][2] = 1;
image[0][2] = (mjtNum)cam_res[0] / 2.0;
image[1][2] = (mjtNum)cam_res[1] / 2.0;
// projection matrix (3x4): product of all 4 matrices
mjtNum proj[3][4] = {0};
for (int i=0; i < 3; i++) {
for (int j=0; j < 3; j++) {
for (int k=0; k < 4; k++) {
for (int l=0; l < 4; l++) {
for (int n=0; n < 4; n++) {
proj[i][n] += image[i][j] * focal[j][k] * rotation[k][l] * translation[l][n];
}
}
}
}
}
// projection matrix multiplies homogenous [x, y, z, 1] vectors
mjtNum pos_hom[4] = {0, 0, 0, 1};
mju_copy3(pos_hom, target_xpos);
// project world coordinates into pixel space, see:
// https://en.wikipedia.org/wiki/3D_projection#Mathematical_formula
mjtNum pixel_coord_hom[3] = {0};
for (int i=0; i < 3; i++) {
for (int j=0; j < 4; j++) {
pixel_coord_hom[i] += proj[i][j] * pos_hom[j];
}
}
// avoid dividing by tiny numbers
mjtNum denom = pixel_coord_hom[2];
if (mju_abs(denom) < mjMINVAL) {
if (denom < 0) {
denom = mju_min(denom, -mjMINVAL);
} else {
denom = mju_max(denom, mjMINVAL);
}
}
// compute projection
sensordata[0] = pixel_coord_hom[0] / denom;
sensordata[1] = pixel_coord_hom[1] / denom;
}
// check if a contact body/geom matches a sensor spec (type, id)
static int checkMatch(const mjModel* m, int body, int geom, mjtObj type, int id) {
if (type == mjOBJ_UNKNOWN) return 1;
if (type == mjOBJ_SITE) return 1; // already passed site filter test
if (type == mjOBJ_GEOM) return id == geom;
if (type == mjOBJ_BODY) return id == body;
if (type == mjOBJ_XBODY) {
// traverse up the tree from body, return true if we land on id
while (body > id) {
body = m->body_parentid[body];
}
return body == id;
}
return 0;
}
// 0: no match
// 1: match, use contact normal
// -1: match, flip contact normal
static int matchContact(const mjModel* m, const mjData* d, int conid,
mjtObj type1, int id1, mjtObj type2, int id2) {
// no criterion: quick match
if (type1 == mjOBJ_UNKNOWN && type2 == mjOBJ_UNKNOWN) {
return 1;
}
// site filter
if (type1 == mjOBJ_SITE) {
if (!mju_insideGeom(d->site_xpos + 3 * id1, d->site_xmat + 9 * id1,
m->site_size + 3 * id1, m->site_type[id1], d->contact[conid].pos)) {
return 0;
}
}
// get geom, body ids
int geom1 = d->contact[conid].geom[0];
int geom2 = d->contact[conid].geom[1];
int body1 = geom1 >= 0 ? m->geom_bodyid[geom1] : -1;
int body2 = geom2 >= 0 ? m->geom_bodyid[geom2] : -1;
// check match of sensor objects with contact objects
int match11 = checkMatch(m, body1, geom1, type1, id1);
int match12 = checkMatch(m, body2, geom2, type1, id1);
int match21 = checkMatch(m, body1, geom1, type2, id2);
int match22 = checkMatch(m, body2, geom2, type2, id2);
// if a sensor object is specified, it must be involved in the contact
if (!match11 && !match12) return 0;
if (!match21 && !match22) return 0;
// determine direction
if (type1 != mjOBJ_UNKNOWN && type2 != mjOBJ_UNKNOWN) {
// both obj1 and obj2 specified: direction depends on order
int order_regular = match11 && match22;
int order_reverse = match12 && match21;
if (order_regular && !order_reverse) return 1;
if (order_reverse && !order_regular) return -1;
if (order_regular && order_reverse) return 1; // ambiguous, return 1
} else if (type1 != mjOBJ_UNKNOWN) {
// only obj1 specified: normal points away from obj1
return match11 ? 1 : -1;
} else if (type2 != mjOBJ_UNKNOWN) {
// only obj2 specified: normal points towards obj2
return match22 ? 1 : -1;
}
// should not occur, all conditions are covered above
return 0;
}
// fill in output data for contact sensor for all fields
// if flg_flip > 0, normal/tangent rotate 180 about frame[2]
// force/torque flip-z s.t. force is equal-and-opposite in new contact frame
static void copySensorData(const mjModel* m, const mjData* d,
mjtNum* data[mjNCONDATA], int id, int flg_flip, int nfound) {
// found flag
if (data[mjCONDATA_FOUND]) *data[mjCONDATA_FOUND] = nfound;
// contact force and torque
if (data[mjCONDATA_FORCE] || data[mjCONDATA_TORQUE]) {
mjtNum forcetorque[6];
mj_contactForce(m, d, id, forcetorque);
if (data[mjCONDATA_FORCE]) {
mju_copy3(data[mjCONDATA_FORCE], forcetorque);
if (flg_flip) data[mjCONDATA_FORCE][2] *= -1;
}
if (data[mjCONDATA_TORQUE]) {
mju_copy3(data[mjCONDATA_TORQUE], forcetorque+3);
if (flg_flip) data[mjCONDATA_TORQUE][2] *= -1;
}
}
// contact penetration distance
if (data[mjCONDATA_DIST]) {
