HTML5 Canvas Javascript - 如何使用 'translate3d' 制作带有瓷砖的可移动 canvas?

HTML5 Canvas Javascript - How to make a moveable canvas with tiles using 'translate3d'?

我在使用可移动的 canvas 时遇到问题,它随着 'player' 在地图上的移动而调整。由于绘制 600 个图块,每秒 60 次非常低效,我转而使用 translate3d 并且在玩家穿过完整的图块后仅使用 draw - 但它一直出现故障并且移动不流畅。我该如何正确地实现这一目标?

const ctx = canvas.getContext('2d');
canvas.height = 200;
canvas.width = 600;
const tileSize = canvas.height/6;
const MAIN = {position:{x: 120, y: 120}};
const canvasRefresh = {x: 0, y: 20};
document.body.onmousemove = e => MAIN.position = {x: e.clientX, y: e.clientY};
const tiles = {x: 20, y: 20}

function update(){
    moveMap();
    requestAnimationFrame(update);
}
function drawMap(){
    for(var i = 0; i < tiles.x; i++){
        for(var j = 0; j < tiles.y; j++){
            ctx.fillStyle = ['black', 'green','orange'][Math.floor((i+j+canvasRefresh.x1+canvasRefresh.y1)%3)];
            ctx.fillRect(tileSize * i, tileSize * j, tileSize, tileSize);
        }
    }
}
function moveMap(){
    const sector = {
        x: Math.round(-MAIN.position.x % tileSize),
        y: Math.round(-MAIN.position.y % tileSize)
    };
    const x2 = Math.floor(MAIN.position.x/tileSize);
    const y2 = Math.floor(MAIN.position.y/tileSize);
    if(canvasRefresh.x1 != x2 || canvasRefresh.y1 != y2){
        canvasRefresh.x1 = x2;
        canvasRefresh.y1 = y2;
        requestAnimationFrame(drawMap);
    }
    $('#canvas').css({
        transform: "translate3d(" + sector.x + "px, " + sector.y + "px, 0)"
    });
}
update();
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<canvas id=canvas></canvas>

根据上面的评论,它表明您只想在现有代码上平滑地移动 canvas 并且不打算修改,您是否尝试过向 canvas 添加缓动过渡元素?

canvas { transition: all 1500ms cubic-bezier(0.250, 0.100, 0.250, 1.000); transition-timing-function: cubic-bezier(0.250, 0.100, 0.250, 1.000); /* ease (default) */ }

const ctx = canvas.getContext('2d');
canvas.height = 200;
canvas.width = 600;
const tileSize = canvas.height/6;
const MAIN = {position:{x: 120, y: 120}};
const canvasRefresh = {x: 0, y: 20};
document.body.onmousemove = e => MAIN.position = {x: e.clientX, y: e.clientY};
const tiles = {x: 20, y: 20}

function update(){
    moveMap();
    requestAnimationFrame(update);
}
function drawMap(){
    for(var i = 0; i < tiles.x; i++){
        for(var j = 0; j < tiles.y; j++){
            ctx.fillStyle = ['black', 'green','orange'][Math.floor((i+j+canvasRefresh.x1+canvasRefresh.y1)%3)];
            ctx.fillRect(tileSize * i, tileSize * j, tileSize, tileSize);
        }
    }
}
function moveMap(){
    const sector = {
        x: Math.round(-MAIN.position.x % tileSize),
        y: Math.round(-MAIN.position.y % tileSize)
    };
    const x2 = Math.floor(MAIN.position.x/tileSize);
    const y2 = Math.floor(MAIN.position.y/tileSize);
    if(canvasRefresh.x1 != x2 || canvasRefresh.y1 != y2){
        canvasRefresh.x1 = x2;
        canvasRefresh.y1 = y2;
        requestAnimationFrame(drawMap);
    }
    $('#canvas').css({
        transform: "translate3d(" + sector.x + "px, " + sector.y + "px, 0)"
    });
}
update();
canvas {
  transition: all 1500ms cubic-bezier(0.250, 0.100, 0.250, 1.000); /* ease (default) */
  transition-timing-function: cubic-bezier(0.250, 0.100, 0.250, 1.000); /* ease (default) */
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<canvas id=canvas></canvas>

