Optimize memory in SDL2

SDL Development
1 
#include <iostream>
#include<stdio.h>
#include <SDL2/SDL.h>
#include<SDL2/SDL_ttf.h>
using namespace std;
    SDL_Window* window = NULL;
    SDL_Surface* surf=NULL;
    SDL_Renderer* renderer = NULL;
    SDL_Texture* txt=NULL;
    TTF_Font* font=NULL;
    bool done =false;
    SDL_Color fg = { 243, 156, 18 };
void output(string text,int cx,int cy)
{
    SDL_Rect srcRest;
    SDL_Rect desRect;
    surf = TTF_RenderText_Solid(font, text.c_str(), fg);
    txt = SDL_CreateTextureFromSurface(renderer, surf);
    TTF_SizeText(font, text.c_str(), &srcRest.w, &srcRest.h);
    srcRest.x = 0;
    srcRest.y =  0;
    desRect.x = cx;
    desRect.y = cy;
    desRect.w = srcRest.w;
    desRect.h = srcRest.h;
    SDL_FreeSurface(surf);
    SDL_RenderCopy(renderer, txt, &srcRest, &desRect);
   }
void createRect(SDL_Rect &rect,int cx,int cy,int cw,int ch)
{
    rect.x=cx;
    rect.y=cy;
    rect.w=cw;
    rect.h=ch;
}
int generateRandomNumber()
{
    return rand() % 100 + 1;
}
int string2Int(string st)
{
    return stoi(st);
}
string int2String(int num)
{
    return to_string(num);
}
int main(int argc, char *argv[])
{
    string inputText="";
    int secretNumber=generateRandomNumber();
    bool isCalled=false,isPressed=false,save=false;
    int point=100;
    SDL_Event event;
    if (SDL_Init(SDL_INIT_VIDEO) == 0) {
    window= SDL_CreateWindow("GuessIt", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 400, 500, SDL_WINDOW_SHOWN);
    renderer=SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);

    SDL_Rect rectInput,rectButton;
    createRect(rectInput,168,100,65,65);
    createRect(rectButton,150,250,100,40);
    if( TTF_Init() == -1 ) cout<<"Error on TTF_init";
    font = TTF_OpenFont("D:/FreeSansBold.ttf", 20);
    if(font==NULL) cout<<"Font Location Error\n";
    //SDL_SetRenderDrawColor(renderer,0,0,0,255);
    SDL_StartTextInput();
    SDL_SetTextInputRect(&rectInput);

    while (!done) {

        SDL_SetRenderDrawColor(renderer,0,0,0,SDL_ALPHA_OPAQUE);
        SDL_RenderClear(renderer);
        while (SDL_PollEvent(&event)) {
            if (event.type == SDL_QUIT)
                done = true;
            else if(event.type==SDL_MOUSEBUTTONDOWN)
                {
                    int cx=event.button.x;
                    int cy=event.button.y;
                    if(cx>150 && cx<250 && cy>250 && cy<290)
                    {
                        isPressed=true;
                        isCalled=true;
                        save=true;
                    }
                }  else if(event.type==SDL_MOUSEBUTTONUP)
                    isPressed=false;
                        else if (event.key.keysym.sym == SDLK_BACKSPACE){
                            isCalled=false;
                            if(inputText.length()>0)
                            inputText.pop_back();
                            }
                                else if (event.type == SDL_TEXTINPUT)
                                inputText += event.text.text;
        }

        if(isCalled==true && inputText.length()!=0) {
            int guessNumber=string2Int(inputText);
            if (guessNumber > secretNumber) {
                if(save){point--;save=false;}
                output("Too Big!",160,350);
            }
            else if (guessNumber < secretNumber) {
                if(save) {point--;save=false;}
                output("Too Small!",160,350);
            }
            else{
                if(save){point=100;save=false;}
                output("You win!!!",160,350);
            }
        }

        string tmp="POINT: "+int2String(point);
        output(tmp,4,5);
        SDL_SetRenderDrawColor(renderer,116,41,215,SDL_ALPHA_OPAQUE);
        SDL_RenderFillRect(renderer, &rectInput);

        if(!isPressed){
        SDL_SetRenderDrawColor(renderer,116,41,215,SDL_ALPHA_OPAQUE);
        SDL_RenderFillRect(renderer, &rectButton);
        }

        output("GuessIt",165,253);
        surf = TTF_RenderText_Solid(font,inputText.c_str(),fg);
        txt= SDL_CreateTextureFromSurface(renderer, surf);
        SDL_FreeSurface(surf);
        SDL_RenderCopy(renderer,txt,NULL,&rectInput);
        SDL_RenderPresent(renderer);
        SDL_UpdateWindowSurface(window);


    }

    if(renderer) SDL_DestroyRenderer(renderer);
    if(window) SDL_DestroyWindow(window);
    }
    SDL_StopTextInput();
    TTF_Quit();
    TTF_CloseFont(font);
    SDL_Quit();
    return 0;
}

Above is my code. The program takes too much space though my Laptop has 8GB RAM, it took up more than 1500MB and then crashed down.

mem
mem1920×1080 263 KB

In my code, some texts are changed and frequently updated, but I know some methods are called many times. I tried to fix this but it didn’t work. Anyone can tell me how to do that?(Thanks in advance!)

2

Write your own bitmap fonts using glyphs

3

you’re creating new textures all the time, but never free them

1 Like
4

Also, you’re not destroying txt

5

Some texts always change like this:

point
point1920×1080 296 KB

Hence textures frequently need to be updated. Any suggestions and tricks?

6

As has been pointed out, the problem is a memory leak because you are not destroying txt. Add the necessary SDL_DestroyTexture() as follows:

    surf = TTF_RenderText_Solid(font,inputText.c_str(),fg);
    txt= SDL_CreateTextureFromSurface(renderer, surf);
    SDL_FreeSurface(surf);
    SDL_RenderCopy(renderer,txt,NULL,&rectInput);
    SDL_DestroyTexture(txt);  // <- add this
    SDL_RenderPresent(renderer);

The SDL_UpdateWindowSurface() is unnecessary and may be deleted.

1 Like