[gameprogrammer] Re: SDL_ttf and OpenGL

[Bob Pendleton <bob@pendleton.com>]

On Sat, 2004-05-01 at 08:34, Kevin Fields wrote:
> Using SDL_ttf in this manner.
> Would you mind if I made use of this in my project?

Not at all!

If you read the T&C on this list you will see that it explicitly states
that by posting to the list you are placing anything you post in the
public domain. That applies to anything I post too.

		Bob Pendleton

> 
> 
> From: Bob Pendleton <bob@pendleton.com>
> Reply-To: gameprogrammer@freelists.org
> To: Gameprogrammer Mailing List <gameprogrammer@freelists.org>
> Subject: [gameprogrammer] Re: SDL_ttf and OpenGL
> Date: Fri, 30 Apr 2004 13:52:00 -0500
> 
> On Fri, 2004-04-30 at 09:25, Kevin Fields wrote:
>  > I would never have thought of doing that.
> 
> Doing what?
> 
>  > My knowledge of both SDL and OpenGL are still rather limited.
> 
> Don't worry about it. You'll get there.
> 
> 		Bob Pendleton
> 
>  >
>  >
>  > From: Bob Pendleton <bob@pendleton.com>
>  > Reply-To: gameprogrammer@freelists.org
>  > To: Gameprogrammer Mailing List <gameprogrammer@freelists.org>
>  > Subject: [gameprogrammer] Re: SDL_ttf and OpenGL
>  > Date: Thu, 29 Apr 2004 09:48:39 -0500
>  >
>  > On Thu, 2004-04-29 at 07:22, Kevin Fields wrote:
>  >  > Hey people,
>  >  >
>  >  > I'm having an issue with trying to get SDL_ttf to work with OpenGL.
>  >  > I've posted on the SDL mailing list, but I'm still not sure how I can 
> go
>  >  > about getting SDL_ttf to render to the screen.
>  >  >
>  >  > One method I was told to use was to take the surface generated by
>  >  > TTF_RenderText_*() and make a texture out of it, then applying that
>  > texture
>  >  > to a quad (or triangle strip) and rendering to the screen. When I 
> tried
>  >  > that, nothing appeared.
>  >  >
>  >  > Has anyone been able to get fonts working with SDL and OpenGL?
>  >
>  > I've been so involved in this list (my list) for the last few days that
>  > I have not been looking at the SDL list and missed you question. I have
>  > indeed gotten SDL_ttf to work with OpenGL. It isn't difficult. Here is
>  > some code that I use for the job:
>  >
>  > //-------------------------------------------------
>  >
>  > class Font
>  > {
>  > private:
>  >    static const int minGlyph = ' ';
>  >    static const int maxGlyph = 126;
>  >
>  >    static int initCounter;
>  >
>  >    typedef struct
>  >    {
>  >      int minx, maxx;
>  >      int miny, maxy;
>  >      int advance;
>  >      SDL_Surface *pic;
>  >      GLuint tex;
>  >      GLfloat texMinX, texMinY;
>  >      GLfloat texMaxX, texMaxY;
>  >    } glyph;
>  >
>  >    int height;
>  >    int ascent;
>  >    int descent;
>  >    int lineSkip;
>  >    glyph glyphs[maxGlyph + 1];
>  >
>  >    unsigned char *address;
>  >    int length;
>  >    int pointSize;
>  >    int style;
>  >    float fgRed, fgGreen, fgBlue;
>  >    float bgRed, bgGreen, bgBlue;
>  >
>  >    TTF_Font *ttfFont;
>  >
>  >    SDL_Color foreground;
>  >    SDL_Color background;
>  >
>  >    void loadChar(char c)
>  >    {
>  >      GLfloat texcoord[4];
>  >      char letter[2] = {0, 0};
>  >
>  >      if ((minGlyph <= c) &&
>  >          (c <= maxGlyph) &&
>  >          (NULL == glyphs[c].pic))
>  >      {
>  >        SDL_Surface *g0 = NULL;
