title: OpenGL Multitexturing - glActiveTexture is NULL
body: <p>I have started a new project, which I want to use multitexturing in.
  I have done multixexturing before, and is supported by my version of OpenGL</p>
  
  <p>In the header I have:</p>
  
  <pre><code>GLuint  m_TerrainTexture[3];//heightmap, texture map and detail map
  GLuint  m_SkyboxTexture[5]; //left, front, right, back and top textures
  
  PFNGLMULTITEXCOORD2FARBPROC glMultiTexCoord2fARB;
  PFNGLACTIVETEXTUREARBPROC   glActiveTexture;
  </code></pre>
  
  <p>In the constructor I have:</p>
  
  <pre><code>glActiveTexture = (PFNGLACTIVETEXTUREARBPROC) wglGetProcAddress((LPCSTR)"glActiveTextureARB");
  glMultiTexCoord2fARB = (PFNGLMULTITEXCOORD2FARBPROC) wglGetProcAddress((LPCSTR)"glMultiTexCoord2fARB");
  
  if(!glActiveTexture || !glMultiTexCoord2fARB)
  {
      MessageBox(NULL, "multitexturing failed", "OGL_D3D Error", MB_OK);
  }
  
  glActiveTexture( GL_TEXTURE0_ARB );
  ...
  </code></pre>
  
  <p>This shows the message box "multitexturing failed" and the contents of glActiveTexture is 0x00000000</p>
  
  <p>when it gets to glActiveTexture( GL_TEXTURE0_ARB ); I get an access violation error</p>
  
  <p>I am implementing the MVC diagram, so this is all in my terrain view class</p>