/**
* Draws a single star at x and y, using the LUM_N colors from offset c.
* The color offset must be the first of the set.
*
* Uses _putpixel(), so use with care. Don't call with invalid x/y values.
*/
void draw_star(BITMAP *buffer, int x, int y, int c) {
int a, b;
int center = LUM_N - 1;
// Center dot.
_putpixel(buffer, center + x, center + y, palette_color[c]);
// All other shades.
for (a = 1; a < LUM_N; ++a) {
_putpixel(buffer, center + x, center - a + y, palette_color[c + a]);
_putpixel(buffer, center + x, center + a + y, palette_color[c + a]);
_putpixel(buffer, center - a + x, center + y, palette_color[c + a]);
_putpixel(buffer, center + a + x, center + y, palette_color[c + a]);
}
}
int main (int argc, char **argv)
{
int gd, gm;
int col;
unsigned int seed;
long int counter;
float j, k, x, y, xx, xp, yp, r, xoffs, yoffs;
if (argc == 2)
seed = atoi (argv [1]); /* no checks! */
else {
printf ("Seed: ");
j = scanf ("%d", &seed);
}
srand (seed);
// random each time:
// srand (time(NULL));
gd = X11;
gm = getmaxmode ();
initgraph(&gd, &gm, "");
setbkcolor (BLACK);
cleardevice ();
setcolor (YELLOW);
outtextxy (0, 0, "Press a key or click to exit: ");
xoffs = getmaxx () / 2;
yoffs = getmaxy () / 3;
j = random (100);
k = random (100);
x = y = xx = xp = yp = r = 0.0;
col = 1; /* colours codes run from 0 (black) to 15 (white) */
counter = 0;
setcolor (col);
while (!kbhit () && !mouseclick ()) {
xx = y - sgn (x) * sqrt (abs (k * x - 1));
y = j - x;
x = xx;
xp = x * 2 + xoffs;
yp = y * 2 + yoffs;
_putpixel (xp, yp);
if (++counter == 20000) {
counter = 0;
col++;
if (col == 16)
col = 1;
}
setcolor (col);
}
closegraph ();
return 0;
}
void Bitmap::PutPixel(int x, int y, color_t color)
{
if (x < 0 || x >= _alBitmap->w || y < 0 || y >= _alBitmap->h)
{
return;
}
switch (bitmap_color_depth(_alBitmap))
{
case 8:
return _putpixel(_alBitmap, x, y, color);
case 15:
return _putpixel15(_alBitmap, x, y, color);
case 16:
return _putpixel16(_alBitmap, x, y, color);
case 24:
return _putpixel24(_alBitmap, x, y, color);
case 32:
return _putpixel32(_alBitmap, x, y, color);
}
assert(0); // this should not normally happen
return putpixel(_alBitmap, x, y, color);
}
void _line( int p_xStart, int p_yStart, int p_xEnd, int p_yEnd/*, int p_color*/ ) {
/** Draw line using Bresenham's line algorithm.
* author Zingl Alois
* code from http://members.chello.at/~easyfilter/bresenham.html */
int dx = abs( p_xEnd - p_xStart ), sx = p_xStart < p_xEnd ? 1 : -1;
int dy = -abs( p_yEnd - p_yStart ), sy = p_yStart < p_yEnd ? 1 : -1;
int err = dx + dy, e2; /* error value e_xy */
for ( ;; ) {
_putpixel( p_xStart, p_yStart/*, p_color*/ );
if ( p_xStart == p_xEnd && p_yStart == p_yEnd ) {
break;
}
e2 = 2 * err;
if ( e2 >= dy ) { /* e_xy + e_x > 0 */
err += dy; p_xStart += sx;
}
if ( e2 <= dx ) { /* e_xy + e_y < 0 */
err += dx; p_yStart += sy;
}
}
}
