view test/threadwin.c @ 2318:0c653886cce7

HandleEvent() returns done each time it is called. If done was set to 0 the program should quit, but because done is not checked until *all* events are handled a following event can reset done to 1 and prevent the program from terminating when told to. I fixed the while loop that handles events to check for the state of done after handling each event. That could leave some events unhandled when the program exits, but it ensures that the program will exit.
author Bob Pendleton <bob@pendleton.com>
date Wed, 20 Feb 2008 23:27:33 +0000
parents 40888832d785
children faa9fc8e7f67
line wrap: on
line source


/* Test out the multi-threaded event handling functions */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "SDL.h"
#include "SDL_thread.h"

/* Are we done yet? */
static int done = 0;

/* Is the cursor visible? */
static int visible = 1;

/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
static void
quit(int rc)
{
    SDL_Quit();
    exit(rc);
}

SDL_Surface *
LoadIconSurface(char *file, Uint8 ** maskp)
{
    SDL_Surface *icon;
    Uint8 *pixels;
    Uint8 *mask;
    int mlen, i;

    *maskp = NULL;

    /* Load the icon surface */
    icon = SDL_LoadBMP(file);
    if (icon == NULL) {
        fprintf(stderr, "Couldn't load %s: %s\n", file, SDL_GetError());
        return (NULL);
    }

    /* Check width and height */
    if ((icon->w % 8) != 0) {
        fprintf(stderr, "Icon width must be a multiple of 8!\n");
        SDL_FreeSurface(icon);
        return (NULL);
    }
    if (icon->format->palette == NULL) {
        fprintf(stderr, "Icon must have a palette!\n");
        SDL_FreeSurface(icon);
        return (NULL);
    }

    /* Set the colorkey */
    SDL_SetColorKey(icon, SDL_SRCCOLORKEY, *((Uint8 *) icon->pixels));

    /* Create the mask */
    pixels = (Uint8 *) icon->pixels;
    printf("Transparent pixel: (%d,%d,%d)\n",
           icon->format->palette->colors[*pixels].r,
           icon->format->palette->colors[*pixels].g,
           icon->format->palette->colors[*pixels].b);
    mlen = icon->w * icon->h;
    mask = (Uint8 *) malloc(mlen / 8);
    if (mask == NULL) {
        fprintf(stderr, "Out of memory!\n");
        SDL_FreeSurface(icon);
        return (NULL);
    }
    memset(mask, 0, mlen / 8);
    for (i = 0; i < mlen;) {
        if (pixels[i] != *pixels)
            mask[i / 8] |= 0x01;
        ++i;
        if ((i % 8) != 0)
            mask[i / 8] <<= 1;
    }
    *maskp = mask;
    return (icon);
}

int SDLCALL
FilterEvents(void *userdata, SDL_Event * event)
{
    static int reallyquit = 0;

    switch (event->type) {

    case SDL_ACTIVEEVENT:
        /* See what happened */
        printf("App %s ", event->active.gain ? "gained" : "lost");
        if (event->active.state & SDL_APPACTIVE)
            printf("active ");
        if (event->active.state & SDL_APPMOUSEFOCUS)
            printf("mouse ");
        if (event->active.state & SDL_APPINPUTFOCUS)
            printf("input ");
        printf("focus\n");

        /* See if we are iconified or restored */
        if (event->active.state & SDL_APPACTIVE) {
            printf("App has been %s\n",
                   event->active.gain ? "restored" : "iconified");
        }
        return (0);

        /* This is important!  Queue it if we want to quit. */
    case SDL_QUIT:
        if (!reallyquit) {
            reallyquit = 1;
            printf("Quit requested\n");
            return (0);
        }
        printf("Quit demanded\n");
        return (1);

        /* Mouse and keyboard events go to threads */
    case SDL_MOUSEMOTION:
    case SDL_MOUSEBUTTONDOWN:
    case SDL_MOUSEBUTTONUP:
    case SDL_KEYDOWN:
    case SDL_KEYUP:
        return (1);

        /* Drop all other events */
    default:
        return (0);
    }
}

int SDLCALL
HandleMouse(void *unused)
{
    SDL_Event events[10];
    int i, found;
    Uint32 mask;

    /* Handle mouse events here */
    mask =
        (SDL_MOUSEMOTIONMASK | SDL_MOUSEBUTTONDOWNMASK |
         SDL_MOUSEBUTTONUPMASK);
    while (!done) {
        found = SDL_PeepEvents(events, 10, SDL_GETEVENT, mask);
        for (i = 0; i < found; ++i) {
            switch (events[i].type) {
                /* We want to toggle visibility on buttonpress */
            case SDL_MOUSEBUTTONDOWN:
            case SDL_MOUSEBUTTONUP:
                if (events[i].button.state == SDL_PRESSED) {
                    visible = !visible;
                    SDL_ShowCursor(visible);
                }
                printf("Mouse button %d has been %s\n",
                       events[i].button.button,
                       (events[i].button.state == SDL_PRESSED) ?
                       "pressed" : "released");
                break;
                /* Show relative mouse motion */
            case SDL_MOUSEMOTION:
                printf("Mouse relative motion: {%d,%d}\n",
                       events[i].motion.xrel, events[i].motion.yrel);
                break;
            }
        }
        /* Give up some CPU to allow events to arrive */
        SDL_Delay(20);
    }
    return (0);
}

int SDLCALL
HandleKeyboard(void *unused)
{
    SDL_Event events[10];
    int i, found;
    Uint32 mask;

