graywin.c
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/* Simple program: Fill a colormap with gray and stripe it down the screen */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "SDL.h"
#ifdef TEST_VGA16 /* Define this if you want to test VGA 16-color video modes */
#define NUM_COLORS 16
#else
#define NUM_COLORS 256
#endif
/* Draw a randomly sized and colored box centered about (X,Y) */
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void DrawBox(SDL_Surface *screen, int X, int Y, int width, int height)
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{
static unsigned int seeded = 0;
SDL_Rect area;
Uint32 color;
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Uint32 randc;
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/* Seed the random number generator */
if ( seeded == 0 ) {
srand(time(NULL));
seeded = 1;
}
/* Get the bounds of the rectangle */
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area.w = (rand()%width);
area.h = (rand()%height);
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area.x = X-(area.w/2);
area.y = Y-(area.h/2);
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randc = (rand()%NUM_COLORS);
if (screen->format->BytesPerPixel==1)
{
color = randc;
}
else
{
color = SDL_MapRGB(screen->format, randc, randc, randc);
}
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/* Do it! */
SDL_FillRect(screen, &area, color);
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if ( screen->flags & SDL_DOUBLEBUF ) {
SDL_Flip(screen);
} else {
SDL_UpdateRects(screen, 1, &area);
}
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}
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void DrawBackground(SDL_Surface *screen)
{
int i, j, k;
Uint8 *buffer;
Uint16 *buffer16;
Uint16 color;
Uint8 gradient;
/* Set the surface pixels and refresh! */
/* Use two loops in case the surface is double-buffered (both sides) */
for ( j=0; j<2; ++j ) {
if ( SDL_LockSurface(screen) < 0 ) {
fprintf(stderr, "Couldn't lock display surface: %s\n",
SDL_GetError());
return;
}
buffer = (Uint8 *)screen->pixels;
if (screen->format->BytesPerPixel!=2) {
for ( i=0; i<screen->h; ++i ) {
memset(buffer,(i*(NUM_COLORS-1))/screen->h, screen->w * screen->format->BytesPerPixel);
buffer += screen->pitch;
}
}
else
{
for ( i=0; i<screen->h; ++i ) {
gradient=((i*(NUM_COLORS-1))/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;
}
}
SDL_UnlockSurface(screen);
if ( screen->flags & SDL_DOUBLEBUF ) {
SDL_Flip(screen);
} else {
SDL_UpdateRect(screen, 0, 0, 0, 0);
break;
}
}
}
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SDL_Surface *CreateScreen(Uint16 w, Uint16 h, Uint8 bpp, Uint32 flags)
{
SDL_Surface *screen;
int i;
SDL_Color palette[NUM_COLORS];
/* Set the video mode */
screen = SDL_SetVideoMode(w, h, bpp, flags);
if ( screen == NULL ) {
fprintf(stderr, "Couldn't set display mode: %s\n",
SDL_GetError());
return(NULL);
}
fprintf(stderr, "Screen is in %s mode\n",
(screen->flags & SDL_FULLSCREEN) ? "fullscreen" : "windowed");
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if (bpp==8) {
/* Set a gray colormap, reverse order from white to black */
for ( i=0; i<NUM_COLORS; ++i ) {
palette[i].r = (NUM_COLORS-1)-i * (256 / NUM_COLORS);
palette[i].g = (NUM_COLORS-1)-i * (256 / NUM_COLORS);
palette[i].b = (NUM_COLORS-1)-i * (256 / NUM_COLORS);
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SDL_SetColors(screen, palette, 0, NUM_COLORS);
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}
return(screen);
}
int main(int argc, char *argv[])
{
SDL_Surface *screen;
Uint32 videoflags;
int done;
SDL_Event event;
int width, height, bpp;
/* Initialize SDL */
if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
exit(1);
}
/* See if we try to get a hardware colormap */
width = 640;
height = 480;
bpp = 8;
videoflags = SDL_SWSURFACE;
while ( argc > 1 ) {
--argc;
if ( argv[argc-1] && (strcmp(argv[argc-1], "-width") == 0) ) {
width = atoi(argv[argc]);
--argc;
} else
if ( argv[argc-1] && (strcmp(argv[argc-1], "-height") == 0) ) {
height = atoi(argv[argc]);
--argc;
} else
if ( argv[argc-1] && (strcmp(argv[argc-1], "-bpp") == 0) ) {
bpp = atoi(argv[argc]);
--argc;
} else
if ( argv[argc] && (strcmp(argv[argc], "-hw") == 0) ) {
videoflags |= SDL_HWSURFACE;
} else
if ( argv[argc] && (strcmp(argv[argc], "-hwpalette") == 0) ) {
videoflags |= SDL_HWPALETTE;
} else
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if ( argv[argc] && (strcmp(argv[argc], "-flip") == 0) ) {
videoflags |= SDL_DOUBLEBUF;
} else
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if ( argv[argc] && (strcmp(argv[argc], "-noframe") == 0) ) {
videoflags |= SDL_NOFRAME;
} else
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if ( argv[argc] && (strcmp(argv[argc], "-resize") == 0) ) {
videoflags |= SDL_RESIZABLE;
} else
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if ( argv[argc] && (strcmp(argv[argc], "-fullscreen") == 0) ) {
videoflags |= SDL_FULLSCREEN;
} else {
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fprintf(stderr, "Usage: %s [-width] [-height] [-bpp] [-hw] [-hwpalette] [-flip] [-noframe] [-fullscreen] [-resize]\n",
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argv[0]);
exit(1);
}
}
/* Set a video mode */
screen = CreateScreen(width, height, bpp, videoflags);
if ( screen == NULL ) {
exit(2);
}
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DrawBackground(screen);
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/* Wait for a keystroke */
done = 0;
while ( !done && SDL_WaitEvent(&event) ) {
switch (event.type) {
case SDL_MOUSEBUTTONDOWN:
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DrawBox(screen, event.button.x, event.button.y, width, height);
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break;
case SDL_KEYDOWN:
/* Ignore ALT-TAB for windows */
if ( (event.key.keysym.sym == SDLK_LALT) ||
(event.key.keysym.sym == SDLK_TAB) ) {
break;
}
/* Center the mouse on <SPACE> */
if ( event.key.keysym.sym == SDLK_SPACE ) {
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SDL_WarpMouse(width/2, height/2);
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break;
}
/* Toggle fullscreen mode on <RETURN> */
if ( event.key.keysym.sym == SDLK_RETURN ) {
videoflags ^= SDL_FULLSCREEN;
screen = CreateScreen(
screen->w, screen->h,
screen->format->BitsPerPixel,
videoflags);
if ( screen == NULL ) {
fprintf(stderr,
"Couldn't toggle fullscreen mode\n");
done = 1;
}
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DrawBackground(screen);
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break;
}
/* Any other key quits the application... */
case SDL_QUIT:
done = 1;
break;
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case SDL_VIDEOEXPOSE:
DrawBackground(screen);
break;
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case SDL_VIDEORESIZE:
screen = CreateScreen(
event.resize.w, event.resize.h,
screen->format->BitsPerPixel,
videoflags);
if ( screen == NULL ) {
fprintf(stderr,
"Couldn't resize video mode\n");
done = 1;
}
DrawBackground(screen);
break;
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default:
break;
}
}
SDL_Quit();
return(0);
}