/* 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 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;

int debug_flip;

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(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;

}

}

/* 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;

debug_flip = 0;

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], "-debugflip") == 0 ) {

debug_flip ^= 1;

} 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("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);

}