free_glyph.h

#ifndef FREE_GLYPH_H_
#define FREE_GLYPH_H_

#include <stdlib.h>
#include "./la.h"

#define GLEW_STATIC
#include <GL/glew.h>

#define GL_GLEXT_PROTOTYPES
#include <SDL3/SDL_opengl.h>

#include <ft2build.h>
#include FT_FREETYPE_H

#include "simple_renderer.h"

#define FREE_GLYPH_FONT_SIZE 64

// https://en.wikibooks.org/wiki/OpenGL_Programming/Modern_OpenGL_Tutorial_Text_Rendering_02

typedef struct {
    float ax; // advance.x
    float ay; // advance.y

    float bw; // bitmap.width;
    float bh; // bitmap.rows;

    float bl; // bitmap_left;
    float bt; // bitmap_top;

    float tx; // x offset of glyph in texture coordinates
} Glyph_Metric;

#define GLYPH_METRICS_CAPACITY 128

typedef struct {
    FT_UInt atlas_width;
    FT_UInt atlas_height;
    GLuint glyphs_texture;
    Glyph_Metric metrics[GLYPH_METRICS_CAPACITY];
} Free_Glyph_Atlas;

void free_glyph_atlas_init(Free_Glyph_Atlas *atlas, FT_Face face);
float free_glyph_atlas_cursor_pos(const Free_Glyph_Atlas *atlas, const char *text, size_t text_size, Vec2f pos, size_t col);
void free_glyph_atlas_measure_line_sized(Free_Glyph_Atlas *atlas, const char *text, size_t text_size, Vec2f *pos);
void free_glyph_atlas_render_line_sized(Free_Glyph_Atlas *atlas, Simple_Renderer *sr, const char *text, size_t text_size, Vec2f *pos, Vec4f color);

#endif // FREE_GLYPH_H_