title: OpenGL ES - Invalid qualifiers in global context error
body: <p>When adding a float attribute to my opengl fragment (i want to find to it later), when I compile, I get:</p>
  
  <pre><code>ERROR: 0:1: Invalid qualifiers 'attribute' in global variable context
  </code></pre>
  
  <p>Here's my code:</p>
  
  <pre><code>const char * sChromaKeyFragment = _STRINGIFY(
                                               attribute float threshold;
  
                                               varying highp vec2 coordinate;
                                               precision mediump float;
  
                                               uniform sampler2D videoframe;
                                               uniform sampler2D videosprite;
                                               uniform vec4 mask;
  
  
  
                                               vec3 normalize(vec3 color, float meanr)
  {
      return color*vec3(0.75 + meanr, 1., 1. - meanr);
  }
  
                                               void main()
  {
  } 
  </code></pre>
  
  <p>New to OpenGL. Any help would be great. Thanks!</p>