Engine COMP

Summary

The Engine COMP will run a .tox file (component) in a separate process. It uses TouchEngine to manage these processes and pass data between the loaded component and the main project.

Inputs and Outputs

The chosen component's top-level Inputs and Outputs are exposed as inputs and outputs on the Engine COMP. Only TOP, CHOP and DAT inputs and outputs are supported.

Custom Parameters

Any custom parameters on the top-level component are added to the Engine COMP's parameters. Custom parameters which refer to other nodes in the network, such as TOP, CHOP and DAT parameters, are not supported - you should use inputs to connect those nodes instead.

Note that parameters work in one direction only - you cannot set a parameter from within the loaded .tox.

External File Paths

By default, relative paths on OPs or in scripts inside the loaded component are relative to the .tox file's location. This can be changed with the 'Asset Paths' parameter. Relative paths as file or folder custom parameters of the component - those that show up on the Engine COMP - are always relative to the main project.

Monitoring Engine Status

It is useful to monitor the state and performance of the Engine COMP. By default, an Info DAT is docked to the Engine COMP and contains file path and process ID. A docked Info CHOP contains three sets of monitoring channels: The Info Type menu is by default set to TouchEngine Status which gives loading / running / error status of the Engine process. Changing the menu to TouchEngine Perform gives the engine's performance statistics, and changing the menu to Initialize/Start give ready / running state information specifically about your loaded component since it can be paused, timed and re-initialized.

Controlling Engine State

The Engine process will be started by the TouchDesigner process and it will run your .tox component automatically. But you can have more control over the time/memory management of multiple components using the Unload, Reload pulse parameters for the currently-loaded .tox file. On the Advanced page, the Launch and Quit Engine Process parameters give you terminate/restart control of the entire Engine process.

Component Lifetime

Under TouchEngine, components are loaded into an already-running instance. For this reason, an Execute DAT's onStart() and onExit() method will never be executed under TouchEngine. The onCreate() method will be executed when the component is loaded, and is a good place to do any setup you would normally do in onStart().

Time in TouchEngine

When the Engine COMP starts the component (after it has loaded, if 'Start when Initialized' is On), the component time in TouchEngine is 0. It will then increase either in sync with the Engine COMP or according to TouchEngine's internal clock, depending on the setting of the 'Clock' parameter on the Tune parameter page.

An input buffer and output buffer are used to allow for differences in cook rate between the Engine COMP and TouchEngine. Often you may want to adjust the parameters on the Tune page to suit your particular setup. The Engine COMP will cook frames to fill its input buffer, if required, prior to starting to cook the component in TouchEngine - then will cook frames in TouchEngine to fill its output buffer prior to emitting output from the Engine COMP. The Auto setting will attempt to keep small buffers sufficient to avoid dropped frames, but you may wish to set a fixed buffer size to suit your setup, particularly if working with audio.

TouchEngine Versions

TouchEngine is installed as part of TouchDesigner, and the currently running version will be used to load the given .tox. If you wish to use a different version of TouchEngine you can either set the environment variable TOUCHENGINE_APP_PATH to the path to a TouchDesigner installation (an installation directory on Windows, or a TouchDesigner app on macOS) or install TouchDesigner into a folder named TouchEngine alongside the .tox (on macOS rename an application from TouchDesigner to TouchEngine) or create a link named TouchEngine alongside the .tox which points to an installation directory or TouchDesigner app.

engineCOMP_Class

Parameters - Engine Page

Tox File file - Specify the .tox file to load with TouchEngine.

Unload unload - Unload the currently loaded component.

Reload reload - Reload the currently loaded component.

Reload on Crash reloadoncrash - If the TouchEngine instance quits for any reason, restart it.

Asset Paths assetpaths - ⊞ - Specify how relative paths inside the component are resolved.

Callbacks DAT callbacks - The Callbacks DAT will execute for events related to the TouchEngine instance.

Parameters - Tune Page

Clock clock - ⊞ - Specify the temporal connection to the TouchEngine instance.

Match Local Component Rate matchrate - When on, the component will be cooked in TouchEngine at the same rate as the Engine COMP.

Frames per Second fps - The framerate for cooking the component in TouchEngine.

Wait for Render wait - When enabled, if a frame takes a long time to cook in TouchEngine the Engine COMP will wait during cooking rather than dropping the late frame.

This behaviour is affected by the size of the output buffer: eg if Out Buffer Frames is 4, the Engine COMP will wait for the 4th most recent frame to complete.

Render Timeout timeout - When waiting for a frame, TouchEngine will give up waiting after this many milliseconds.

In Buffer Auto inauto - Automatically manage the number of input frames queued.

In Buffer Frames inframes - The number of input frames to queue before passing them to the TouchEngine instance.

To accommodate potential fluctuations in time-slice in the TouchEngine instance, CHOP inputs must send a number of frames ahead of time.

Out Buffer Auto outauto - Automatically manage the number of output frames queued.

