What is an invariant varying in OpenGL Shader Language
<p>I was reading the OpenGL ES 2  Shading Language specification (<a href="https://www.khronos.org/files/opengles_shading_language.pdf" rel="nofollow" title="PDF">PDF</a>), when I went through this code:</p>

<pre><code>      invariant varying mediump vec3 Color;
</code></pre>

<p>I think understand the invariance concept, but the meaning of an "invariant varying" seems quite puzzling to me.</p>

<p>Can someone explain to me the meaning and why this is useful ? </p>