How to Rendering text from true type Fonts Using SDL

One way to render text with SDL is with the extension library SDL_ttf. SDL_ttf allows you to create images from TrueType fonts which use here to create textures from font text.

//Using SDL, SDL_image, SDL_ttf, standard IO, math, and strings
#include <SDL.h>
#include <SDL_image.h>
#include <SDL_ttf.h>
#include <stdio.h>
#include <string>

#include <cmath>

To use SDL_ttf, you have to set up the SDL_ttf extension library just like you would set up SDL_image. Like before, it's just a matter of having the headers files, library files, and binary files in the right place with your compiler configured to use them.

//The window be rendering to
SDL_Window* gWindow = NULL;

//The window renderer
SDL_Renderer* gRenderer = NULL;

//Globally used font
TTF_Font *gFont = NULL;

//Rendered texture

LTexture gTextTexture;

For this and future tutorials, using a global font for our text rendering. In SDL_ttf, the data type for fonts is TTF_Font.


and also have a texture which will be generated from the font.

 //Initialize PNG loading
                int imgFlags = IMG_INIT_PNG;
                if( !( IMG_Init( imgFlags ) & imgFlags ) )
                {
                    printf( "SDL_image could not initialize! SDL_image Error: %s\n", IMG_GetError() );
                    success = false;
                }

                 //Initialize SDL_ttf
                if( TTF_Init() == -1 )
                {
                    printf( "SDL_ttf could not initialize! SDL_ttf Error: %s\n", TTF_GetError() );
                    success = false;

                }

Just like SDL_image, we have to initialize it or the font loading and rendering functions won't work properly.start up SDL_ttf using TTF_init. We can check for errors using TTF_GetError().

void close()
{
    //Free loaded images
    gTextTexture.free();

    //Free global font
    TTF_CloseFont( gFont );
    gFont = NULL;

    //Destroy window    
    SDL_DestroyRenderer( gRenderer );
    SDL_DestroyWindow( gWindow );
    gWindow = NULL;
    gRenderer = NULL;

    //Quit SDL subsystems
    TTF_Quit();
    IMG_Quit();
    SDL_Quit();

}

In our clean up function, we want to free the font using TTF_CloseFont. We also want to quit the SDL_ttf library with TTF_Quit to complete the clean up.