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http://ftp.x.org/contrib/applications/xscreensaver-2.34.tar.gz
[xscreensaver] / hacks / distort.c
diff --git a/hacks/distort.c b/hacks/distort.c
index a18df51bc598dd5948957b6fa4538b8ce8543293..4a0bdc8e0477c7e53a29471d195a2d5b7a4cb217 100644 (file)
--- a/hacks/distort.c
+++ b/hacks/distort.c
@@ -41,11 +41,12 @@ struct coo {
 };
 static struct coo xy_coo[10];
 
-static int delay, radius, speed, number, blackhole, vortex, magnify;
+static int delay, radius, speed, number, blackhole, vortex, magnify, reflect;
 static XWindowAttributes xgwa;
 static GC gc;
 static Window g_window;
-static Display *g_dpy; 
+static Display *g_dpy;
+static unsigned long black_pixel;
 
 static XImage *orig_map, *buffer_map;
 
@@ -78,14 +79,15 @@ static void init_distort(Display *dpy, Window window)
        blackhole = get_boolean_resource("blackhole", "Boolean");
        vortex = get_boolean_resource("vortex", "Boolean");
        magnify = get_boolean_resource("magnify", "Boolean");
+       reflect = get_boolean_resource("reflect", "Boolean");
        
        if (get_boolean_resource ("swamp", "Boolean"))
                effect = &swamp_thing;
-       if (get_boolean_resource ("bounce", "Boolean"))
+       if (get_boolean_resource ("bounce", "Boolean") || reflect)
                effect = &move_lense;
 
        if (effect == NULL && radius == 0 && speed == 0 && number == 0
-               && !blackhole && !vortex && !magnify) {
+               && !blackhole && !vortex && !magnify && !reflect) {
 /* if no cmdline options are given, randomly choose one of:
  * -radius 50 -number 4 -speed 1 -bounce
  * -radius 50 -number 4 -speed 1 -blackhole
@@ -170,6 +172,7 @@ static void init_distort(Display *dpy, Window window)
                effect = &move_lense;
 
        XGetWindowAttributes (dpy, window, &xgwa);
+       black_pixel = BlackPixelOfScreen( xgwa.screen );
 
        gcv.function = GXcopy;
        gcv.subwindow_mode = IncludeInferiors;
@@ -240,12 +243,16 @@ static void init_distort(Display *dpy, Window window)
 static void make_round_lense(int radius, int loop)
 {
        int i, j;
+       double theta;
 
        for (i = 0; i < 2*radius+speed+2; i++) {
                for(j = 0; j < 2*radius+speed+2; j++) {
                        double r, d;
                        r = sqrt ((i-radius)*(i-radius)+(j-radius)*(j-radius));
-                       d=r/loop;
+                       if (loop == 0)
+                         d=0.0;
+                       else
+                         d=r/loop;
 
                        if (r < loop-1) {
 
@@ -256,12 +263,18 @@ static void make_round_lense(int radius, int loop)
                 * Copyright (C) 1996 Federico Mena Quintero
                 */
                /* 2.5 is just a constant used because it looks good :) */
-                                       angle = 2.5*(1-r/loop)*(1-r/loop);
+                                       angle = 2.5*(1-d)*(1-d);
 
-                                       from[i][j][0] = radius + cos(angle -
-                                               atan2(radius-j,-(radius-i)))*r;
-                                       from[i][j][1] = radius + sin(angle -
-                                               atan2(radius-j,-(radius-i)))*r;
+
+        /* Avoid atan2: DOMAIN error message */
+        if ((radius-j) == 0.0 && (radius-i) == 0.0)
+            theta = 0.0;
+        else
+            theta = atan2(radius-j, radius-i);
+        from[i][j][0] = radius +
+                        cos(angle - theta)*r;
+        from[i][j][1] = radius +
+                        sin(angle - theta)*r;
 
                                        if (magnify) {
                                                r = sin(d*M_PI_2);
@@ -291,6 +304,10 @@ static void make_round_lense(int radius, int loop)
        }
 }
 
