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Implement viscous pause in Studio

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Viscous pause is like pause but the simulation continues with zero gravity, high viscosity and passive springs disabled. It is useful to move things like cabinets with shelves---just move the shelf and the drawers come along as well.

* Updated the simulation control widgets
* Added Ctrl-space shortcut to toggle play/viscous pause

PiperOrigin-RevId: 869810053
Change-Id: Icf649e1f2631c2a64a5d2f25af9537b6a12bdf2c
This commit is contained in:
Matija Kecman
2026-02-13 11:10:22 -08:00
committed by Copybara-Service
parent 5274e5f720
commit 1808079c62
6 changed files with 200 additions and 69 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/experimental/platform/gui.cc
+1 -1
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@@ -627,7 +627,7 @@ void PhysicsGui(mjModel* model, float min_width) {
ImGui_InputN("Wind", opt.wind, 3);
ImGui_InputN("Magnetic", opt.magnetic, 3);
ImGui_Input("Density", &opt.density, {.min = .1, .max = 1});
ImGui_Input("Viscosity", &opt.viscosity, {.min = .1, .max = 1});
ImGui_Input("Viscosity", &opt.viscosity, {.min = .1, .max = 10});
ImGui_Input("Imp Ratio", &opt.impratio, {.min = .1, .max = 1});
ImGui::TreePop();
};
src/experimental/platform/imgui_widgets.h
+19
View File
@@ -39,6 +39,7 @@ static constexpr const char ICON_FA_DIAMOND[] = "\xEF\x88\x99";
static constexpr const char ICON_FA_EJECT[] = "\xEF\x81\x92";
static constexpr const char ICON_FA_FAST_FORWARD[] = "\xEF\x81\x90";
static constexpr const char ICON_FA_MOON[] = "\xEF\x86\x86";
static constexpr const char ICON_FA_MAGIC[] = "\xEF\x83\x90";
static constexpr const char ICON_FA_PAUSE[] = "\xEF\x81\x8C";
static constexpr const char ICON_FA_PLAY[] = "\xEF\x81\x8B";
static constexpr const char ICON_FA_REFRESH[] = "\xEF\x80\xA1";
@@ -262,6 +263,24 @@ inline bool ImGui_IsChordJustPressed(ImGuiKeyChord chord) {
return ImGui::IsKeyChordPressed(chord, 0);
}
// Stateful button that displays the given color when active, and shows a
// semi-transparent hover color (controlled by hover_alpha) when inactive.
inline bool ImGui_ColorButton(const char* label, bool active, ImColor color,
const ImVec2& size = ImVec2(0, 0),
float hover_alpha = 0.5f) {
ScopedStyle style;
const ImColor hover(color.Value.x, color.Value.y, color.Value.z,
color.Value.w * hover_alpha);
if (active) {
style.Color(ImGuiCol_Button, color);
style.Color(ImGuiCol_ButtonHovered, color);
} else {
style.Color(ImGuiCol_ButtonHovered, hover);
}
style.Color(ImGuiCol_ButtonActive, color);
return ImGui::Button(label, size);
}
// Begin a boxed section with outer borders - use EndBoxSection to close.
inline bool BeginBoxSection(const char* id, ImGuiTableFlags extra_flags = 0) {
ImGuiTableFlags flags = ImGuiTableFlags_BordersOuter | extra_flags;
src/experimental/platform/step_control.cc
+35 -17
View File
@@ -13,10 +13,12 @@
// limitations under the License.