*data[mjCONDATA_DIST] = d->contact[id].dist;
}
// contact position
if (data[mjCONDATA_POS]) {
mju_copy3(data[mjCONDATA_POS], d->contact[id].pos);
}
// contact normal
if (data[mjCONDATA_NORMAL]) {
mju_copy3(data[mjCONDATA_NORMAL], d->contact[id].frame);
if (flg_flip) mju_scl3(data[mjCONDATA_NORMAL], data[mjCONDATA_NORMAL], -1);
}
// contact first tangent
if (data[mjCONDATA_TANGENT]) {
mju_copy3(data[mjCONDATA_TANGENT], d->contact[id].frame+3);
if (flg_flip) mju_scl3(data[mjCONDATA_TANGENT], data[mjCONDATA_TANGENT], -1);
}
}
// compute total wrench about one point, in the global frame
static void total_wrench(mjtNum force[3], mjtNum torque[3], const mjtNum point[3], int n,
const mjtNum *wrench, const mjtNum *pos, const mjtNum *frame) {
mju_zero3(force);
mju_zero3(torque);
for (int j = 0; j < n; ++j) {
// rotate force, torque from contact frame to global frame
mjtNum force_j[3], torque_j[3];
mju_mulMatTVec3(force_j, frame + 9*j, wrench + 6*j);
mju_mulMatTVec3(torque_j, frame + 9*j, wrench + 6*j + 3);
// add to total force, torque
mju_addTo3(force, force_j);
mju_addTo3(torque, torque_j);
// add induced moment: torque += (pos - point) x force
mjtNum diff[3];
mju_sub3(diff, pos + 3*j, point);
mjtNum induced_torque[3];
mju_cross(induced_torque, diff, force_j);
mju_addTo3(torque, induced_torque);
}
}
//-------------------------------- sensor ----------------------------------------------------------
// position-dependent sensors
void mj_sensorPos(const mjModel* m, mjData* d) {
int ne = d->ne, nf = d->nf, nefc = d->nefc, nsensor = m->nsensor;
int nusersensor = 0;
// disabled sensors: return
if (mjDISABLED(mjDSBL_SENSOR)) {
return;
}
// process sensors matching stage
for (int i=0; i < nsensor; i++) {
mjtSensor type = (mjtSensor) m->sensor_type[i];
// skip sensor plugins -- these are handled after builtin sensor types
if (type == mjSENS_PLUGIN) {
continue;
}
if (m->sensor_needstage[i] == mjSTAGE_POS) {
// get sensor info
int objtype = m->sensor_objtype[i];
int objid = m->sensor_objid[i];
int refid = m->sensor_refid[i];
int reftype = m->sensor_reftype[i];
int adr = m->sensor_adr[i];
mjtNum rvec[3], *xpos, *xmat, *xpos_ref, *xmat_ref;
// process according to type
switch (type) {
case mjSENS_MAGNETOMETER: // magnetometer
mju_mulMatTVec(d->sensordata+adr, d->site_xmat+9*objid, m->opt.magnetic, 3, 3);
break;
case mjSENS_CAMPROJECTION: // camera projection
cam_project(d->sensordata+adr, d->site_xpos+3*objid, d->cam_xpos+3*refid,
d->cam_xmat+9*refid, m->cam_resolution+2*refid, m->cam_fovy[refid],
m->cam_intrinsic+4*refid, m->cam_sensorsize+2*refid);
break;
case mjSENS_RANGEFINDER: // rangefinder
rvec[0] = d->site_xmat[9*objid+2];
rvec[1] = d->site_xmat[9*objid+5];
rvec[2] = d->site_xmat[9*objid+8];
d->sensordata[adr] = mj_ray(m, d, d->site_xpos+3*objid, rvec, NULL, 1,
m->site_bodyid[objid], NULL);
break;
case mjSENS_JOINTPOS: // jointpos
d->sensordata[adr] = d->qpos[m->jnt_qposadr[objid]];
break;
case mjSENS_TENDONPOS: // tendonpos
d->sensordata[adr] = d->ten_length[objid];
break;
case mjSENS_ACTUATORPOS: // actuatorpos
d->sensordata[adr] = d->actuator_length[objid];
break;
case mjSENS_BALLQUAT: // ballquat
mju_copy4(d->sensordata+adr, d->qpos+m->jnt_qposadr[objid]);
mju_normalize4(d->sensordata+adr);
break;
case mjSENS_JOINTLIMITPOS: // jointlimitpos
d->sensordata[adr] = 0;
for (int j=ne+nf; j < nefc; j++) {
if (d->efc_type[j] == mjCNSTR_LIMIT_JOINT && d->efc_id[j] == objid) {
d->sensordata[adr] = d->efc_pos[j] - d->efc_margin[j];
break;
}
}
break;
case mjSENS_TENDONLIMITPOS: // tendonlimitpos
d->sensordata[adr] = 0;
for (int j=ne+nf; j < nefc; j++) {
if (d->efc_type[j] == mjCNSTR_LIMIT_TENDON && d->efc_id[j] == objid) {
d->sensordata[adr] = d->efc_pos[j] - d->efc_margin[j];
break;
}
}
break;
case mjSENS_FRAMEPOS: // framepos
case mjSENS_FRAMEXAXIS: // framexaxis
case mjSENS_FRAMEYAXIS: // frameyaxis
case mjSENS_FRAMEZAXIS: // framezaxis
// get xpos and xmat pointers for object frame
get_xpos_xmat(d, objtype, objid, i, &xpos, &xmat);
// reference frame unspecified: global frame
if (refid == -1) {
if (type == mjSENS_FRAMEPOS) {
mju_copy3(d->sensordata+adr, xpos);
} else {
// offset = (0 or 1 or 2) for (x or y or z)-axis sensors, respectively
int offset = type - mjSENS_FRAMEXAXIS;
d->sensordata[adr] = xmat[offset];
