有SDL_TTF和OPENGL一起工作的麻煩

對於我正在開發的遊戲，我希望可以使用OpenGL處理很多圖形，並且使用SDL_TTF作爲文本。我可以同時工作但不能同時工作。這裏是我的代碼（基於關閉懶惰美孚）：有SDL_TTF和OPENGL一起工作的麻煩

#include "SDL/SDL.h" 
#include "SDL/SDL_ttf.h" 
#include "GL/gl.h" 

const bool useOpenGl = true; 

//The surfaces 
SDL_Surface *message = NULL; 
SDL_Surface *screen = NULL; 

//The event structure 
SDL_Event event; 

//The font that's going to be used 
TTF_Font *font = NULL; 

//The color of the font 
SDL_Color textColor = {255, 255, 255}; 

void apply_surface(int x, int y, SDL_Surface* source, SDL_Surface* destination, SDL_Rect* clip = NULL) 
{ 
    //Holds offsets 
    SDL_Rect offset; 

    //Get offsets 
    offset.x = x; 
    offset.y = y; 

    //Blit 
    SDL_BlitSurface(source, clip, destination, &offset); 
} 

bool init() 
{ 
    SDL_Init (SDL_INIT_EVERYTHING); 
    if (useOpenGl) 
    { 
     screen = SDL_SetVideoMode (1280, 720, 32, SDL_SWSURFACE | SDL_OPENGL); //With SDL_OPENGL flag only opengl is sceen, without only text is 
    } else { 
     screen = SDL_SetVideoMode (1280, 720, 32, SDL_SWSURFACE); 
    } 

    TTF_Init(); 

    SDL_WM_SetCaption ("TTF Not Working With OpenGL", NULL); 

    if (useOpenGl) 
    { 
     glClearColor(1.0, 0.0, 0.0, 0.0); 
     glMatrixMode(GL_PROJECTION); 
     glLoadIdentity(); 
     glOrtho(0.0, screen->w, screen->h, 1.0, -1.0, 1.0); 
     glEnable(GL_BLEND); 
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); 
    } 

    return true; 
} 

bool load_files() 
{ 
    font = TTF_OpenFont ("arial.ttf", 28); 

    return true; 
} 

void clean_up() 
{ 
    SDL_FreeSurface (message); 

    TTF_CloseFont (font); 
    TTF_Quit(); 

    SDL_Quit(); 
} 

int main(int argc, char* args[]) 
{ 
    //Quit flag 
    bool quit = false; 

    init(); 
    load_files(); 

    if (useOpenGl) 
    { 
     glClear(GL_COLOR_BUFFER_BIT); //clearing the screen 
     glPushMatrix(); 


     glBegin(GL_QUADS); 
     glColor3f(1.0, 0.0, 0.0); 
     glVertex2f(0, 0); 
     glColor3f(0.0, 1.0, 0.0); 
     glVertex2f(1280, 0); 
     glColor3f(0.0, 0.0, 1.0); 
     glVertex2f(1280, 720); 
     glColor4f(0.5, 0.5, 1.0, 0.1); 
     glVertex2f(0, 720); 
     glEnd(); 

     glPopMatrix(); 
     glFlush(); 
    } 

    //Render the text 
    message = TTF_RenderText_Solid (font, "The quick brown fox jumps over the lazy dog", textColor); 

    //Apply the images to the screen 
    apply_surface (0, 150, message, screen); 

    //I'm guessing this is where the problem is coming from 
    SDL_GL_SwapBuffers(); 
    SDL_Flip (screen); 


    while (quit == false) 
    { 
     while (SDL_PollEvent (&event)) 
     { 
      if (event.type == SDL_QUIT) 
      { 
       quit = true; 
      } 
     } 
    } 

    clean_up(); 

    return 0; 
}

如果變量useOpenGl設置爲false，程序將只使用SDL_TTF，如果它設置爲true，它會同時使用SDL_TTF和OpenGL。從這個問題來看，問題似乎與創建窗口時是否使用「SDL_OPENGL」標誌有關。

來源

2013-02-05 user2043798

SDL_TTF使用軟件渲染，並且與OpenGL模式不兼容。

您可能需要尋找另一個庫，例如FTGL或freetype-gl。

來源

2013-02-05 18:37:11 Benlitz

有SDL_TTF和OPENGL一起工作的麻煩

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