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我们用Flash ActionScript代码制作一个模拟弹弓弓弦弹性形变的小游戏教程，我们一步一步由浅入深来详细说明制作步骤。
思路：准备三个小球元件，使其中一个小球可以拖动，在使它沿着一条线移动，用ActionScript代码计算移动的角度，最后实现弹弓弓弦弹性形变的一个互动游戏。
一、Flash制作小球随鼠标拖动
启动Flash，首先我们绘制两个元件，非常简单的。绘制一个小球然后转变为影片剪辑元件，同样方法再建议一个不同颜色的小球的影片剪辑。
然后在主场景中直接输入如下代码：
attachMovie(sling, sling_1, _root.getNextHighestDepth(), {_x:20, _y:200});
attachMovie(sling, sling_2, _root.getNextHighestDepth(), {_x:480, _y:200});
attachMovie(ball, ball, _root.getNextHighestDepth(), {_x:250, _y:100});
_root.createEmptyMovieClip(elastic, _root.getNextHighestDepth());
ball.onPress = function() {
startDrag(this);
};
ball.onRelease = function() {
stopDrag();
};
二、Flash制作随小球移动的弦
然后我们通过修改上面的代码，在两个小球之间绘制一条线，可以随中间小球任意移动。
attachMovie(sling, sling_1, _root.getNextHighestDepth(), {_x:20, _y:200});
attachMovie(sling, sling_2, _root.getNextHighestDepth(), {_x:480, _y:200});
attachMovie(ball, ball, _root.getNextHighestDepth(), {_x:250, _y:100});
_root.createEmptyMovieClip(elastic, _root.getNextHighestDepth());
ball.onPress = function() {
startDrag(this);
};
ball.onRelease = function() {
stopDrag();
};
elastic.onEnterFrame = function() {
this.clear();
this.lineStyle(2, 0x009900);
this.moveTo(sling_1._x, sling_1._y);
if (ball._y>182) {
dist_x = ball._x-sling_1._x;
dist_y = ball._y-sling_1._y;
distance_from_sling = Math.sqrt(dist_x*dist_x+dist_y*dist_y);
elastic_length = Math.sqrt(distance_from_sling*distance_from_sling-18*18);
angle = Math.atan2(dist_y, dist_x)+Math.asin(18/distance_from_sling);
this.lineTo(sling_1._x+elastic_length*Math.cos(angle), sling_1._y+elastic_length*Math.sin(angle));
} else {
this.lineTo(sling_2._x, sling_2._y);
}
this.moveTo(sling_2._x, sling_2._y);
if (ball._y>182) {
dist_x = ball._x-sling_2._x;
dist_y = ball._y-sling_2._y;
distance_from_sling = Math.sqrt(dist_x*dist_x+dist_y*dist_y);
elastic_length = Math.sqrt(distance_from_sling*distance_from_sling-18*18);
angle = Math.atan2(dist_y, dist_x)+Math.asin(18/distance_from_sling)*-1;
this.lineTo(sling_2._x+elastic_length*Math.cos(angle), sling_2._y+elastic_length*Math.sin(angle));
} else {
this.lineTo(sling_2._x, sling_2._y);
}
};
三、Flash计算弦的形变角度
在这里我们可以很轻松的计算出小球在线上的角度来。
稍微做一下改动。
attachMovie(sling, sling_1, _root.getNextHighestDepth(), {_x:20, _y:200});
attachMovie(sling, sling_2, _root.getNextHighestDepth(), {_x:480, _y:200});
attachMovie(ball, ball, _root.getNextHighestDepth(), {_x:250, _y:100});
_root.createEmptyMovieClip(elastic, _root.getNextHighestDepth());
xspeed = 0;
yspeed = 0;
fire = false;
ball.onPress = function() {
fire = false;
startDrag(this);
};
ball.onRelease = function() {
stopDrag();
fire = true;
};
ball.onEnterFrame = function() {
if (fire) {
this._x += (xspeed*0.001);
this._y += (yspeed*0.001);
}
};
elastic.onEnterFrame = function() {
this.clear();