d->sensordata[adr+1] = xmat[offset+3];
d->sensordata[adr+2] = xmat[offset+6];
}
}
// reference frame specified
else {
get_xpos_xmat(d, reftype, refid, i, &xpos_ref, &xmat_ref);
if (type == mjSENS_FRAMEPOS) {
mju_sub3(rvec, xpos, xpos_ref);
mju_mulMatTVec3(d->sensordata+adr, xmat_ref, rvec);
} else {
// offset = (0 or 1 or 2) for (x or y or z)-axis sensors, respectively
int offset = type - mjSENS_FRAMEXAXIS;
mjtNum axis[3] = {xmat[offset], xmat[offset+3], xmat[offset+6]};
mju_mulMatTVec3(d->sensordata+adr, xmat_ref, axis);
}
}
break;
case mjSENS_FRAMEQUAT: // framequat
{
// get global object quaternion
mjtNum objquat[4];
get_xquat(m, d, objtype, objid, i, objquat);
// reference frame unspecified: copy object quaternion
if (refid == -1) {
mju_copy4(d->sensordata+adr, objquat);
} else {
// reference frame specified, get global reference quaternion
mjtNum refquat[4];
get_xquat(m, d, reftype, refid, i, refquat);
// relative quaternion
mju_negQuat(refquat, refquat);
mju_mulQuat(d->sensordata+adr, refquat, objquat);
}
}
break;
case mjSENS_SUBTREECOM: // subtreecom
mju_copy3(d->sensordata+adr, d->subtree_com+3*objid);
break;
case mjSENS_INSIDESITE: // insidesite
get_xpos_xmat(d, objtype, objid, i, &xpos, &xmat);
d->sensordata[adr] = mju_insideGeom(d->site_xpos + 3*refid,
d->site_xmat + 9*refid,
m->site_size + 3*refid,
m->site_type[refid],
xpos);
break;
case mjSENS_GEOMDIST: // signed distance between two geoms
case mjSENS_GEOMNORMAL: // normal direction between two geoms
case mjSENS_GEOMFROMTO: // segment between two geoms
{
// use cutoff for collision margin
mjtNum margin = m->sensor_cutoff[i];
// initialize outputs
mjtNum dist = margin; // collision distance
mjtNum fromto[6] = {0}; // segment between geoms
// get lists of geoms to collide
int n1, id1;
if (objtype == mjOBJ_BODY) {
n1 = m->body_geomnum[objid];
id1 = m->body_geomadr[objid];
} else {
n1 = 1;
id1 = objid;
}
int n2, id2;
if (reftype == mjOBJ_BODY) {
n2 = m->body_geomnum[refid];
id2 = m->body_geomadr[refid];
} else {
n2 = 1;
id2 = refid;
}
// collide all pairs
for (int geom1=id1; geom1 < id1+n1; geom1++) {
for (int geom2=id2; geom2 < id2+n2; geom2++) {
mjtNum fromto_new[6] = {0};
mjtNum dist_new = mj_geomDistance(m, d, geom1, geom2, margin, fromto_new);
if (dist_new < dist) {
dist = dist_new;
mju_copy(fromto, fromto_new, 6);
}
}
}
// write sensordata for this sensor and all subsequent sensors with identical signature
int write_sensor = 1;
while (write_sensor) {
// write geom distance
if (type == mjSENS_GEOMDIST) {
d->sensordata[adr] = dist;
}
// write distance normal
else if (type == mjSENS_GEOMNORMAL) {
mjtNum normal[3] = {fromto[3]-fromto[0], fromto[4]-fromto[1], fromto[5]-fromto[2]};
if (normal[0] || normal[1] || normal[2]) {
mju_normalize3(normal);
}
mju_copy3(d->sensordata + adr, normal);
}
// write distance fromto
else {
mju_copy(d->sensordata + adr, fromto, 6);
}
// if this is the last sensor, break
if (i+1 == nsensor) {
break;
}
// type of the next sensor
mjtSensor type_next = m->sensor_type[i+1];
// check if signature of next sensor matches this sensor
write_sensor = (type_next == mjSENS_GEOMDIST ||
type_next == mjSENS_GEOMNORMAL ||
type_next == mjSENS_GEOMFROMTO) &&
m->sensor_objtype[i+1] == objtype &&
m->sensor_objid[i+1] == objid &&
m->sensor_reftype[i+1] == reftype &&
m->sensor_refid[i+1] == refid &&
m->sensor_cutoff[i+1] == margin;
// if signature matches, increment external loop variable i
if (write_sensor) {
i++;
// update adr and type, everything else is the same
adr = m->sensor_adr[i];
type = type_next;
}
}
}
break;
case mjSENS_E_POTENTIAL: // potential energy
mj_energyPos(m, d);
d->sensordata[adr] = d->energy[0];
break;
case mjSENS_E_KINETIC: // kinetic energy
mj_energyVel(m, d);
d->sensordata[adr] = d->energy[1];
break;
case mjSENS_CLOCK: // clock
d->sensordata[adr] = d->time;
break;
case mjSENS_USER: // user
nusersensor++;
break;
default:
mjERROR("invalid sensor type in POS stage, sensor %d", i);
}
}
}
// fill in user sensors if detected
if (nusersensor && mjcb_sensor) {
mjcb_sensor(m, d, mjSTAGE_POS);
}
// compute plugin sensor values
if (m->nplugin) {
const int nslot = mjp_pluginCount();
for (int i=0; i < m->nplugin; i++) {
const int slot = m->plugin[i];
const mjpPlugin* plugin = mjp_getPluginAtSlotUnsafe(slot, nslot);
if (!plugin) {
