testbitmap.c
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/* Simple program: Test bitmap blits */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "SDL.h"
#include "picture.xbm"
SDL_Surface *LoadXBM(SDL_Surface *screen, int w, int h, Uint8 *bits)
{
SDL_Surface *bitmap;
Uint8 *line;
/* Allocate the bitmap */
bitmap = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 1, 0, 0, 0, 0);
if ( bitmap == NULL ) {
fprintf(stderr, "Couldn't allocate bitmap: %s\n",
SDL_GetError());
return(NULL);
}
/* Copy the pixels */
line = (Uint8 *)bitmap->pixels;
w = (w+7)/8;
while ( h-- ) {
memcpy(line, bits, w);
/* X11 Bitmap images have the bits reversed */
{ int i, j; Uint8 *buf, byte;
for ( buf=line, i=0; i<w; ++i, ++buf ) {
byte = *buf;
*buf = 0;
for ( j=7; j>=0; --j ) {
*buf |= (byte&0x01)<<j;
byte >>= 1;
}
}
}
line += bitmap->pitch;
bits += w;
}
return(bitmap);
}
int main(int argc, char *argv[])
{
SDL_Surface *screen;
SDL_Surface *bitmap;
Uint8 video_bpp;
Uint32 videoflags;
Uint8 *buffer;
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int i, k, done;
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SDL_Event event;
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Uint16 *buffer16;
Uint16 color;
Uint8 gradient;
SDL_Color palette[256];
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/* Initialize SDL */
if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
exit(1);
}
atexit(SDL_Quit);
video_bpp = 0;
videoflags = SDL_SWSURFACE;
while ( argc > 1 ) {
--argc;
if ( strcmp(argv[argc-1], "-bpp") == 0 ) {
video_bpp = atoi(argv[argc]);
--argc;
} else
if ( strcmp(argv[argc], "-warp") == 0 ) {
videoflags |= SDL_HWPALETTE;
} else
if ( strcmp(argv[argc], "-hw") == 0 ) {
videoflags |= SDL_HWSURFACE;
} else
if ( strcmp(argv[argc], "-fullscreen") == 0 ) {
videoflags |= SDL_FULLSCREEN;
} else {
fprintf(stderr,
"Usage: %s [-bpp N] [-warp] [-hw] [-fullscreen]\n",
argv[0]);
exit(1);
}
}
/* Set 640x480 video mode */
if ( (screen=SDL_SetVideoMode(640,480,video_bpp,videoflags)) == NULL ) {
fprintf(stderr, "Couldn't set 640x480x%d video mode: %s\n",
video_bpp, SDL_GetError());
exit(2);
}
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if (video_bpp==8) {
/* Set a gray colormap, reverse order from white to black */
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);
}
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/* Set the surface pixels and refresh! */
if ( SDL_LockSurface(screen) < 0 ) {
fprintf(stderr, "Couldn't lock the display surface: %s\n",
SDL_GetError());
exit(2);
}
buffer=(Uint8 *)screen->pixels;
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if (screen->format->BytesPerPixel!=2) {
for ( i=0; i<screen->h; ++i ) {
memset(buffer,(i*255)/screen->h, screen->pitch);
buffer += screen->pitch;
}
}
else
{
for ( i=0; i<screen->h; ++i ) {
gradient=((i*255)/screen->h);
color = SDL_MapRGB(screen->format, gradient, gradient, gradient);
buffer16=(Uint16*)buffer;
for (k=0; k<screen->w; k++)
{
*(buffer16+k)=color;
}
buffer += screen->pitch;
}
}
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SDL_UnlockSurface(screen);
SDL_UpdateRect(screen, 0, 0, 0, 0);
/* Load the bitmap */
bitmap = LoadXBM(screen, picture_width, picture_height,
(Uint8 *)picture_bits);
if ( bitmap == NULL ) {
exit(1);
}
/* Wait for a keystroke */
done = 0;
while ( !done ) {
/* Check for events */
while ( SDL_PollEvent(&event) ) {
switch (event.type) {
case SDL_MOUSEBUTTONDOWN: {
SDL_Rect dst;
dst.x = event.button.x - bitmap->w/2;
dst.y = event.button.y - bitmap->h/2;
dst.w = bitmap->w;
dst.h = bitmap->h;
SDL_BlitSurface(bitmap, NULL,
screen, &dst);
SDL_UpdateRects(screen,1,&dst);
}
break;
case SDL_KEYDOWN:
/* Any key press quits the app... */
done = 1;
break;
case SDL_QUIT:
done = 1;
break;
default:
break;
}
}
}
SDL_FreeSurface(bitmap);
return(0);
}