title: FreeType text upside down
body: <p>I am working on a OpenGL and C++ project (a little 2D game) and i am currently implementing font rendering. I am using FreeType to handle font file and glyphs and i have successfully (kinda) rendered the glyphs onto the screen. However the glyphs appear to be upside down and my sprites are the correct way up.</p>
  
  <p>Texture coords for a sprite (these go into a vbo then into a vao)</p>
  
  <pre><code>vec2 uv_topLeft(0.0, 0.0);
  vec2 uv_topRight(1.0, 0.0);
  vec2 uv_bottomRight(1.0, 1.0);
  vec2 uv_bottomLeft(0.0, 1.0);
  
  uvs.push_back(uv_topLeft);
  uvs.push_back(uv_bottomLeft);
  uvs.push_back(uv_bottomRight);
  uvs.push_back(uv_bottomRight);
  uvs.push_back(uv_topRight);
  uvs.push_back(uv_topLeft);
  </code></pre>
  
  <p>I just have a projection matrix whcih i use to transform the vertex positions to NDC coordinates. </p>
  
  <p>Projection matrix:(WINDOW_WIDTH=960, WINDOW_HEIGHT=640)<br>
      glm::ortho(0.0, (double)WINDOW_WIDTH, 0.0, (double)WINDOW_HEIGHT);</p>
  
  <p><a href="https://i.stack.imgur.com/RQinG.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/RQinG.png" alt="Picture of game with sprites and text"></a></p>
  
  <p>I saw somewhere that openGL and Freetype use different coordinate systems is that true?</p>