#include "experimental/platform/step_control.h"
#include <algorithm>
#include <chrono>
#include <cstdlib>
#include <ratio>
#include <mujoco/mujoco.h>
namespace mujoco::platform {
@@ -28,17 +30,11 @@ static mjtNum Timer() {
return Milliseconds(Clock::now() - start).count();
}
StepControl::StepControl() {
mjcb_time = Timer;
}
StepControl::StepControl() { mjcb_time = Timer; }
float StepControl::GetSpeedMeasured() const {
return speed_measured_;
}
float StepControl::GetSpeedMeasured() const { return speed_measured_; }
float StepControl::GetSpeed() const {
return speed_;
}
float StepControl::GetSpeed() const { return speed_; }
void StepControl::SetSpeed(float speed_percent_real_time) {
speed_ = std::clamp(speed_percent_real_time, .1f, 100.f);
@@ -59,12 +55,34 @@ void StepControl::SetNoiseParameters(float ctrl_noise_scale,
ctrl_noise_rate_ = ctrl_noise_rate;
}
StepControl::Status StepControl::Advance(const mjModel* m, mjData* d) {
void StepControl::SetPauseState(PauseState state, mjModel* m) {
if (pause_state_ == PauseState::kViscousPaused &&
state != PauseState::kViscousPaused && m) {
mju_copy3(m->opt.gravity, saved_gravity_);
m->opt.viscosity = saved_viscosity_;
m->opt.disableflags = saved_disableflags_;
}
if (state == PauseState::kViscousPaused &&
pause_state_ != PauseState::kViscousPaused && m) {
mju_copy3(saved_gravity_, m->opt.gravity);
saved_viscosity_ = m->opt.viscosity;
saved_disableflags_ = m->opt.disableflags;
mju_zero3(m->opt.gravity);
m->opt.viscosity = 10;
m->opt.disableflags |= mjDSBL_SPRING;
}
pause_state_ = state;
}
StepControl::Status StepControl::Advance(mjModel* m, mjData* d) {
if (!m) {
return Status::kOk;
}
if (paused_) {
if (pause_state_ == PauseState::kNormalPaused) {
// When we eventually unpause, we need to make sure we sync to immediately
// and step once. Without this we could step many times before rendering
// resulting in a noticeable delay before the simulation restarts
@@ -151,7 +169,7 @@ StepControl::Status StepControl::Advance(const mjModel* m, mjData* d) {
for (mjtWarning w : kDivergedWarnings) {
if (d->warning[w].number > 0) {
// Stop stepping if the simulation diverged.
paused_ = true;
pause_state_ = PauseState::kNormalPaused;
return Status::kDiverged;
}
}
@@ -179,7 +197,7 @@ void StepControl::InjectNoise(const mjModel* m, mjData* d) {
// convert rate and scale to discrete time (Ornstein–Uhlenbeck)
mjtNum rate = mju_exp(-m->opt.timestep / ctrl_noise_rate_);
mjtNum scale = ctrl_noise_std_ * mju_sqrt(1-rate*rate);
mjtNum scale = ctrl_noise_std_ * mju_sqrt(1 - rate * rate);
for (int i = 0; i < m->nu; i++) {
mjtNum bottom = 0;
@@ -187,14 +205,14 @@ void StepControl::InjectNoise(const mjModel* m, mjData* d) {
mjtNum midpoint = 0;
mjtNum halfrange = 1;
if (m->actuator_ctrllimited[i]) {
bottom = m->actuator_ctrlrange[2*i];
top = m->actuator_ctrlrange[2*i+1];
midpoint = 0.5 * (top + bottom); // target of exponential decay
bottom = m->actuator_ctrlrange[2 * i];
top = m->actuator_ctrlrange[2 * i + 1];
midpoint = 0.5 * (top + bottom); // target of exponential decay
halfrange = 0.5 * (top - bottom); // scales noise
}
// exponential convergence to midpoint at ctrl_noise_rate
d->ctrl[i] = rate * d->ctrl[i] + (1-rate) * midpoint;
d->ctrl[i] = rate * d->ctrl[i] + (1 - rate) * midpoint;
// add noise
d->ctrl[i] += scale * halfrange * mju_standardNormal(nullptr);
src/experimental/platform/step_control.h
+18 -9
View File
@@ -36,6 +36,10 @@ class StepControl {
// Simulation was not stepped because it is paused.
kPaused,
// Simulation is viscously paused (stepping with zero gravity, high
// viscosity, and no spring forces).
kViscousPaused,
// Simulation diverged with autoreset enabled.
kAutoReset,
@@ -49,7 +53,7 @@ class StepControl {
mjWARN_BADQACC, mjWARN_BADQVEL, mjWARN_BADQPOS};
// Steps physics forward, respecting speed settings and refresh budget.
