3

每次我运行这个程序时，我都会遇到这个错误：

分段故障

测试.cpp

#include <iostream>
#include <cstdint>
#include <SDL.h>
#include <SDL_image.h>

#include "Surface.h"
#include "Point2D.h"

int main() {
    if (SDL_Init(SDL_INIT_EVERYTHING) != 0) {
        std::cerr << "Can not init SDL" << std::endl;
        return -1;
    }

    SDL_Surface *scr = SDL_SetVideoMode(800, 600, 0, SDL_HWSURFACE | SDL_DOUBLEBUF);

    if ( scr == NULL ) {
        std::cerr << "Can not open window" << std::endl;
        return -1;
    }

    SDL_WM_SetCaption("Test Surface class", NULL);

    Surface screen;
    Surface image;

    screen.set(SDL_GetVideoSurface());

    if (image.load("./data/images/logo.png") == false) {
        std::cerr << "Can not open file" << std::endl;
        return -1;
    }

    bool run = true;
    uint32_t sticks = SDL_GetTicks();

    while(run) {
        if (screen.draw(image, Rectangle(0, 0, image.getWidth(), image.getHeight()), Point2D(0, 0)) == false) {
            std::cerr << "Can not draw to window" << std::endl;
            return -1;
        }

        if ((SDL_GetTicks() - sticks)/1000 > 5) {
            std::cerr << "End of time" << std::endl;
            run = false;
        }

        SDL_Flip(screen.sdlSurface());
    }

    std::cerr << "Done" << std::endl;
    SDL_Quit();

    return 0;
}

有Surface类的源代码

#include "Surface.h"
#include "Color.h"

Surface::Surface() {
    this->surface = NULL;
}

Surface::~Surface() {
    SDL_FreeSurface(this->surface);
    this->surface = NULL;
}

bool Surface::draw(Surface source, Rectangle source_area, Point2D position) {
    SDL_Rect sr = source_area.sdlRect();
    SDL_Rect tr = {position.getX(), position.getY(), 0, 0};

    std::cout << sr.x << "," << sr.y << "," << sr.w << "," << sr.h << std::endl;
    std::cout << tr.x << "," << tr.y << "," << tr.w << "," << tr.h << std::endl;

    std::cout << source.sdlSurface() << std::endl;
    std::cout << this->surface << std::endl;

    // TR and SR are currently unused. Just for case of testing
    if (SDL_BlitSurface(source.sdlSurface(), NULL, this->surface, NULL) != 0) {
        return false;
    }

    return true;
}

bool Surface::fill(Color color, Rectangle area) {
    SDL_Rect tr = area.sdlRect();

    std::cout << tr.x << "," << tr.y << "," << tr.w << "," << tr.h << std::endl;
    std::cout << (int)color.sdlColor() << std::endl;

    if ( SDL_FillRect(this->surface, &tr, color.sdlColor()) != 0) {
        return false;
    }

    return true;
}

Rectangle Surface::getSize() {
    return Rectangle(0, 0, this->getWidth(), this->getHeight());
}

bool Surface::load(std::string file) {
    SDL_Surface *src = IMG_Load(file.c_str());

    if (src == NULL) {
        std::cout << "cyh" << std::endl;
        std::cout << IMG_GetError() << std::endl;
        return false;
    }

    this->surface = SDL_DisplayFormatAlpha(src);
    if (this->surface == NULL) {
        std::cout << "cyh1" << std::endl;
        std::cout << SDL_GetError() << std::endl;
        return false;
    }

    SDL_FreeSurface(src);
    src = NULL;
    return true;
}

void Surface::set(SDL_Surface *surface) {
    this->surface = surface;
}

void Surface::set(Surface surface) {
    this->surface = surface.sdlSurface();
}

问题可能出在绘图功能中。如果我改变这一行：

if (SDL_BlitSurface(source.sdlSurface(), NULL, this->surface, NULL) != 0) {

至：

if (SDL_BlitSurface(IMG_Load("./data/images/logo.png"), NULL, this->surface, NULL) != 0) {

一切似乎都很好。你能给我一个建议，应该是哪里出了问题？

4

1 回答 1

3

你违反了 3 法则。

您需要定义一个复制构造函数和一个复制赋值运算符才能使其正常工作。

当您将Surfacein 传递给 draw 方法时，您正在制作它的副本。由于您在 Surface 类 ( SDL_Surface*) 中管理资源，因此您将拥有多个指向同一表面的类实例，因此当调用析构函数时，您将SDL_Surface*多次释放相同的实例。

编辑：我建议通过 const 引用传递您的参数。Surface当您想要绘制对象时，您不需要制作对象的副本。

这个：

bool Surface::draw(Surface source, Rectangle source_area, Point2D position);

会变成这样：

bool Surface::draw(const Surface &source, const Rectangle &source_area, const Point2D &position);

这也可以应用于您的其他功能。

于 2013-06-03T17:25:56.160 回答