>  >        SDL_Surface *g1 = NULL;
>  >
>  >        letter[0] = c;
>  >
>  >        TTF_GlyphMetrics(ttfFont,
>  >                         (Uint16)c,
>  >                         &glyphs[c].minx,
>  >                         &glyphs[c].maxx,
>  >                         &glyphs[c].miny,
>  >                         &glyphs[c].maxy,
>  >                         &glyphs[c].advance);
>  >
>  >        g0 = TTF_RenderText_Shaded(ttfFont,
>  >                                   letter,
>  >                                   foreground,
>  >                                   background);
>  >
>  >        if (NULL != g0)
>  >        {
>  >          g1 = SDL_DisplayFormat(g0);
>  >          SDL_FreeSurface(g0);
>  >        }
>  >
>  >        if (NULL != g1)
>  >        {
>  >          glyphs[c].pic = g1;
>  >          glyphs[c].tex = loadTextureColorKey(g1, texcoord, 0, 0, 0);
>  >          glyphs[c].texMinX = texcoord[0];
>  >          glyphs[c].texMinY = texcoord[1];
>  >          glyphs[c].texMaxX = texcoord[2];
>  >          glyphs[c].texMaxY = texcoord[3];
>  >        }
>  >      }
>  >    }
>  >
>  > public:
>  >
>  >    Font(unsigned char *address,
>  >         int length,
>  >         int pointSize,
>  >         int style,
>  >         float fgRed, float fgGreen, float fgBlue,
>  >         float bgRed, float bgGreen, float bgBlue):
>  >      address(address), length(length),
>  >      pointSize(pointSize),
>  >      style(style),
>  >      fgRed(fgRed), fgGreen(fgGreen), fgBlue(fgBlue),
>  >      bgRed(bgRed), bgGreen(bgGreen), bgBlue(bgBlue),
>  >      ttfFont(NULL)
>  >    {
>  >      if (0 == initCounter)
>  >      {
>  >        if (TTF_Init() < 0)
>  >        {
>  >          errorExit("Can't init SDL_ttf");
>  >        }
>  >      }
>  >      initCounter++;
>  >      initFont();
>  >    }
>  >
>  >    ~Font()
>  >    {
>  >      initCounter--;
>  >      if (0 == initCounter)
>  >      {
>  >        TTF_Quit();
>  >      }
>  >    }
>  >
>  >    void initFont()
>  >    {
>  >      SDL_RWops *src = NULL;
>  >      int i;
>  >
>  >      src = SDL_RWFromMem(address, length);
>  >
>  >      ttfFont = TTF_OpenFontRW(src, 1, pointSize);
>  >      if (NULL == ttfFont)
>  >      {
>  >        errorExit("Can't open font file");
>  >      }
>  >
>  >      TTF_SetFontStyle(ttfFont, style);
>  >
>  >      foreground.r = (Uint8)(255 * fgRed);
>  >      foreground.g  = (Uint8)(255 * fgGreen);
>  >      foreground.b = (Uint8)(255 * fgBlue);
>  >
>  >      background.r = (Uint8)(255 * bgRed);
>  >      background.g = (Uint8)(255 * bgGreen);
>  >      background.b = (Uint8)(255 * bgBlue);
>  >
>  >      height = TTF_FontHeight(ttfFont);
>  >      ascent = TTF_FontAscent(ttfFont);
>  >      descent = TTF_FontDescent(ttfFont);
>  >      lineSkip = TTF_FontLineSkip(ttfFont);
>  >
>  >      for (i = minGlyph; i <= maxGlyph; i++)
>  >      {
>  >        glyphs[i].pic = NULL;
>  >        glyphs[i].tex = 0;
>  >      }
>  >    }
>  >
>  >    int getLineSkip()
>  >    {
>  >      return lineSkip;
>  >    }
>  >
>  >    int getHeight()
>  >    {
>  >      return height;
>  >    }
>  >
>  >    void textSize(char *text,
>  >                  SDL_Rect *r)
>  >    {
>  >      int maxx = 0;
>  >      int advance = 0;
>  >
>  >      r->x = 0;
>  >      r->y = 0;
>  >      r->w = 0;
