view test/testsprite.c @ 1199:2d6dc7de1145

From: Mike Frysinger <vapier@gentoo.org> To: sdl@libsdl.org Date: Sun, 11 Dec 2005 22:57:37 -0500 Subject: [SDL] exec stack in libsdl update i posted back in September a patch to remove executable stacks: http://www.devolution.com/pipermail/sdl/2005-September/070626.html later in November, a similar patch was merged it seems: http://www.libsdl.org/cgi/cvsweb.cgi/SDL12/src/hermes/mmx_main.asm however, this lacks the additional output format checks that i posted in my patch ... this isnt a problem if the hermes asm code is only ever used to produce ELF objects, but if this is not true, then the additional checks in my original patch will need to be merged -mike
author Ryan C. Gordon <icculus@icculus.org>
date Mon, 12 Dec 2005 09:13:12 +0000
parents be9c9c8f6d53
children 31103dbf1c26
line wrap: on
line source

/* Simple program:  Move N sprites around on the screen as fast as possible */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#include <time.h>

#include "SDL.h"

#define DEBUG_FLIP 1

#define NUM_SPRITES	100
#define MAX_SPEED 	1

SDL_Surface *sprite;
int numsprites;
SDL_Rect *sprite_rects;
SDL_Rect *positions;
SDL_Rect *velocities;
int sprites_visible;
Uint16 sprite_w, sprite_h;

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

int LoadSprite(SDL_Surface *screen, char *file)
{
	SDL_Surface *temp;

	/* Load the sprite image */
	sprite = SDL_LoadBMP(file);
	if ( sprite == NULL ) {
		fprintf(stderr, "Couldn't load %s: %s", file, SDL_GetError());
		return(-1);
	}

	/* Set transparent pixel as the pixel at (0,0) */
	if ( sprite->format->palette ) {
		SDL_SetColorKey(sprite, (SDL_SRCCOLORKEY|SDL_RLEACCEL),
						*(Uint8 *)sprite->pixels);
	}

	/* Convert sprite to video format */
	temp = SDL_DisplayFormat(sprite);
	SDL_FreeSurface(sprite);
	if ( temp == NULL ) {
		fprintf(stderr, "Couldn't convert background: %s\n",
							SDL_GetError());
		return(-1);
	}
	sprite = temp;

	/* We're ready to roll. :) */
	return(0);
}

void MoveSprites(SDL_Surface *screen, Uint32 background)
{
	int i, nupdates;
	SDL_Rect area, *position, *velocity;

	nupdates = 0;
	/* Erase all the sprites if necessary */
	if ( sprites_visible ) {
		SDL_FillRect(screen, NULL, background);
	}

	/* Move the sprite, bounce at the wall, and draw */
	for ( i=0; i<numsprites; ++i ) {
		position = &positions[i];
		velocity = &velocities[i];
		position->x += velocity->x;
		if ( (position->x < 0) || (position->x >= (screen->w - sprite_w)) ) {
			velocity->x = -velocity->x;
			position->x += velocity->x;
		}
		position->y += velocity->y;
		if ( (position->y < 0) || (position->y >= (screen->h - sprite_w)) ) {
			velocity->y = -velocity->y;
			position->y += velocity->y;
		}

		/* Blit the sprite onto the screen */
		area = *position;
		SDL_BlitSurface(sprite, NULL, screen, &area);
		sprite_rects[nupdates++] = area;
	}

#if DEBUG_FLIP
    {
	if ( (screen->flags & SDL_DOUBLEBUF) == SDL_DOUBLEBUF ) {
            static int t = 0;

            Uint32 color = SDL_MapRGB (screen->format, 255, 0, 0);
            SDL_Rect r;
            r.x = (sin((float)t * 2 * 3.1459) + 1.0) / 2.0 * (screen->w-20);
            r.y = 0;
            r.w = 20;
            r.h = screen->h;
        
            SDL_FillRect (screen, &r, color);
            t+=2;
        }
    }
#endif
    
	/* Update the screen! */
	if ( (screen->flags & SDL_DOUBLEBUF) == SDL_DOUBLEBUF ) {
		SDL_Flip(screen);
	} else {
		SDL_UpdateRects(screen, nupdates, sprite_rects);
	}
	sprites_visible = 1;
}

/* This is a way of telling whether or not to use hardware surfaces */
Uint32 FastestFlags(Uint32 flags, int width, int height, int bpp)
{
	const SDL_VideoInfo *info;

	/* Hardware acceleration is only used in fullscreen mode */
	flags |= SDL_FULLSCREEN;

	/* Check for various video capabilities */
	info = SDL_GetVideoInfo();
	if ( info->blit_hw_CC && info->blit_fill ) {
		/* We use accelerated colorkeying and color filling */
		flags |= SDL_HWSURFACE;
	}
	/* If we have enough video memory, and will use accelerated
	   blits directly to it, then use page flipping.
	 */
	if ( (flags & SDL_HWSURFACE) == SDL_HWSURFACE ) {
		/* Direct hardware blitting without double-buffering
		   causes really bad flickering.
		 */
		if ( info->video_mem*1024 > (height*width*bpp/8) ) {
			flags |= SDL_DOUBLEBUF;
		} else {
			flags &= ~SDL_HWSURFACE;
		}
	}

	/* Return the flags */
	return(flags);
}

int main(int argc, char *argv[])
{
	SDL_Surface *screen;
	Uint8 *mem;
	int width, height;
	Uint8  video_bpp;
	Uint32 videoflags;
	Uint32 background;
	int    i, done;
	SDL_Event event;
	Uint32 then, now, frames;

