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author | Simon Rettberg | 2018-10-16 10:08:48 +0200 |
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committer | Simon Rettberg | 2018-10-16 10:08:48 +0200 |
commit | d3a98cf6cbc3bd0b9efc570f58e8812c03931c18 (patch) | |
tree | cbddf8e50f35a9c6e878a5bfe3c6d625d99e12ba /hacks/lightning.c | |
download | xscreensaver-d3a98cf6cbc3bd0b9efc570f58e8812c03931c18.tar.gz xscreensaver-d3a98cf6cbc3bd0b9efc570f58e8812c03931c18.tar.xz xscreensaver-d3a98cf6cbc3bd0b9efc570f58e8812c03931c18.zip |
Original 5.40
Diffstat (limited to 'hacks/lightning.c')
-rw-r--r-- | hacks/lightning.c | 601 |
1 files changed, 601 insertions, 0 deletions
diff --git a/hacks/lightning.c b/hacks/lightning.c new file mode 100644 index 0000000..027bc75 --- /dev/null +++ b/hacks/lightning.c @@ -0,0 +1,601 @@ +/* -*- Mode: C; tab-width: 4 -*- */ +/* lightning --- fractal lightning bolds */ + +#if 0 +static const char sccsid[] = "@(#)lightning.c 5.00 2000/11/01 xlockmore"; +#endif + +/*- + * Copyright (c) 1996 by Keith Romberg <kromberg@saxe.com> + * + * Permission to use, copy, modify, and distribute this software and its + * documentation for any purpose and without fee is hereby granted, + * provided that the above copyright notice appear in all copies and that + * both that copyright notice and this permission notice appear in + * supporting documentation. + * + * This file is provided AS IS with no warranties of any kind. The author + * shall have no liability with respect to the infringement of copyrights, + * trade secrets or any patents by this file or any part thereof. In no + * event will the author be liable for any lost revenue or profits or + * other special, indirect and consequential damages. + * + * Revision History: + * 01-Nov-2000: Allocation checks + * 10-May-1997: Compatible with xscreensaver + * 14-Jul-1996: Cleaned up code. + * 27-Jun-1996: Written and submitted by Keith Romberg <kromberg@saxe.com>. + */ + +#ifdef STANDALONE +# define MODE_lightning +# define DEFAULTS "*delay: 10000 \n" \ + "*ncolors: 64 \n" + +# define BRIGHT_COLORS +# define free_lightning 0 +# define release_lightning 0 +# define reshape_lightning 0 +# define lightning_handle_event 0 +# include "xlockmore.h" /* in xscreensaver distribution */ +#else /* STANDALONE */ +# include "xlock.h" /* in xlockmore distribution */ +#endif /* STANDALONE */ + +#ifdef MODE_lightning + +ENTRYPOINT ModeSpecOpt lightning_opts = +{0, (XrmOptionDescRec *) NULL, 0, (argtype *) NULL, (OptionStruct *) NULL}; + +#ifdef USE_MODULES +ModStruct lightning_description = +{"lightning", "init_lightning", "draw_lightning", (char *) NULL, + "refresh_lightning", "init_lightning", (char *) NULL, &lightning_opts, + 10000, 1, 1, 1, 64, 0.6, "", + "Shows Keith's fractal lightning bolts", 0, NULL}; + +#endif + +#define BOLT_NUMBER 4 +#define BOLT_ITERATION 4 +#define LONG_FORK_ITERATION 3 +#define MEDIUM_FORK_ITERATION 2 +#define SMALL_FORK_ITERATION 1 + +#define WIDTH_VARIATION 30 +#define HEIGHT_VARIATION 15 + +#define DELAY_TIME_AMOUNT 15 +#define MULTI_DELAY_TIME_BASE 5 + +#define MAX_WIGGLES 16 +#define WIGGLE_BASE 8 +#define WIGGLE_AMOUNT 14 + +#define RANDOM_FORK_PROBILITY 4 + +#define FIRST_LEVEL_STRIKE 0 +#define LEVEL_ONE_STRIKE 1 +#define LEVEL_TWO_STRIKE 2 + +#define BOLT_VERTICIES ((1<<BOLT_ITERATION)-1) + /* BOLT_ITERATION = 4. 