title: Android OpenGL combination of SurfaceTexture (external image) and ordinary texture
body: <p>I would like to mix camera preview <code>SurfaceTexture</code> with some overlay texture. I am using these shaders for processing:</p>
  <pre><code>private final String vss = &quot;attribute vec2 vPosition;\n&quot;
          + &quot;attribute vec2 vTexCoord;\n&quot;
          + &quot;varying vec2 texCoord;\n&quot;
          + &quot;void main() {\n&quot; 
          + &quot;  texCoord = vTexCoord;\n&quot;
          + &quot;  gl_Position = vec4 ( vPosition.x, vPosition.y, 0.0, 1.0 );\n&quot;
          + &quot;}&quot;;
  
  private final String fss = &quot;#extension GL_OES_EGL_image_external : require\n&quot;
          + &quot;precision mediump float;\n&quot;
          + &quot;uniform samplerExternalOES sTexture;\n&quot;
          + &quot;uniform sampler2D filterTexture;\n&quot;
          + &quot;varying vec2 texCoord;\n&quot;
          + &quot;void main() {\n&quot;
          +&quot;  vec4 t_camera = texture2D(sTexture,texCoord);\n&quot;
          //+&quot;  vec4 t_overlayer = texture2D(filterTexture, texCoord);\n&quot; 
          //+ &quot;  gl_FragColor = t_overlayer;\n&quot; + &quot;}&quot;;
          + &quot;  gl_FragColor = t_camera;\n&quot; + &quot;}&quot;;
  </code></pre>
  <p>My goal is to mix <code>t_camera</code> and <code>t_overlayer</code>. When I show <code>t_camera</code> or <code>t_overlayer</code> separately, it works (showing camera preview or texture). But when I uncomment <code>t_overlayer</code>, then <code>t_camera</code> becomes black (somehow badly sampled). My overlayer texture is 512x512 and <code>CLAMPT_TO_EDGE</code>.
  This problem occurs only for example on: Android Emulator, HTC Evo 3D.
  But on SGS3, HTC One X, it works just fine.</p>
  <p>What is wrong? Is it Evo 3D missing some extension or what?</p>