Diff for "VbDotNetExample" - Methods
location: Diff for "VbDotNetExample"
Differences between revisions 10 and 11
Revision 10 as of 2007-09-03 17:03:46
Size: 4442
Editor: pc0041
Comment:
Revision 11 as of 2007-09-03 17:04:45
Size: 4442
Editor: pc0041
Comment:
Deletions are marked like this. Additions are marked like this.
Line 47: Line 47:
ExpTrialList stores a list of trials, and knows how to randomise it (or individual parameters), run all of the trials, and dump various things to the output file. AttentionTrialList is a specific implementation for this experiment, that also prepares the grating stimuli. ExpTrialList stores a list of trials, and knows how to randomize it (or individual parameters), run all of the trials, and dump various things to the output file. AttentionTrialList is a specific implementation for this experiment, that also prepares the grating stimuli.

A sample experiment in VB.net

Download

The example is here attachment:ExperimentTemplate.zip

This is an attention monitoring experiment. It may be used in the scanner, or out of the scanner, with a simple switch of a parameter. It contains a colleciton of modules (starting Exp...) that contain functions that should be generally useful for many experiments.

This program is provided as an illustration only. You should always check your code carefully.

Program components

ExpSettings

General experimental settings. Most useful is probably

Public FullScreen As Boolean == True

By default, the experiment acquires the whole screen, to give accurate timing, and prevent other programs from being displayed. However, this can be irritating when debugging, so set this to False when programming.

ExpDisp

Contains various subroutines to help you use DirectX for display.

Initialize()

Sets up screen, in full screen or windowed mode. Make sure the number of colours (third argument in

             DXDevice.SetDisplayMode(ES.ScreenWidth, ES.ScreenHeight, 32, 0, False)

is set to the same as the colour depth that windows was started in, if you use .FROMARGB anywhere to convert RGB values to colours.

ClearScreen

Clears the screen

DrawFixation

Draws a fixation cross

FlipSurface

To ensure that graphics are displayed tidily, drawing is done on an "off screen surface" and then flipped to the display. This command flips the display. If in fullscreen mode, a DirectX flip command is used, which will be executed by the graphics card, and give high performance. In the testing windowed mode, a copy command is used to emulate the action of the flip.

ExpTimingAndReponses

Various routines for getting accurate timing, synchronising with the scanner (if used), checking button boxes and the keyboard.

Set USESCANNER and USEBUTTONBOX to True to use the software on the scanner or mimic machines.

ExpTrial & AttentionTrial

The ExpTrial class that represents a single trial, storing the parameters of the trial. This class would usually be used as a base for your own class, which more fully implements the particular experiment in question. Here, this is done in AttentionTrial, which inherits ExpTrial, but extends the "Run" method to display an attention monitoring trial.

ExpTrialList & AttentionTrialList

ExpTrialList stores a list of trials, and knows how to randomize it (or individual parameters), run all of the trials, and dump various things to the output file. AttentionTrialList is a specific implementation for this experiment, that also prepares the grating stimuli.

frmStart

This is the main form. The code behind the "Start" button actually runs the experiment. This code contains the definitions of the trials:

Dim NUMCONDS = 4
Dim NUMSUBBLOCKS = 12
Dim ATTENDLIST() = {0, 3, 12, 15}

Modify these definitions to describe the design of your experiment. You may choose to represent each condition by a number of definitions (e.g. a trial may be defined by CONGRUENCY, SOA, DELAY and PRIMEPRESENCE).

Then a list of trials is created:

TL = New AttentionTrialList(NUMCONDS * NUMSUBBLOCKS, txtOutputFilename.Text, txtSubjectCode.Text)

Here, you have three arguments separated by commas: (NewNumTrials, NewOutputFilename, NewSubjectCode); dictate the value of the first argument in relation to the definitions described above.

Finally, the list is populated by the different parameters relevant to each experimental trial, again dependent on the definitions above:

For i = 0 To NUMSUBBLOCKS - 1
            For j = 0 To NUMCONDS - 1
                TL.TrialList(ind).AddParameter("Subblock", i)
                TL.TrialList(ind).AddParameter("MonitorDur", ((MAXBLOCKDUR - MINBLOCKDUR) * i / (NUMSUBBLOCKS - 1.0)) + MINBLOCKDUR)
                TL.TrialList(ind).AddParameter("AttendTo", ATTENDLIST(j))
                ind = ind + 1
            Next
        Next

This nested function ensures all trials are created different. Expand/modify this depending on the structuring of your trials.

Author & Acknowledgements

Page and example program created by Rhodri Cusack. Thanks to Daniel Mitchell & Alejandro Vicente-Grabovetsky who contributed parts to this code.

None: VbDotNetExample (last edited 2013-03-08 10:28:25 by localhost)