>  >      r->h = height;
>  >
>  >      while (0 != *text)
>  >      {
>  >        if ((minGlyph <= *text) && (*text <= maxGlyph))
>  >        {
>  >          loadChar(*text);
>  >
>  >          maxx = glyphs[*text].maxx;
>  >          advance = glyphs[*text].advance;
>  >          r->w += advance;
>  >        }
>  >
>  >        text++;
>  >      }
>  >
>  >      r->w = r->w - advance + maxx;
>  >    }
>  >
>  >    void drawText(char *text, int x, int y)
>  >    {
>  >      GLfloat left, right;
>  >      GLfloat top, bottom;
>  >      GLfloat texMinX, texMinY;
>  >      GLfloat texMaxX, texMaxY;
>  >
>  >      glPushAttrib(GL_ALL_ATTRIB_BITS);
>  >
>  >      glEnable(GL_BLEND);
>  >      glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
>  >
>  >      glEnable(GL_TEXTURE_2D);
>  >      glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
>  >
>  >      while (0 != *text)
>  >      {
>  >        if ((minGlyph <= *text) && (*text <= maxGlyph))
>  >        {
>  >          loadChar(*text);
>  >
>  >          texMinX = glyphs[*text].texMinX;
>  >          texMinY = glyphs[*text].texMinY;
>  >          texMaxX = glyphs[*text].texMaxX;
>  >          texMaxY = glyphs[*text].texMaxY;
>  >
>  >          left   = x;
>  >          right  = x + glyphs[*text].pic->w;
>  >          top    = y;
>  >          bottom = y + glyphs[*text].pic->h;
>  >
>  >          glBindTexture(GL_TEXTURE_2D, glyphs[*text].tex);
>  >
>  >          glBegin(GL_TRIANGLE_STRIP);
>  >
>  >          glTexCoord2f(texMinX, texMinY); glVertex2f( left,    top);
>  >          glTexCoord2f(texMaxX, texMinY); glVertex2f(right,    top);
>  >          glTexCoord2f(texMinX, texMaxY); glVertex2f( left, bottom);
>  >          glTexCoord2f(texMaxX, texMaxY); glVertex2f(right, bottom);
>  >
>  >          glEnd();
>  >
>  >          x += glyphs[*text].advance;
>  >        }
>  >
>  >        text++;
>  >      }
>  >
>  >      glPopAttrib();
>  >    }
>  > };
>  >
>  > //-------------------------------------------------
>  >
>  > int Font::initCounter = 0;
>  >
>  > 		Bob Pendleton
>  >
>  >  >
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>  > --
>  > +--------------------------------------+
>  > + Bob Pendleton: writer and programmer +
>  > + email: Bob@Pendleton.com             +
>  > + blog:  www.Stonewolf.net             +
>  > + web:   www.GameProgrammer.com        +
>  > +--------------------------------------+
>  >
>  > _________________________________________________________________
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> --
> +--------------------------------------+
> + Bob Pendleton: writer and programmer +
> + email: Bob@Pendleton.com             +
> + blog:  www.Stonewolf.net             +
> + web:   www.GameProgrammer.com        +
> +--------------------------------------+
> 
> _________________________________________________________________
> http://join.msn.com/?pgmarket=en-ca&page=byoa/prem&xAPID=1994&DI=1034&SU=http://hotmail.com/enca&HL=Market_MSNIS_Taglines
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-- 
+--------------------------------------+
+ Bob Pendleton: writer and programmer +
+ email: Bob@Pendleton.com             +
+ blog:  www.Stonewolf.net             +
+ web:   www.GameProgrammer.com        +
+--------------------------------------+