Coin Project 3: Limiting the value of your changing variable

by Leanne Richer

You will need the results of this tutorial to complete this series of tutorials.

OBJECTIVE: In Flash MX we will script a movie clip on the X and Y axis and use a condition to keep the movie clip on the stage.

2. Click Actions => Conditions/Loops => double-click on "if" to add it to the right side of the Actions panel. In the Condition field type "mania >= 575" without the quotes. (575 represents the width of the stqage +half the width of the coin) The lines of script will appear like this in the Actions panel:

if (mania >= 575) {
}

Basically the script reads "If the variable mania is greater than or equal to 575 pixels". Having said that something needs to happen if this condition were true. In this case we want the mania variable to reset itself on the x axis.

Highlight the line "if (mania >= 575) {" in the Actions panel so our new line of script will be inserted directly after this line. Click Actions => Variables => double-click "set variable" to bring it to the right side of the Actions panel.

• In the Variable field type "mania" without the quotes and leave the Expression box unchecked.
• In the Value field type "5" without the quotes and check the Expression box.

The script will appear like this in the Actions panel:

if (mania >= 575) {
   mania = -25;
}

3. Let's click Control => Test Movie to see the results. Save your work: File => Save

Now that we have completed the scripting for the mania variable let's finish scripting the ruby variable. We are going to use a slightly longer method this time so we can get better acquainted with the Actions panel.

4. Click in frame 2 of the Actions layer. In the Actions panel, highlight the line of script that contains the ruby variable in the Actions panel. Click Actions => Conditions/Loops => double-click on "if" to add it to the right side of the Actions panel. In the Condition field type "ruby" without the quotes. The lines of script will appear like this in the Actions panel:

if (ruby) {
}

Put your cursor in the Condition field after ruby and add a space. On the left side of the Actions panel click Actions => Operators => Comparison Operators and then double-click on ">=". Put a space after >= in the Condition field and then type 420. (420 represents the height of the stage + half the coin width)We put the spaces in to make the script easier to read. It would have worked the same if we had entered ruby>=420 in the Condition field. These lines of script will appear like this in the Actions panel:

if (ruby >= 420) {
}

Highlight the line "if (ruby >= 420) {" and click Actions => Variables => double-click on set variable to bring it into the right side of the panel. In the Variable field type "ruby" without the quotes and leave the Expression box unchecked. In the Value field type "-20" without the quotes and check the Expression box.

This will look like:

if (ruby >= 420) {
ruby = -20;
}

5. Click Control => Test Movie to see the results. Save your work: File => Save

The order of the lines in a script is very important and may mean the difference from everything working smoothly to getting syntax errors. In keeping with this principle we are going to organize the scrips on frame 2 of the actions panel so we make our variable change value first, then test the new value of the variables.

The script on frame 2 should look like this:

If any of the lines are out of order it's easy enough to fix. Highlight the line you'd like to move in the Actions panel, in this case. I want to move ruby= ruby + 4 up right under mania = mania + 5 so I highlight ruby = ruby + 4. Just above our script in the lower right corner you will notice 2 buttons. The one with a arrow pointing up is the "Move the selected action(s) up" button and the one with the arrow pointing down is the "Move the selected action(s) down" button. Use these 2 buttons to change the order of the lines until the line order match the script shown above.

Save your work: File => Save You can watch your variables in your text boxes display the value as it increases and resets as it gets to the high point we set of 575 for mania and 425 for ruby.

Before you close your movie I would suggest you experiment a little. Change the values for the variables in frame 2 of the Actions layer to change the speed of the movie clip. Use these scripts in your own movie clips.

Congratulations on a job well done!  Next tutorial is setting some button actions to control position of the coin.