testsprite.c
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/* 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 <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;
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Uint16 sprite_w, sprite_h;
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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;
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if ( (position->x < 0) || (position->x >= (screen->w - sprite_w)) ) {
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velocity->x = -velocity->x;
position->x += velocity->x;
}
position->y += velocity->y;
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if ( (position->y < 0) || (position->y >= (screen->h - sprite_w)) ) {
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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;
}
/* 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 */
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Uint32 FastestFlags(Uint32 flags, int width, int height, int bpp)
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{
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.
*/
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if ( info->video_mem*1024 > (height*width*bpp/8) ) {
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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());
exit(1);
}
atexit(SDL_Quit);
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 ) {
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videoflags = FastestFlags(videoflags, width, height, video_bpp);
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} 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]);
exit(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());
exit(2);
}
/* Load the sprite */
if ( LoadSprite(screen, "icon.bmp") < 0 ) {
exit(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");
exit(2);
}
sprite_rects = (SDL_Rect *)mem;
positions = sprite_rects;
sprite_rects += numsprites;
velocities = sprite_rects;
sprite_rects += numsprites;
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sprite_w = sprite->w;
sprite_h = sprite->h;
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srand(time(NULL));
for ( i=0; i<numsprites; ++i ) {
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positions[i].x = rand()%(screen->w - sprite_w);
positions[i].y = rand()%(screen->h - sprite_h);
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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_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));
}
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SDL_Quit();
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return(0);
}