this.lineStyle(2, 0x009900);
this.moveTo(sling_1._x, sling_1._y);
if (ball._y>182) {
dist_x = ball._x-sling_1._x;
dist_y = ball._y-sling_1._y;
distance_from_sling = Math.sqrt(dist_x*dist_x+dist_y*dist_y);
elastic_length = Math.sqrt(distance_from_sling*distance_from_sling-18*18);
angle = Math.atan2(dist_y, dist_x)+Math.asin(18/distance_from_sling);
saved_angle = angle;
this.lineTo(sling_1._x+elastic_length*Math.cos(angle), sling_1._y+elastic_length*Math.sin(angle));
this.lineTo(ball._x,ball._y);
} else {
this.lineTo(sling_2._x, sling_2._y);
}
this.moveTo(sling_2._x, sling_2._y);
if (ball._y>182) {
dist_x = ball._x-sling_2._x;
dist_y = ball._y-sling_2._y;
distance_from_sling = Math.sqrt(dist_x*dist_x+dist_y*dist_y);
elastic_length = Math.sqrt(distance_from_sling*distance_from_sling-18*18);
angle = Math.atan2(dist_y, dist_x)+Math.asin(18/distance_from_sling)*-1;
this.lineTo(sling_2._x+elastic_length*Math.cos(angle), sling_2._y+elastic_length*Math.sin(angle));
this.lineTo(ball._x,ball._y);
} else {
this.lineTo(sling_2._x, sling_2._y);
}
};
三、Flash计算弦的形变角度
在这里我们可以很轻松的计算出小球在线上的角度来。
稍微做一下改动。
attachMovie(sling, sling_1, _root.getNextHighestDepth(), {_x:20, _y:200});
attachMovie(sling, sling_2, _root.getNextHighestDepth(), {_x:480, _y:200});
attachMovie(ball, ball, _root.getNextHighestDepth(), {_x:250, _y:100});
_root.createEmptyMovieClip(elastic, _root.getNextHighestDepth());
xspeed = 0;
yspeed = 0;
fire = false;
ball.onPress = function() {
fire = false;
startDrag(this);
};
ball.onRelease = function() {
stopDrag();
fire = true;
};
ball.onEnterFrame = function() {
if (fire) {
this._x += (xspeed*0.001);
this._y += (yspeed*0.001);
}
};
elastic.onEnterFrame = function() {
this.clear();
this.lineStyle(2, 0x009900);
this.moveTo(sling_1._x, sling_1._y);
if (ball._y>182) {
dist_x = ball._x-sling_1._x;
dist_y = ball._y-sling_1._y;
distance_from_sling = Math.sqrt(dist_x*dist_x+dist_y*dist_y);
elastic_length = Math.sqrt(distance_from_sling*distance_from_sling-18*18);
angle = Math.atan2(dist_y, dist_x)+Math.asin(18/distance_from_sling);
saved_angle = angle;
this.lineTo(sling_1._x+elastic_length*Math.cos(angle), sling_1._y+elastic_length*Math.sin(angle));
this.lineTo(ball._x,ball._y);
} else {
this.lineTo(sling_2._x, sling_2._y);
}
this.moveTo(sling_2._x, sling_2._y);
if (ball._y>182) {
dist_x = ball._x-sling_2._x;
dist_y = ball._y-sling_2._y;
distance_from_sling = Math.sqrt(dist_x*dist_x+dist_y*dist_y);
elastic_length = Math.sqrt(distance_from_sling*distance_from_sling-18*18);
angle = Math.atan2(dist_y, dist_x)+Math.asin(18/distance_from_sling)*-1;
this.lineTo(sling_2._x+elastic_length*Math.cos(angle), sling_2._y+elastic_length*Math.sin(angle));
this.lineTo(ball._x,ball._y);
} else {
this.lineTo(sling_2._x, sling_2._y);
}
};
详解Flash AS代码实现弹弓弓弦弹性形变 |
