Invaders Sample Problem

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Flash Applets embedded in WeBWorK questions invaders Example

Flash applet with game like interface Sample Problem

This sample problem shows how to use the invaders applet.

A standard WeBWorK PG file with an embedded applet has six sections:

  1. A tagging and description section, that describes the problem for future users and authors,
  2. An initialization section, that loads required macros for the problem,
  3. A problem set-up section that sets variables specific to the problem,
  4. An Applet link section that inserts the applet and configures it, (this section is not present in WeBWorK problems without an embedded applet)
  5. A text section, that gives the text that is shown to the student, and
  6. An answer and solution section, that specifies how the answer(s) to the problem is(are) marked for correctness, and gives a solution that may be shown to the student after the problem set is complete.

The sample file attached to this page shows this; below the file is shown to the left, with a second column on its right that explains the different parts of the problem that are indicated above. The flash applet below illustrates how the applet would work within WeBWorK. The homework question below the applet is a screenshot of the WeBWorK problem created by the pg file documented below.
<flash>file=Graph_limit1derWiki.swf|height=653px|width=467px</flash>

      • page under construction ***

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PG problem file Explanation
##DESCRIPTION
##  derivatives practice 
##ENDDESCRIPTION

##KEYWORDS('derivatives', 'Flash applets','NSF-0941388')

## DBsubject('Calculus')
## DBchapter('Limits and Derivatives')
## DBsection('Derivatives')
## Date('1/12/2012')
## Author('Barbara Margolius')
## Institution('Cleveland State University')
## TitleText1('')
## EditionText1('2012')
## AuthorText1('')
## Section1('')
## Problem1('')
########################################
# This work is supported in part by the 
# National Science Foundation 
# under the grant DUE-0941388.
########################################

This is the tagging and description section of the problem. Note that any line that begins with a "#" character is a comment for other authors who read the problem, and is not interpreted by WeBWorK.

The description is provided to give a quick summary of the problem so that someone reading it later knows what it does without having to read through all of the problem code.

All of the tagging information exists to allow the problem to be easily indexed. Because this is a sample problem there isn't a textbook per se, and we've used some default tagging values. There is an on-line list of current chapter and section names and a similar list of keywords. The list of keywords should be comma separated and quoted (e.g., KEYWORDS('calculus','derivatives')).

DOCUMENT();        

loadMacros(
  "PGanswermacros.pl",
  "PGstandard.pl",
  "AppletObjects.pl",
  "MathObjects.pl",
);

This is the initialization section of the problem. The first executed line of the problem must be the DOCUMENT(); command. Note that every command must end with a semicolon.

The loadMacros command loads information that works behind the scenes. For our purposes we can usually just load the macros shown here and not worry about things further.

# Set up problem
TEXT(beginproblem());
$showPartialCorrectAnswers = 1;
Context("Numeric"); 

$high = 0;
$baseSpeed = 0.25;

$ans =Compute("1");

This is the problem set-up section of the problem.

The invaders.swf applet will accepts a $basespeed setting that determines the initial speed of the descending tiles. The default is 0.5. The setting here of 0.25 is a fairly slow initial speed. As the student matches function/derivative pairs, the tiles descend more quickly.

###################################
# Create  link to applet 
###################################
$appletName = "invaders";
$applet =  FlashApplet(
  codebase              
    => findAppletCodebase("$appletName.swf"),
  appletName            
    => $appletName,
  appletId              
    => $appletName,
  setStateAlias         => 'setXML',
  getStateAlias         => 'getXML',
  setConfigAlias        => 'setConfig',
  maxInitializationAttempts => 10,   
  height                => '600',
  width                 => '360',
  bgcolor               => '#ffffff',
 debugMode             =>  0,
       submitActionScript  =>  
  qq{getQE("answerBox").value=getApplet("$appletName").getAnswer() },
     );
###################################
# Configure applet
###################################


$applet->configuration(qq{<xml><high>$high</high><baseSpeed>$baseSpeed</baseSpeed></xml>});
$applet->initialState(qq{<xml><high>$high</high><baseSpeed>$baseSpeed</baseSpeed></xml>});


TEXT( MODES(TeX=>'object code', HTML=>$applet->insertAll(
  debug=>0,
  includeAnswerBox=>1,
#   reinitialize_button=>$permissionLevel>=10,
   )));

TEXT(MODES(TeX=>"", HTML=><<'END_TEXT'));
<script>
if (navigator.appVersion.indexOf("MSIE") > 0) {
	document.write("<div width='3in' align='center' 
        style='background:yellow'>You seem to be using Internet Explorer.<br/>
        It is recommended that another browser be used to view this page.</div>");
}
</script>
END_TEXT



This is the Applet link section of the problem.


