VBScript Plugin

Please be sure to read the Plugins page to get a general sense of if the VBScript module is a good fit for your project.

The VBScript module provides a way to create custom Visual Basic scripts that can be used to process image statistics and map then toward servo/motor values. This module is intented to be used as a way to quickly perform custom operations without needing to implement a Plugin or use the API which typically require external tools.

The interface allows two methods for specifying your code. One technique requires that you specify a text file as the source of the program. You can use your favorite text editor to edit/create this file. The file should be a regular text file containing VBScript commands/functions/operators. The program interface displays the current file being used, available system or user variables (and their values) and any messages the program produces.

The alternate way is to include the VBScript text within the provided text box (see below). Using this technique allows you to include the VBScript code within the .robo program and not require another user to save the code and reference a text file as needed by the above file based technique. Using the text box provides a quick way to enter in text but is NOT meant as a replacement for a full featured text editor as its editing features are very basic.

Interface

RoboRealm Specific Functions

• VariableExists("variable_name") - returns true or false depending on if the specified variable exists in RoboRealm. Several of the variable return functions below will return a valid value regardless of if the variable exists or not. You can use this function to determine if the value returned from one of these functions is a valid value.

• GetVariable("variable_name") - returns an integer value of the specified variable. Zero is returned when the variable does not exist.

• GetFloatVariable("variable_name") - returns the float value of the specified variable. A zero is returned when the variable does not exist.

• GetStrVariable("variable_name") - returns the string value of the specified variable. An empty string "" is returned when the variable does not exist.

• GetArrayVariable("array_variable_name") - returns the array associated with the specified variable. An array is ALWAYS returned but the length (ubound) will be zero if the array does not exist.

• SetArrayVariable "array_variable_name", array_variable - sets an array associated with the specified variable name; for example

  ReDim points(4)
  
  points(0) = 100
  points(1) = 100
  points(2) = 150
  points(3) = 200
  
  SetArrayVariable "waypoints", points
  

• SetVariable "variable_name", variable_value - sets the variable value to the specified variable

• SetTimedVariable "variable_name", variable_value, timeout - sets the variable value to the specified variable after the timeout (milliseconds) has passed

• GetPixels - returns an array of RGB values of the current image

• SetPixels pixel_data_array - sets the current image to the specified pixel RGB data

• SetParameter "module_name", index, "param_name", "param_value" - changes the specified parameter in the specified module to the specified value. This is useful when a GUI dialog does not have a variable selection as part of the dropdown. Avoid using this function unless necessary as it is slow to update the GUI.

• GetParameter("module_name", index, "param_name") - returns the specified parameter in the specified module. This is useful when a GUI dialog does not expose a value within a variable.

• GetFloatParameter("module_name", index, "param_name") - the float version of the above routine.

• GetStrParameter("module_name", index, "param_name") - the string version of the above routine.

• Write "text" - sends text to the VBScript module message output area in the dialog interface (used for debugging)

• StopProcessing - stops RoboRealm from continuing to process the images with the remaining modules

• CameraOff - switches off the image capturing from the current camera

• CameraOn - switches on the image capturing using the current camera

• PushButton "Module_Name", Module_Index, "Button" - automates pushing a button in one of the RoboRealm GUI windows. For example:

  if GetStrVariable("test") <> "pushed" then
    SetVariable "test", "pushed"
    PushButton "Read_AVI", 0, "Start"
  end if
  

  will cause the Read_AVI module (assuming one exists in the pipeline) to start playback.

  PushButton "RoboRealm", 0, "Snap"
  

  will cause RoboRealm to create a snapshot of the current image.

• atan2(x,y) - arc tangent function not present in VBScript but useful for trigonometric calculations

• sqrt(x) - square root function not present in VBScript but useful for trigonometric calculations

Examples

To access variables from your VBScript file/script use the following commands:

MyVar = GetVariable("variable_name")

Or to create a new variable use

SetVariable "variable_name", variable_value

Once a new variable is created this variable becomes available to control functions (such as in the SSC module) that can be used to automatically control a servo/motor.

You can also get variable arrays using

MyVar = GetArrayVariable("variable_array_name")

or get individual entries in an array using

MyVar = GetVariable("variable_array_name:2")

which would return the second entry in an array.

To change a variable's value in X milliseconds you can use

SetTimedVariable "variable_name", variable_value, timeout_in_milliseconds

which is very useful for resetting motor values after a period of time.

All regular VB Script commands and operators are available for use in the VBScript file. See Microsoft Scripting for complete documentation on how to use these commands or view the sample files for examples.

For example the following program (assuming you have added the Center Of Gravity module) will map COG to servo motors:

Note that the COGX values range from 0 to 320. COGY ranges from 0 to 160. These values are bounded by the current image size. These values may change if you crop, shrink, etc. the image dimensions.

You could then use a module like the SSC module to map the "left_motor" and "right_motor" variables to actual servos.

You can also process the image pixels directly using VBScript. This is useful for prototyping but not recommended due to performance reasons for actual usage. The VBScript module supports two routines to get and set the image pixels. Following is the example SwapColor module but in VBScript.

To write variables or debug statements to a log file you can use

If you need to wait for a specific condition in a loop you will have to setup a trigger variable. You can't really sleep, wait or loop in the VBScript module as that would stop all image processing while it is waiting for the loop or sleep to finish. As the pipeline is essentially an infinite loop (i.e. grab an image, process it, then grab another, etc) adding a sleep would cease all execution which is usually not desired. If you prevent the ending of the loop by putting a while loop in the code it will not allow the system to capture new images and continue processing. So instead you can use the SetTimedVariable to cause the variable to change value after X number of milliseconds. Your script would look something like

Note that VBScript can access external activeX objects such as the Microsoft XML Http object. The following example shows this technique to issue a custom URL to a remote machine. Be sure to also have a look at the HTTP module for such tasks.

Variables

On each successful run of the script the SCRIPT_COUNT variable is incremented. Thus you can use this variable to indicate a first run state where variables can be initialized to default values. Note that the Reload and Run button will reset this count to 0.

Downloads

If RoboRealm complains about missing components you may need to download the Microsoft Script Control.

See Also

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