js实现方块

使用Canvas绘制方块

通过HTML5的Canvas API可以轻松绘制方块。创建一个canvas元素，获取其上下文后使用fillRect方法绘制矩形。

<canvas id="canvas" width="200" height="200"></canvas>
<script>
  const canvas = document.getElementById('canvas');
  const ctx = canvas.getContext('2d');
  ctx.fillStyle = 'blue';
  ctx.fillRect(50, 50, 100, 100); // x, y, width, height
</script>

使用CSS和DOM创建方块

通过JavaScript动态创建div元素，并为其添加CSS样式来实现方块效果。

const square = document.createElement('div');
square.style.width = '100px';
square.style.height = '100px';
square.style.backgroundColor = 'red';
document.body.appendChild(square);

使用SVG绘制方块

利用SVG的rect元素结合JavaScript动态生成方块。

<svg id="svg" width="200" height="200"></svg>
<script>
  const svg = document.getElementById('svg');
  const rect = document.createElementNS('http://www.w3.org/2000/svg', 'rect');
  rect.setAttribute('x', '50');
  rect.setAttribute('y', '50');
  rect.setAttribute('width', '100');
  rect.setAttribute('height', '100');
  rect.setAttribute('fill', 'green');
  svg.appendChild(rect);
</script>

使用WebGL绘制3D方块

通过WebGL可以创建更复杂的3D方块效果。以下是一个基础示例。

<canvas id="glCanvas" width="500" height="500"></canvas>
<script>
  const canvas = document.getElementById('glCanvas');
  const gl = canvas.getContext('webgl');

  if (!gl) {
    alert('WebGL not supported');
  }

  const vertices = [
    // Front face
    -0.5, -0.5,  0.5,
     0.5, -0.5,  0.5,
     0.5,  0.5,  0.5,
    -0.5,  0.5,  0.5,
  ];

  const vertexBuffer = gl.createBuffer();
  gl.bindBuffer(gl.ARRAY_BUFFER, vertexBuffer);
  gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);

  const vertexShader = gl.createShader(gl.VERTEX_SHADER);
  gl.shaderSource(vertexShader, `
    attribute vec3 position;
    void main() {
      gl_Position = vec4(position, 1.0);
    }
  `);
  gl.compileShader(vertexShader);

  const fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);
  gl.shaderSource(fragmentShader, `
    void main() {
      gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
    }
  `);
  gl.compileShader(fragmentShader);

  const shaderProgram = gl.createProgram();
  gl.attachShader(shaderProgram, vertexShader);
  gl.attachShader(shaderProgram, fragmentShader);
  gl.linkProgram(shaderProgram);
  gl.useProgram(shaderProgram);

  const position = gl.getAttribLocation(shaderProgram, 'position');
  gl.enableVertexAttribArray(position);
  gl.vertexAttribPointer(position, 3, gl.FLOAT, false, 0, 0);

  gl.clearColor(0.0, 0.0, 0.0, 1.0);
  gl.clear(gl.COLOR_BUFFER_BIT);
  gl.drawArrays(gl.TRIANGLE_FAN, 0, 4);
</script>

使用CSS动画让方块移动

为方块添加CSS动画效果，使其能够移动。

const square = document.createElement('div');
square.style.width = '100px';
square.style.height = '100px';
square.style.backgroundColor = 'purple';
square.style.position = 'absolute';
square.style.left = '0px';
document.body.appendChild(square);

let pos = 0;
function animate() {
  pos += 1;
  square.style.left = pos + 'px';
  if (pos < 300) {
    requestAnimationFrame(animate);
  }
}
animate();