title: Using mipmap filtering on iOS 5.0 OpenGL ES 2.0 texture caches
body: <p>I'm using a texture cache to draw video frames to the screen, just like the RosyWriter sample application from Apple.</p>
  
  <p>I want to downsample an image from 1080p down to around 320x480 (for various reasons, I don't want to capture at a lower resolution) and use mipmap filtering to get rid of aliasing. However, when I try adding:</p>
  
  <pre><code>glGenerateMipmap(CVOpenGLESTextureGetTarget(inputTexture));
  glTexParameteri(CVOpenGLESTextureGetTarget(inputTexture), GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
  </code></pre>
  
  <p>I just get a black screen, as though the mipmaps aren't being generated. I'm rendering offscreen from one texture to another. Both source and destination are mapped to pixel buffers using texture caches.</p>