Learn about the snow Effect of Flash (59) every day

On this day, I went hiking by myself, and the National Day was a bit stuffy. However, mountain climbing will make people feel relaxed and enjoy the happy time to communicate with nature without pressure. In the evening, I wrote a snow effect. Although this effect has been very backward, but when I was studying flash, this programming helped me understand a lot.

 

Bored, suddenly remembered the joy of Zhimo's Snowflake. But accidentally starts the story of the memories. Xu Zhimo, Lin Huiyin, and Liang sicheng Jin Yuelin.

Well, I don't have to talk about it.

 

Snowflake production principle:

Create a video clip snow, which is the key Snowflake. When making a ball, use a gray ball and then blur it with a filter to change the brightness. The timer allows the snowflake to generate different time intervals, and the snowflake will be deleted automatically when it falls down to a height. Otherwise, the memory overhead will be high and the card will be generated.

Next, you need to prepare a background image. It is better to have a relationship with snow.

After completing the preparation, you can start writing code.

 

Design document class: Main. As, and Snow. As can complete the basic work.

Snow writing

 

 

Package COM. effect <br/>{</P> <p> Import flash. display. movieclip; <br/> Import flash. events. *; <br/> Public Class Snow extends movieclip <br/> {<br/> public function snow () <br/>{</P> <p >}< br/>}

 

Package <br/> {</P> <p> Import flash. display. movieclip; <br/> Import flash. events. *; <br/> Import flash. utils. timer; <br/> Import flash. display. stage; <br/> Import flash. display. displayobject; <br/> Import COM. effect. snow; <br/> public class main extends movieclip <br/> {<br/> private var time: timer; <br/> private var speed: Int = 5; <br/> private var contain: movieclip = new movieclip (); // store the snowflake container </P> <p> public function main () <br/>{< br/> Init (); <br/>}< br/> // initialization timer <br/> private function Init (): void <br/>{< br/> addchild (contain); <br/> time = new timer (200); <br/> time. addeventlistener (timerevent. timer, ontimer); <br/> time. start (); <br/>}< br/> private function ontimer (Event: timerevent): void <br/>{< br/> creatsnow (); <br/> creatsnow (); <br/>}</P> <p> // copy snowflake <br/> private function creatsnow (): void <br/>{< br/> var mysnow: snow = new snow (); <br/> contain. addchild (mysnow); <br/> mysnow. y = 0; <br/> mysnow. X = math. random () * stage. stagewidth; <br/> mysnow. scalex = mysnow. scaley = math. random () + 0.1; <br/> mysnow. addeventlistener (event. enter_frame, run); <br/>}< br/> private function run (Event: Event): void <br/>{< br/> var MC: movieclip = movieclip (event. currenttarget); <br/> MC. Y + = speed; <br/> MC. rotation = math. random () * 360; <br/> If (MC. y> 650) <br/>{< br/> contain. removechild (MC); // Delete the MC in the memory <br/> MC. removeeventlistener (event. enter_frame, run); // deletion event <br/> MC = NULL; <br/>}< br/>}

 

Time timer usage:

Key programs mainly use counters to produce an object. Timer generates an object every 200 milliseconds, which produces a downward running effect.

Construct a timer when using the init () method.

 

 

Object motion

The snow object we created needs to be run, so we adopt event in a simple way. for event listening such as enter, we can call this event at every frame.

In this way, when we change the Y axis, a displacement change can be generated. In the process of dropping, changing the angle will produce different results.

 

 

Delete object 

It is not difficult to delete a node. However, when using the removechild method, pay attention to the node relationship.

Private var contain: movieclip = new movieclip (); // the snowflake container is used to store snow objects,

Contain. addchilc (mysnow );

 

In this way, we can easily know the relationship between the node parent and child. As a parent node, contain can only delete nodes in its container.

Contain. removechild (MC); // deletes the MC in the memory.

 

Similarly, delete event listening is required for deleted objects. When the event. enter_frame event is not used, delete the event. Otherwise, an error occurs.

MC. removeeventlistener (event. enter_frame, run); // delete an event