view test/threadwin.c @ 4216:5b99971a27b4 SDL-1.2

Fixed bug #698 Hans de Goede 2009-02-13 01:10:52 PST Since the new "glitch free" version of pulseaudio (used in Fedora 10 amongst others), the sound of SDL using apps (like a simple playmus call) has been crackling. While looking in to fixing this I noticed that the current pulseaudio code in SDL uses pa_simple. However pa_simple uses a thread to pump pulseaudio events and ipc, given that SDL already has its own thread for audio handling this is clearly suboptimal, leading to unnecessary context switching IPC, etc. Also pa_simple does not allow one to implement the WaitAudio() callback for SDL audiodrivers properly. Given that my work is mostly a rewrite (although some original pieces remain) I'm attaching the new .c and .h file, as that is easier to review then the huge diff. Let me know if you also want the diff. This new version has the following features: -no longer use an additional thread next to the SDL sound thread -do not crackle with glitch free audio -when used with a newer pulse, which does glitch free audio, the total latency is the same as with the alsa driver -proper WaitAudio() implementation, saving another mixlen worth of latency -adds a WaitDone() implementation This patch has been written in consultancy with Lennart Poetering (the pulseaudio author) and has been reviewed by him for correct use of the pa API.
author Sam Lantinga <slouken@libsdl.org>
date Mon, 21 Sep 2009 09:27:08 +0000
parents 3868bebb9f5b
children
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(const 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);

	/* 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);
}