I was following this tutorial: http://en.wikibooks.org/wiki/OpenGL_Programming/Modern_OpenGL_Tutorial_Text_Rendering_01,

and trying to get text to render to a quad on the screen. I followed all the rules. I don't know why it isn't working.

Here is my code. I try to render only one character, the letter 'H'. I only get a green colored quad :/.

int main()
{
    glfwInit();

    FT_Library ftLibrary;
    if(FT_Init_FreeType(&ftLibrary))
    {
        MessageBox(0, "wouldn't initialize?", "f", MB_OK);
    }

    FT_Face ftFace;
    if(FT_New_Face(ftLibrary, "arial.ttf", 0, &ftFace))
    {
        MessageBox(0, "didn't find the file", "m", MB_OK);
    }

    FT_Set_Pixel_Sizes(ftFace, 0, 64);

    ...

    GLint location;

    glDepthMask(GL_TRUE);
    //glEnable(GL_DEPTH_TEST);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    GroupOfLetters word1("H", 24, 0.6f, 0.8f, 0.2f, 1.0f);

    GLuint currentLetterTex;

    glActiveTexture(GL_TEXTURE0);
    glGenTextures(1, &currentLetterTex);
    glBindTexture(GL_TEXTURE_2D, currentLetterTex);


    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

    while(!glfwWindowShouldClose(window))
    {
        glClearColor(0.2f, 0.4f, 0.6f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glUseProgram(testProgram);

        if(FT_Load_Char(ftFace,
        'H',
        FT_LOAD_RENDER))
        {
            MessageBox(0, "A SERIOUS ERROR!", "m", MB_OK);
        }

        FT_GlyphSlot glyphSlot = ftFace->glyph;

        glTexImage2D(GL_TEXTURE_2D,
                0,
                GL_ALPHA,
                glyphSlot->bitmap.width,
                glyphSlot->bitmap.rows,
                0,
                GL_ALPHA,
                GL_UNSIGNED_BYTE,
                glyphSlot->bitmap.buffer);

        float letterColor[4];
        letterColor[0] = word1.Getred();
        letterColor[1] = word1.Getgreen();
        letterColor[2] = word1.Getblue();
        letterColor[3] = word1.Getalpha();

        scaleMatrix = glm::scale(glm::mat4(1.0f), glm::vec3(0.5f, 0.5f, 1.0f));
        translationMatrix = glm::translate(glm::mat4(1.0f),
                glm::vec3(0.0f, 0.0f, -1.0f));

        worldMatrix = translationMatrix * scaleMatrix;

        location = glGetUniformLocation(testProgram, "worldMatrix");
        glUniformMatrix4fv(location, 1, GL_FALSE, (GLfloat*)&worldMatrix);

        location = glGetUniformLocation(testProgram, "viewMatrix");
        glUniformMatrix4fv(location, 1, GL_FALSE, (GLfloat*)&viewMatrix);

        location = glGetUniformLocation(testProgram, "projectionMatrix");
        glUniformMatrix4fv(location, 1, GL_FALSE, (GLfloat*)&projectionMatrix);

        location = glGetUniformLocation(testProgram, "inTextColor");
        glUniform4fv(location, 1, letterColor);

        location = glGetUniformLocation(testProgram, "diffuse");
        glUniform1i(location, 0);

        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indiceBuffer);
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, (void*)0);

        glfwSwapBuffers(window);
        glfwPollEvents();

    }

    glfwDestroyWindow(window);

    glfwTerminate();

    return 0;
}

I don't get any errors at all, just a friggin green quad staring right back at me DX<.

The shaders are working fine, I tested them with a texture I made with alpha, and it worked. Just what the hell could I possibly be doing wrong here!?

Update: Still haven't fixed the problem, but here's what I found out:

I tried outputting the glyph data that was grabbed. Apparently it is working, this is the letter 'i':

6
46
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ






ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ
ÿÿÿÿÿÿ

So it is apparently working... so it must be a problem with the openGL code. But I don't see what could possibly be wrong..

The text of the font rendering tutorial is incorrect.

Passing GL_ALPHA as the texture's format and internal format parameter is incorrect. What you want instead if pass GL_RED as the texture's format/internal-format and access the .r component from the texture sampling in your shaders like so:

outColor = vec4(1, 1, 1, texture(glyphTexture, TexCoords).r);

Holy shit it worked. Thank you so much you are a life saver ^w^. Now to get my vengence... jk.

Not at all someone should probably update the wiki

I just did lel.