Sequential Index Loop

2024-07-11 10:20 UTC gpt-4o Open in ChatGPT ↗

You

I’m working in Touchdesigner, currently using this script to randomly switch the input index of a switch top. Rather than randomly switching I’d like to iterate between each index, incrementing by 1 each time a new message is received and looping back to 0 after the max index is reached:

Import the necessary module

import random

Initialize variables

Ensure these are stored at the module level to persist between calls

previous_index = -1 min_index = 0 max_index = 7 # Maximum index, inclusive

def onValueChange(channel, sampleIndex, val, prev): global previous_index new_index = previous_index

# Debugging: Print previous index
#print(f"Previous index: {previous_index}")

# Ensure the new index is different from the previous index
while new_index == previous_index:
    new_index = random.randint(min_index, max_index)

# Debugging: Print new index
#print(f"New index: {new_index}")

# Update the Switch TOP's index parameter
op('switch1').par.index = new_index

# Update the previous index variable
previous_index = new_index

return

The function onValueChange is triggered when a value changes in the monitored CHOP

Make sure to set the channel’s parameter to value change in the CHOP Execute DAT settings

ChatGPT

To achieve the desired behavior of iterating through each index sequentially and looping back to 0 after reaching the maximum index, you can modify your script as follows:

1. Initialize the previous_index to -1 to start from 0.
2. Increment the previous_index by 1 each time the onValueChange function is called.
3. If previous_index exceeds max_index, reset it to 0.

Here’s the modified script:

# Initialize variables
# Ensure these are stored at the module level to persist between calls
previous_index = -1
min_index = 0
max_index = 7  # Maximum index, inclusive

def onValueChange(channel, sampleIndex, val, prev):
    global previous_index

    # Increment the previous index
    previous_index += 1

    # Loop back to 0 if the max index is exceeded
    if previous_index > max_index:
        previous_index = min_index

    # Debugging: Print new index
    #print(f"New index: {previous_index}")

    # Update the Switch TOP's index parameter
    op('switch1').par.index = previous_index

    return

# The function onValueChange is triggered when a value changes in the monitored CHOP
# Make sure to set the channel's parameter to value change in the CHOP Execute DAT settings

With this script:

• The previous_index starts at -1.
• Each time onValueChange is called, previous_index is incremented by 1.
• If previous_index exceeds max_index, it is reset to 0.
• The new value of previous_index is then assigned to the index parameter of switch1.

You

it still seems to be changing randomly?

ChatGPT

It seems like the issue might be related to the initialization of the script or the persistence of the previous_index variable. Let’s ensure the variable is properly initialized and maintained across calls. Additionally, ensure that no other part of the script or TouchDesigner setup is affecting the switch index.

Here’s a revised version of the script with more detailed comments to ensure everything is clear:

# Initialize variables
# Ensure these are stored at the module level to persist between calls
if 'previous_index' not in globals():
    previous_index = -1
min_index = 0
max_index = 7  # Maximum index, inclusive

def onValueChange(channel, sampleIndex, val, prev):
    global previous_index

    # Increment the previous index
    previous_index += 1

    # Loop back to 0 if the max index is exceeded
    if previous_index > max_index:
        previous_index = min_index

    # Debugging: Print new index
    #print(f"New index: {previous_index}")

    # Update the Switch TOP's index parameter
    op('switch1').par.index = previous_index

    return

# The function onValueChange is triggered when a value changes in the monitored CHOP
# Make sure to set the channel's parameter to value change in the CHOP Execute DAT settings

Make sure you check the following in TouchDesigner:

1. The script is correctly placed in a DAT Execute DAT, and the onValueChange function is set to trigger on value change.
2. The previous_index variable is declared at the module level to persist between calls.
3. No other scripts or operators are modifying the index parameter of switch1.

If the issue persists, you might want to add print statements for debugging purposes to verify the flow of the script:

# Initialize variables
# Ensure these are stored at the module level to persist between calls
if 'previous_index' not in globals():
    previous_index = -1
min_index = 0
max_index = 7  # Maximum index, inclusive

def onValueChange(channel, sampleIndex, val, prev):
    global previous_index

    # Increment the previous index
    previous_index += 1

    # Loop back to 0 if the max index is exceeded
    if previous_index > max_index:
        previous_index = min_index

    # Debugging: Print new index
    print(f"New index: {previous_index}")

    # Update the Switch TOP's index parameter
    op('switch1').par.index = previous_index

    return

# The function onValueChange is triggered when a value changes in the monitored CHOP
# Make sure to set the channel's parameter to value change in the CHOP Execute DAT settings

This will print the new index value to the console each time the function is called, allowing you to verify that the script is incrementing and setting the index correctly.