如何用javascript代码从webgl着色器中获取统一的值

// 创建WebGL上下文
var canvas = document.getElementById("canvas");
var gl = canvas.getContext("webgl");

// 创建着色器程序
var vertexShaderSource = `
    // 顶点着色器代码
    attribute vec4 position;
    void main() {
        gl_Position = position;
    }
`;

var fragmentShaderSource = `
    // 片元着色器代码
    uniform vec3 uniformValue;
    void main() {
        gl_FragColor = vec4(uniformValue, 1.0);
    }
`;

var vertexShader = gl.createShader(gl.VERTEX_SHADER);
gl.shaderSource(vertexShader, vertexShaderSource);
gl.compileShader(vertexShader);

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

var program = gl.createProgram();
gl.attachShader(program, vertexShader);
gl.attachShader(program, fragmentShader);
gl.linkProgram(program);
gl.useProgram(program);

// 获取uniform变量的位置
var uniformLocation = gl.getUniformLocation(program, "uniformValue");

// 设置统一的值
var uniformValue = [1.0, 0.0, 0.0]; // 红色
gl.uniform3fv(uniformLocation, uniformValue);

// 绘制图形
// ...