webgl画个点

function main(){
    var canvas = document.getElementById("webgl");
    var gl = getWebGLContext(canvas)
    if (!gl){
        console.log("Fail to get WebGL context");
        return;
    }else{
        ;
    }
    var VSHADER_SOURCE = function(){
        /*
         void main(){
         gl_Position = vec4(0.0,0.0,0.0,1.0);
         gl_PointSize = 10.0;
         }
         */
    }.toString().match(/\/\*([^]*)\*\//)[1];

    var FSHADER_SOURCE = function(){
        /*
         void main(){
         gl_FragColor = vec4(1.0,0.0,0.0,1.0);
         }
         */
    }.toString().match(/\/\*([^]*)\*\//)[1];

    if (!initShaders(gl,VSHADER_SOURCE,FSHADER_SOURCE)){
        console.log('Fail to init shaders');
        return;
    }
    gl.clearColor(0.0,0.0,0.0,0.8);
    gl.clear(gl.COLOR_BUFFER_BIT);
    gl.drawArrays(gl.POINTS, 0, 1);
}