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/*
* cacaball metaballs effect for libcaca
* Copyright (c) 2003-2004 Jean-Yves Lamoureux <jylam@lnxscene.org>
* All Rights Reserved
*
* $Id: cacaball.c 236 2004-01-12 14:25:46Z sam $
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
* 02111-1307 USA
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#ifndef M_PI
# define M_PI 3.14159265358979323846
#endif
#include "caca.h"
/* Virtual buffer size */
#define XSIZ 256
#define YSIZ 256
#define METASIZE 100
#define METABALLS 16
/* Colour index where to crop balls */
#define CROPBALL 160
static void create_ball(void);
static void draw_ball(unsigned int, unsigned int);
static unsigned char pixels[XSIZ * YSIZ];
static unsigned char metaball[METASIZE * METASIZE];
int main(int argc, char **argv)
{
int r[256], g[256], b[256], a[256];
float d[METABALLS], di[METABALLS], dj[METABALLS], dk[METABALLS];
unsigned int x[METABALLS], y[METABALLS];
struct caca_bitmap *caca_bitmap;
float i = 10.0, j = 17.0, k = 11.0;
int p, frame = 0;
if(caca_init())
return 1;
caca_set_delay(20000);
/* Make the palette eatable by libcaca */
for(p = 0; p < 256; p++)
r[p] = g[p] = b[p] = a[p] = 0x0;
r[255] = g[255] = b[255] = 0xfff;
/* Create a libcaca bitmap smaller than our pixel buffer, so that we
* display only the interesting part of it */
caca_bitmap = caca_create_bitmap(8, XSIZ - METASIZE, YSIZ - METASIZE,
XSIZ, 0, 0, 0, 0);
/* Generate ball sprite */
create_ball();
for(p = 0; p < METABALLS; p++)
{
d[p] = caca_rand(0, 100);
di[p] = (float)caca_rand(500, 4000) / 6000.0;
dj[p] = (float)caca_rand(500, 4000) / 6000.0;
dk[p] = (float)caca_rand(500, 4000) / 6000.0;
}
/* Go ! */
while(!caca_get_event(CACA_EVENT_KEY_PRESS))
{
frame++;
/* Crop the palette */
for(p = CROPBALL; p < 255; p++)
{
int t1, t2, t3;
t1 = p < 0x40 ? 0 : p < 0xc0 ? (p - 0x40) * 0x20 : 0xfff;
t2 = p < 0xe0 ? 0 : (p - 0xe0) * 0x80;
t3 = p < 0x40 ? p * 0x40 : 0xfff;
r[p] = (1.0 + sin((double)frame * M_PI / 60)) * t1 / 4
+ (1.0 + sin((double)(frame + 40) * M_PI / 60)) * t2 / 4
+ (1.0 + sin((double)(frame + 80) * M_PI / 60)) * t3 / 4;
g[p] = (1.0 + sin((double)frame * M_PI / 60)) * t2 / 4
+ (1.0 + sin((double)(frame + 40) * M_PI / 60)) * t3 / 4
+ (1.0 + sin((double)(frame + 80) * M_PI / 60)) * t1 / 4;
b[p] = (1.0 + sin((double)frame * M_PI / 60)) * t3 / 4
+ (1.0 + sin((double)(frame + 40) * M_PI / 60)) * t1 / 4
+ (1.0 + sin((double)(frame + 80) * M_PI / 60)) * t2 / 4;
}
/* Set the palette */
caca_set_bitmap_palette(caca_bitmap, r, g, b, a);
/* Silly paths for our balls */
for(p = 0; p < METABALLS; p++)
{
float u = di[p] * i + dj[p] * j + dk[p] * sin(di[p] * k);
float v = d[p] + di[p] * j + dj[p] * k + dk[p] * sin(dk[p] * i);
u = sin(i + u * 2.1) * (1.0 + sin(u));
v = sin(j + v * 1.9) * (1.0 + sin(v));
x[p] = (XSIZ - METASIZE) / 2 + u * (XSIZ - METASIZE) / 4;
y[p] = (YSIZ - METASIZE) / 2 + v * (YSIZ - METASIZE) / 4;
}
i += 0.011;
j += 0.017;
k += 0.019;
memset(pixels, 0, XSIZ * YSIZ);
/* Here is all the trick. Maybe if you're that
* clever you'll understand. */
for(p = 0; p < METABALLS; p++)
draw_ball(x[p], y[p]);
/* Draw our virtual buffer to screen, letting libcaca resize it */
caca_draw_bitmap(0, 0, caca_get_width() - 1, caca_get_height() - 1,
caca_bitmap, pixels + (METASIZE / 2) * (1 + XSIZ));
caca_refresh();
}
/* End, bye folks */
caca_end();
return 0;
}
/* Generate ball sprite
* You should read the comments, I already wrote that before ... */
static void create_ball(void)
{
int x, y;
float distance;
for(y = 0; y < METASIZE; y++)
for(x = 0; x < METASIZE; x++)
{
distance = ((METASIZE/2) - x) * ((METASIZE/2) - x)
+ ((METASIZE/2) - y) * ((METASIZE/2) - y);
distance = sqrt(distance) * 64 / METASIZE;
metaball[x + y * METASIZE] = distance > 15 ? 0 : (255 - distance) * 15;
}
}
/* You missed the trick ? */
static void draw_ball(unsigned int bx, unsigned int by)
{
unsigned int color;
unsigned int i, e = 0;
unsigned int b = (by * XSIZ) + bx;
for(i = 0; i < METASIZE * METASIZE; i++)
{
color = pixels[b] + metaball[i];
if(color > 255)
color = 255;
pixels[b] = color;
if(e == METASIZE)
{
e = 0;
b += XSIZ - METASIZE;
}
b++;
e++;
}
}
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