title: After disabling Vertex Attribute Array how glDrawArrays() works?
body: <p>I have started learning Opengl ES 2.0 for android. I am working with code segment taken from the following site:
  <a href="http://www.learnopengles.com/android-lesson-two-ambient-and-diffuse-lighting/" rel="nofollow">http://www.learnopengles.com/android-lesson-two-ambient-and-diffuse-lighting/</a>
  Here is a light point with 4 numbers:</p>
  
  <pre><code>    private final float[] mLightPosInModelSpace = new float[] {0.0f, 0.0f, 0.0f, 1.0f};
  </code></pre>
  
  <p>This lightpoint is in model space. The following function is used to draw the point with disabled Vertex Attribute Array.  </p>
  
  <pre><code>private void drawLight()
  {
      final int pointMVPMatrixHandle = GLES20.glGetUniformLocation(mPointProgramHandle, "u_MVPMatrix");
      final int pointPositionHandle = GLES20.glGetAttribLocation(mPointProgramHandle, "a_Position");
  
      // Pass in the position.
      GLES20.glVertexAttrib3f(pointPositionHandle, mLightPosInModelSpace[0], mLightPosInModelSpace[1], mLightPosInModelSpace[2]);
  
      // Since we are not using a buffer object, disable vertex arrays for this attribute.
      GLES20.glDisableVertexAttribArray(pointPositionHandle);  
  
      // Pass in the transformation matrix.
      Matrix.multiplyMM(mMVPMatrix, 0, mViewMatrix, 0, mLightModelMatrix, 0);
      Matrix.multiplyMM(mMVPMatrix, 0, mProjectionMatrix, 0, mMVPMatrix, 0);
      GLES20.glUniformMatrix4fv(pointMVPMatrixHandle, 1, false, mMVPMatrix, 0);
  
  
      // Draw the point.
      GLES20.glDrawArrays(GLES20.GL_POINTS, 0, 1);
  }
  </code></pre>
  
  <p>I read the documentation from here: <a href="https://www.khronos.org/opengles/sdk/docs/man/xhtml/glEnableVertexAttribArray.xml" rel="nofollow">https://www.khronos.org/opengles/sdk/docs/man/xhtml/glEnableVertexAttribArray.xml</a><br>
  and see that after enabling vertex Attribute Array <code>glDrawArrays()</code> get points from that enabled array. But my question is from where <code>glDrawArrays()</code> get the points? In this example and it works fine taking the point from <code>mLightPosInModelSpace</code> . Thanks in advance. </p>