mjERROR("invalid plugin slot: %d", slot);
}
if ((plugin->capabilityflags & mjPLUGIN_SENSOR) &&
(plugin->needstage == mjSTAGE_POS || plugin->needstage == mjSTAGE_NONE)) {
if (!plugin->compute) {
mjERROR("`compute` is a null function pointer for plugin at slot %d", slot);
}
plugin->compute(m, d, i, mjPLUGIN_SENSOR);
}
}
}
// cutoff
apply_cutoff(m, d, mjSTAGE_POS);
}
// velocity-dependent sensors
void mj_sensorVel(const mjModel* m, mjData* d) {
int objtype, objid, reftype, refid, adr, nusersensor = 0;
int ne = d->ne, nf = d->nf, nefc = d->nefc;
mjtNum xvel[6];
// disabled sensors: return
if (mjDISABLED(mjDSBL_SENSOR)) {
return;
}
// process sensors matching stage
int subtreeVel = 0;
for (int i=0; i < m->nsensor; i++) {
// skip sensor plugins -- these are handled after builtin sensor types
if (m->sensor_type[i] == mjSENS_PLUGIN) {
continue;
}
if (m->sensor_needstage[i] == mjSTAGE_VEL) {
// get sensor info
mjtSensor type = m->sensor_type[i];
objtype = m->sensor_objtype[i];
objid = m->sensor_objid[i];
refid = m->sensor_refid[i];
reftype = m->sensor_reftype[i];
adr = m->sensor_adr[i];
// call mj_subtreeVel when first relevant sensor is encountered
if (subtreeVel == 0 &&
(type == mjSENS_SUBTREELINVEL ||
type == mjSENS_SUBTREEANGMOM ||
type == mjSENS_USER)) {
// compute subtree_linvel, subtree_angmom
mj_subtreeVel(m, d);
// mark computed
subtreeVel = 1;
}
// process according to type
switch (type) {
case mjSENS_VELOCIMETER: // velocimeter
// xvel = site velocity, in site frame
mj_objectVelocity(m, d, mjOBJ_SITE, objid, xvel, 1);
// assign linear velocity
mju_copy3(d->sensordata+adr, xvel+3);
break;
case mjSENS_GYRO: // gyro
// xvel = site velocity, in site frame
mj_objectVelocity(m, d, mjOBJ_SITE, objid, xvel, 1);
// assign angular velocity
mju_copy3(d->sensordata+adr, xvel);
break;
case mjSENS_JOINTVEL: // jointvel
d->sensordata[adr] = d->qvel[m->jnt_dofadr[objid]];
break;
case mjSENS_TENDONVEL: // tendonvel
d->sensordata[adr] = d->ten_velocity[objid];
break;
case mjSENS_ACTUATORVEL: // actuatorvel
d->sensordata[adr] = d->actuator_velocity[objid];
break;
case mjSENS_BALLANGVEL: // ballangvel
mju_copy3(d->sensordata+adr, d->qvel+m->jnt_dofadr[objid]);
break;
case mjSENS_JOINTLIMITVEL: // jointlimitvel
d->sensordata[adr] = 0;
for (int j=ne+nf; j < nefc; j++) {
if (d->efc_type[j] == mjCNSTR_LIMIT_JOINT && d->efc_id[j] == objid) {
d->sensordata[adr] = d->efc_vel[j];
break;
}
}
break;
case mjSENS_TENDONLIMITVEL: // tendonlimitvel
d->sensordata[adr] = 0;
for (int j=ne+nf; j < nefc; j++) {
if (d->efc_type[j] == mjCNSTR_LIMIT_TENDON && d->efc_id[j] == objid) {
d->sensordata[adr] = d->efc_vel[j];
break;
}
}
break;
case mjSENS_FRAMELINVEL: // framelinvel
case mjSENS_FRAMEANGVEL: // frameangvel
// xvel = 6D object velocity, in global frame
mj_objectVelocity(m, d, objtype, objid, xvel, 0);
if (refid > -1) { // reference frame specified
mjtNum *xpos, *xmat, *xpos_ref, *xmat_ref, xvel_ref[6], rel_vel[6], cross[3], rvec[3];
// in global frame: object and reference position, reference orientation and velocity
get_xpos_xmat(d, objtype, objid, i, &xpos, &xmat);
get_xpos_xmat(d, reftype, refid, i, &xpos_ref, &xmat_ref);
mj_objectVelocity(m, d, reftype, refid, xvel_ref, 0);
// subtract velocities
mju_sub(rel_vel, xvel, xvel_ref, 6);
// linear velocity: add correction due to rotating reference frame
mju_sub3(rvec, xpos, xpos_ref);
mju_cross(cross, rvec, xvel_ref);
mju_addTo3(rel_vel+3, cross);
// project into reference frame
mju_mulMatTVec3(xvel, xmat_ref, rel_vel);
mju_mulMatTVec3(xvel+3, xmat_ref, rel_vel+3);
}
// copy linear or angular component
if (m->sensor_type[i] == mjSENS_FRAMELINVEL) {
mju_copy3(d->sensordata+adr, xvel+3);
} else {
mju_copy3(d->sensordata+adr, xvel);
}
break;
case mjSENS_SUBTREELINVEL: // subtreelinvel
mju_copy3(d->sensordata+adr, d->subtree_linvel+3*objid);
break;
case mjSENS_SUBTREEANGMOM: // subtreeangmom
mju_copy3(d->sensordata+adr, d->subtree_angmom+3*objid);
break;
case mjSENS_USER: // user
nusersensor++;
break;
default:
mjERROR("invalid type in VEL stage, sensor %d", i);
}
}
}
// fill in user sensors if detected
if (nusersensor && mjcb_sensor) {
mjcb_sensor(m, d, mjSTAGE_VEL);
}
// trigger computation of plugins
if (m->nplugin) {
const int nslot = mjp_pluginCount();
for (int i=0; i < m->nplugin; i++) {
