* configure.ac:

+ Check for -lm.
  * examples/cacaplas.c:
    + New demo, cacaplas, that displays a colour plasma.

configure.ac

@@ -30,6 +30,7 @@ AC_ARG_ENABLE(x11,
 
 AC_CHECK_HEADERS(inttypes.h endian.h)
 AC_CHECK_FUNCS(vsnprintf getenv putenv strcasecmp usleep Sleep)
+AC_CHECK_LIB(m, sin, MATH_LIBS="${MATH_LIBS} -lm")
 
 CACA_DRIVERS="" 
 
@@ -120,6 +121,7 @@ else
   AC_MSG_RESULT([${CACA_DRIVERS}])
 fi
 
+AC_SUBST(MATH_LIBS)
 AC_SUBST(CACA_LIBS)
 
 # Optimizations

examples/Makefile.am

@@ -6,10 +6,10 @@ pkgdata_DATA = caca.txt
 
 EXTRA_DIST = caca.txt
 
-bin_PROGRAMS = cacademo cacafire cacaball cacaview
+bin_PROGRAMS = cacademo cacafire cacaball cacaplas cacaview
 
 cacademo_SOURCES = demo.c
-cacademo_LDADD = ../src/libcaca.a @CACA_LIBS@ -lm
+cacademo_LDADD = ../src/libcaca.a @CACA_LIBS@ @MATH_LIBS@
 cacademo_CPPFLAGS = -I$(top_srcdir)/src -DDATADIR=\"$(pkgdatadir)\"
 
 cacafire_SOURCES = aafire.c
@@ -17,9 +17,13 @@ cacafire_LDADD = ../src/libcaca.a @CACA_LIBS@
 cacafire_CPPFLAGS = -I$(top_srcdir)/src -DLIBCACA=1
 
 cacaball_SOURCES = cacaball.c
-cacaball_LDADD = ../src/libcaca.a @CACA_LIBS@
+cacaball_LDADD = ../src/libcaca.a @CACA_LIBS@ @MATH_LIBS@
 cacaball_CPPFLAGS = -I$(top_srcdir)/src
 
+cacaplas_SOURCES = cacaplas.c
+cacaplas_LDADD = ../src/libcaca.a @CACA_LIBS@ @MATH_LIBS@
+cacaplas_CPPFLAGS = -I$(top_srcdir)/src
+
 cacaview_SOURCES = cacaview.c
 cacaview_LDADD = ../src/libcaca.a @CACA_LIBS@
 cacaview_CPPFLAGS = -I$(top_srcdir)/src -DX_DISPLAY_MISSING=1

examples/cacaplas.c

@@ -0,0 +1,140 @@
+/*
+ *  cacaplas      plasma effect for libcaca
+ *  Copyright (c) 2004 Sam Hocevar <sam@zoy.org>
+ *                1998 Bini Michele <mibin@tin.it>
+ *                All Rights Reserved
+ *
+ *  $Id$
+ *
+ *  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 <math.h>
+
+#ifndef M_PI
+#   define M_PI 3.14159265358979323846
+#endif
+
+#include "caca.h"
+
+/* Virtual buffer size */
+#define XSIZ 256
+#define YSIZ 256
+
+#define TABLEX (XSIZ * 2)
+#define TABLEY (YSIZ * 2)
+
+static unsigned char screen[XSIZ * YSIZ];
+static unsigned char table[TABLEX * TABLEY];
+
+static void do_plasma(unsigned char *,
+                      double, double, double, double, double, double);
+
+int main (int argc, char **argv)
+{
+    int red[256], green[256], blue[256], alpha[256];
+    double r[3], R[6];
+    struct caca_bitmap *bitmap;
+    int i, x, y, frame;
+
+    if(caca_init() < 0)
+        return 1;
+
+    caca_set_delay(10000);
+
+    /* Fill various tables */
+    for(i = 0 ; i < 256; i++)
+        red[i] = green[i] = blue[i] = alpha[i] = 0;
+
+    for(i = 0; i < 3; i++)
+        r[i] = (double)(caca_rand(1, 1000)) / 30000 * M_PI;
+
+    for(i = 0; i < 6; i++)
+        R[i] = (double)(caca_rand(1, 1000)) / 5000;
+
+    for(y = 0 ; y < TABLEY ; y++)
+        for(x = 0 ; x < TABLEX ; x++)
+    {
+        double tmp = (((double)((x - (TABLEX / 2)) * (x - (TABLEX / 2))
+                              + (y - (TABLEX / 2)) * (y - (TABLEX / 2))))
+                      * (M_PI / (TABLEX * TABLEX + TABLEY * TABLEY)));
+
+        table[x + y * TABLEX] = (1.0 + sin(12.0 * sqrt(tmp))) * 256 / 6;
+    }
+
+    /* Create a libcaca bitmap */
+    bitmap = caca_create_bitmap(8, XSIZ, YSIZ, XSIZ, 0, 0, 0, 0);
+
+    /* Main loop */
+    for(frame = 0; !caca_get_event(CACA_EVENT_KEY_PRESS); frame++)
+    {
+        for(i = 0 ; i < 256; i++)
+        {
+            double z = ((double)i) / 256 * 6 * M_PI;
+
+            red[i] = (1.0 + cos(z + r[0] * frame)) / 2 * 0xfff;
+            green[i] = (1.0 + sin(z + r[1] * frame)) / 2 * 0xfff;
+            blue[i] = (1.0 + cos(z + r[2] * frame)) / 2 * 0xfff;
+        }
+
+        /* Set the palette */
+        caca_set_bitmap_palette(bitmap, red, green, blue, alpha);
+
+        do_plasma(screen,
+                  (1.0 + sin(((double)frame) * R[0])) / 2,
+                  (1.0 + sin(((double)frame) * R[1])) / 2,
+                  (1.0 + sin(((double)frame) * R[2])) / 2,
+                  (1.0 + sin(((double)frame) * R[3])) / 2,
+                  (1.0 + sin(((double)frame) * R[4])) / 2,
+                  (1.0 + sin(((double)frame) * R[5])) / 2);
+
+        caca_draw_bitmap(0, 0, caca_get_width() - 1, caca_get_height() - 1,
+                         bitmap, screen);
+        caca_refresh();
+    }
+
+    caca_free_bitmap(bitmap);
+    caca_end();
+
+    return 0;
+}
+
+static void do_plasma(unsigned char *pixels, double x_1, double y_1,
+                      double x_2, double y_2, double x_3, double y_3)
+{
+    unsigned int X1 = x_1 * (TABLEX / 2),
+                 Y1 = y_1 * (TABLEY / 2),
+                 X2 = x_2 * (TABLEX / 2),
+                 Y2 = y_2 * (TABLEY / 2),
+                 X3 = x_3 * (TABLEX / 2),
+                 Y3 = y_3 * (TABLEY / 2);
+    unsigned int y;
+    unsigned char * t1 = table + X1 + Y1 * TABLEX,
+                  * t2 = table + X2 + Y2 * TABLEX,
+                  * t3 = table + X3 + Y3 * TABLEX;
+
+    for(y = 0; y < YSIZ; y++)
+    {
+        unsigned int x;
+        unsigned char * tmp = pixels + y * YSIZ;
+        unsigned int ty = y * TABLEX, tmax = ty + XSIZ;
+        for(x = 0; ty < tmax; ty++, tmp++)
+            tmp[0] = t1[ty] + t2[ty] + t3[ty];
+    }
+}
+