Formatting a string on a variadic parameter function without using GC

[David G. Maziero via Digitalmars-d-learn]

Hi. I think it's the first time I post here.
I've been flirting with D for some time, but now I decided to 
start a little project.

Consider the following function:

void RenderText( FontBMP font, int x, int y, const char* text )
{
        SDL_Rect rect1, rect2;
        rect2.x = x;
        rect2.y = y;
        rect2.w = font.width;
        rect2.h = font.height;
        rect1.w = font.width;
        rect1.h = font.height;
        for( int r=0; text[r]!='\0'; ++r )
        {
                char letter = text[r];
                rect1.x = font.width*(letter%font.horizontal_count);
                rect1.y = font.height*(letter/font.horizontal_count);
		if( letter>=33 ) SDL_RenderCopy( g_renderer, font.texture, 
&rect1, &rect2 );
                rect2.x += font.spacing_x;
                if( letter==10 )
                {
                        rect2.x = x;
                        rect2.y += font.spacing_y;
                }
        }
}

And the use code:

        char[256] text;
	sprintf( &text[0], "Player: pos:%.3f - speed:%.3f", 
player.position, player.speed );
        RenderText( font, 0, 0, cast(char*)text );

I could simply do "RenderText(font,0,0,"FPS: "~to!string(fps));" 
but I want to avoid GC entirely.
The ideal scenario is to have something like "void RenderText( 
/*etc*/, const char* fmt, ... )" but I can't seem to figure a way 
to pass the variadic parameters to sprintf.

Any ideas?
Thanks in advance.