3. Uploading cube map textures

• Create and bind texture buffer

• Upload images by glTexImage2D(). For example,

  
      glTexImage2D(
          GL_TEXTURE_CUBE_MAP_POSITIVE_X, 0, GL_RGBA,
          w, h, 0, GL_BGR, GL_UNSIGNED_BYTE, bitmap_data );
  
  

  where texture targets are

  
          GL_TEXTURE_CUBE_MAP_POSITIVE_X
          GL_TEXTURE_CUBE_MAP_NEGATIVE_X
          GL_TEXTURE_CUBE_MAP_POSITIVE_Y
          GL_TEXTURE_CUBE_MAP_NEGATIVE_Y
          GL_TEXTURE_CUBE_MAP_POSITIVE_Z
          GL_TEXTURE_CUBE_MAP_NEGATIVE_Y