This repository has been archived by the owner on Feb 11, 2021. It is now read-only.
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"
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#ifdef TEST_VGA16 /* Define this if you want to test VGA 16-color video modes */
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#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;
Uint32 randc;
/* Seed the random number generator */
if (seeded == 0) {
srand(time(NULL));
seeded = 1;
}
/* Get the bounds of the rectangle */
area.w = (rand() % width);
area.h = (rand() % height);
area.x = X - (area.w / 2);
area.y = Y - (area.h / 2);
randc = (rand() % NUM_COLORS);
if (screen->format->BytesPerPixel == 1) {
color = randc;
} else {
color = SDL_MapRGB(screen->format, randc, randc, randc);
}
/* Do it! */
SDL_FillRect(screen, &area, color);
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)
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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;
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buffer += screen->pitch;
}
}
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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)
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{
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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");
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);
}
SDL_SetColors(screen, palette, 0, NUM_COLORS);
}
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return (screen);
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}
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int
main(int argc, char *argv[])
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{
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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 if (argv[argc] && (strcmp(argv[argc], "-flip") == 0)) {
videoflags |= SDL_DOUBLEBUF;
} else if (argv[argc] && (strcmp(argv[argc], "-noframe") == 0)) {
videoflags |= SDL_NOFRAME;
} else if (argv[argc] && (strcmp(argv[argc], "-resize") == 0)) {
videoflags |= SDL_RESIZABLE;
} else if (argv[argc] && (strcmp(argv[argc], "-fullscreen") == 0)) {
videoflags |= SDL_FULLSCREEN;
} else {
fprintf(stderr,
"Usage: %s [-width] [-height] [-bpp] [-hw] [-hwpalette] [-flip] [-noframe] [-fullscreen] [-resize]\n",
argv[0]);
exit(1);
}
}
/* Set a video mode */
screen = CreateScreen(width, height, bpp, videoflags);
if (screen == NULL) {
exit(2);
}
DrawBackground(screen);
/* Wait for a keystroke */
done = 0;
while (!done && SDL_WaitEvent(&event)) {
switch (event.type) {
case SDL_MOUSEBUTTONDOWN:
DrawBox(screen, event.button.x, event.button.y, width, height);
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) {
SDL_WarpMouse(width / 2, height / 2);
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;
}
DrawBackground(screen);
break;
}
/* Any other key quits the application... */
case SDL_QUIT:
done = 1;
break;
case SDL_VIDEOEXPOSE:
DrawBackground(screen);
break;
case SDL_VIDEORESIZE:
printf("Screen resized to %dx%d\n", event.resize.w,
event.resize.h);
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;
default:
break;
}
}
SDL_Quit();
return (0);
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}