osdtext.h

#ifndef CMU462_TEXTOSD_H
#define CMU462_TEXTOSD_H

#include <string>
#include <vector>

#include "GL/glew.h"

#include "color.h"

// forward declare freetype stuff
struct FT_LibraryRec_;
typedef struct FT_LibraryRec_* FT_Library;
struct FT_FaceRec_;
typedef struct FT_FaceRec_*  FT_Face;

namespace CMU462 {

// base64 encoded embeded font
extern "C" char osdfont_base64[];

struct OSDLine {

  // UID of the line
  int id;

  // screen space anchor position
  float x, y;

  // line content
  std::string text;

  // font size
  size_t size;

  // font color
  Color color;

};

class OSDText {
 public:

  OSDText();

  ~OSDText();

  int init(bool use_hdpi);

  void render();

    void clear();

  void resize(size_t w, size_t h);

  int add_line(float x, float y, std::string text = "",
               size_t size = 16, Color color = Color::White);

  void del_line(int line_id);

  void set_anchor(int line_id, float x, float y);

  void set_text(int line_id, std::string text);

  void set_size(int line_id, size_t size);

  void set_color(int line_id, Color color);

 private:

  // draw a single line
  void draw_line(OSDLine line);

  // HDPI displays
  bool use_hdpi;

  // internal scale factors
  float sx, sy;

  // line id counter
  int next_id;

  // freetype
  char* font; size_t font_size;
  FT_Library* ft; FT_Face* face;

  // lines to draw
  std::vector<OSDLine> lines;

  // GL stuff
  GLuint vbo;
  GLuint program;
  GLint attribute_coord;
  GLint uniform_tex;
  GLint uniform_color;

  // GL helpers
  GLuint compile_shaders();
  GLint  get_attribu(GLuint program, const char *name);
  GLint  get_uniform(GLuint program, const char *name);

}; // class textOSD

} // namespace CMU462

#endif // CMU462_TEXTOSD_H