CScript (picoc) Plugin

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

The CScript module provides a way to create custom C scripts that can be used to process image statistics and map then toward servo/motor values. This module is intended 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 .c file containing CScript 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 CScript text within the provided text box (see below). Using this technique allows you to include the CScript 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.

The CScript module interprets C code using the PicoC - A very small C interpreter project and thus will not have the full Windows API available to use. If you need additional capabilities have a look at the Plugin or API architecture where you can use the full Visual Studio tools and still communicate with RoboRealm.

As PicoC is interpreted it will run slower than regular C. This will be fine for most applications but if you chose to do image processing directly in this module (similar to the SwapColor example below) the FPS (frames per second) will decrease dramatically as a result.

Interface

RoboRealm Specific Functions

int variableExists(char *variable_name); - returns true (1) or false (0) 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.
int getVariable(char *var); - returns an integer value of the specified variable
float getFloatVariable(char *var); - returns the float value of the specified variable
char *getStrVariable(char *var); - returns the string value of the specified variable
int getArrayVariable(char *var, int *arr, int max); - returns the int array associated with the specified variable in the array "arr" for max entries.
int getFloatArrayVariable(char *var, float *arr, int max); - returns the float array associated with the specified variable in the array "arr" for max entries.
int getStrArrayVariable(char *var, char *arr, int max); - returns the string array associated with the specified variable in the char buffer "arr" up to max size. Each entry is spaced within 64 characters of arr such that &arr[0] is record 1, &arr[64] is record 2, etc. Note that max is the total maximum number of characters to be used including any padding below 64.
```
int arr[64];

int num = getArrayVariable("BLOBS", arr, 64);

printf("%d %d", num, arr[0]);

arr[0]=33;

setArrayVariable("BLOBS", arr, num);
```
void setVariable(char *var, int value); - sets the integer variable value to the specified variable
void setFloatVariable(char *var, float value); - sets the float variable value to the specified variable
void setStrVariable(char *var, char *value); - sets the string variable value to the specified variable
void setTimedVariable(char *key, int value, int timeout); - sets the int variable value to the specified variable after the timeout (milliseconds) has passed
void setFloatTimedVariable(char *key, float value, int timeout); - sets the float variable value to the specified variable after the timeout (milliseconds) has passed
void setStrTimedVariable(char *key, char *value, int timeout); - sets the string variable value to the specified variable after the timeout (milliseconds) has passed
unsigned char *getPixels(int *width, int *height); - returns an array of BGR values of the current image and sets width and height of the image. Note that the returned array is an unsigned char with Blue first.
void setPixels(unsigned char *, int , int); - sets the current image to the specified pixel BGR data
void setParameter(char *module, int module_index, char *parameter_name, int paramter_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.
void setFloatParameter(char *module, int module_index, char *parameter_name, float paramter_value); - float value of above routine.
void setStrParameter(char *module, int module_index, char *parameter_name, char *paramter_value); - char value of above routine.
int getParameter(char *module, int module_index, char *parameter_name); - returns the specified parameter in the specified module. This is useful when a GUI dialog does not expose a value within a variable.
float getFloatParameter(char *module, int module_index, char *parameter_name); - the float version of the above routine.
char *getStrParameter(char *module, int module_index, char *parameter_name); - the string version of the above routine.
void stopProcessing(); - stops RoboRealm from continuing to process the images with the remaining modules
void cameraOff(); - switches off the image capturing from the current camera
void cameraOn(); - switches on the image capturing using the current camera
void pushButton(char *module, int index, char *key); - automates pushing a button in one of the RoboRealm GUI windows. For example:
```
if (strcmp(getStrVariable("test"), "pushed")!=0)
{
  setStrVariable("test", "pushed");
  pushButton("Read_AVI", 0, "Start");
}
```
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.
float atan2(x,y); - arc tangent function not present in picoC but useful for trigonometric calculations

Examples

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

int value = 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

int list[256]; int num = GetArrayVariable("variable_array_name", list, 256);

or get individual entries in an array using

int val = 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.

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

int cogx = getVariable("cog_x");
int cogy = getVariable("cog_y");
int left_motor;
int right_motor;

if (cogx < 140)
{
left_motor = 60;
right_motor = 128;
}
else
{
  if (cogx > 180)
  {
    left_motor = 128;
    right_motor = 60;
  }
  else
  {
    left_motor = 128;
    right_motor = 128;
  }
}

setVariable("left_motor", left_motor);
setVariable("right_motor", right_motor);

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 CScript. This is useful for prototyping but not recommended due to performance reasons for actual usage. The CScript module supports two routines to get and set the image pixels. Following is the example SwapColor module but in CScript.

int width, height;
int i;
unsigned char c;
unsigned char *pixels = getPixels(&width, &height);

for (i=0;i<(width*height*3);i+=3)
{
  c = pixels[i];
  pixels[i]=pixels[i+2];
  pixels[i+2]=c;
}

setPixels(pixels, width, height);

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 CScript 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

int period = 2000;
int step = getVariable("step");
if (step == 0)
{
  setVariable("data", 2);
  setVariable("step", 1);
  setTimedVariable("step", 2, period);
}
else
{
  if (step == 2)
  {
     setVariable("data", 4);
     setVariable("step", 3);
     setTimedVariable("step", 0, period);
  }
}

which would cause the variable data to oscillate between 2 and 4 with a period of 2000 seconds. Note that usage of step and setting it to 1 and 3 which are dummy steps where nothing is done.

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.

For more information

picoc - Project Hosting on Google Code