title: How send eigen a matrix to GLSL?
body: <p>How send "Eigen matrix" to GLSL?
  For example this:</p>
  
  <pre><code>// Set up the model and projection matrix
  Eigen::Matrix&lt;GLfloat,4,4&gt; projection_matrix;
  
  projection_matrix = frustum(-1.0f, 1.0f, -aspect, aspect, 1.0f, 500.0f);
  glUniformMatrix4fv(render_projection_matrix_loc, 1, GL_FALSE, &amp;projection_matrix.data()[0]);
  </code></pre>
  
  <p>I looked this <code>way(matrix.date()[0])</code> for uBLAS, but Eigen isn't uBLAS. How I can do this?</p>