2^(BOLT_ITERATION) - 1 = 15 */ + +#define NUMBER_FORK_VERTICIES 9 + +#define FLASH_PROBILITY 20 +#define MAX_FLASH_AMOUNT 2 /* half the total duration of the bolt */ + +typedef struct { + XPoint ForkVerticies[NUMBER_FORK_VERTICIES]; + int num_used; +} Fork; + +typedef struct { + XPoint end1, end2; + XPoint middle[BOLT_VERTICIES]; + int fork_number; + int forks_start[2]; + Fork branch[2]; + int wiggle_number; + int wiggle_amount; + int delay_time; + int flash; + int flash_begin, flash_stop; + int visible; + int strike_level; +} Lightning; + +typedef struct { + Lightning bolts[BOLT_NUMBER]; + int scr_width, scr_height; + int multi_strike; + int give_it_hell; + int draw_time; + int stage; + int busyLoop; + unsigned long color; +} Storm; + +static Storm *Helga = (Storm *) NULL; + +/*------------------- function prototypes ----------------------------*/ + +static int distance(XPoint a, XPoint b); + +static int setup_multi_strike(void); +static int flashing_strike(void); +static void flash_duration(int *start, int *end, int total_duration); +static void random_storm(Storm * st); +static void generate(XPoint A, XPoint B, int iter, XPoint * verts, int *vert_index); +static void create_fork(Fork * f, XPoint start, XPoint end, int level); + +static void first_strike(Lightning bolt, ModeInfo * mi); +static void draw_bolt(Lightning * bolt, ModeInfo * mi); +static void draw_line(ModeInfo * mi, XPoint * p, int number, GC use, int x_offset); +static void level1_strike(Lightning bolt, ModeInfo * mi); +static void level2_strike(Lightning bolt, ModeInfo * mi); + +static int storm_active(Storm * st); +static void update_bolt(Lightning * bolt, int time_now); +static void wiggle_bolt(Lightning * bolt); +static void wiggle_line(XPoint * p, int number, int wiggle_amount); + +/*------------------------- functions ---------------------------------*/ + +static int +setup_multi_strike(void) +{ + int result, multi_prob; + + multi_prob = NRAND(100); + + if (multi_prob < 50) + result = 1; + else if ((multi_prob >= 51) && (multi_prob < 75)) + result = 2; + else if ((multi_prob >= 76) && (multi_prob < 92)) + result = 3; + else + result = BOLT_NUMBER; /* 4 */ + + return (result); +} + +/*-------------------------------------------------------------------------*/ + +static int +flashing_strike(void) +{ + int tmp = NRAND(FLASH_PROBILITY); + + if (tmp <= FLASH_PROBILITY) + return (1); + return (0); +} + +/*-------------------------------------------------------------------------*/ + +static void +flash_duration(int *start, int *end, int total_duration) +{ + int mid, d; + + mid = total_duration / MAX_FLASH_AMOUNT; + d = NRAND(total_duration / MAX_FLASH_AMOUNT) / 2; + *start = mid - d; + *end = mid + d; +} + +/*-------------------------------------------------------------------------*/ + +static void +random_storm(Storm * st) +{ + int i, j, tmp; + XPoint p; + + for (i = 0; i < st->multi_strike; i++) { + st->bolts[i].end1.x = NRAND(st->scr_width); + st->bolts[i].end1.y = 0; + st->bolts[i].end2.x = NRAND(st->scr_width); + st->bolts[i].end2.y = st->scr_height; + st->bolts[i].wiggle_number = WIGGLE_BASE + NRAND(MAX_WIGGLES); + if ((st->bolts[i].flash = flashing_strike())) + flash_duration(&(st->bolts[i].flash_begin), &(st->bolts[i].flash_stop), + st->bolts[i].wiggle_number); + else + st->bolts[i].flash_begin = st->bolts[i].flash_stop = 0; + st->bolts[i].wiggle_amount = WIGGLE_AMOUNT; + if (i == 0) + st->bolts[i].delay_time = NRAND(DELAY_TIME_AMOUNT); + else + st->bolts[i].delay_time = NRAND(DELAY_TIME_AMOUNT) + + (MULTI_DELAY_TIME_BASE * i); + st->bolts[i].strike_level = FIRST_LEVEL_STRIKE; + tmp = 