Javascript 将精灵图像移动到选定位置
目前我正在制作一个鱼类动画。我的鱼精灵是动画,能够在画布上自由移动。第二,我想给画布上的鱼添加食物。但是现在我被卡住了,当食物在画布上画的时候,我无法让鱼游向食物 下面是我的鱼精灵是如何随机移动的:Javascript 将精灵图像移动到选定位置,javascript,html5-canvas,sprite-sheet,Javascript,Html5 Canvas,Sprite Sheet,目前我正在制作一个鱼类动画。我的鱼精灵是动画,能够在画布上自由移动。第二,我想给画布上的鱼添加食物。但是现在我被卡住了,当食物在画布上画的时候,我无法让鱼游向食物 下面是我的鱼精灵是如何随机移动的: Fish.prototype.changeDirection = function () { var me = this; var speedXSign = Math.random() < 0.5 ? 1 : -1; var speedYSign = Math.rand
Fish.prototype.changeDirection = function () {
var me = this;
var speedXSign = Math.random() < 0.5 ? 1 : -1;
var speedYSign = Math.random() < 0.5 ? 1 : -1;
this.speedX = speedXSign * (1 + Math.random() * 1.6);
this.speedY = speedYSign * (1 + Math.random() * 1.6);
var time = 1000 + 2000*Math.random();
setTimeout(function() {me.changeDirection()}, time);
};
Fish.prototype.move = function () {
this.animIndex++;
if ( this.animIndex == animFrames.length) this.animIndex = 0;
this.xPos += this.speedX;
if ((this.xPos + this.frameWidth * this.frameScale / 1.8) >= canvas.width && this.speedX > 0 ||
(this.xPos - this.frameWidth * this.frameScale / 1.8) <= 0 && this.speedX <= 0) {
this.speedX = -this.speedX;
}
this.yPos += this.speedY;
if ((this.yPos + this.frameHeight * this.frameScale / 1.8) >= canvas.height && this.speedY > 0 ||
(this.yPos - this.frameHeight * this.frameScale / 1.8) <= 0 && this.speedY <= 0) {
this.speedY = -this.speedY;
}
};
Fish.prototype.changeDirection=函数(){
var me=这个;
var speedXSign=Math.random()<0.5?1:-1;
var speedYSign=Math.random()<0.5?1:-1;
this.speedX=speedXSign*(1+Math.random()*1.6);
this.speedY=speedYSign*(1+Math.random()*1.6);
var time=1000+2000*Math.random();
setTimeout(函数(){me.changeDirection()},时间);
};
Fish.prototype.move=函数(){
这个.animIndex++;
如果(this.animIndex==animFrames.length)this.animIndex=0;
this.xPos+=this.speedX;
如果((this.xPos+this.frameWidth*this.frameScale/1.8)>=canvas.width&&this.speedX>0 | |
(this.xPos-this.frameWidth*this.frameScale/1.8)0 |
(this.yPos-this.frameHeight*this.frameScale/1.8)这是我的更新,现在我将解释我所做的更改
添加食物宽度和高度的变量:
...
var foodArray = [];
var foodWidth = 50;
var foodHeight = 50;
var food;
...
更新draw函数以使用这些变量:
function addFood(foodArray) {
...
var x = foodArray[m].x;
var y = foodArray[m].y;
context.drawImage(iiimage, x, y, foodWidth, foodHeight);
...
}
添加查找最近食物的功能:
Fish.prototype.closestFood = function () {
var closestFoodIndex = -1;
var shortestDistance = Infinity;
for (var i = 0; i < foodArray.length; i++) {
var distance = Math.max(Math.abs(this.xPos - foodArray[i].x), Math.abs(this.yPos - foodArray[i].y));
if (distance < shortestDistance) {
shortestDistance = distance;
closestFoodIndex = i;
}
}
return closestFoodIndex;
};
添加一个功能,可以吃鱼下面的任何食物:
Fish.prototype.eatFood = function() {
var foodX, foodY;
var halfWidth = this.frameWidth * this.frameScale / 2;
var halfHeight = this.frameHeight * this.frameScale / 2;
// Loop backward because we are removing elements.
for (var i = foodArray.length-1; i >= 0; i--) {
foodX = foodArray[i].x + foodWidth / 2;
foodY = foodArray[i].y + foodHeight / 2;
if (foodX > this.xPos - halfWidth &&
foodX < this.xPos + halfWidth &&
foodY > this.yPos - halfHeight&&
foodY < this.yPos + halfHeight)
{
foodArray.splice(i, 1);
}
}
};
更新“更改方向”功能,仅在不追逐食物时更改方向:
function Fish(xPos, yPos, speedX, speedY, imgFish, frameWidth, frameHeight) {
...
this.chasingFood = false;
...
}
Fish.prototype.changeDirection = function () {
var me = this;
if (!this.chasingFood) {
var speedXSign = Math.random() < 0.5 ? 1 : -1;
var speedYSign = Math.random() < 0.5 ? 1 : -1;
this.speedX = speedXSign * (1 + Math.random() * 1.6);
this.speedY = speedYSign * (1 + Math.random() * 1.6);
}
var time = 1000 + 2000 * Math.random();
setTimeout(function () {
me.changeDirection();
}, time);
};
Fish.prototype.changeDirection=函数(){
var me=这个;
如果(!这个。查辛食品){
var speedXSign=Math.random()<0.5?1:-1;
var speedYSign=Math.random()<0.5?1:-1;
this.speedX=speedXSign*(1+Math.random()*1.6);
this.speedY=speedYSign*(1+Math.random()*1.6);
}
var time=1000+2000*Math.random();
setTimeout(函数(){
我。改变方向();
},时间);
};
这只会使鱼改变x和y方向,而不会改变速度。可以修改chaseFood功能使其加快速度,或者直接吃食物(尽管这可能会使动画看起来很奇怪)
如果您需要对任何新代码进行更多解释,请留下评论。是的,在Windows和Ubuntu上使用Chrome对我来说效果很好。我可以再问您一个问题吗?是否可以在画布上放置一个按钮来启用/禁用馈送?@Jaredneil本人从未这样做过,但似乎它可以回答您的问题。
Fish.prototype.eatFood = function() {
var foodX, foodY;
var halfWidth = this.frameWidth * this.frameScale / 2;
var halfHeight = this.frameHeight * this.frameScale / 2;
// Loop backward because we are removing elements.
for (var i = foodArray.length-1; i >= 0; i--) {
foodX = foodArray[i].x + foodWidth / 2;
foodY = foodArray[i].y + foodHeight / 2;
if (foodX > this.xPos - halfWidth &&
foodX < this.xPos + halfWidth &&
foodY > this.yPos - halfHeight&&
foodY < this.yPos + halfHeight)
{
foodArray.splice(i, 1);
}
}
};
Fish.prototype.move = function () {
...
this.eatFood();
var closestFoodIndex = this.closestFood();
if (closestFoodIndex >= 0) {
this.chasingFood = true;
this.chaseFood(closestFoodIndex);
} else {
this.chaseingFood = false;
}
...
};
Fish.prototype.changeDirection = function () {
var me = this;
if (!this.chasingFood) {
var speedXSign = Math.random() < 0.5 ? 1 : -1;
var speedYSign = Math.random() < 0.5 ? 1 : -1;
this.speedX = speedXSign * (1 + Math.random() * 1.6);
this.speedY = speedYSign * (1 + Math.random() * 1.6);
}
var time = 1000 + 2000 * Math.random();
setTimeout(function () {
me.changeDirection();
}, time);
};