WebGL中多边形的console.log绘制计数

const canvas = document.getElementById('canvas');
const gl = canvas.getContext('webgl');

// 定义顶点数据
const vertices = [
  -0.5, 0.5, 0.0,
  -0.5, -0.5, 0.0,
  0.5, -0.5, 0.0,
  0.5, 0.5, 0.0
];

// 定义顶点索引
const indices = [
  0, 1, 2,
  0, 2, 3
];

// 创建顶点缓冲对象
const vertexBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, vertexBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);

// 创建索引缓冲对象
const indexBuffer = gl.createBuffer();
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexBuffer);
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array(indices), gl.STATIC_DRAW);

// 定义顶点着色器
const vertexShaderSource = `
  attribute vec3 aPosition;
  void main() {
    gl_Position = vec4(aPosition, 1.0);
  }
`;

// 定义片元着色器
const fragmentShaderSource = `
  void main() {
    gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
  }
`;

// 创建着色器程序
const vertexShader = gl.createShader(gl.VERTEX_SHADER);
gl.shaderSource(vertexShader, vertexShaderSource);
gl.compileShader(vertexShader);

const fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);
gl.shaderSource(fragmentShader, fragmentShaderSource);
gl.compileShader(fragmentShader);

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

// 获取顶点属性位置
const positionAttributeLocation = gl.getAttribLocation(shaderProgram, 'aPosition');
gl.enableVertexAttribArray(positionAttributeLocation);
gl.vertexAttribPointer(positionAttributeLocation, 3, gl.FLOAT, false, 0, 0);

gl.clearColor(0.0, 0.0, 0.0, 1.0);
gl.clear(gl.COLOR_BUFFER_BIT);

gl.drawElements(gl.TRIANGLES, indices.length, gl.UNSIGNED_SHORT, 0);

console.log('绘制计数:', indices.length / 3);