    /* Handle mouse events here */
    mask = (SDL_KEYDOWNMASK | SDL_KEYUPMASK);
    while (!done) {
        found = SDL_PeepEvents(events, 10, SDL_GETEVENT, mask);
        for (i = 0; i < found; ++i) {
            switch (events[i].type) {
                /* We want to toggle visibility on buttonpress */
            case SDL_KEYDOWN:
            case SDL_KEYUP:
                printf("Key '%c' (keysym==%d) has been %s\n",
                       events[i].key.keysym.unicode,
                       (int) events[i].key.keysym.sym,
                       (events[i].key.state == SDL_PRESSED) ?
                       "pressed" : "released");

                /* Allow hitting <ESC> to quit the app */
                if (events[i].key.keysym.sym == SDLK_ESCAPE) {
                    done = 1;
                }

                /* skip events now that aren't KEYUPs... */
                if (events[i].key.state == SDL_PRESSED)
                    break;

                if (events[i].key.keysym.sym == SDLK_f) {
                    int rc = 0;
                    printf("attempting to toggle fullscreen...\n");
                    rc = SDL_WM_ToggleFullScreen(SDL_GetVideoSurface());
                    printf("SDL_WM_ToggleFullScreen returned %d.\n", rc);
                }

                if (events[i].key.keysym.sym == SDLK_g) {
                    SDL_GrabMode m;
                    m = SDL_WM_GrabInput(SDL_GRAB_QUERY) ==
                        SDL_GRAB_ON ? SDL_GRAB_OFF : SDL_GRAB_ON;
                    printf
                        ("attempting to toggle input grab to %s...\n",
                         m == SDL_GRAB_ON ? "ON" : "OFF");
                    SDL_WM_GrabInput(m);
                    printf("attempt finished.\n");
                }

                break;
            }
        }
        /* Give up some CPU to allow events to arrive */
        SDL_Delay(20);
    }
    return (0);
}

int
main(int argc, char *argv[])
{
    SDL_Surface *screen;
    SDL_Surface *icon;
    Uint8 *icon_mask;
    int i, parsed;
    Uint8 *buffer;
    SDL_Color palette[256];
    Uint32 init_flags;
    Uint8 video_bpp;
    Uint32 video_flags;
    SDL_Thread *mouse_thread;
    SDL_Thread *keybd_thread;

    /* Set the options, based on command line arguments */
    init_flags = SDL_INIT_VIDEO;
    video_bpp = 8;
    video_flags = SDL_SWSURFACE;
    parsed = 1;
    while (parsed) {
        /* If the threaded option is enabled, and the SDL library hasn't
           been compiled with threaded events enabled, then the mouse and
           keyboard won't respond.
         */
        if ((argc >= 2) && (strcmp(argv[1], "-threaded") == 0)) {
            init_flags |= SDL_INIT_EVENTTHREAD;
            argc -= 1;
            argv += 1;
            printf("Running with threaded events\n");
        } else if ((argc >= 2) && (strcmp(argv[1], "-fullscreen") == 0)) {
            video_flags |= SDL_FULLSCREEN;
            argc -= 1;
            argv += 1;
        } else if ((argc >= 3) && (strcmp(argv[1], "-bpp") == 0)) {
            video_bpp = atoi(argv[2]);
            argc -= 2;
            argv += 2;
        } else {
            parsed = 0;
        }
    }

    /* Initialize SDL with the requested flags */
    if (SDL_Init(init_flags) < 0) {
        fprintf(stderr, "Couldn't initialize SDL: %s\n", SDL_GetError());
        return (1);
    }

    /* Set the icon -- this must be done before the first mode set */
    icon = LoadIconSurface("icon.bmp", &icon_mask);
    if (icon != NULL) {
        SDL_WM_SetIcon(icon, icon_mask);
    }
    if (icon_mask != NULL)
        free(icon_mask);

    /* Initialize the display */
    screen = SDL_SetVideoMode(640, 480, video_bpp, video_flags);
    if (screen == NULL) {
        fprintf(stderr, "Couldn't set 640x480x%d video mode: %s\n",
                video_bpp, SDL_GetError());
        quit(1);
    }
    printf("Running in %s mode\n", screen->flags & SDL_FULLSCREEN ?
           "fullscreen" : "windowed");

    /* Enable printable characters */
    SDL_EnableUNICODE(1);

    /* Set an event filter that discards everything but QUIT */
    SDL_SetEventFilter(FilterEvents, NULL);

    /* Create the event handling threads */
    mouse_thread = SDL_CreateThread(HandleMouse, NULL);
    keybd_thread = SDL_CreateThread(HandleKeyboard, NULL);

    /* Set the surface pixels and refresh! */
    for (i = 0; i < 256; ++i) {
        palette[i].r = 255 - i;
        palette[i].g = 255 - i;
        palette[i].b = 255 - i;
    }
    SDL_SetColors(screen, palette, 0, 256);
    if (SDL_LockSurface(screen) < 0) {
        fprintf(stderr, "Couldn't lock display surface: %s\n",
                SDL_GetError());
        quit(2);
    }
    buffer = (Uint8 *) screen->pixels;
    for (i = 0; i < screen->h; ++i) {
        memset(buffer, (i * 255) / screen->h,
               screen->w * screen->format->BytesPerPixel);
        buffer += screen->pitch;
    }
    SDL_UnlockSurface(screen);
    SDL_UpdateRect(screen, 0, 0, 0, 0);

    /* Loop, waiting for QUIT */
    while (!done) {
        if (!(init_flags & SDL_INIT_EVENTTHREAD)) {
            SDL_PumpEvents();   /* Needed when event thread is off */
        }
        if (SDL_PeepEvents(NULL, 0, SDL_PEEKEVENT, SDL_QUITMASK)) {
            done = 1;
        }
        /* Give up some CPU so the events can accumulate */
        SDL_Delay(20);
    }
    SDL_WaitThread(mouse_thread, NULL);
    SDL_WaitThread(keybd_thread, NULL);
    SDL_Quit();
    return (0);
}