const int slot = m->plugin[i];
const mjpPlugin* plugin = mjp_getPluginAtSlotUnsafe(slot, nslot);
if (!plugin) {
mjERROR("invalid plugin slot: %d", slot);
}
if ((plugin->capabilityflags & mjPLUGIN_SENSOR) && plugin->needstage == mjSTAGE_VEL) {
if (!plugin->compute) {
mjERROR("`compute` is null for plugin at slot %d", slot);
}
if (subtreeVel == 0) {
// compute subtree_linvel, subtree_angmom
// TODO(b/247107630): add a flag to allow plugin to specify whether it actually needs this
mj_subtreeVel(m, d);
// mark computed
subtreeVel = 1;
}
plugin->compute(m, d, i, mjPLUGIN_SENSOR);
}
}
}
// cutoff
apply_cutoff(m, d, mjSTAGE_VEL);
}
// acceleration/force-dependent sensors
void mj_sensorAcc(const mjModel* m, mjData* d) {
int rootid, bodyid, objtype, objid, adr, nusersensor = 0;
int ne = d->ne, nf = d->nf, nefc = d->nefc, nu = m->nu;
mjtNum tmp[6], conforce[6], conray[3], frc;
const mjContact* con;
// disabled sensors: return
if (mjDISABLED(mjDSBL_SENSOR)) {
return;
}
// process sensors matching stage
int rnePost = 0;
for (int i=0; i < m->nsensor; i++) {
// skip sensor plugins -- these are handled after builtin sensor types
if (m->sensor_type[i] == mjSENS_PLUGIN) {
continue;
}
if (m->sensor_needstage[i] == mjSTAGE_ACC) {
// get sensor info
mjtSensor type = m->sensor_type[i];
objtype = m->sensor_objtype[i];
objid = m->sensor_objid[i];
adr = m->sensor_adr[i];
// call mj_rnePostConstraint when first relevant sensor is encountered
if (rnePost == 0 && (type == mjSENS_ACCELEROMETER ||
type == mjSENS_FORCE ||
type == mjSENS_TORQUE ||
type == mjSENS_FRAMELINACC ||
type == mjSENS_FRAMEANGACC ||
type == mjSENS_USER)) {
// compute cacc, cfrc_int, cfrc_ext
mj_rnePostConstraint(m, d);
// mark computed
rnePost = 1;
}
// process according to type
switch (type) {
case mjSENS_TOUCH: // touch
// extract body data
bodyid = m->site_bodyid[objid];
// clear result
d->sensordata[adr] = 0;
// find contacts in sensor zone, add normal forces
for (int j=0; j < d->ncon; j++) {
// contact pointer, contacting bodies (-1 for flex)
con = d->contact + j;
int conbody[2];
for (int k=0; k < 2; k++) {
conbody[k] = (con->geom[k] >= 0) ? m->geom_bodyid[con->geom[k]] : -1;
}
// select contacts involving sensorized body
if (con->efc_address >= 0 && (bodyid == conbody[0] || bodyid == conbody[1])) {
// get contact force:torque in contact frame
mj_contactForce(m, d, j, conforce);
// nothing to do if normal is zero
if (conforce[0] <= 0) {
continue;
}
// convert contact normal force to global frame, normalize
mju_scl3(conray, con->frame, conforce[0]);
mju_normalize3(conray);
// flip ray direction if sensor is on body2
if (bodyid == conbody[1]) {
mju_scl3(conray, conray, -1);
}
// add if ray-zone intersection (always true when con->pos inside zone)
if (mju_rayGeom(d->site_xpos+3*objid, d->site_xmat+9*objid,
m->site_size+3*objid, con->pos, conray,
m->site_type[objid]) >= 0) {
d->sensordata[adr] += conforce[0];
}
}
}
break;
case mjSENS_CONTACT: // contact
{
// local reduce enum for readability
enum {
REDUCE_NONE = 0,
REDUCE_MINDIST = 1,
REDUCE_MAXFORCE = 2,
REDUCE_NETFORCE = 3,
};
// prepare sizes and indices
int dataspec = m->sensor_intprm[i*mjNSENS];
int size = mju_condataSize(dataspec); // size of each slot
int dim = m->sensor_dim[i]; // total sensor array dimension
int num = dim / size; // number of slots
int reftype = m->sensor_reftype[i];
int refid = m->sensor_refid[i];
int reduce = m->sensor_intprm[i*mjNSENS+1];
// clear all outputs, prepare data pointers
mjtNum* ptr = d->sensordata + adr;
mju_zero(ptr, dim);
mjtNum* data[mjNCONDATA] = {NULL};
for (int j=0; j < mjNCONDATA; j++) {
if (dataspec & (1 << j)) {
data[j] = ptr;
ptr += mjCONDATA_SIZE[j];
}
}
// prepare for matching loop
int nmatch = 0;
mj_markStack(d);
ContactInfo *match = mjSTACKALLOC(d, d->ncon, ContactInfo);
// find matching contacts
for (int j=0; j < d->ncon; j++) {
// check match condition
int match_j = matchContact(m, d, j, objtype, objid, reftype, refid);
if (!match_j) {
continue;
}
// save id and flip flag
match[nmatch].id = j;
match[nmatch].flip = match_j < 0;
// save sorting criterion, if required
if (reduce == REDUCE_MINDIST) {
match[nmatch].criterion = d->contact[j].dist;
} else if (reduce == REDUCE_MAXFORCE) {
mjtNum forcetorque[6];
mj_contactForce(m, d, j, forcetorque);
