pointing_right.html - Android社区 - https://www.androidos.net.cn/

<html>
  <body style="margin: 0">
    <canvas width="100" height="100"></canvas>
  </body>
</html>
<script>
    var canvas = document.getElementsByTagName("canvas")[0];
    gl = canvas.getContext("experimental-webgl");
    gl.clearColor(0.0, 1.0, 0.0, 1.0);
    gl.viewport(0, 0, canvas.width, canvas.height);

    var vertexShader = gl.createShader(gl.VERTEX_SHADER);
    gl.shaderSource(vertexShader, "attribute vec4 vPosition;\nvoid main() { gl_Position = vPosition; }");
    gl.compileShader(vertexShader);

    var 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);

    var shaderProgram = gl.createProgram();
    gl.attachShader(shaderProgram, vertexShader);
    gl.attachShader(shaderProgram, fragmentShader);
    gl.bindAttribLocation(shaderProgram, 0, "vPosition");
    gl.linkProgram(shaderProgram);

    gl.useProgram(shaderProgram);

    var buffer = gl.createBuffer();
    gl.bindBuffer(gl.ARRAY_BUFFER, buffer);

    var vertices = [-1.0, -1.0,
                    0.0, 0.0,
                    -1.0, 1.0];
    var seedX = -1.0;
    var seedY = 1.0;
    vertices
    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);


    gl.vertexAttribPointer(0, 2, gl.FLOAT, false, 0, 0);
    gl.enableVertexAttribArray(0);
    gl.clear(gl.COLOR_BUFFER_BIT);
    gl.drawArrays(gl.TRIANGLES, 0, 3);
    gl.flush();
</script>