Status Advance(const mjModel* m, mjData* d);
Status Advance(mjModel* m, mjData* d);
// Ensures the next call to Advance() will synchronize time and step once.
void ForceSync();
@@ -63,13 +67,14 @@ class StepControl {
void GetNoiseParameters(float& noise_scale, float& noise_rate) const;
void SetNoiseParameters(float noise_scale, float noise_rate);
// Returns true if the simulation is paused.
bool IsPaused() { return paused_; }
enum class PauseState { kUnpaused, kNormalPaused, kViscousPaused };
// Pauses/unpauses the simulation.
void Pause() { paused_ = true; }
void Unpause() { paused_ = false; }
void TogglePause() { paused_ = !paused_; }
// Sets the pause state of the simulation.
// m must be non-null for viscous pausing.
void SetPauseState(PauseState state, mjModel* m = nullptr);
// Gets the current pause state of the simulation.
PauseState GetPauseState() const { return pause_state_; }
// If the simulation is paused, will perform a single step on the next
// Advance() call.
@@ -104,8 +109,12 @@ class StepControl {
// Maximum mis-alignment before re-sync (simulation seconds)
double sync_misalign_ = .1;
// Whether or not the simulation is paused.
bool paused_ = false;
PauseState pause_state_ = PauseState::kUnpaused;
// Viscous pause state variables
mjtNum saved_gravity_[3] = {0};
mjtNum saved_viscosity_ = 0;
int saved_disableflags_ = 0;
// Perform only a single step on the next call to Advance() if the simulation
// is paused.
src/experimental/studio/app.cc
+124 -42
View File
@@ -17,6 +17,7 @@
#include <algorithm>
#include <array>
#include <cfloat>
#include <cmath>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
@@ -32,8 +33,8 @@
#include <imgui.h>
#include <implot.h>
#include <mujoco/mujoco.h>
#include "experimental/platform/gui.h"
#include "experimental/platform/file_dialog.h"
#include "experimental/platform/gui.h"
#include "experimental/platform/helpers.h"
#include "experimental/platform/imgui_widgets.h"
#include "experimental/platform/interaction.h"
@@ -46,6 +47,8 @@
namespace mujoco::studio {
using PauseState = platform::StepControl::PauseState;
static void ToggleFlag(mjtByte& flag) { flag = flag ? 0 : 1; }
static void ToggleWindow(bool& window) {
@@ -66,6 +69,7 @@ static void SelectParentPerturb(const mjModel* model, mjvPerturb& perturb) {
static constexpr const char* ICON_PLAY = platform::ICON_FA_PLAY;
static constexpr const char* ICON_PAUSE = platform::ICON_FA_PAUSE;
static constexpr const char* ICON_VISCOUS_PAUSE = platform::ICON_FA_MAGIC;
static constexpr const char* ICON_COPY_CAMERA = platform::ICON_FA_COPY;
static constexpr const char* ICON_UNLOAD_MODEL = platform::ICON_FA_EJECT;
static constexpr const char* ICON_RELOAD_MODEL = platform::ICON_FA_REFRESH;
@@ -101,8 +105,7 @@ static constexpr std::array<const char*, 31> kPercentRealTime = {
};
// clang-format on
App::App(Config config)
: ini_path_(std::move(config.ini_path)) {
App::App(Config config) : ini_path_(std::move(config.ini_path)) {
platform::Window::Config window_config;
window_config.renderer_backend = platform::Renderer::GetBackend();
window_config.offscreen_mode = config.offscreen_mode;
@@ -173,11 +176,11 @@ void App::OnModelLoaded(std::string filename, ModelKind model_kind) {
model_path_ = std::move(filename);
if (model_kind_ == kEmptyModel) {
step_control_.Unpause();
step_control_.SetPauseState(PauseState::kUnpaused);
}
model_kind_ = model_kind;
if (model_kind_ == kEmptyModel) {
step_control_.Pause();
step_control_.SetPauseState(PauseState::kNormalPaused);
}
// Reset/reinitialize everything that depends on the new mjModel.
