Sdl ttf crashed with multithread

SDL Development
1

Hi, everybody, how to use sdl ttf with multithread, it crashed
#include
#include “include/SDL.h”
#include “include/SDL_ttf.h”

#include
#include <pthread.h>
#include <unistd.h>

#define MAX_THREAD_NUMBER 100

TTF_Font *m_font = NULL;
SDL_Window *Screen[1024] = {NULL};//创建窗口
SDL_Renderer render[1024] = {NULL};
int Test(void pData)
{
if(pData){
int nIndex = (int)(pData);
if(Screen[nIndex]){
if(render[nIndex]){
//
SDL_Color textColor = { 255, 255, 255 };
wchar_t wcText[1024] = { L"计算机" };

            //
            std::vector<int>vWidth;
            std::vector<SDL_Surface*>vSurface;
            std::vector<SDL_Texture*>vTexture;
            for(int i = 0; i < wcslen(wcText); i++){
                wchar_t wcData[1024] = {0};
                wcData[0] = wcText[i];
                SDL_Surface *surface_font = TTF_RenderUNICODE_Solid(m_font, (Uint16*)wcData, textColor);
                if(surface_font != NULL){
                    SDL_Texture *texture_font = SDL_CreateTextureFromSurface(render[nIndex], surface_font);
                    if(texture_font != NULL){
                        int nWidth = 0;
                        int nHeight = 0;
                        if(TTF_SizeUNICODE(m_font, (Uint16*)wcData, &nWidth, &nHeight) == 0){//计算每个字符的宽度
                            vWidth.push_back(nWidth);
                            vSurface.push_back(surface_font);
                            vTexture.push_back(texture_font);
                        }
                        else{
                            SDL_FreeSurface(surface_font);
                            SDL_DestroyTexture(texture_font);
                        }
                    }
                    else{
                        SDL_FreeSurface(surface_font);
                    }
                }
            }

            //
            SDL_RenderClear(render[nIndex]);

            //
            for(int i = 0; i < vTexture.size(); i++){
                long nTotal = 0;
                for(int j = 0; j < i; j++){
                    nTotal += vWidth.at(j);
                }

                SDL_Rect rect_Font;//字体在哪里输出
                rect_Font.x = 200 + nTotal;//计算每个字符从起始点有多少偏移量
                rect_Font.y = 100;
                rect_Font.w = vWidth.at(i);//每个字符本身宽度
                rect_Font.h = 100;

                SDL_RenderCopy(render[nIndex], vTexture[i], NULL, &rect_Font);//拷贝字体数据
            }

            //
            SDL_RenderPresent(render[nIndex]);

            //
            SDL_Event event;
            while (1){
                SDL_PollEvent(&event);
                if (event.type == SDL_QUIT){
                    break;
                }
            }


            for(int i = 0; i < vSurface.size(); i++){
                SDL_FreeSurface(vSurface.at(i));//释放字体
            }
            vSurface.clear();

            for(int i = 0; i < vTexture.size(); i++){
                SDL_DestroyTexture(vTexture.at(i));//释放纹理
            }
            vTexture.clear();
        }
    }

    delete pData;
    pData = NULL;
}

return NULL;

}

int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);

TTF_Init();
m_font = TTF_OpenFont("/usr/share/fonts/opentype/noto/NotoSerifCJK-Black.ttc", 100);
if (!m_font){
    return 0;
}

//
SDL_Init(SDL_INIT_EVERYTHING);//SDL只初始化一次

for(int i = 0; i < MAX_THREAD_NUMBER; i++){
    Screen[i] = SDL_CreateWindow("Title", 100, 100, 640, 480, SDL_WINDOW_RESIZABLE);//在线程外创建窗口
    if(Screen[i]){
        render[i] = SDL_CreateRenderer(Screen[i], -1, 0);//创建渲染器
    }
}
for(int i = 0; i < MAX_THREAD_NUMBER; i++){
    int* pData = new int(i);
    SDL_CreateThread(Test, "", pData);
}

sleep(1000000);//类似等待界面退出
for(int i = 0; i < MAX_THREAD_NUMBER; i++){
    if(Screen[i]){
        SDL_DestroyWindow(Screen[i]);//销毁窗口
        Screen[i] = NULL;
    }
    if(render[i]){
        SDL_DestroyRenderer(render[i]);//释放渲染器
        render[i] = NULL;
    }
}

TTF_CloseFont(m_font);//释放字体资源
TTF_Quit();
SDL_Quit();//退出

return a.exec();

}

2

You may only access textures in the thread which created the renderer (you can access surfaces in other threads, but not textures). So SDL_CreateTextureFromSurface() must be moved from your child thread into main.

3

thank you ,i will try it