SDL-displaying variable with SDL_ttf

This is a discussion on SDL-displaying variable with SDL_ttf within the Game Programming forums, part of the General Programming Boards category; This is my slot machine game with SDL, it is not complete but i have two questions. How do i ...

  1. #1
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    SDL-displaying variable with SDL_ttf

    This is my slot machine game with SDL, it is not complete but i have two questions.

    How do i display a variable with the extension library SDL_ttf

    When you run the program and the welcome text is displayed, even though i call SDL_FreeSurface to remove the text from memory, it still displays on the screen.

    Code:
    #include <iostream>
    #include <cstdlib>
    #include <ctime>
    #include <string>
    #include "SDL.h"
    #include "SDL_ttf.h"
    
    using namespace std;
    
    typedef unsigned short int USHORT;
    
    unsigned short int tokens = 24;
    
    bool quitSlot = false;
    
    SDL_Event event;
    
    SDL_Surface* screen = NULL;
    TTF_Font *arialFont = NULL;
    
    SDL_Color textColourBlack = {0, 0, 0};
    
    void applySurface( int xCoord, int yCoord, SDL_Surface* source, SDL_Surface* destination )
    {
        //Make a temporary rectangle to hold the offsets
        SDL_Rect offset;
    
        //Give the offsets to the rectangle
        offset.x = xCoord;
        offset.y = yCoord;
    
        //Blit the surface
        SDL_BlitSurface( source, NULL, destination, &offset );
    }
    
    void cleanUpQuit()
    {
    	TTF_Quit(); 
    	SDL_Quit();
    }
    
    void welcome()
    {
    	SDL_Surface* welcomeLineOne = NULL;
    	SDL_Surface* welcomeLineTwo = NULL;
    	SDL_Surface* welcomeLineThree = NULL;
    	SDL_Surface* welcomeLineFour = NULL;
    	welcomeLineOne = TTF_RenderText_Solid(arialFont, "Welcome to the most amazing text-based Slot Machine!", textColourBlack);
    	welcomeLineTwo = TTF_RenderText_Solid(arialFont, "Our fine Slot Machines may or maynot grant you wishes!", textColourBlack);
    	welcomeLineThree = TTF_RenderText_Solid(arialFont, "Anyways, You have tokens.", textColourBlack);
    	welcomeLineFour = TTF_RenderText_Solid (arialFont, "Soooo, have fun with these few tokens as you will have none left very, very, very SOON!", textColourBlack);
    	applySurface ( 0, 50, welcomeLineOne, screen);
    	applySurface ( 0, 70, welcomeLineTwo, screen);
    	applySurface ( 0, 90, welcomeLineThree, screen);
    	applySurface ( 0, 110, welcomeLineFour, screen);
    	SDL_Flip ( screen);
    	SDL_FreeSurface ( welcomeLineOne );
    	SDL_FreeSurface ( welcomeLineTwo );
    	SDL_FreeSurface ( welcomeLineThree );
    	SDL_FreeSurface ( welcomeLineFour );
    	TTF_CloseFont ( arialFont );
    }
    
    void outcome(int firstNumber, int secondNumber, int thirdNumber)
    {
    
        const USHORT tokensThree = 3;
        const USHORT tokensTwo = 2;
        if(firstNumber == secondNumber && secondNumber == thirdNumber && firstNumber == thirdNumber)
        {
            tokens += tokensThree;
            cout << endl << "Congrats! You won 3 Tokens!" << endl;
            cout << "You have " << tokens << " tokens." << endl;
            return;
        }
        if(firstNumber == secondNumber || secondNumber == thirdNumber || firstNumber == thirdNumber)
        {
            tokens += tokensTwo;
            cout << endl << endl << "Congrats! You won 2 Tokens!" << endl;
            cout << "You have " << tokens << " tokens." << endl;
        }
        else
        {
            tokens -= tokensThree;
            cout << endl << endl << "Sorry! You lost 3 Tokens." << endl;
            cout << "You have " << tokens << " tokens." << endl;
        }
        return;
    }
    