@@ -251,7 +254,7 @@ void App::UpdatePhysics() {
});
if (!stepped) {
if (!step_control_.IsPaused()) {
if (step_control_.GetPauseState() != PauseState::kNormalPaused) {
mju_zero(data()->xfrc_applied, 6 * model()->nbody);
mjv_applyPerturbPose(model(), data(), &perturb_, 0);
mjv_applyPerturbForce(model(), data(), &perturb_);
@@ -299,7 +302,7 @@ void App::LoadHistory(int offset) {
std::span<mjtNum> state = history_.SetIndex(offset);
if (!state.empty()) {
// Pause simulation when entering history mode.
step_control_.Pause();
step_control_.SetPauseState(PauseState::kNormalPaused);
// Load the state into the data buffer.
mj_setState(model(), data(), state.data(), mjSTATE_INTEGRATION);
@@ -540,19 +543,32 @@ void App::HandleKeyboardEvents() {
} else if (ImGui_IsChordJustPressed(ImGuiKey_Equal)) {
SetSpeedIndex(tmp_.speed_index - 1);
} else if (ImGui_IsChordJustPressed(ImGuiKey_LeftArrow)) {
if (step_control_.IsPaused()) {
if (step_control_.GetPauseState() == PauseState::kNormalPaused) {
LoadHistory(history_.GetIndex() - 1);
}
} else if (ImGui_IsChordJustPressed(ImGuiKey_RightArrow)) {
if (step_control_.IsPaused()) {
if (step_control_.GetPauseState() == PauseState::kNormalPaused) {
if (history_.GetIndex() == 0) {
step_control_.RequestSingleStep();
} else {
LoadHistory(history_.GetIndex() + 1);
}
}
} else if (ImGui_IsChordJustPressed(ImGuiMod_Ctrl | ImGuiKey_Space)) {
if (step_control_.GetPauseState() == PauseState::kViscousPaused) {
step_control_.SetPauseState(PauseState::kUnpaused, model());
} else {
step_control_.SetPauseState(PauseState::kViscousPaused, model());
tmp_.viscous_pause_time = ImGui::GetTime();
}
} else if (ImGui_IsChordJustPressed(ImGuiKey_Space)) {
step_control_.TogglePause();
if (step_control_.GetPauseState() == PauseState::kViscousPaused) {
step_control_.SetPauseState(PauseState::kNormalPaused, model());
} else if (step_control_.GetPauseState() == PauseState::kUnpaused) {
step_control_.SetPauseState(PauseState::kNormalPaused);
} else {
step_control_.SetPauseState(PauseState::kUnpaused);
}
} else if (ImGui_IsChordJustPressed(ImGuiKey_Backspace)) {
ResetPhysics();
} else if (ImGui_IsChordJustPressed(ImGuiKey_PageUp)) {
@@ -854,14 +870,16 @@ void App::BuildGui() {
style.Var(ImGuiStyleVar_Alpha, 0.6f);
if (ImGui::Begin("Stats", &tmp_.stats)) {
const float fps = renderer_->GetFps();
platform::StatsGui(model(), data(), step_control_.IsPaused(), fps);
platform::StatsGui(
model(), data(),
step_control_.GetPauseState() == PauseState::kNormalPaused, fps);
}
ImGui::End();
}
// Display a drag-and-drop message if no model is loaded.
