loat u_specular;
varying vec3 v_normal;
varying vec3 v_surfaceToLight;
varying vec3 v_surfaceToView;

void main() {
  vec3 normal = normalize(v_normal);
  vec3 surfaceToLight = normalize(v_surfaceToLight);
  vec3 surfaceToView = normalize(v_surfaceToView);
  vec3 halfVector = normalize(surfaceToLight + surfaceToView);
  float lit = dot(normal, surfaceToLight) * .5 + .5;
  gl_FragColor = vec4(u_color.rgb * lit, u_color.a);
}
</script>
<script>
"use strict";
var m4 = twgl.m4;
var v3 = twgl.v3;

var fPosition;