match[nmatch].criterion = -mju_dot3(forcetorque, forcetorque);
}
// increment number of matching contacts
nmatch++;
}
// number of slots to be filled
int nslot = mjMIN(num, nmatch);
// partial sort to get bottom nslot contacts if sorted reduction
if (reduce == REDUCE_MINDIST || reduce == REDUCE_MAXFORCE) {
ContactInfo *heap = mjSTACKALLOC(d, nslot, ContactInfo);
ContactSelect(match, heap, nmatch, nslot, NULL);
}
// netforce reduction
else if (reduce == REDUCE_NETFORCE) {
mjtNum *wrench = mjSTACKALLOC(d, nmatch * 6, mjtNum);
mjtNum *pos = mjSTACKALLOC(d, nmatch * 3, mjtNum);
mjtNum *frame = mjSTACKALLOC(d, nmatch * 9, mjtNum);
// precompute wrenches, positions, and frames, maybe flip wrench
for (int j=0; j < nmatch; j++) {
int conid = match[j].id;
mj_contactForce(m, d, conid, wrench + 6*j);
mju_copy3(pos + 3*j, d->contact[conid].pos);
mju_copy(frame + 9*j, d->contact[conid].frame, 9);
if (match[j].flip) {
mju_scl(wrench + 6*j , wrench + 6*j, -1, 6);
}
}
// compute point: force-weighted centroid of contact positions
mjtNum point[3] = {0};
mjtNum total_force = 0;
for (int j=0; j < nmatch; j++) {
mjtNum weight = mju_norm3(wrench + 6*j);
mju_addToScl3(point, pos + 3*j, weight);
total_force += weight;
}
mju_scl3(point, point, 1.0 / mjMAX(total_force, mjMINVAL));
// compute total wrench about point, in the global frame
mjtNum force[3], torque[3];
total_wrench(force, torque, point, nmatch, wrench, pos, frame);
// write data to slot 0
if (data[mjCONDATA_FOUND]) *data[mjCONDATA_FOUND] = nmatch;
if (data[mjCONDATA_FORCE]) mju_copy3(data[mjCONDATA_FORCE], force);
if (data[mjCONDATA_TORQUE]) mju_copy3(data[mjCONDATA_TORQUE], torque);
if (data[mjCONDATA_DIST]) *data[mjCONDATA_DIST] = 0;
if (data[mjCONDATA_POS]) mju_copy3(data[mjCONDATA_POS], point);
if (data[mjCONDATA_NORMAL]) data[mjCONDATA_NORMAL][0] = 1;
if (data[mjCONDATA_TANGENT]) data[mjCONDATA_TANGENT][1] = 1;
// done with this sensor
mj_freeStack(d);
break;
}
// copy data into slots, increment pointers
for (int j=0; j < nslot; j++) {
copySensorData(m, d, data, match[j].id, match[j].flip, nmatch);
for (int k=0; k < mjNCONDATA; k++) {
if (data[k]) data[k] += size;
}
}
mj_freeStack(d);
}
break;
case mjSENS_TACTILE: // tactile
{
mj_markStack(d);
// get parent weld id
int mesh_id = m->sensor_objid[i];
int geom_id = m->sensor_refid[i];
int parent_body = m->geom_bodyid[geom_id];
int parent_weld = m->body_weldid[parent_body];
int nchannel = m->sensor_dim[i] / m->mesh_vertnum[mesh_id];
// clear sensordata and distance matrix
mjtNum* sensordata = d->sensordata + m->sensor_adr[i];
mju_zero(sensordata, m->sensor_dim[i]);
// count contacts and get contact geom ids
// TODO: use a more efficient C version of unordered_set
int* contact_geom_ids = mj_stackAllocInt(d, d->ncon);
int ncontact = 0;
for (int k = 0; k < d->ncon; k++) {
int body1 = m->body_weldid[m->geom_bodyid[d->contact[k].geom1]];
int body2 = m->body_weldid[m->geom_bodyid[d->contact[k].geom2]];
if (body1 == parent_weld) {
int add = 1;
for (int j = 0; j < ncontact; j++) {
if (contact_geom_ids[j] == d->contact[k].geom2) {
add = 0;
break;
}
}
if (add) {
contact_geom_ids[ncontact] = d->contact[k].geom2;
ncontact++;
}
}
if (body2 == parent_weld) {
int add = 1;
for (int j = 0; j < ncontact; j++) {
if (contact_geom_ids[j] == d->contact[k].geom1) {
add = 0;
break;
}
}
if (add) {
contact_geom_ids[ncontact] = d->contact[k].geom1;
ncontact++;
}
}
}
// no contacts, return
if (ncontact == 0) {
mj_freeStack(d);
break;
}
// all of the quadrature points are contact points
int ncon = m->mesh_vertnum[mesh_id];
// get site frame
mjtNum* geom_pos = d->geom_xpos + 3*geom_id;
mjtNum* geom_mat = d->geom_xmat + 9*geom_id;
// allocate contact forces and positions
mjtNum* forcesT = mj_stackAllocNum(d, ncon*3);
mju_zero(forcesT, ncon*3);
// iterate over colliding geoms
for (int g = 0; g < ncontact; g++) {
int geom = contact_geom_ids[g];
int body = m->geom_bodyid[geom];
// get sdf plugin of the geoms
int sdf_instance[2] = {-1, -1};
mjtGeom geomtype[2] = {mjGEOM_SDF, mjGEOM_SPHERE};
const mjpPlugin* sdf_ptr[2] = {NULL, NULL};
if (m->geom_type[geom] == mjGEOM_SDF) {
sdf_instance[0] = m->geom_plugin[geom];
sdf_ptr[0] = mjc_getSDF(m, geom);
} else if (m->geom_type[geom] == mjGEOM_MESH) {
sdf_instance[0] = m->geom_dataid[geom];