+#ifndef EXIT_FAILURE
+# define EXIT_FAILURE -1
+#endif
+
 static void allocate_lense(void)
 {
        int i, j;
@@ -346,16 +363,51 @@ static void init_round_lense(void)
 void draw(int k)
 {
        int i, j;
+       int     cx, cy;
+       int     ly, lysq, lx, ny, dist, rsq = radius * radius;
+       if (reflect) {
+               cx = cy = radius;
+               if (xy_coo[k].ymove > 0)
+                       cy += speed;
+               if (xy_coo[k].xmove > 0)
+                       cx += speed;
+       }
        for(i = 0 ; i < 2*radius+speed+2; i++) {
+               if (reflect) {
+                       ly = i - cy;
+                       lysq = ly * ly;
+                       ny = xy_coo[k].y + i;
+               }
                for(j = 0 ; j < 2*radius+speed+2 ; j++) {
-                       if (xy_coo[k].x+from[i][j][0] >= 0 &&
-                                       xy_coo[k].x+from[i][j][0] < xgwa.width &&
-                                       xy_coo[k].y+from[i][j][1] >= 0 &&
-                                       xy_coo[k].y+from[i][j][1] < xgwa.height)
+                       if (reflect) {
+                               lx = j - cx;
+                               dist = lx * lx + lysq;
+                               if (dist > rsq ||
+                                       ly < -radius || ly > radius ||
+                                       lx < -radius || lx > radius)
+                                       XPutPixel( buffer_map, j, i,
+                                                          XGetPixel( orig_map, xy_coo[k].x + j, ny ));
+                               else if (dist == 0)
+                                       XPutPixel( buffer_map, j, i, black_pixel );
+                               else {
+                                       int     x = xy_coo[k].x + cx + (lx * rsq / dist);
+                                       int     y = xy_coo[k].y + cy + (ly * rsq / dist);
+                                       if (x < 0 || x > xgwa.width ||
+                                               y < 0 || y > xgwa.height)
+                                               XPutPixel( buffer_map, j, i, black_pixel );
+                                       else
+                                               XPutPixel( buffer_map, j, i,
+                                                                  XGetPixel( orig_map, x, y ));
+                               }
+                       } else if (xy_coo[k].x+from[i][j][0] >= 0 &&
+                                          xy_coo[k].x+from[i][j][0] < xgwa.width &&
+                                          xy_coo[k].y+from[i][j][1] >= 0 &&
+                                          xy_coo[k].y+from[i][j][1] < xgwa.height) {
                                XPutPixel(buffer_map, i, j,
-                                               XGetPixel(orig_map,
-                                                       xy_coo[k].x+from[i][j][0],
-                                                       xy_coo[k].y+from[i][j][1]));
+                                                 XGetPixel(orig_map,
+                                                                       xy_coo[k].x+from[i][j][0],
+                                                                       xy_coo[k].y+from[i][j][1]));
+                       }
                }
        }
 
@@ -391,11 +443,11 @@ static void move_lense(int k)
 {
        int i;
 
-       if (xy_coo[k].x + 4*radius/2 >= xgwa.width)
+       if (xy_coo[k].x + 2*radius + speed + 2 >= xgwa.width)
                xy_coo[k].xmove = -abs(xy_coo[k].xmove);
        if (xy_coo[k].x <= speed) 
                xy_coo[k].xmove = abs(xy_coo[k].xmove);
-       if (xy_coo[k].y + 4*radius/2 >= xgwa.height)
+       if (xy_coo[k].y + 2*radius + speed + 2 >= xgwa.height)
                xy_coo[k].ymove = -abs(xy_coo[k].ymove);
        if (xy_coo[k].y <= speed)
                xy_coo[k].ymove = abs(xy_coo[k].ymove);
@@ -471,6 +523,7 @@ char *defaults [] = {
        "*magnify:                      False",
        "*swamp:                        False",
        "*bounce:                       False",
+       "*reflect:                      False",
        "*blackhole:            False",
 #ifdef HAVE_XSHM_EXTENSION
        "*useSHM:                       False",         /* xshm turns out not to help. */
@@ -485,6 +538,7 @@ XrmOptionDescRec options [] = {
        { "-number",    ".number",      XrmoptionSepArg, 0 },
        { "-swamp",     ".swamp",       XrmoptionNoArg, "True" },
        { "-bounce",    ".bounce",      XrmoptionNoArg, "True" },
+       { "-reflect",   ".reflect",     XrmoptionNoArg, "True" },
        { "-vortex",    ".vortex",      XrmoptionNoArg, "True" },
        { "-magnify",   ".magnify",     XrmoptionNoArg, "True" },
        { "-blackhole", ".blackhole",   XrmoptionNoArg, "True" },
Archive of old xscreensaver versions (http://www.jwz.org/xscreensaver/)