0; + generate(st->bolts[i].end1, st->bolts[i].end2, BOLT_ITERATION, + st->bolts[i].middle, &tmp); + st->bolts[i].fork_number = 0; + st->bolts[i].visible = 0; + for (j = 0; j < BOLT_VERTICIES; j++) { + if (st->bolts[i].fork_number >= 2) + break; + if (NRAND(100) < RANDOM_FORK_PROBILITY) { + p.x = NRAND(st->scr_width); + p.y = st->scr_height; + st->bolts[i].forks_start[st->bolts[i].fork_number] = j; + create_fork(&(st->bolts[i].branch[st->bolts[i].fork_number]), + st->bolts[i].middle[j], p, j); + st->bolts[i].fork_number++; + } + } + } +} + +static void +generate(XPoint A, XPoint B, int iter, XPoint * verts, int *vert_index) +{ + XPoint mid; + + mid.x = (A.x + B.x) / 2 + NRAND(WIDTH_VARIATION) - WIDTH_VARIATION / 2; + mid.y = (A.y + B.y) / 2 + NRAND(HEIGHT_VARIATION) - HEIGHT_VARIATION / 2; + + if (!iter) { + verts[*vert_index].x = mid.x; + verts[*vert_index].y = mid.y; + (*vert_index)++; + return; + } + generate(A, mid, iter - 1, verts, vert_index); + generate(mid, B, iter - 1, verts, vert_index); +} + +/*------------------------------------------------------------------------*/ + +static void +create_fork(Fork * f, XPoint start, XPoint end, int level) +{ + int tmp = 1; + + f->ForkVerticies[0].x = start.x; + f->ForkVerticies[0].y = start.y; + + if (level <= 6) { + generate(start, end, LONG_FORK_ITERATION, f->ForkVerticies, &tmp); + f->num_used = 9; + } else if ((level > 6) && (level <= 11)) { + generate(start, end, MEDIUM_FORK_ITERATION, f->ForkVerticies, &tmp); + f->num_used = 5; + } else { + if (distance(start, end) > 100) { + generate(start, end, MEDIUM_FORK_ITERATION, f->ForkVerticies, &tmp); + f->num_used = 5; + } else { + generate(start, end, SMALL_FORK_ITERATION, f->ForkVerticies, &tmp); + f->num_used = 3; + } + } + + f->ForkVerticies[f->num_used - 1].x = end.x; + f->ForkVerticies[f->num_used - 1].y = end.y; +} + +/*------------------------------------------------------------------------*/ + +static void +update_bolt(Lightning * bolt, int time_now) +{ + wiggle_bolt(bolt); + if ((bolt->wiggle_amount == 0) && (bolt->wiggle_number > 2)) + bolt->wiggle_number = 0; + if (((time_now % 3) == 0)) + bolt->wiggle_amount++; + + if (((time_now >= bolt->delay_time) && (time_now < bolt->flash_begin)) || + (time_now > bolt->flash_stop)) + bolt->visible = 1; + else + bolt->visible = 0; + + if (time_now == bolt->delay_time) + bolt->strike_level = FIRST_LEVEL_STRIKE; + else if (time_now == (bolt->delay_time + 1)) + bolt->strike_level = LEVEL_ONE_STRIKE; + else if ((time_now > (bolt->delay_time + 1)) && + (time_now <= (bolt->delay_time + bolt->flash_begin - 2))) + bolt->strike_level = LEVEL_TWO_STRIKE; + else if (time_now == (bolt->delay_time + bolt->flash_begin - 1)) + bolt->strike_level = LEVEL_ONE_STRIKE; + else if (time_now == (bolt->delay_time + bolt->flash_stop + 1)) + bolt->strike_level = LEVEL_ONE_STRIKE; + else + bolt->strike_level = LEVEL_TWO_STRIKE; +} + +/*------------------------------------------------------------------------*/ + +static void +draw_bolt(Lightning * bolt, ModeInfo * mi) +{ + if (bolt->visible) { + if (bolt->strike_level == FIRST_LEVEL_STRIKE) + first_strike(*bolt, mi); + else if (bolt->strike_level == LEVEL_ONE_STRIKE) + level1_strike(*bolt, mi); + else + level2_strike(*bolt, mi); + } +} + +/*------------------------------------------------------------------------*/ + +static void +first_strike(Lightning bolt, ModeInfo * mi) +{ + Display *display = MI_DISPLAY(mi); + Window window = MI_WINDOW(mi); + GC gc = MI_GC(mi); + int