geomtype[0] = (mjtGeom)m->geom_type[geom];
} else {
sdf_instance[0] = geom;
geomtype[0] = (mjtGeom)m->geom_type[geom];
}
// skip mesh geoms not having an octree
if (geomtype[0] == mjGEOM_MESH &&
m->mesh_octadr[m->geom_dataid[geom]] == -1) {
continue;
}
// set SDF parameters
mjSDF geom_sdf;
geom_sdf.id = &sdf_instance[0];
geom_sdf.type = mjSDFTYPE_SINGLE;
geom_sdf.plugin = &sdf_ptr[0];
geom_sdf.geomtype = &geomtype[0];
// get forces in mesh coordinates
int node = 0;
float* mesh_vert = m->mesh_vert + 3*m->mesh_vertadr[mesh_id];
float* mesh_normal = m->mesh_normal + 3*m->mesh_normaladr[mesh_id];
for (int j = 0; j < ncon; j++) {
// position in site frame
mjtNum pos[3] = {mesh_vert[3 * j + 0], mesh_vert[3 * j + 1],
mesh_vert[3 * j + 2]};
// position in global frame
mjtNum xpos[3];
mju_mulMatVec3(xpos, geom_mat, pos);
mju_addTo3(xpos, geom_pos);
// position in other geom frame
mjtNum lpos[3];
mju_sub3(tmp, xpos, d->geom_xpos + 3*geom);
mju_mulMatTVec3(lpos, d->geom_xmat + 9*geom, tmp);
// SDF plugins are in the original mesh frame
if (sdf_ptr[0] != NULL) {
mjtNum mesh_mat[9];
mju_quat2Mat(mesh_mat, m->mesh_quat + 4 * m->geom_dataid[geom]);
mju_mulMatVec3(lpos, mesh_mat, lpos);
mju_addTo3(lpos, m->mesh_pos + 3 * m->geom_dataid[geom]);
}
// compute distance
mjtNum depth = mju_min(mjc_distance(m, d, &geom_sdf, lpos), 0);
if (depth == 0) {
node++;
continue;
}
// get velocity in global frame
mjtNum vel_sensor[6], vel_other[6], vel_rel[3];
mju_transformSpatial(
vel_sensor, d->cvel + 6 * parent_weld, 0, xpos,
d->subtree_com + 3 * m->body_rootid[parent_weld], NULL);
mju_transformSpatial(
vel_other, d->cvel + 6 * body, 0, d->geom_xpos + 3 * geom,
d->subtree_com + 3 * m->body_rootid[body], NULL);
mju_sub3(vel_rel, vel_sensor+3, vel_other+3);
mjtNum normal[3] = {mesh_normal[9 * j + 0], mesh_normal[9 * j + 1],
mesh_normal[9 * j + 2]};
mjtNum tang1[3] = {mesh_normal[9 * j + 3], mesh_normal[9 * j + 4],
mesh_normal[9 * j + 5]};
mjtNum tang2[3] = {mesh_normal[9 * j + 6], mesh_normal[9 * j + 7],
mesh_normal[9 * j + 8]};
// get contact force/torque, rotate into node frame
mju_rotVecQuat(normal, normal, m->mesh_quat + 4 * mesh_id);
mju_rotVecQuat(tang1, tang1, m->mesh_quat + 4 * mesh_id);
mju_rotVecQuat(tang2, tang2, m->mesh_quat + 4 * mesh_id);
mjtNum force[3];
mjtNum kMaxDepth = 0.05;
mjtNum pressure = depth / mju_max(kMaxDepth - depth, mjMINVAL);
mju_scl3(force, normal, pressure);
// one row of mat^T * force
forcesT[0*ncon + node] = mju_dot3(force, normal);
forcesT[1*ncon + node] = mju_abs(mju_dot3(vel_rel, tang1));
forcesT[2*ncon + node] = mju_abs(mju_dot3(vel_rel, tang2));
node++;
}
}
// compute sensor output
for (int c = 0; c < nchannel; c++) {
if (!mju_isZero(forcesT + c*ncon, ncon)) {
mju_addTo(sensordata + c*ncon, forcesT + c*ncon, ncon);
}
}
mj_freeStack(d);
}
break;
case mjSENS_ACCELEROMETER: // accelerometer
// tmp = site acceleration, in site frame
mj_objectAcceleration(m, d, mjOBJ_SITE, objid, tmp, 1);
// assign linear acceleration
mju_copy3(d->sensordata+adr, tmp+3);
break;
case mjSENS_FORCE: // force
// extract body data
bodyid = m->site_bodyid[objid];
rootid = m->body_rootid[bodyid];
// tmp = interaction force between body and parent, in site frame
mju_transformSpatial(tmp, d->cfrc_int+6*bodyid, 1,
d->site_xpos+3*objid, d->subtree_com+3*rootid, d->site_xmat+9*objid);
// assign force
mju_copy3(d->sensordata+adr, tmp+3);
break;
case mjSENS_TORQUE: // torque
// extract body data
bodyid = m->site_bodyid[objid];
rootid = m->body_rootid[bodyid];
// tmp = interaction force between body and parent, in site frame
mju_transformSpatial(tmp, d->cfrc_int+6*bodyid, 1,
d->site_xpos+3*objid, d->subtree_com+3*rootid, d->site_xmat+9*objid);
// assign torque
mju_copy3(d->sensordata+adr, tmp);
break;
case mjSENS_ACTUATORFRC: // actuatorfrc
d->sensordata[adr] = d->actuator_force[objid];
break;
case mjSENS_JOINTACTFRC: // jointactfrc
d->sensordata[adr] = d->qfrc_actuator[m->jnt_dofadr[objid]];
break;
case mjSENS_TENDONACTFRC: // tendonactfrc
frc = 0.0;
for (int j=0; j < nu; j++) {
if (m->actuator_trntype[j] == mjTRN_TENDON && m->actuator_trnid[2*j] == objid) {
frc += d->actuator_force[j];
}
}
d->sensordata[adr] = frc;
break;
case mjSENS_JOINTLIMITFRC: // jointlimitfrc
d->sensordata[adr] = 0;
for (int j=ne+nf; j < nefc; j++) {