    void lever()
    {
        SDL_Surface* firstImageNumber = NULL;
    	SDL_Surface* secondImageNumber = NULL;
    	SDL_Surface* thirdImageNumber = NULL;
    	SDL_Surface* fourthImageNumber = NULL;
    	SDL_Surface* fifthImageNumber = NULL;
    	SDL_Surface* sixthImageNumber = NULL;
    	firstImageNumber = SDL_LoadBMP ( "Images/1.bmp" );
    	secondImageNumber = SDL_LoadBMP ( "Images/2.bmp" );
    	thirdImageNumber = SDL_LoadBMP ( "Images/3.bmp" );
    	fourthImageNumber = SDL_LoadBMP ( "Images/4.bmp" );
    	fifthImageNumber = SDL_LoadBMP ( "Images/5.bmp" );
    	sixthImageNumber = SDL_LoadBMP ( "Images/6.bmp" );
    	const USHORT highRandom = 6;
    	string imputYes;
    	string playYes = ("yes");
    	string playY = ("y");
    	USHORT randomNumber;
        USHORT randomNumberTwo ;
        USHORT randomNumberThree ;
        time_t clockTime;
        time(&clockTime);
        srand((unsigned int) clockTime);
        randomNumber = rand() % highRandom + 1;
        randomNumberTwo = rand() % highRandom + 1;
        randomNumberThree = rand() % highRandom + 1;
        cout << endl << "Do you want to pull the Lever?" << endl;
    	cin >> imputYes;
        if (imputYes == playY || imputYes == playYes)
        {
            if(randomNumber == 1)
    		{
    			//Apply image to screen
    			applySurface ( 180, 100, firstImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    			
    			
    			//Free the loaded image
    			SDL_FreeSurface( firstImageNumber );
    		}
    		if(randomNumber == 2)
    		{
    			//Apply image to screen
    			applySurface ( 180, 100, secondImageNumber, screen);;
    
    			//Update Screen
    			SDL_Flip( screen );
    
    			
    			//Free the loaded image
    			SDL_FreeSurface( secondImageNumber );
    		}
    		if(randomNumber == 3)
    		{
    			//Apply image to screen
    			applySurface ( 180, 100, thirdImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    			
    			
    			//Free the loaded image
    			SDL_FreeSurface( thirdImageNumber );
    		}
    		if(randomNumber == 4)
    		{
    			//Apply image to screen
    			applySurface ( 180, 100, fourthImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    			
    			
    			//Free the loaded image
    			SDL_FreeSurface( fourthImageNumber );
    		}
    		if(randomNumber == 5)
    		{
    			//Apply image to screen
    			applySurface ( 180, 100, fifthImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    			
    			
    			//Free the loaded image
    			SDL_FreeSurface( fifthImageNumber );
    		}
    		if(randomNumber == 6)
    		{
    			//Apply image to screen
    			applySurface ( 180, 100, sixthImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    			
    			
    			//Free the loaded image
    			SDL_FreeSurface( sixthImageNumber );
    		}
    		if(randomNumberTwo == 1)
    		{
    			//Apply image to screen
    			applySurface ( 180, 140, firstImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    			
    			
    			//Free the loaded image
    			SDL_FreeSurface( firstImageNumber );
    		}
    		if(randomNumberTwo == 2)
    		{
    			//Apply image to screen
    			applySurface ( 180, 140, secondImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    			
    			
    			//Free the loaded image
    			SDL_FreeSurface( secondImageNumber );
    		}
    		if(randomNumberTwo == 3)
    		{
    			//Apply image to screen
    			applySurface ( 180, 140, thirdImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    			
    			
    			//Free the loaded image
    			SDL_FreeSurface( thirdImageNumber );
    		}
    		if(randomNumberTwo == 4)
    		{
    			//Apply image to screen
    			applySurface ( 180, 140, fourthImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    			
    			
    			//Free the loaded image
    			SDL_FreeSurface( fourthImageNumber );
    		}
    		if(randomNumberTwo == 5)
    		{
    			//Apply image to screen
    			applySurface ( 180, 140, fifthImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    			
    			
    			//Free the loaded image
    			SDL_FreeSurface( fifthImageNumber );
    		}
    		if(randomNumberTwo == 6)
    		{
    			//Apply image to screen
    			applySurface ( 180, 140, sixthImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    			
    			