if (model_kind_ == kEmptyModel) {
#ifndef __EMSCRIPTEN__
#ifndef __EMSCRIPTEN__
const char* text = "Load model file or drag-and-drop model file here.";
const float width = window_->GetWidth() * ImGui::GetWindowDpiScale();
@@ -881,7 +899,7 @@ void App::BuildGui() {
ImGui::Text("%s", text);
}
ImGui::End();
#endif // !__EMSCRIPTEN__
#endif // !__EMSCRIPTEN__
}
FileDialogGui();
@@ -1159,6 +1177,7 @@ void App::HelpGui() {
ImGui::Text("Toggle Fullscreen");
ImGui::Text("Free Camera");
ImGui::Text("Toggle Pause");
ImGui::Text("Toggle Visc Pause");
ImGui::Text("Reset Sim");
ImGui::Text("Toggle Left UI");
ImGui::Text("Toggle Right UI");
@@ -1184,6 +1203,7 @@ void App::HelpGui() {
ImGui::Text("F11");
ImGui::Text("Esc");
ImGui::Text("Spc");
ImGui::Text("Ctrl+Spc");
ImGui::Text("Bksp");
ImGui::Text("Tab");
ImGui::Text("Sh+Tab");
@@ -1265,7 +1285,7 @@ void App::ToolBarGui() {
const float scale = ImGui::GetWindowDpiScale();
const float right_width = 520.f * scale;
const ImVec2 button_size(48.f * scale, 32.f * scale);
const ImVec2 play_button_size(120.f * scale, 32.f * scale);
const ImVec2 play_button_size(80.f * scale, 32.f * scale);
ImGui::TableSetupColumn("", ImGuiTableColumnFlags_WidthStretch);
ImGui::TableSetupColumn("", ImGuiTableColumnFlags_WidthFixed, right_width);
@@ -1273,21 +1293,35 @@ void App::ToolBarGui() {
ImGui::TableNextColumn();
ImGui::Text("%s", " ");
// Unload button.
ImGui::SameLine();
style.Color(ImGuiCol_ButtonHovered, red);
if (ImGui::Button(ICON_UNLOAD_MODEL, button_size)) {
InitEmptyModel();
}
ImGui::SetItemTooltip("%s", "Unload");
style.Reset();
// Combined (Unload, Reload) widget
{
style.Var(ImGuiStyleVar_FrameRounding, 2.0f);
// Reload button.
ImGui::SameLine();
if (ImGui::Button(ICON_RELOAD_MODEL, button_size)) {
RequestModelReload();
// Unload button.
ImGui::SameLine();
{
const ImColor a = red;
const ImColor h(a.Value.x, a.Value.y, a.Value.z, a.Value.w * 0.6f);
style.Color(ImGuiCol_ButtonHovered, h);
style.Color(ImGuiCol_ButtonActive, a);
if (ImGui::Button(ICON_UNLOAD_MODEL, button_size)) {
InitEmptyModel();
}
ImGui::SetItemTooltip("%s", "Unload");
style.Reset();
}
// Reload button.
ImGui::SameLine(0, 0);
if (ImGui::Button(ICON_RELOAD_MODEL, button_size)) {
RequestModelReload();
}
ImGui::SetItemTooltip("%s", "Reload");
}
ImGui::SetItemTooltip("%s", "Reload");
ImGui::SameLine(0, 0);
ImGui::Text(" ");
// Reset button.
ImGui::SameLine();
@@ -1296,15 +1330,54 @@ void App::ToolBarGui() {
}
ImGui::SetItemTooltip("%s", "Reset");
// Play/pause button.
ImGui::SameLine();
const bool paused = step_control_.IsPaused();
style.Color(ImGuiCol_Button, paused ? yellow : green);
if (ImGui::Button(paused ? ICON_PLAY : ICON_PAUSE, play_button_size)) {
step_control_.TogglePause();
ImGui::SameLine(0, 0);
ImGui::Text(" ");
// Combined (Normal Pause, Viscous Pause, Play) widget
{
style.Var(ImGuiStyleVar_FrameRounding, 2.0f);
// Normal pause button.
ImGui::SameLine();
ImColor paused_color = yellow;
bool paused = step_control_.GetPauseState() == PauseState::kNormalPaused;
if (platform::ImGui_ColorButton(ICON_PAUSE, paused, paused_color,
button_size)) {
if (!paused) {
step_control_.SetPauseState(PauseState::kNormalPaused, model());
}
}
ImGui::SetItemTooltip("%s", "Pause");
// Viscous pause button.
