remove a bit more unnecessary code

glsl/raymarching.js

    h = canvas.height = window.innerHeight;
    gl.viewport(0, 0, w, h);
    gl.uniform2f(iResolution, w, h);
    gl.clearColor(0.0, 0.0, 0.0, 1.0);
    gl.clear(gl.COLOR_BUFFER_BIT);
    render();
  };
  
  render();
} catch (e) {
  //alert(e);
  var msg = document.createElement("pre");
  msg.style = "color: red; position: absolute; right: 0; bottom: 0";
  msg.textContent = e;