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

	numsprites = NUM_SPRITES;
	videoflags = SDL_SWSURFACE|SDL_ANYFORMAT;
	width = 640;
	height = 480;
	video_bpp = 8;
	while ( argc > 1 ) {
		--argc;
		if ( strcmp(argv[argc-1], "-width") == 0 ) {
			width = atoi(argv[argc]);
			--argc;
		} else
		if ( strcmp(argv[argc-1], "-height") == 0 ) {
			height = atoi(argv[argc]);
			--argc;
		} else
		if ( strcmp(argv[argc-1], "-bpp") == 0 ) {
			video_bpp = atoi(argv[argc]);
			videoflags &= ~SDL_ANYFORMAT;
			--argc;
		} else
		if ( strcmp(argv[argc], "-fast") == 0 ) {
			videoflags = FastestFlags(videoflags, width, height, video_bpp);
		} else
		if ( strcmp(argv[argc], "-hw") == 0 ) {
			videoflags ^= SDL_HWSURFACE;
		} else
		if ( strcmp(argv[argc], "-flip") == 0 ) {
			videoflags ^= SDL_DOUBLEBUF;
		} else
		if ( strcmp(argv[argc], "-fullscreen") == 0 ) {
			videoflags ^= SDL_FULLSCREEN;
		} else
		if ( isdigit(argv[argc][0]) ) {
			numsprites = atoi(argv[argc]);
		} else {
			fprintf(stderr, 
	"Usage: %s [-bpp N] [-hw] [-flip] [-fast] [-fullscreen] [numsprites]\n",
								argv[0]);
			quit(1);
		}
	}

	/* Set video mode */
	screen = SDL_SetVideoMode(width, height, video_bpp, videoflags);
	if ( ! screen ) {
		fprintf(stderr, "Couldn't set %dx%d video mode: %s\n",
					width, height, SDL_GetError());
		quit(2);
	}

	/* Load the sprite */
	if ( LoadSprite(screen, "icon.bmp") < 0 ) {
		quit(1);
	}

	/* Allocate memory for the sprite info */
	mem = (Uint8 *)malloc(4*sizeof(SDL_Rect)*numsprites);
	if ( mem == NULL ) {
		SDL_FreeSurface(sprite);
		fprintf(stderr, "Out of memory!\n");
		quit(2);
	}
	sprite_rects = (SDL_Rect *)mem;
	positions = sprite_rects;
	sprite_rects += numsprites;
	velocities = sprite_rects;
	sprite_rects += numsprites;
	sprite_w = sprite->w;
	sprite_h = sprite->h;
	srand(time(NULL));
	for ( i=0; i<numsprites; ++i ) {
		positions[i].x = rand()%(screen->w - sprite_w);
		positions[i].y = rand()%(screen->h - sprite_h);
		positions[i].w = sprite->w;
		positions[i].h = sprite->h;
		velocities[i].x = 0;
		velocities[i].y = 0;
		while ( ! velocities[i].x && ! velocities[i].y ) {
			velocities[i].x = (rand()%(MAX_SPEED*2+1))-MAX_SPEED;
			velocities[i].y = (rand()%(MAX_SPEED*2+1))-MAX_SPEED;
		}
	}
	background = SDL_MapRGB(screen->format, 0x00, 0x00, 0x00);

	/* Print out information about our surfaces */
	printf("Screen is at %d bits per pixel\n",screen->format->BitsPerPixel);
	if ( (screen->flags & SDL_HWSURFACE) == SDL_HWSURFACE ) {
		printf("Screen is in video memory\n");
	} else {
		printf("Screen is in system memory\n");
	}
	if ( (screen->flags & SDL_DOUBLEBUF) == SDL_DOUBLEBUF ) {
		printf("Screen has double-buffering enabled\n");
	}
	if ( (sprite->flags & SDL_HWSURFACE) == SDL_HWSURFACE ) {
		printf("Sprite is in video memory\n");
	} else {
		printf("Sprite is in system memory\n");
	}
	/* Run a sample blit to trigger blit acceleration */
	{ SDL_Rect dst;
		dst.x = 0;
		dst.y = 0;
		dst.w = sprite->w;
		dst.h = sprite->h;
		SDL_BlitSurface(sprite, NULL, screen, &dst);
		SDL_FillRect(screen, &dst, background);
	}
	if ( (sprite->flags & SDL_HWACCEL) == SDL_HWACCEL ) {
		printf("Sprite blit uses hardware acceleration\n");
	}
	if ( (sprite->flags & SDL_RLEACCEL) == SDL_RLEACCEL ) {
		printf("Sprite blit uses RLE acceleration\n");
	}

	/* Loop, blitting sprites and waiting for a keystroke */
	frames = 0;
	then = SDL_GetTicks();
	done = 0;
	sprites_visible = 0;
	while ( !done ) {
		/* Check for events */
		++frames;
		while ( SDL_PollEvent(&event) ) {
			switch (event.type) {
				case SDL_MOUSEBUTTONDOWN:
					SDL_WarpMouse(screen->w/2, screen->h/2);
					break;
				case SDL_KEYDOWN:
					/* Any keypress quits the app... */
				case SDL_QUIT:
					done = 1;
					break;
				default:
					break;
			}
		}
		MoveSprites(screen, background);
	}
	SDL_FreeSurface(sprite);
	free(mem);

	/* Print out some timing information */
	now = SDL_GetTicks();
	if ( now > then ) {
		printf("%2.2f frames per second\n",
					((double)frames*1000)/(now-then));
	}
	SDL_Quit();
	return(0);
}