SDL/OpenGL 浮点异常

Question

我正在用 C++ (SDL/OpenGL) 编写一个简单的乒乓球游戏，但是我在 Ubuntu 上编译时遇到了问题。当我使用SDL_OPENGL 作为SDL_SetVideoMode(WIDTH, HEIGHT, 32, SDL_OPENGL); 的标志时，我得到一个浮点异常。它是用g++ 编译的，它似乎用Visual C++ 编译得很好（没有错误）。

这是我的代码：

#include <SDL/SDL.h>
#include <gl/GL.h>
#include <SDL/SDL_opengl.h>

const int WIDTH = 640;
const int HEIGHT = 480;

struct Paddle
{
    float x, y, w, h;
    Paddle(float a, float b)
    {
        x = a;
        y = b;
        w = 10;
        h = 80;
    }
};

struct Ball
{
    float x, y, r;
    float velx, vely;
    Ball(float a, float b)
    {
        x = a;
        y = b;
        r = 7;
        velx = (float)0.2;
        vely = (float)0.2;
    }
};

bool testCollision(Ball b, Paddle p)
{
    if (b.x + b.r < p.x) return false;
    if (b.x > p.x + p.w) return false;
    if (b.y + b.r < p.y) return false;
    if (b.y > p.y + p.h) return false;
    return true;
}

void init()
{
    SDL_Init(SDL_INIT_EVERYTHING);
    SDL_WM_SetCaption("Pong~~", NULL);
    SDL_SetVideoMode(WIDTH, HEIGHT, 32, SDL_OPENGL);
    glClearColor(0, 0, 0, 1);
    //glViewport(0, 0, WIDTH, HEIGHT);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glDisable(GL_DEPTH_TEST);
    glOrtho(0, WIDTH, HEIGHT, 0, -1, 1);
    SDL_GL_SwapBuffers();
    //glMatrixMode(GL_MODELVIEW);
}

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

    Paddle p1(10.0, 80.0);
    Paddle p2(620.0, 80.0);
    Ball b(50, 50);

    bool press[4] = {false, false, false, false};

    SDL_Event event;
    bool running = true;
    while (running)
    {
        while (SDL_PollEvent(&event))
        {
            if (event.type == SDL_KEYDOWN)
            {
                switch (event.key.keysym.sym)
                {
                case SDLK_ESCAPE:
                    running = false;
                    break;

                case SDLK_w:
                    press[0] = true;
                    break;

                case SDLK_s:
                    press[1] = true;
                    break;

                case SDLK_UP:
                    press[2] = true;
                    break;

                case SDLK_DOWN:
                    press[3] = true;
                    break;
                }
            }

            else if (event.type == SDL_KEYUP)
            {
                switch (event.key.keysym.sym)
                {
                case SDLK_w:
                    press[0] = false;
                    break;

                case SDLK_s:
                    press[1] = false;
                    break;

                case SDLK_UP:
                    press[2] = false;
                    break;

                case SDLK_DOWN:
                    press[3] = false;
                    break;
                }
            }
        }

        //Logic
        if (press[0] == true) p1.y -= (float)0.2;
        if (press[1] == true) p1.y += (float)0.2;
        if (press[2] == true) p2.y -= (float)0.2;
        if (press[3] == true) p2.y += (float)0.2;

        if (p1.y < 0) p1.y = 0;
        else if (p1.y + p1.h > HEIGHT) p1.y = HEIGHT - p1.h;
        if (p2.y < 0) p2.y = 0;
        else if (p2.y + p2.h > HEIGHT) p2.y = HEIGHT - p2.h;

        b.x += b.velx;
        b.y += b.vely;

        if (b.x < 0) b.velx = -b.velx;
        else if (b.x + b.r > WIDTH) b.velx = -b.velx;
        if (b.y < 0) b.vely = -b.vely;
        else if (b.y + b.r > HEIGHT) b.vely = -b.vely;

        if (testCollision(b, p1) == true) b.velx = -b.velx;
        else if (testCollision(b, p2) == true) b.velx = -b.velx;
        glClear(GL_COLOR_BUFFER_BIT);
        glPushMatrix();

        //Draw ball
        glBegin(GL_QUADS);
            glColor4ub(255, 5, 255, 255);
            glVertex2f(b.x, b.y);
            glVertex2f(b.x + b.r, b.y);
            glVertex2f(b.x + b.r, b.y + b.r);
            glVertex2f(b.x, b.y + b.r);
        glEnd();

        //Draw paddles
        glBegin(GL_QUADS);
            glColor4ub(255, 5, 5, 255);
            glVertex2f(p1.x, p1.y);
            glVertex2f(p1.x + p1.w, p1.y);
            glVertex2f(p1.x + p1.w, p1.y + p1.h);
            glVertex2f(p1.x, p1.y + p1.h);

            glVertex2f(p2.x, p2.y);
            glVertex2f(p2.x + p2.w, p2.y);
            glVertex2f(p2.x + p2.w, p2.y + p2.h);
            glVertex2f(p2.x, p2.y + p2.h);
        glEnd();

        glPopMatrix();
        SDL_GL_SwapBuffers();
    }
    return 0;
}

Answer 1

[已解决]

首先，我说错了。当我说它不是编译时，它是；该程序实际上没有运行，在 Ubuntu 11.10 的终端中给了我一个模棱两可的“浮点异常”错误。在和我的朋友研究这个问题几个小时后，无济于事，我最后一次尝试并更新了我的图形驱动程序。是的，这解决了所有问题。

要更新我的 AMD (fglrx) 图形驱动程序，我只需打开终端并输入：

sudo apt-get install fglrx-updates-dev

继续并重新启动，并激活专有图形驱动程序！