#define WIDTH 800
#define HEIGHT 600
+#include <stdio.h>
+#include <stdlib.h>
#include <SDL.h>
#include <SDL_image.h>
+#define SWAP(x, y) do { \
+ x ^= y; y ^= x; x ^= y; \
+ } while (0)
+
+#define ABS(x) ((x) < 0 ? -(x) : (x))
+
#define IS_CENTER(cx, cy, x, y) \
((x + WIDTH/2 == cx) && (y + HEIGHT/2 == cy))
-SDL_Rect points[] = {
- {400, 300, 800, 600},
- {450, 350, 800, 600}
-};
+SDL_Rect *points;
+int psize;
+
+void
+ReadPoints (char *filename)
+{
+ FILE *file;
+ char *buffer;
+ char *next;
+ size_t len;
+ int i;
+ file = fopen (filename, "r");
+ fscanf (file, "%d\n", &psize);
+ points = malloc (sizeof (SDL_Rect) * psize);
+ if (points == NULL)
+ abort ();
+ buffer = NULL;
+ len = 0;
+ for (i = 0; i < psize; i++)
+ {
+ getline (&buffer, &len, file);
+ points[i].x = strtol (buffer, &next, 0);
+ points[i].y = strtol (next+1, NULL, 0);
+ }
+ fclose (file);
+}
SDL_Rect *
GetNextPoint (void)
{
static SDL_Rect rect = {0, 0, WIDTH, HEIGHT};
- static int cur = 0;
- int dx, dy;
+ static int cur = -1;
+ static int inc, err, thre, swap;
+ static int x1, y1, x2, y2;
+ static int x, y;
int next;
- next = (cur + 1) % (sizeof (points) / sizeof (SDL_Rect));
- if (IS_CENTER (points[next].x, points[next].y, rect.x, rect.y))
+ next = (cur + 1) % psize;
+ if (IS_CENTER (points[next].x, points[next].y, rect.x, rect.y) || cur == -1)
{
cur = next;
- next = (cur + 1) % (sizeof (points) / sizeof (SDL_Rect));
+ next = (cur + 1) % psize;
+ err = 0;
+ swap = 0;
+ x1 = points[cur].x;
+ y1 = points[cur].y;
+ x2 = points[next].x;
+ y2 = points[next].y;
+ inc = y2 - y1;
+ thre = x2 - x1;
+ if (ABS (inc) > ABS (thre))
+ {
+ SWAP (inc, thre);
+ SWAP (x1, y1);
+ SWAP (x2, y2);
+ swap = 1;
+ }
+ x = x1;
+ y = y1;
+ }
+ rect.x = (swap ? y : x) - WIDTH/2;
+ rect.y = (swap ? x : y) - HEIGHT/2;
+ (x2 < x1) ? x-- : x++;
+ err += ABS (inc);
+ if (err >= ABS (thre))
+ {
+ err -= ABS (thre);
+ y += (inc < 0) ? -1 : 1;
}
- dx = (points[next].x > points[cur].x) ? 1 : -1;
- dy = (points[next].y > points[cur].y) ? 1 : -1;
- rect.x = (rect.x + dx) % WIDTH;
- rect.y = (rect.y + dy) % HEIGHT;
return ▭
}
SDL_Surface *screen;
SDL_Surface *image;
SDL_Event event;
+ ReadPoints ("pro-gnu");
SDL_Init (SDL_INIT_VIDEO | SDL_INIT_TIMER);
- screen = SDL_SetVideoMode (800, 600, 32, SDL_HWSURFACE | SDL_DOUBLEBUF | SDL_FULLSCREEN);
+ screen = SDL_SetVideoMode (800, 600, 32, SDL_HWSURFACE | SDL_DOUBLEBUF);
image = IMG_Load ("/home/cascardo/fotos/debconf.jpg");
SDL_AddTimer (0, ShowNext, NULL);
while (SDL_WaitEvent (&event))
}
SDL_FreeSurface (image);
SDL_Quit ();
+ free (points);
return 0;
}