我个人不会移动 canvas 本身,但会移动其中的元素,方法是在方向上添加一个 row/column 并移除相反方向的方块。但是,这应该可以解决问题

提出的问题

发生了一些事情:

立即调用 drawMap 而不是使用 requestAnimationFrame

正如 ggorlen 在评论中提到的,在更新周期中多次使用 requestAnimationFrame 是一种不寻常的做法。当您使用 requestAnimationFrame 时,您将在下一帧更新时调用该函数,这意味着将有一个帧不会重新绘制地图,从而导致轻微的闪烁。相反,如果您立即调用它,它将重新绘制该帧的地图。此外,将所有绘制和更新合并到 requestAnimationFrame 的一次调用是个好主意,因为它可以更清楚地说明更新的顺序。

所以你应该把requestAnimationFrame(drawMap);改成drawMap();

使用非整数求余数

模运算(即 % 运算符)通常适用于整数。在您有 MAIN.position.x % tileSize 的情况下,它会经常出现故障,因为 tileSize 不是整数 (200 / 6)。要使用非整数求余数,我们可以使用自定义函数:

function remainder(a, b) {
  return a - Math.floor(a / b) * b;
}

并用我们的新函数替换模运算实例(例如,将 MAIN.position.x % tileSize 更改为 remainder(MAIN.position.x, tileSize)

Math.round 对比 Math.floor

最后,您可能想使用 Math.floor 而不是 Math.round,因为 Math.round returns 0,两者的范围都在 (-1, 0) 和 ( 0, 1), 而 Math.floor returns -1, 和 0.

使用容器和 css 隐藏 canvas

的移动部分

您可能希望使用包含 div 和对应的 css 来隐藏正在重绘的 canvas 的边缘:

在HTML:

<div class="container">
<canvas id=canvas></canvas>
</div>

在CSS:

.container {
  width: 560px;
  height: 160px;
  overflow: hidden;
}

一起

整体看起来像这样:

const ctx = canvas.getContext('2d');
canvas.height = 200;
canvas.width = 600;
const tileSize = canvas.height/6;
const MAIN = {position:{x: 120, y: 120}};
const canvasRefresh = {x: 0, y: 20};
document.body.onmousemove = e => MAIN.position = {x: e.clientX, y: e.clientY};
const tiles = {x: 20, y: 20}

function update(){
    moveMap();
    requestAnimationFrame(update);
}
function drawMap(){
    for(var i = 0; i < tiles.x; i++){
        for(var j = 0; j < tiles.y; j++){
            ctx.fillStyle = ['black', 'green','orange'][Math.floor((i+j+canvasRefresh.x1+canvasRefresh.y1)%3)];
            ctx.fillRect(tileSize * i, tileSize * j, tileSize, tileSize);
        }
    }
}
function remainder(a, b) {
  return a - Math.floor(a / b) * b;
}
function moveMap(){
    const sector = {
        x: Math.floor(-remainder(MAIN.position.x, tileSize)),
        y: Math.floor(-remainder(MAIN.position.y, tileSize))
    };
    const x2 = Math.floor(MAIN.position.x/tileSize);
    const y2 = Math.floor(MAIN.position.y/tileSize);
    if(canvasRefresh.x1 != x2 || canvasRefresh.y1 != y2){
        canvasRefresh.x1 = x2;
        canvasRefresh.y1 = y2;
        drawMap();
    }
    $('#canvas').css({
        transform: "translate3d(" + sector.x + "px, " + sector.y + "px, 0)"
    });
}
update();
.container {
  width: 560px;
  height: 160px;
  overflow: hidden;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="container">
<canvas id=canvas></canvas>
</div>