Those portions of the code that begin the line with # are comments and can be omitted or replaced with comments appropriate to your particular problem.

You must include the section that follows # Create link to applet. If you are embedding a different applet, from the invaders applet, put your applet name in place of 'invaders' in the line $appletName = "invaders";. Enter the height of the applet in the line height => '600', in place of 600 and the width in the line width => '360', in place of 360.


The lines $applet->configuration (qq{<xml><high>$high</high><baseSpeed>$baseSpeed</baseSpeed></xml>}); and $applet->initialState (qq{<xml><high>$high</high><baseSpeed>$baseSpeed</baseSpeed></xml>}); configure the applet. The configuration of the applet is done in xml.


TEXT( MODES(TeX=>'object code', HTML=>$applet->insertAll( debug=>0, includeAnswerBox=>0, reinitialize_button=>$permissionLevel>=10, ))); actually embeds the applet in the WeBWorK problem.


TEXT(MODES(TeX=>"", HTML=><<'END_TEXT'));
<script>
if (navigator.appVersion.indexOf("MSIE") > 0) {
    document.write("<div width='3in' 
    align='center' style='background:yellow'>
    You seem to be using Internet Explorer.
    <br/>It is recommended that another 
    browser be used to view this page.</div>");
}
</script>
END_TEXT

The text between the <script> tags detects whether the student is using Internet Explorer. If the student is using this browser, a warning is issued and the student is advised to use another browser. IE mis-sizes the applets. Some will work correctly when displayed at the wrong size, but others will fail. We do not recommend using IE with WeBWorK problems with Flash embedded.

BEGIN_TEXT

$BR

$BR list all intervals for which
$BR
a)
\(f^\prime(x)>0\)
\{ans_rule(35) \}
$BR
b)
\(f^\prime(x)<0\)
\{ans_rule(35) \}

$BR
c)
\(f^\prime(x)=0\)
\{ans_rule(35) \}

$BR

END_TEXT
Context()->normalStrings;

This is the text section of the problem. The TEXT(beginproblem()); line displays a header for the problem, and the Context()->texStrings line sets how formulas are displayed in the text, and we reset this after the text section. Everything between the BEGIN_TEXT and END_TEXT lines (each of which must appear alone on a line) is shown to the student.

Mathematical equations are delimited by \( \) (for inline equations) or \[ \] (for displayed equations); in these contexts inserted text is assumed to be TeX code.

There are a number of variables that set formatting: $PAR is a paragraph break (like \par in TeX). This page gives a list of variables like this. Finally, \{ \} sets off code that will be executed in the problem text. Here, ans_rule(35) is a function that inserts an answer blank 35 characters wide.

######################################
#
#  Answers
#
## answer evaluators

ANS( $correctAnswer1->
  cmp(strings=>['None']) );   
  #checks AnSwEr00001
ANS( $correctAnswer2->
  cmp(strings=>['None']) );   
  #checks AnSwEr00002
ANS( $correctAnswer3->
  cmp(strings=>['None']) );   
  #checks AnSwEr00003


ENDDOCUMENT();   

This is the answer section of the problem. The problem answer is set by the ANS( $correctAnswer1-> cmp(strings=> ['None']) );, ANS( $correctAnswer2-> cmp(strings=> ['None']) );, ANS( $correctAnswer3-> cmp(strings=> ['None']) ); lines. These compare the student's answer with the answers returned from the applet. The answers allow for either a list of intervals answer or the string 'None' for empty lists.

The solution is embedded in the applet and becomes available when the due date has passed.

The ENDDOCUMENT(); command is the last command in the file.