    			//Free the loaded image
    			SDL_FreeSurface( sixthImageNumber );
    		}
    		if(randomNumberThree == 1)
    		{
    			//Apply image to screen
    			applySurface ( 180, 180, firstImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    			
    			
    			//Free the loaded image
    			SDL_FreeSurface( firstImageNumber );
    		}
    		if(randomNumberThree == 2)
    		{
    			//Apply image to screen
    			applySurface ( 180, 180, secondImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    			
    			
    			//Free the loaded image
    			SDL_FreeSurface( secondImageNumber );
    		}
    		if(randomNumberThree == 3)
    		{
    			//Apply image to screen
    			applySurface ( 180, 180, thirdImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    		
    			
    			//Free the loaded image
    			SDL_FreeSurface( thirdImageNumber );
    		}
    		if(randomNumberThree == 4)
    		{
    			//Apply image to screen
    			applySurface ( 180, 180, fourthImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    			
    			
    			//Free the loaded image
    			SDL_FreeSurface( fourthImageNumber );
    		}
    		if(randomNumberThree == 5)
    		{
    			//Apply image to screen
    			applySurface ( 180, 180, fifthImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    
    			
    			//Free the loaded image
    			SDL_FreeSurface( fifthImageNumber );
    		}
    		if(randomNumberThree == 6)
    		{
    			//Apply image to screen
    			applySurface ( 180, 180, sixthImageNumber, screen);
    
    			//Update Screen
    			SDL_Flip( screen );
    
    
    			
    			//Free the loaded image
    			SDL_FreeSurface( sixthImageNumber );
    		}
            outcome(randomNumber, randomNumberTwo, randomNumberThree);
        }
        else
        {
    		cout << "Goodbye!" << endl;
    		exit(0);
        }
    }
    
    int main( int argc, char* args[] )
    {
    	SDL_Surface* background = NULL;
    	SDL_Init( SDL_INIT_EVERYTHING );
    	TTF_Init();
    	arialFont = TTF_OpenFont ( "Fonts/arial.ttf", 14);
    
    	const USHORT screenHeight = 480;
    	const USHORT screenWidth = 640;
    	const USHORT screenBpp = 32;
    	
    	screen = SDL_SetVideoMode ( screenWidth, screenHeight, screenBpp, SDL_SWSURFACE );
    		
    	SDL_WM_SetCaption ( "Slot Machine", NULL);
    	
    	background = SDL_LoadBMP ( "Images/BG.bmp" );
    	applySurface ( 0, 0, background, screen );
    	SDL_Flip (  screen );
    	SDL_FreeSurface ( background );
    	welcome();
    	
    	
    	while ( quitSlot == false)
    	{
    		
    		while ( SDL_PollEvent (&event));
    		{
    			
    			if(event.type == SDL_QUIT )
    			{
    				quitSlot = true;
    			}
    		}
    	}
    
    	
    	cleanUpQuit();
    	return 0;
    }

  2. #2
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    Post the smallest possible code that demonstrates the problem.

  3. #3
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    First, very repetitive, and without much reason.

    Your problem I believe would be that you are never actually clearing the screen. Just rendering over everything.

    Freeing the memory has nothing to do with what is on the screen.

  4. #4
    Registered User rogster001's Avatar
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    Not quite sure whats going on there but i think you should use a sprite sheet instead of all those different image files if you are just wanting to display a number at a time

    Lazy Foo' Productions

    you would just need one image file and you 'clip' the portion that you require of it, only storing that section in a surface, you then just show this section on the screen, or blit it with another surface then to screen. I think you did something similar in there at one point but hard to tell....

    Also yeah, your visible screen is not refreshed by using freesurface call, it just frees the memory, whatever you have drawn on your screen surface there remains as lit pixels until you colour them otherwise.
    Last edited by rogster001; 11-12-2009 at 01:17 AM.

  5. #5
    Registered User rogster001's Avatar
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    Also your code as already mentioned is much too repetitive, only call the function that actually displaysyour image on screen once in your big if block, the rest of your if statements could be a switch and only write the new image into memory ready to display after the correct case has been matched,
    If you insist on sticking with a seperate image file for each number picked in your program load the surfaces at the beginning of and free the surfaces at the end of your function, again this will clear up what you are working with, and everyone else has to look at.

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