if (d->efc_type[j] == mjCNSTR_LIMIT_JOINT && d->efc_id[j] == objid) {
d->sensordata[adr] = d->efc_force[j];
break;
}
}
break;
case mjSENS_TENDONLIMITFRC: // tendonlimitfrc
d->sensordata[adr] = 0;
for (int j=ne+nf; j < nefc; j++) {
if (d->efc_type[j] == mjCNSTR_LIMIT_TENDON && d->efc_id[j] == objid) {
d->sensordata[adr] = d->efc_force[j];
break;
}
}
break;
case mjSENS_FRAMELINACC: // framelinacc
case mjSENS_FRAMEANGACC: // frameangacc
// get 6D object acceleration, in global frame
mj_objectAcceleration(m, d, objtype, objid, tmp, 0);
// copy linear or angular component
if (m->sensor_type[i] == mjSENS_FRAMELINACC) {
mju_copy3(d->sensordata+adr, tmp+3);
} else {
mju_copy3(d->sensordata+adr, tmp);
}
break;
case mjSENS_USER: // user
nusersensor++;
break;
default:
mjERROR("invalid type in ACC stage, sensor %d", i);
}
}
}
// fill in user sensors if detected
if (nusersensor && mjcb_sensor) {
mjcb_sensor(m, d, mjSTAGE_ACC);
}
// trigger computation of plugins
if (m->nplugin) {
const int nslot = mjp_pluginCount();
for (int i=0; i < m->nplugin; i++) {
const int slot = m->plugin[i];
const mjpPlugin* plugin = mjp_getPluginAtSlotUnsafe(slot, nslot);
if (!plugin) {
mjERROR("invalid plugin slot: %d", slot);
}
if ((plugin->capabilityflags & mjPLUGIN_SENSOR) && plugin->needstage == mjSTAGE_ACC) {
if (!plugin->compute) {
mjERROR("`compute` is null for plugin at slot %d", slot);
}
if (rnePost == 0) {
// compute cacc, cfrc_int, cfrc_ext
// TODO(b/247107630): add a flag to allow plugin to specify whether it actually needs this
mj_rnePostConstraint(m, d);
// mark computed
rnePost = 1;
}
plugin->compute(m, d, i, mjPLUGIN_SENSOR);
}
}
}
// cutoff
apply_cutoff(m, d, mjSTAGE_ACC);
}
//-------------------------------- energy ----------------------------------------------------------
// position-dependent energy (potential)
void mj_energyPos(const mjModel* m, mjData* d) {
int padr;
mjtNum dif[3], quat[4], stiffness;
// init potential energy: -sum_i body(i).mass * mju_dot(body(i).pos, gravity)
d->energy[0] = 0;
if (!mjDISABLED(mjDSBL_GRAVITY)) {
for (int i=1; i < m->nbody; i++) {
d->energy[0] -= m->body_mass[i] * mju_dot3(m->opt.gravity, d->xipos+3*i);
}
}
// add joint-level springs
if (!mjDISABLED(mjDSBL_SPRING)) {
for (int i=0; i < m->njnt; i++) {
stiffness = m->jnt_stiffness[i];
padr = m->jnt_qposadr[i];
switch ((mjtJoint) m->jnt_type[i]) {
case mjJNT_FREE:
mju_sub3(dif, d->qpos+padr, m->qpos_spring+padr);
d->energy[0] += 0.5*stiffness*mju_dot3(dif, dif);
// continue with rotations
padr += 3;
mjFALLTHROUGH;
case mjJNT_BALL:
// convert quaternion difference into angular "velocity"
mju_copy4(quat, d->qpos+padr);
mju_normalize4(quat);
mju_subQuat(dif, d->qpos + padr, m->qpos_spring + padr);
d->energy[0] += 0.5*stiffness*mju_dot3(dif, dif);
break;
case mjJNT_SLIDE:
case mjJNT_HINGE:
d->energy[0] += 0.5*stiffness*
(d->qpos[padr] - m->qpos_spring[padr])*
(d->qpos[padr] - m->qpos_spring[padr]);
break;
}
}
}
// add tendon-level springs
if (!mjDISABLED(mjDSBL_SPRING)) {
for (int i=0; i < m->ntendon; i++) {
stiffness = m->tendon_stiffness[i];
mjtNum length = d->ten_length[i];
mjtNum displacement = 0;
// compute spring displacement
mjtNum lower = m->tendon_lengthspring[2*i];
mjtNum upper = m->tendon_lengthspring[2*i+1];
if (length > upper) {
displacement = upper - length;
} else if (length < lower) {
displacement = lower - length;
}
d->energy[0] += 0.5*stiffness*displacement*displacement;
}
}
// add flex-level springs for dim=1
if (!mjDISABLED(mjDSBL_SPRING)) {
for (int i=0; i < m->nflex; i++) {
stiffness = m->flex_edgestiffness[i];
if (m->flex_rigid[i] || stiffness == 0 || m->flex_dim[i] > 1) {
continue;
}
// process non-rigid edges of this flex
int flex_edgeadr = m->flex_edgeadr[i];
int flex_edgenum = m->flex_edgenum[i];
for (int e=flex_edgeadr; e < flex_edgeadr+flex_edgenum; e++) {
if (!m->flexedge_rigid[e]) {
mjtNum displacement = m->flexedge_length0[e] - d->flexedge_length[e];
d->energy[0] += 0.5*stiffness*displacement*displacement;
};
}
}
}
}
// velocity-dependent energy (kinetic)
void mj_energyVel(const mjModel* m, mjData* d) {
mj_markStack(d);
mjtNum *vec = mjSTACKALLOC(d, m->nv, mjtNum);
// kinetic energy: 0.5 * qvel' * M * qvel
mj_mulM(m, d, vec, d->qvel);
d->energy[1] = 0.5*mju_dot(vec, d->qvel, m->nv);
mj_freeStack(d);
}