ImGui::SameLine(0, 0);
ImColor vpaused_color = green;
float t = 0.f;
bool vpaused =
step_control_.GetPauseState() == PauseState::kViscousPaused;
if (vpaused) {
t = ImGui::GetTime() - tmp_.viscous_pause_time;
t = std::sqrt(std::min(t / 0.75f, 1.0f));
vpaused_color = ImColor(ImLerp(green.Value, yellow.Value, t));
}
if (platform::ImGui_ColorButton(ICON_VISCOUS_PAUSE, vpaused,
vpaused_color, button_size,
t < 1.0f ? 1.0f : 0.5f)) {
if (!vpaused) {
step_control_.SetPauseState(PauseState::kViscousPaused, model());
tmp_.viscous_pause_time = ImGui::GetTime();
}
}
ImGui::SetItemTooltip("%s", "Viscous Pause");
// Play button.
ImGui::SameLine(0, 0);
if (platform::ImGui_ColorButton(
ICON_PLAY, step_control_.GetPauseState() == PauseState::kUnpaused,
green, button_size, 0.6f)) {
step_control_.SetPauseState(PauseState::kUnpaused, model());
}
}
ImGui::SetItemTooltip("%s", paused ? "Play" : "Pause");
style.Reset();
ImGui::SameLine();
ImGui::Text("%s", " |");
@@ -1433,7 +1506,10 @@ void App::StatusBarGui() {
if (!has_model()) {
ImGui::Text("No model loaded");
} else if (step_control_.IsPaused()) {
} else if (step_control_.GetPauseState() == PauseState::kViscousPaused) {
ImGui::Text("Viscous Pause");
ImGui::SetItemTooltip("Zero gravity, high viscosity, no spring forces");
} else if (step_control_.GetPauseState() == PauseState::kNormalPaused) {
ImGui::Text("Paused");
} else {
const float desired_realtime = step_control_.GetSpeed();
@@ -1504,7 +1580,7 @@ void App::StatusBarGui() {
void App::MainMenuGui() {
if (ImGui::BeginMainMenuBar()) {
if (ImGui::BeginMenu("File")) {
#ifndef __EMSCRIPTEN__
#ifndef __EMSCRIPTEN__
if (ImGui::MenuItem("Open Model File", "Ctrl+O")) {
tmp_.file_dialog = UiTempState::FileDialog_Load;
}
@@ -1526,22 +1602,28 @@ void App::MainMenuGui() {
tmp_.file_dialog = UiTempState::FileDialog_PrintData;
}
ImGui::Separator();
#endif // !__EMSCRIPTEN__
#endif // !__EMSCRIPTEN__
if (ImGui::MenuItem("Unload", "Ctrl+U")) {
InitEmptyModel();
}
#ifndef __EMSCRIPTEN__
#ifndef __EMSCRIPTEN__
ImGui::Separator();
if (ImGui::MenuItem("Quit", "Ctrl+Q")) {
tmp_.should_exit = true;
}
#endif // !__EMSCRIPTEN__
#endif // !__EMSCRIPTEN__
ImGui::EndMenu();
}
if (ImGui::BeginMenu("Simulation")) {
if (ImGui::MenuItem("Pause", "Space", step_control_.IsPaused())) {
step_control_.TogglePause();
if (ImGui::MenuItem(
"Pause", "Space",
step_control_.GetPauseState() == PauseState::kNormalPaused)) {
if (step_control_.GetPauseState() != PauseState::kNormalPaused) {
step_control_.SetPauseState(PauseState::kNormalPaused);
} else {
step_control_.SetPauseState(PauseState::kUnpaused, model());
}
}
if (ImGui::MenuItem("Reset", "Backspace")) {
ResetPhysics();
src/experimental/studio/app.h
+3
View File
@@ -123,6 +123,9 @@ class App {
// Controls.
bool perturb_active = false;
// Time at which viscous pause was activated, for the green→yellow button
// color animation.
double viscous_pause_time = 0;
int speed_index = 0;
float cam_speed = 0.0f;