FreeType2 add outline to text - c++

Question

I'm trying to add border/outline to text's drawn using freetype. So far I've found freetype's docs about it but they are a bit inconsistent. Some functions/structs are visible on my project but some are not. For example I can create an outline object like this FT_Outline border; but I can't call the function I need to call in order to apply that outline like the docs says me to do like this: FT_Outline_New( FT_Library library, FT_UInt numPoints, FT_Int numContours, FT_Outline *anoutline );. This question is of no help either, almost all of the functions/structs are not present on my setup.
I'm a bit lost, how am I supposed to implement outlines to my text? Are these methods outdated if so what is the modern method? Am I linking/importing/compiling freetype wrong? I have no errors with freetype whatsoever so I don't think there are any errors with my freetype implementation.
Here is how my text-rendering process looks like:
Text.cpp
Text::Text(text_attributes&& atrib, int gl_width, int gl_height)
{
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
shader = Shader("./src/opengl/shaders/text.vs", "./src/opengl/shaders/text.fs");
glm::mat4 projection = glm::ortho(0.0f, static_cast<float>(SCR_WIDTH), 0.0f, static_cast<float>(SCR_HEIGHT));
shader.use();
glUniformMatrix4fv(glGetUniformLocation(shader.ID, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
if (FT_Init_FreeType(&ft))
{
exit(0);
}
std::string font_name = "./src/opengl/fonts/" + *atrib.__font_name + ".ttf";
FT_Face face;
if (FT_New_Face(ft, font_name.c_str(), 0, &face)) {
VI_ERROR("ERROR::FREETYPE: Failed to load font");
exit(0) ;
} else {
FT_Outline border;
FT_Set_Pixel_Sizes(face, 0, atrib.__font_size);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
for (unsigned char c = 0; c < 128; c++)
{
// Load character glyph
if (FT_Load_Char(face, c, FT_LOAD_RENDER))
{
VI_ERROR("ERROR::FREETYTPE: Failed to load Glyph");
continue;
}
// generate texture
GLuint texture;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(
GL_TEXTURE_2D,
0,
GL_RED,
face->glyph->bitmap.width,
face->glyph->bitmap.rows,
0,
GL_RED,
GL_UNSIGNED_BYTE,
face->glyph->bitmap.buffer
);
// set texture options
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// now store character for later use
Character character = {
texture,
glm::ivec2(face->glyph->bitmap.width, face->glyph->bitmap.rows),
glm::ivec2(face->glyph->bitmap_left, face->glyph->bitmap_top),
static_cast<unsigned int>(face->glyph->advance.x)
};
Characters.insert(std::pair<char, Character>(c, character));
}
glBindTexture(GL_TEXTURE_2D, 0);
}
FT_Done_Face(face);
FT_Done_FreeType(ft);
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 6 * 4, NULL, GL_DYNAMIC_DRAW);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 4 * sizeof(float), 0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
}
void Text::render_text(std::string text, float x, float y, float z, std::string hex_color, float angle_rad, bool bg)
{
static const int scale = 1;
shader.use();
glUniform3f(glGetUniformLocation(shader.ID, "textColor"), 0.1, 0.1, 0.1);//color.get_color_float(Utils::RED), color.get_color_float(Utils::GREEN), color.get_color_float(Utils::BLUE));
glActiveTexture(GL_TEXTURE0);
glBindVertexArray(VAO);
GLfloat vertices[6][4] = {
{ 0.0, 1.0, 0.0, 0.0 },
{ 0.0, 0.0, 0.0, 1.0 },
{ 1.0, 0.0, 1.0, 1.0 },
{ 0.0, 1.0, 0.0, 0.0 },
{ 1.0, 0.0, 1.0, 1.0 },
{ 1.0, 1.0, 1.0, 0.0 }
};
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertices), vertices); // Be sure to use glBufferSubData and not glBufferData
glBindBuffer(GL_ARRAY_BUFFER, 0);
glm::mat4 rotateM = glm::rotate(glm::mat4(1.0f), glm::radians(angle_rad), glm::vec3(0.0f, 0.0f, 1.0f));
glm::mat4 transOriginM = glm::translate(glm::mat4(1.0f), glm::vec3(x, y, z));
std::string::const_iterator c;
GLfloat char_x = 0.0f;
for (c = text.begin(); c != text.end(); c++)
{
Character ch = Characters[*c];
GLfloat w = ch.Size.x * scale;
GLfloat h = ch.Size.y * scale;
GLfloat xrel = char_x + ch.Bearing.x * scale;
GLfloat yrel = y - (ch.Size.y - ch.Bearing.y) * scale;
char_x += (ch.Advance >> 6) * scale; // Bitshift by 6 to get value in pixels (2^6 = 64 (divide amount of 1/64th pixels by 64 to get amount of pixels))
glm::mat4 scaleM = glm::scale(glm::mat4(1.0f), glm::vec3(w, h, 1.0f));
glm::mat4 transRelM = glm::translate(glm::mat4(1.0f), glm::vec3(xrel, yrel, z));
glm::mat4 modelM = transOriginM * rotateM * transRelM * scaleM;
GLint model_loc = glGetUniformLocation(shader.ID, "model");
glUniformMatrix4fv(model_loc, 1, GL_FALSE, glm::value_ptr(modelM));
glBindTexture(GL_TEXTURE_2D, ch.TextureID);
glDrawArrays(GL_TRIANGLES, 0, 6);
}
glBindVertexArray(0);
glBindTexture(GL_TEXTURE_2D, 0);
}
Text.h
extern "C"{
#include <ft2build.h>
#include FT_FREETYPE_H
}
class Text{
Text(text_attributes&& atrib, int w, int h);
render_text(std::string text, float x, float y, float z, std::string hex_color, float angle_rad, bool bg);
};

Answer 1

You should also include:
#include FT_GLYPH_H //optional glyph management component
#include FT_OUTLINE_H //scalable outline management
#include FT_STROKER_H //functions to stroke outline paths
See also:
https://freetype.org/freetype2/docs/reference/ft2-header_file_macros.html
If you want to render an outline (in the specified order):
FT_Stroker_New
FT_Stroker_Set
FT_Get_Glyph
FT_Glyph_Stroke
if glyph->format == FT_GLYPH_FORMAT_OUTLINE
FT_Raster_Params params
params.flags = FT_RASTER_FLAG_AA | FT_RASTER_FLAG_DIRECT
params.gray_spans = outlineRenderCallback
params.user = user_data
FT_Outline_Render