Question

我想在as3中制作一个自上而下的策略游戏，我希望用户能够使用鼠标标记多个动画片段，就像在操作系统中按下鼠标按钮然后拖动鼠标一样，它将创建一个矩形。你是如何在as3中做到的？

Answer 1

您可以这样做（将以下代码复制并粘贴到“动作”面板中）：

var s:Shape = new Shape();
s.graphics.beginFill(0xC2C2C2, 0.2);
s.graphics.lineStyle(0, 0x666666);
s.graphics.drawRect(0, 0, 100, 100);

function mouseDownHandler(e:MouseEvent):void {
    addChild(s);
    s.x = e.stageX;
    s.y = e.stageY;
    addEventListener(Event.ENTER_FRAME, enterFrameHandler);
}

function enterFrameHandler(e:Event):void {  
    s.scaleX = (mouseX - s.x) / 100;
    s.scaleY = (mouseY - s.y) / 100;
}

function mouseUpHandler(e:MouseEvent):void {
    removeEventListener(Event.ENTER_FRAME, enterFrameHandler);
    removeChild(s);
}

stage.addEventListener(MouseEvent.MOUSE_DOWN, mouseDownHandler);
stage.addEventListener(MouseEvent.MOUSE_UP, mouseUpHandler);

Answer 2

stage.addEventListener(MouseEvent.MOUSE_DOWN, onDown);
stage.addEventListener(MouseEvent.MOUSE_UP,   onUp);

var sp : Sprite = new Sprite();
var p1 : Point  = new Point();
var p2 : Point  = new Point();

function onDown(e:MouseEvent) : void {
    p1.x = mouseX;
    p1.y = mouseY;
    addEventListener(Event.ENTER_FRAME, onMove);
}

function onMove(e:Event) : void {
    p2.x = mouseX;
    p2.y = mouseY;
    draw();
}

function onUp(e:MouseEvent) : void {
    removeEventListener(Event.ENTER_FRAME, onMove);
    stage.removeChild(sp);
}

function draw() : void {
    sp.graphics.clear();
    p2.x = p2.x - p1.x;
    p2.y = p2.y - p1.y;
    sp.graphics.lineStyle(1, 0x0000FF);
    sp.graphics.beginFill(0xC2C2C2, 0.2);
    sp.graphics.drawRect(p1.x, p1.y, p2.x, p2.y);
    stage.addChild(sp);
}

希望这会有所帮助......

Answer 3

有一个简单的选择框很好，但是一些可选择的对象呢？

看看我有什么，它很简单，大部分代码都是为了视觉效果。

// Add 100 green circles.
var objects:Vector.<Sprite> = new Vector.<Sprite>();
for(var i:int = 0; i < 100; ++i){
    var object:Sprite = new Sprite();
    object.x = Math.random() * stage.stageWidth;
    object.y = Math.random() * stage.stageHeight;
    object.graphics.lineStyle(2, 0x00FF00);
    object.graphics.beginFill(0x00FF00, 0.5);
    object.graphics.drawCircle(0,0,15);
    object.graphics.endFill();
    objects.push(object);
    addChild(object);
}

// Main variables we'll be using.
var startPos:Point = new Point();
var selection:Rectangle = new Rectangle();
var isSelecting:Boolean = false;

// Mouse listeners.
stage.addEventListener(MouseEvent.MOUSE_DOWN, mDown);
stage.addEventListener(MouseEvent.MOUSE_UP, mUp);
function mDown(e:MouseEvent):void {
    startPos.x = stage.mouseX;
    startPos.y = stage.mouseY;
    isSelecting = true;
}
function mUp(e:MouseEvent):void {
    isSelecting = false;
}

// Main loop; check if we're intersecting with any of the sprites; if so render them yellow.
stage.addEventListener(Event.ENTER_FRAME, loop);
function loop(e:Event):void {
    graphics.clear();
    if(isSelecting) {
        selection = new Rectangle(startPos.x, startPos.y, stage.mouseX - startPos.x, stage.mouseY - startPos.y);
        normalize(selection);

        graphics.lineStyle(2, 0xFF0000);
        graphics.beginFill(0xFF0000, 0.5);
        graphics.drawRect(selection.x, selection.y, selection.width, selection.height);
        graphics.endFill();

        for (var j:int = 0; j < objects.length; ++j) {
            var object:Sprite = objects[j];
            if(selection.intersects(object.getBounds(this))){
                object.graphics.clear();
                object.graphics.lineStyle(2, 0xFFCC00);
                object.graphics.beginFill(0xFFCC00, 0.5);
                object.graphics.drawCircle(0,0,15);
                object.graphics.endFill();
            }
        }
    }
}

// Intersection requires positive values.
function normalize(rect:Rectangle):void {
    if (rect.width < 0) {
        rect.width = -rect.width;
        rect.x -= rect.width;
    }
    if (rect.height < 0) {
        rect.height = -rect.height;
        rect.y -= rect.height;
    }
}

AS3 - 用鼠标创建矩形

3 个答案: