Reacting to Multiple Conditions

Open rocketLaunch1.fla in the Lesson08/Assets folder.

This file contains a single scene made up of eight layers, named according to their contents. Let's look at the various elements in the scene.

The Weather layer contains a movie clip instance the size of the movie itself. This movie clip, named weather_mc, represents the background sky in the scene. Its timeline contains three frame labels: Sunny, Rainy, and Night. At each of these frame labels, the sky graphic changes to match the name of the label. At Sunny, the sky appears sunny; at Rainy, it appears overcast; at Night, it looks dark.

The Ground/Central Graphics layer contains the mountains, ground, and main Central Command graphics. There is also a small movie clip instance of a red dot, which blinks to indicate the launch location on the globe.

The Rocket layer obviously contains our rocketthat is, a movie clip instance named rocket_mc. Its timeline contains two frame labels: off and on. At the off label, the rocket doesn't show a flame; at the on label, it does, providing a visual indicator of the rocket in motion.

The Control Panel layer contains several elements, the most conspicuous of which is the red Launch button named launch_btn. This button will be used not only to launch the rocket but also to reset the scene after a launch has been attempted. Below this button is a movie clip instance named thrustBoost_mc that includes the text "Thrusters." This clip also contains two frame labels: on and off. At the on label, the text appears big and red to provide a visual indication that thrust is being applied to the rocket. This layer's last element is a text field in the lower-right portion of the stage with an instance name of weatherText_txt. This text field provides a textual indication of current weather conditions.

The Status layer contains a movie clip instance named status_mc that appears as a small circle in the middle of the sky. It looks this way because the first frame of its timeline contains no graphical content. This clip provides a text message about the launch's success or failure. There are three frame labels on this movie clip's timeline: off, abort, and success. At the off frame label, the status displays no text. At the abort label, a text message appears: "Launch Aborted." At the success label, a different text message appears: "Launch Successful."

The Launch Window layer contains a movie clip instance named launchWindow_mc, showing two red bars. The space between the red bars represents the launch windowthe area the rocket must pass through to have a successful launch.

The Sound Clips layer contains a movie clip instance named sounds_mc that also appears as a small circle just above the stage, on the left side. Its timeline contains frame labels named intro, launch, abort, and success. At each of these labels is an appropriate sound clip (the launch label has a launch sound, the abort label has an abort sound, and so on). Various scripts will send this clip to these frame labels to provide audio effects for the project.

With the Actions panel open, select Frame 1 of the Actions layer and add the following script:

var noThrust:Number;

var thrust:Number;

function setWeatherConditions(){

var randomWeather:Number = random (3);

var conditions:String;

if (randomWeather == 0) {

    conditions = "Sunny";

    noThrust = 3;

    thrust = 6;

} else if (randomWeather == 1) {

    conditions = "Rainy";

    noThrust = 2;

    thrust = 4;

} else {

    conditions = "Night";

    noThrust = 1;

    thrust = 2;

}

}

The first two lines of this script declare two variables: noThrust and thrust. (We'll elaborate on the purposes of these two variables in a moment.) This function is used to make the project react to random weather conditions. The function's first action sets the value of the randomWeather variable, based on a randomly generated number (from three possibilities: 0, 1, or 2). The next line declares the conditions variable, which will be used later in the function.

Next, an if statement within the function definition analyzes the value of randomWeather so that the values of three other variables can be set. If randomWeather has a value of 0, the variable named conditions is created on this timeline and assigned a string value of "Sunny". In addition, the values of noThrust and thrust are set to 3 and 6, respectively. If the value of randomWeather isn't 0, that part of the statement is ignored, at which point an else if statement checks whether randomWeather has a value of 1. If so, the variables are instead assigned values of "Rainy", 2, and 4, respectively. If the value of randomWeather isn't 1, that part of the statement is ignored, at which point the actions following the else statement are executed.

Remember that an else statement enables you to define what happens if none of the previous conditions in the statement has proven true but you still want something to happen. In this case, if the previous conditions proved false, the actions under the else statement are executed, setting the value of the variables we've been discussing to "Night", 1, and 2, respectively.

Add this script after the end of the if statement (but within the function definition):

weather_mc.gotoAndStop (conditions);

weatherText_txt.text = "Weather: " + conditions;

Add this script at the end of the function definition:

setWeatherConditions();

Choose Control > Test Movie to test the functionality of the project at this point.

While still in the testing environment, choose Debug > List Variables.

Close the test environment to return to the authoring environment, and save your work as rocketLaunch2.fla.