Out Buffer Frames outframes - The number of output frames to queue after receiving them from the TouchEngine instance.

To accommodate potential fluctuations in time-slice in the Engine COMP, CHOP outputs must send a number of frames ahead of time.

Parameters - InitStart Page

Pre-Roll preroll - At initialization, run for this long before entering the ready state.

Pre-Roll Units prerollunits - ⊞ - The units in which the Pre-Roll is measured.

Ready when readywhen - ⊞ - Specify when the Engine COMP will go into the ready state.

Start when Initialized startoninit - When enabled, playback will start as soon as the component has initialized and is in the ready state.

Initialize initialize - Reload the .tox file, restarting the TouchEngine instance.

Start start - Starts playback of the component in the TouchEngine instance.

Play play - Turn cooking in the TouchEngine instance on or off.

Go to Done gotodone - Puts the Engine COMP in the done state.

On Done ondone - ⊞ - Determines the actions taken, if any, when the Engine COMP enters the done state.

Parameters - Advanced Page

On Engine COMP Create oncompcreate - ⊞ - Specify what happens when the Engine COMP is created, for example when the project is loaded.

Launch Engine Process launch - Starts the TouchEngine process if it is not running.

Quit Engine Process quit - Stops the TouchEngine process if it is running.

Parameters - Extensions Page

The Extensions parameter page sets the component's python extensions. Please see extensions for more information.

Object ext0object - A number of class instances that can be attached to the component.

Name ext0name - Optional name to search by, instead of the instance class name.

Promote ext0promote - Controls whether or not the extensions are visible directly at the component level, or must be accessed through the .ext member. Example: n.Somefunction vs n.ext.Somefunction

Re-Init Extensions reinitextensions - Recompile all extension objects. Normally extension objects are compiled only when they are referenced and their definitions have changed.

Parameters - Common Page

The Common parameter page sets the component's node viewer and clone relationships.

Parent Shortcut parentshortcut - Specifies a name you can use anywhere inside the component as the path to that component. See Parent Shortcut.

Global OP Shortcut opshortcut - Specifies a name you can use anywhere at all as the path to that component. See Global OP Shortcut.

Shortcut iop0shortcut - Specifies a name you can use anywhere inside the component as a path to "Internal OP" below. See Internal Operators.

OP iop0op - The path to the Internal OP inside this component. See Internal Operators.

Operator Viewer opviewer - Select which operator's node viewer to use when the Node View parameter above is set to Operator Viewer.

Enable Cloning enablecloning - Control if the OP should be actively cloneing. Turning this off causes this node to stop cloning it's 'Clone Master'.

Enable Cloning Pulse enablecloningpulse - Instantaneously clone the contents.

Clone Master clone - Path to a component used as the Master Clone.

Load on Demand loadondemand - Loads the component into memory only when required. Good to use for components that are not always used in the project.

Enable External .tox enableexternaltox - When on (default), the external .tox file will be loaded when the .toe starts and the contents of the COMP will match that of the external .tox. This can be turned off to avoid loading from the referenced external .tox on startup if desired (the contents of the COMP are instead loaded from the .toe file). Useful if you wish to have a COMP reference an external .tox but not always load from it unless you specifically push the Re-Init Network parameter button.

Enable External .tox Pulse enableexternaltoxpulse - This button will re-load from the external .tox file (if present).

External .tox Path externaltox - Path to a .tox file on disk which will source the component's contents upon start of a .toe. This allows for components to contain networks that can be updated independently. If the .tox file can not be found, whatever the .toe file was saved with will be loaded.

Reload Custom Parameters reloadcustom - When this checkbox is enabled, the values of the component's Custom Parameters are reloaded when the .tox is reloaded. This only affects top-level parameters on the component, all parameters on nodes inside the component are always reloaded with the .tox.

Reload Built-In Parameters reloadbuiltin - When this checkbox is enabled, the values of the component's built-in parameters are reloaded when the .tox is reloaded. This only affects top-level parameters on the component, all parameters on nodes inside the component are always reloaded with the .tox.

Save Backup of External savebackup - When this checkbox is enabled, a backup copy of the component specified by the External .tox parameter is saved in the .toe file. This backup copy will be used if the External .tox can not be found. This may happen if the .tox was renamed, deleted, or the .toe file is running on another computer that is missing component media.

Sub-Component to Load subcompname - When loading from an External .tox file, this option allows you to reach into the .tox and pull out a COMP and make that the top-level COMP, ignoring everything else in the file (except for the contents of that COMP). For example if a .tox file named project1.tox contains project1/geo1, putting geo1 as the Sub-Component to Load, will result in geo1 being loaded in place of the current COMP. If this parameter is blank, it just loads the .tox file normally using the top level COMP in the file.

Relative File Path Behavior relpath - ⊞ - Set whether the child file paths within this COMP are relative to the .toe itself or the .tox, or inherit from parent.

