如何将 freetypegl 与 {0, w, h, 0} 正交投影一起使用？

freetypegl 被编写为与 {0, w, 0, h) 投影一起使用，该库中包含的几乎所有演示都与该投影一起工作。我更喜欢 {0, w, h, 0} 并且我不知道如何更改代码才能使用该正交。我尝试反转 uvs，但随后文本与上限对齐，看起来不太好。

如何更改代码以使用 {0, w, h, 0} 投影？

void AddGlyph(Vector2& position, const char c, uint color, texture_font_t* ftFont)
{
    texture_glyph_t* glyph = texture_font_get_glyph(ftFont, &c);
    if (c) {
        if (string) {
            position.x += texture_glyph_get_kerning(glyph, &c- 1) * scale;
        }

        //One glyph is a quad and quad has 4 vertices and 6 elements, 
        //it does not impact the case
        MapBuffer(4, 6);

        float x0 = position.x + static_cast<float>(glyph->offset_x),
              y0 = position.y + static_cast<float>(glyph->offset_y),
              x1 = x0 + static_cast<float>(glyph->width),
              y1 = y0 - static_cast<float>(glyph->height),

              u0 = glyph->s0,
              v0 = glyph->t0,
              u1 = glyph->s1,
              v1 = glyph->t1;

        //vertex struct is position, uv, color
        AddVertexData(Vector2(x0, y0), Vector2(u0, v0), color);
        AddVertexData(Vector2(x0, y1), Vector2(u0, v1), color);
        AddVertexData(Vector2(x1, y1), Vector2(u1, v1), color);
        AddVertexData(Vector2(x1, y0), Vector2(u1, v0), color);

        //default rectangle elements dependence
        AddRectElements();

        position.x += glyph->advance_x * scale;
    }
}

void DrawString(const std::string& text, Vector2& position, uint color, const Font& font)
{
    using namespace ftgl;
    texture_font_t* ftFont = font.getFTFont();

    for (const auto& c : text) {
        AddGlyph(position, c, color, ftFont);
    } 
}

也许我应该更改库代码？如果是这样，我应该改变什么？