Rendering FreeType fonts

Question

I have been trying to render FreeType2 fonts in OpenGL 3. I used NeHe's tutorial http://nehe.gamedev.net/tutorial/freetype_fonts_in_opengl/24001/ . however, I modified it a little for modern OpenGL 3+. Actually, I use glBufferData(...,GL_DYNAMIC_DRAW) to update vertex buffer for every character. The arrays of vertices are created during glyph loading as NeHe does with display lists:

    int width = next_p2(bitmap.width);
    int height = next_p2(bitmap.rows);

    float   x=(float)bitmap.width / (float)width,
        y= (float)bitmap.rows / (float)height;


    using namespace glm;
    glyphsVertices[c] = new pxgVertex2dT[4];
    glyphsVertices[c][0] = {  vec2(0,bitmap.rows), vec2(0,y) };
    glyphsVertices[c][1] = {  vec2(0,0), vec2(0,0) };
    glyphsVertices[c][2] = {  vec2(bitmap.width,0), vec2(x,0) };
    glyphsVertices[c][3] = {  vec2(bitmap.width,bitmap.rows), vec2(x,y) };

Where glyphVertices is two-dimentional array of such structure:

   struct Vertex2dT
   {
       glm::vec2 pos;
       glm::vec2 texCoord;
   };

Unfortunately, I get the following result:

So, what am I doing wrong?

Answer 1

As SAKrisT correctly pointed out, the problem was caused by incorrect offset by Y axis. Playing a bit with the code, I figured out the solution:

   if(FT_Load_Char(face, c, FT_LOAD_RENDER))
     return;

    FT_GlyphSlot g = face->glyph;

    int width = next_p2(g->bitmap.width);
    int height = next_p2(g->bitmap.rows);

    ...

    float   x=(float)g->bitmap.width / (float)width,
            y= (float)g->bitmap.rows / (float)height;



    float x2 = g->bitmap_left;
    float y2 = g->bitmap_top;
    float w = g->bitmap.width;
    float h = g->bitmap.rows;


    using namespace glm;
    glyphsVertices[c] = new pxgVertex2dT[4];
    glyphsVertices[c][0] = {  vec2(0,h-y2), vec2(0,y) };
    glyphsVertices[c][1] = {  vec2(0,-y2), vec2(0,0) };
    glyphsVertices[c][2] = {  vec2(w,-y2), vec2(x,0) };
    glyphsVertices[c][3] = {  vec2(w,h-y2), vec2(x,y) };

Now it works perfectly!