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Starry Night Flash ActionScript Particle System

Part 2: Scale and set Alpha of Stars

This is the second step to create the Starry Night Particle System, let's resize and set alpha to all stars randomly.

Please update flash player to view this Flash ActionScript tutorial!

Flash Tutorial Content:

The stars created on previous Flash ActionScript Particle System tutorials are not very realistic - same size and same brightness. In this starry night Particle system tutorial, we make the stars looking more realistic by resizing and setting alpha of the stars randomly.

The Flash Movie of this Flash ActionScript Particle System tutorial is shown as above.

Flash ActionScript Codes:

// Declare number of star
var numOfStars:uint = 60;

// Creates 60 stars randomly on the stage.
for (var i:uint = 0; i < numOfStars; i++) {

// Create a new star
// Remember to set linkage in Movie Library
var star:Star = new Star();

// Add the star to the stage
addChild(star);

// Assign start location of star
// stage.stageHeight and stage.stageWidth do not work in rubbish IE 6.0
//star.x = Math.random() * stage.stageWidth;
//star.y = Math.random() * stage.stageHeight;
star.y = Math.random() * 384;
star.x = Math.random() * 512;

// Assign random alpha to star
// Math.random returns value between 0 - 1
// i.e.
// Minimum value = 0.4 + 0 = 0.4
// Maximum value = 0.4 + 0.6 = 1.0
// Summary:
// Assign random alpha between 0.4 and 1.0
star.alpha = 0.4 + Math.random() * 0.6;

// Assign random scale to star
// Math.random returns value between 0 - 1
// i.e.
// Minimum value = 0.2 + 0 = 0.2
// Maximum value = 0.2 + 0.5 = 0.7
// Summary:
// Assign random scale between 0.2 and 0.7
star.scaleX = 0.2 + Math.random() * 0.5;
star.scaleY = star.scaleX;

}

 

/////////////////////////////////////////////////////////////
///// Add the Night Scenery MovieClip //////
////////////////////////////////////////////////////////////

// Create a new MovieClip
var nightScenery:MovieClip = new NightScenery();

// Add the new MovieClip to the MainTimeline
// so that we can see it.
addChild(nightScenery);

// Set the location of the new MovieClip
nightScenery.x = 256;
nightScenery.y = 273;

Remarks:

This Flash ActionScript Starry Night Particle System tutorial shows how to resize and set alpha to all stars randomly.