Cocos Creator 橡皮差(刮刮卡)功能（转）

实现一个刮刮卡的效果，于是在论坛里搜集了一些资料并且看了一下CCMask的源码，做出来一套可用的教程，分享给大家。（WEBGL和Native端测试可用）

maskNode是详细设置如下

我们在 scratchCardCtr上挂载了一个脚本 scratchCardNodeCtrl

直接上这个脚本的代码吧

cc.Class({
    extends: cc.Component,

    properties: {
        rsultLabel:cc.Label,
        mask:cc.Mask,
        promptLabel:cc.Label,
    },

    // use this for initialization
    onLoad: function (){
        this.node.on(cc.Node.EventType.TOUCH_START, this._onTouchBegin, this);
        this.node.on(cc.Node.EventType.TOUCH_MOVE, this._onTouchMoved, this);
        this.node.on(cc.Node.EventType.TOUCH_END, this._onTouchEnd, this);
        this.node.on(cc.Node.EventType.TOUCH_CANCEL, this._onTouchCancel, this);
    },

    onDestroy:function () {
        this.node.off(cc.Node.EventType.TOUCH_START, this._onTouchBegin, this);
        this.node.off(cc.Node.EventType.TOUCH_MOVE, this._onTouchMoved, this);
        this.node.off(cc.Node.EventType.TOUCH_END, this._onTouchEnd, this);
        this.node.off(cc.Node.EventType.TOUCH_CANCEL, this._onTouchCancel, this);
    },

    start:function () {
       //

        // var x =-100;
        // var y =-100;
        // var width =300;
        // var height = 200;
        // var rectangle = [cc.v2(x, y),
        //     cc.v2(x + width, y),
        //     cc.v2(x + width, y + height),
        //     cc.v2(x, y + height)];
        //
        // stencil.drawPoly(rectangle, color, 0, color);

        // stencil.drawPoly(this.mask._calculateCircle(cc.p(0,0),cc.p(100,100), 64), color, 0, color);
        //
        // stencil.drawPoly(this.mask._calculateCircle(cc.p(200,200),cc.p(50,50), 64), color, 0, color);

    },

    _onTouchBegin:function (event) {

        cc.log('touchBegin');

        var point = event.touch.getLocation();
        point = this.node.convertToNodeSpaceAR(point);
        this._addCircle(point);
    },

    _onTouchMoved:function (event) {
        var point = event.touch.getLocation();
        point = this.node.convertToNodeSpaceAR(point);
        this._addCircle(point);
    },

    _onTouchEnd:function (event) {
        var point = event.touch.getLocation();
        point = this.node.convertToNodeSpaceAR(point);
        this._addCircle(point);
    },

    _onTouchCancel:function (event) {
        // var point = event.touch.getLocation();
        // point = this.node.convertToNodeSpaceAR(point);
        // this._addCircle(point);
    },

    _addCircle:function (point) {
        var stencil = this.mask._clippingStencil;
        var color = cc.color(255, 255, 255, 0);
        stencil.drawPoly(this.mask._calculateCircle(point,cc.p(50,50), 64), color, 0, color);
        if (!CC_JSB) {
            cc.renderer.childrenOrderDirty = true;
        }
    },

    // called every frame, uncomment this function to activate update callback
    // update: function (dt) {

    // },
});