[SDL_TTF]Printing variables?
Author
Hello,
I've recently run into a problem with a program I'm working on, what I need is to show text on the screen, and within it include some integer variables(Pretty much like printf()'s %d does for the console box), I've looked into the documentation of it, but I can't seem to find anything =
Can someone point me at a solution please?
Thanks
You need to convert your integer to a string and pass the string to SDL_TTF. The best way to do that would depend on what programming language you are using.
Author
C++.
I thought about converting it earlier, but I couldn't find a way, and didn't want to dig too much into it in case there was just another function for it on the TTF that I might've missed or something, I'll try looking into that then, thanks.
I thought about converting it earlier, but I couldn't find a way, and didn't want to dig too much into it in case there was just another function for it on the TTF that I might've missed or something, I'll try looking into that then, thanks.
One way is to use boost::lexical_cast. Alternately you can manually convert using a std::stringstream.
std::stringstream sstr;sstr << my_int;std::string my_int_as_string = sstr.str();
The Standard C++ Library provides a class that can be used to convert data to and from text. It is called stringstream, and it works in the same way as file streams and the standard stream objects (std::cout, std::cin etc) work.
Example:
The boost library provides a convenience function, boost::lexial cast:
Example:
std::stringstream stream;stream << "The value of the variable foo is " << foo;stream << " and the value of the variable bar is " << bar;SDL_Surface * surface = TTF_RenderText_Solid(font, stream.str().c_str(),colour);The boost library provides a convenience function, boost::lexial cast:
std::string string = "foo is " + boost::lexical_cast<std::string>(foo);SDL_Surface * surface = TTF_RenderText_Solid(font, string.c_str(),colour);
Author
Wow, you guys are fast O.o
Thanks alot for the answers.
Just one last thing, when I try to make a stringstream like you showed, I get the following:
error C2079: 'str' uses undefined class 'std::basic_stringstream<_Elem,_Traits,_Alloc>'
1> with
1> [
1> _Elem=char,
1> _Traits=std::char_traits<char>,
1> _Alloc=std::allocator<char>
1> ]
Am I missing an #include(I already have fstream, iostream, string, cstring and ctype to deal with streams and strings I need on the program) or did I do something wrong?
Thanks alot for the answers.
Just one last thing, when I try to make a stringstream like you showed, I get the following:
error C2079: 'str' uses undefined class 'std::basic_stringstream<_Elem,_Traits,_Alloc>'
1> with
1> [
1> _Elem=char,
1> _Traits=std::char_traits<char>,
1> _Alloc=std::allocator<char>
1> ]
Am I missing an #include(I already have fstream, iostream, string, cstring and ctype to deal with streams and strings I need on the program) or did I do something wrong?
create a function
#include <sstream>#include <stdarg.h>void drawText(SDL_Surface* dst_surf,TTF_Font* font, SDL_Color txt_color, const char* format,...){ va_list args; va_start (args, format); vsprintf (buffer,format, args); va_end (args); txt=buffer; SDL_Surface* txtSurface = TTF_RenderText_Blended(font, txt,txt_color); int x=100;int y=100; SDL_Rect txtLocation ={x,y,0,0}; SDL_BlitSurface(txtSurface, NULL, dst_surf,&txtLocation);}example:drawText(screen,font,color,"hello, world %i",123456);
Don't forget to free the surface if you are going to use a function. You should also include error checking.
For C++, you can take advantage of some of the language features to automate the memory management and cache the text so that you reduce the number of calls to TTF_RenderText:
This way, you can still set the text to whatever you want, using std::stringstream:
For C++, you can take advantage of some of the language features to automate the memory management and cache the text so that you reduce the number of calls to TTF_RenderText:
class Text{ Text(const std::string &text, const SDL_Color &colour, TTF_Font *font) : surface(0), colour(colour), font(font) { assert(font); surface = generate(text); } ~Text() { SDL_FreeSurface(text); } void render(int x, int y, SDL_Surface *destination) { SDL_Rect rect = {x,y}; SDL_BlitSurface(surface, 0, destination, &rect); } void updateText(const std::string &text) { SDL_Surface *temp = generate(text); std::swap(temp, surface); SDL_FreeSurface(temp); }private: SDL_Surface *generate(const std::string &text) { SDL_Surface *surface = TTF_RenderText_Blended(font, text.c_str(), colour); if(!surface) { throw std::runtime_error(TTF_GetError()); } return surface; } SDL_Surface *surface; SDL_Color colour; TTF_Font *font; // disable copying Text(const Text &); Text &operator=(const Text &);};This way, you can still set the text to whatever you want, using std::stringstream:
#include <sstream>int main(){ bool running = true; Text status("nothing yet", someColour, someFont); while(running) { if(player.hits(rocket)) { if(player.died()) { status.updateText("You died!"); } else { std::stringstream stream; stream << "Your health is " << player.health(); status.updateText(stream.str()); } } status.render(10, 10, screen); }}This topic is closed to new replies.
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