Info CHOP Channels

Extra Information for the Engine COMP can be accessed via an Info CHOP.

Specific Engine COMP Info Channels

• input_buffer_frames - The number of frames in the input buffer. This is affected by parameters on the Tune parameter page.

• output_buffer_frames - The number of frames in the output buffer. This is affected by parameters on the Tune parameter page.

• output_cook_abs_frame - The value of cook_abs_frame when the current output was cooked. This is affected by the number of frames in the output buffer.

• output_did_wait - 1 when the Engine COMP waited for output to cook. This will only be 1 when Wait for Render is On and is affected by the time taken to complete a frame in TouchEngine and the number of input and output buffers. See the Tune parameter page for more details.

• initializing - 1 while the Engine COMP is in the initializing state.

• initialize_fail - 1 if an error occurred during initialization. This would normally indicate an error loading the component in TouchEngine.

• ready - 1 after initialization completes and before starting.

• running - 1 after starting and until the Engine COMP enters the done state or is re-initialized.

• done - 1 when the Engine COMP is in the done state.

• timer_seconds - In the Engine COMP, this matches playing_seconds.

• playing_seconds - Seconds elapsed since starting, accounting for play state.

• running_seconds - Seconds elapsed since starting.

• engine_launching - 1 when TouchEngine is starting, prior to loading any component.

• engine_running - 1 when TouchEngine has started and is running.

• engine_none - 1 when TouchEngine is not running.

• engine_error - 1 when TouchEngine has encountered an error unrelated to the component.

• component_loading - 1 when TouchEngine is loading a component.

• component_loaded - 1 when TouchEngine has successfully loaded a component.

• component_unloading - 1 when TouchEngine is unloading a component.

• component_none - 1 when TouchEngine has no loaded component.

• component_error - 1 when TouchEngine encountered an error loading or running a component.

• crash_reload_count - The number of times the component has been reloaded due to an error when Reload on Crash is On.

• engine_absolute_frame - The value for absolute time in frames in TouchEngine.

• engine_absolute_seconds - The value for absolute time in seconds in TouchEngine.

• engine_fps - The number of frames rendered in the last second in TouchEngine.

• engine_frame_msec - Amount of time each frame takes to cook in msec in TouchEngine.

• engine_cook - Is equal to 1 when a frame is cooked and equal to 0 when a frame is skipped in TouchEngine.

• engine_dropped_frames - The number of frames dropped between the last frame and the current frame in TouchEngine.

• engine_read_ahead_misses - How many times the movie read ahead failed to maintain the number of specified Read Ahead frames in TouchEngine.

• engine_gpu_mem_used - Amount of GPU memory used in TouchEngine (in megabytes).

• engine_total_gpu_mem - Total amount of GPU memory available on the system (in megabytes).

• engine_active_ops - How many OPs are actively cooking in TouchEngine.

• engine_deactivated_ops - Number of calls to cook a component that has its Cooking Flag turned off in TouchEngine.

• engine_total_ops - Total number of OPs in TouchEngine.

• engine_cpu_mem_used - Amount of CPU memory used in TouchEngine (in megabytes).

• engine_cookstate - Monitors which frames actually cooked in TouchEngine.

• engine_cookrealtime - Monitors the state of the realtime flag, determining if TouchEngine is running in realtime mode or not.

• engine_cookrate - The global target cook rate (frames per second) of TouchEngine. This is the frames per second of the root component, root.time.rate, typically 60, though due to frames taking too long to cook, the actual frames per second may be lower.

• engine_timeslice_step - The number of frames that TouchEngine stepped forward for the current cook. It's the length of the Time Slice in frames. It will be equal to 1 when the system is taking 1000/root.time.rate msec or less to complete one frame (16.666 msec for a rate of 60).

• engine_timeslice_msec - The length of the current Time Slice in milliseconds.

• engine_active_expressions - The number of active python expressions found in TouchEngine.

• engine_active_expressions - The number of python expressions that have been optimized in TouchEngine.

• engine_cached_expressions - The number of python expressions that have been cached in TouchEngine.

Common COMP Info Channels

• num_children - Number of children in this component.

Common Operator Info Channels

• total_cooks - Number of times the operator has cooked since the process started.

• cook_time - Duration of the last cook in milliseconds.

• cook_frame - Frame number when this operator was last cooked relative to the component timeline.

• cook_abs_frame - Frame number when this operator was last cooked relative to the absolute time.

• cook_start_time - Time in milliseconds at which the operator started cooking in the frame it was cooked.

• cook_end_time - Time in milliseconds at which the operator finished cooking in the frame it was cooked.

• cooked_this_frame - 1 if operator was cooked this frame.

• warnings - Number of warnings in this operator if any.

• errors - Number of errors in this operator if any.

TouchDesigner Build: Latest\nwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditorwikieditormw-replace2023.112802022.241402021.100002020.200002019.146502018.28070before 2018.28070