i; + + XSetForeground(display, gc, MI_WHITE_PIXEL(mi)); + XDrawLine(display, window, gc, + bolt.end1.x, bolt.end1.y, bolt.middle[0].x, bolt.middle[0].y); + draw_line(mi, bolt.middle, BOLT_VERTICIES, gc, 0); + XDrawLine(display, window, gc, + bolt.middle[BOLT_VERTICIES - 1].x, bolt.middle[BOLT_VERTICIES - 1].y, + bolt.end2.x, bolt.end2.y); + + for (i = 0; i < bolt.fork_number; i++) + draw_line(mi, bolt.branch[i].ForkVerticies, bolt.branch[i].num_used, + gc, 0); +} + +/*------------------------------------------------------------------------*/ + +static void +draw_line(ModeInfo * mi, XPoint * points, int number, GC to_use, int offset) +{ + int i; + + for (i = 0; i < number - 1; i++) { + if (points[i].y <= points[i + 1].y) + XDrawLine(MI_DISPLAY(mi), MI_WINDOW(mi), to_use, points[i].x + offset, + points[i].y, points[i + 1].x + offset, points[i + 1].y); + else { + if (points[i].x < points[i + 1].x) + XDrawLine(MI_DISPLAY(mi), MI_WINDOW(mi), to_use, points[i].x + + offset, points[i].y + offset, points[i + 1].x + offset, + points[i + 1].y + offset); + else + XDrawLine(MI_DISPLAY(mi), MI_WINDOW(mi), to_use, points[i].x - + offset, points[i].y + offset, points[i + 1].x - offset, + points[i + 1].y + offset); + } + } +} + +/*------------------------------------------------------------------------*/ + +static void +level1_strike(Lightning bolt, ModeInfo * mi) +{ + Display *display = MI_DISPLAY(mi); + Window window = MI_WINDOW(mi); + Storm *st = &Helga[MI_SCREEN(mi)]; + GC gc = MI_GC(mi); + int i; + + if (MI_NPIXELS(mi) > 2) /* color */ + XSetForeground(display, gc, MI_PIXEL(mi, st->color)); + else + XSetForeground(display, gc, MI_WHITE_PIXEL(mi)); + XDrawLine(display, window, gc, + bolt.end1.x - 1, bolt.end1.y, bolt.middle[0].x - 1, bolt.middle[0].y); + draw_line(mi, bolt.middle, BOLT_VERTICIES, gc, -1); + XDrawLine(display, window, gc, + bolt.middle[BOLT_VERTICIES - 1].x - 1, + bolt.middle[BOLT_VERTICIES - 1].y, bolt.end2.x - 1, bolt.end2.y); + XDrawLine(display, window, gc, + bolt.end1.x + 1, bolt.end1.y, bolt.middle[0].x + 1, bolt.middle[0].y); + draw_line(mi, bolt.middle, BOLT_VERTICIES, gc, 1); + XDrawLine(display, window, gc, + bolt.middle[BOLT_VERTICIES - 1].x + 1, + bolt.middle[BOLT_VERTICIES - 1].y, bolt.end2.x + 1, bolt.end2.y); + + for (i = 0; i < bolt.fork_number; i++) { + draw_line(mi, bolt.branch[i].ForkVerticies, bolt.branch[i].num_used, + gc, -1); + draw_line(mi, bolt.branch[i].ForkVerticies, bolt.branch[i].num_used, + gc, 1); + } + first_strike(bolt, mi); +} + +/*------------------------------------------------------------------------*/ + +static int +distance(XPoint a, XPoint b) +{ + return ((int) sqrt((double) (a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y))); +} + +/*------------------------------------------------------------------------*/ + +static void +level2_strike(Lightning bolt, ModeInfo * mi) +{ + Display *display = MI_DISPLAY(mi); + Window window = MI_WINDOW(mi); + Storm *st = &Helga[MI_SCREEN(mi)]; + GC gc = MI_GC(mi); + int i; + + /* This was originally designed to be a little darker then the + level1 strike. This was changed to get it to work on + multiscreens and to add more color variety. I tried + stippling but it did not look good. */ + if (MI_NPIXELS(mi) > 2) + XSetForeground(display, gc, MI_PIXEL(mi, st->color)); + else + XSetForeground(display, gc, MI_WHITE_PIXEL(mi)); + XDrawLine(display, window, gc, + bolt.end1.x - 2, bolt.end1.y, bolt.middle[0].x - 2, bolt.middle[0].y); + draw_line(mi, bolt.middle, BOLT_VERTICIES, gc, -2); + XDrawLine(display, window, gc, + bolt.middle[BOLT_VERTICIES - 1].x - 2, + bolt.middle[BOLT_VERTICIES - 1].y, bolt.end2.x - 2, bolt.end2.y); + + XDrawLine(display, window, gc, + bolt.end1.x + 2, bolt.end1.y, bolt.middle[0].x + 2, bolt.middle[0].y); + draw_line(mi, bolt.middle, BOLT_VERTICIES, gc, 2); + XDrawLine(display, window, gc, + bolt.middle[BOLT_VERTICIES - 1].x + 2, + bolt.middle[BOLT_VERTICIES - 1].y, bolt.end2.x + 2, bolt.end2.y); + + for (i = 0; i < bolt.fork_number; i++) { + draw_line(mi, bolt.branch[i].ForkVerticies, bolt.branch[i].num_used, + gc, -2); + draw_line(mi, bolt.branch[i].ForkVerticies, bolt.branch[i].num_used, + gc, 2); + } + level1_strike(bolt, mi); +} + +/*------------------------------------------------------------------------*/ + +static int +storm_active(Storm * st) +{ + int i, atleast_1 = 0; + + for (i = 0; i < st->multi_strike; i++) + if (st->bolts[i].wiggle_number > 0) + atleast_1++; + + return (atleast_1); +} + +/*------------------------------------------------------------------------*/ + +static void +wiggle_bolt(Lightning * bolt) +{ + int i; + + wiggle_line(bolt->middle, BOLT_VERTICIES, bolt->wiggle_amount); + bolt->end2.x += NRAND(bolt->wiggle_amount) - bolt->wiggle_amount / 2; + bolt->end2.y += NRAND(bolt->wiggle_amount) - bolt->wiggle_amount / 2; + + for (i = 0; i < bolt->fork_number; i++) { + wiggle_line(bolt->branch[i].ForkVerticies, bolt->branch[i].num_used, + bolt->wiggle_amount); + bolt->branch[i].ForkVerticies[0].x = bolt->middle[bolt->forks_start[i]].x; + bolt->branch[i].ForkVerticies[0].y = bolt->middle[bolt->forks_start[i]].y; + } + + if (bolt->wiggle_amount > 1) + bolt->wiggle_amount -= 1; + else + bolt->wiggle_amount = 0; +} + +/*------------------------------------------------------------------------*/ + +static void +wiggle_line(XPoint * p, int number, int amount) +{ + int i; + + for (i = 0; i < number; i++) { + p[i].x += NRAND(amount) - amount / 2; + p[i].y += NRAND(amount) - amount / 2; + } +} + +/*------------------------------------------------------------------------*/ + +ENTRYPOINT void +init_lightning (ModeInfo * mi) +{ + Storm *st; + + MI_INIT (mi, Helga); + st = &Helga[MI_SCREEN(mi)]; + + st->scr_width = MI_WIDTH(mi); + st->scr_height = MI_HEIGHT(mi); + + st->multi_strike = setup_multi_strike(); + random_storm(st); + st->stage = 0; +} + +/*------------------------------------------------------------------------*/ + +ENTRYPOINT void +draw_lightning (ModeInfo * mi) +{ + int i; + Storm *st; + + if (Helga == NULL) + return; + st = &Helga[MI_SCREEN(mi)]; + MI_IS_DRAWN(mi) = True; + switch (st->stage) { + case 0: + XClearWindow(MI_DISPLAY(mi), MI_WINDOW(mi)); + + st->color = NRAND(MI_NPIXELS(mi)); + st->draw_time = 0; + if (storm_active(st)) + st->stage++; + else + st->stage = 4; + break; + case 1: + for (i = 0; i < st->multi_strike; i++) { + if (st->bolts[i].visible) + draw_bolt(&(st->bolts[i]), mi); + update_bolt(&(st->bolts[i]), st->draw_time); + } + st->draw_time++; + st->stage++; + st->busyLoop = 0; + break; + case 2: + if (++st->busyLoop > 6) { + st->stage++; + st->busyLoop = 0; + } + break; + case 3: + XClearWindow(MI_DISPLAY(mi), MI_WINDOW(mi)); + + if (storm_active(st)) + st->stage = 1; + else + st->stage++; + break; + case 4: + if (++st->busyLoop > 100) { + st->busyLoop = 0; + } + init_lightning(mi); + break; + } +} + +#ifndef STANDALONE +ENTRYPOINT void +refresh_lightning(ModeInfo * mi) +{ + /* Do nothing, it will refresh by itself */ +} +#endif + +XSCREENSAVER_MODULE ("Lightning", lightning) + + +#endif /* MODE_lightning */ |