From 28dc4dc20085b83cb1b177f7e0e8a49217fb55c1 Mon Sep 17 00:00:00 2001
From: Joshua Wise <joshua@nyus.joshuawise.com>
Date: Fri, 25 Jul 2008 00:39:51 -0400
Subject: [PATCH] initial import

---
 mandelbrot.c | 488 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 488 insertions(+)
 create mode 100644 mandelbrot.c

diff --git a/mandelbrot.c b/mandelbrot.c
new file mode 100644
index 0000000..1765630
--- /dev/null
+++ b/mandelbrot.c
@@ -0,0 +1,488 @@
+#include "SDL.h"
+#include <math.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <ctype.h>
+#include <zlib.h>
+
+/* Algorithmic variables */
+int maxiters = 256;
+#define BAILOUT 2.0
+int xres = 600;
+int yres = 600;
+double xmin = -2, ymin = -2, xmax = 2, ymax = 2;
+
+/* Display variables */
+SDL_Surface* screen;
+SDL_Color palette[256],origpalette[256];
+int ppm = 0;
+int sdl = 1;
+int cycling = 0;
+
+int iterate(double x, double y)
+{
+	int i;
+	double cplxr, cplxi;
+	cplxr = y;
+	cplxi = x;
+	i = 0;
+	while ((i < maxiters) && (hypot(cplxr, cplxi) < BAILOUT))
+	{
+		double a=cplxr, b=cplxi, c=cplxr, d=cplxi;
+		i++;
+		cplxr = a*c-b*d+y;
+		cplxi = a*d+b*c+x;
+	}
+	return i;
+}
+
+void set_palette()
+{
+	if (sdl)
+		SDL_SetColors(screen, palette, 0, 256);
+}
+
+void cycle_colors()
+{
+	SDL_Color x;
+	int i;
+	x = palette[0];
+	for (i=0; i<255; i++)
+		palette[i] = palette[i+1];
+	palette[255] = x;
+	set_palette();
+}
+
+Uint32 cycle_colors_cbk(Uint32 interval)
+{
+	cycle_colors();
+	return interval;
+}
+
+void init_palette()
+{
+	int i;
+	for (i=0; i<256; i++)
+	{
+		palette[i].r = sin(((double)i)/256.0*2.0*M_PI*5.0f)*256.0;
+		palette[i].g = sin(((double)(i+64))/256.0*2.0*M_PI*4.0f)*256.0;
+		palette[i].b = sin(((double)(i+128))/256.0*2.0*M_PI*3.0f)*256.0;
+		origpalette[i] = palette[i];
+	}
+}
+
+int videoflags = SDL_SWSURFACE | SDL_RESIZABLE;
+
+void start_sdl()
+{
+	if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER) < 0)
+	{
+		printf("SDL init failed: %s\n", SDL_GetError());
+		exit(1);
+	}
+	atexit(SDL_Quit);
+	
+	screen = SDL_SetVideoMode(xres, yres, 8, videoflags);
+	if (!screen)
+	{
+		printf("SDL video init failed: %s\n", SDL_GetError());
+		exit(1);
+	}
+	
+	SDL_WM_SetCaption("Mandelbrot Set", "Mandelbrot");
+}
+
+double pxltofltx(int x)
+{
+	return ((double)x)*((double)(xmax-xmin))/((double)xres)+xmin;
+}
+double pxltoflty(int y)
+{
+	return ((double)y)*((double)(ymax-ymin))/((double)yres)+ymin;
+}
+
+void render()
+{
+	int x,y;
+	Uint8* buffer;
+	if (ppm)
+		printf("P6\n%d %d\n255\n", xres, yres);
+	if (sdl)
+	{
+		cycling = 0;
+		SDL_WM_SetCaption("Mandelbrot Set [working]", "Mandelbrot");
+		SDL_SetTimer(0, NULL);
+		SDL_LockSurface(screen);
+		buffer = (Uint8*)screen->pixels;
+	}
+	for (y=0;y<yres;y++)
+	{
+		for (x=0;x<xres;x++)
+		{
+			int val = iterate(pxltofltx(x), pxltoflty(y));
+			if (ppm)
+				printf("%c%c%c", palette[val].r, palette[val].g, palette[val].b);
+			if (sdl)
+				buffer[x] = val;
+		}
+		if (sdl)
+			buffer += screen->pitch;
+		if (!(y%10))
+		{
+			if (sdl)
+			{
+				for (x=0;x<xres;x++)
+					buffer[x]=0;
+				SDL_UpdateRect(screen,0,0,0,0);
+			} else 
+				fprintf(stderr, "%d\n", y);
+		}
+	}
+	if (sdl)
+	{
+		SDL_UpdateRect(screen, 0, 0, 0, 0);
+		SDL_UnlockSurface(screen);
+		SDL_WM_SetCaption("Mandelbrot Set", "Mandelbrot");
+	}
+}
+
+int load_palette(char* name)
+{
+	gzFile file;
+	char c[1024];
+	int idx;
+	file = gzopen(name, "rb");
+	if (file == NULL)
+	{
+		perror("gzopen");
+		return 0;
+	}
+	for (idx = 0; idx < 256; idx++)
+	{
+		char* cidx = c;
+		int accum;
+		int element;
+		gzgets(file, c, 1024);
+		
+		if ((c[0] == '\r') || (c[0] == '\n'))
+		{
+			idx--;
+			continue;
+		}
+		if (c[0] == 0x1A /* EOF */)
+		{
+			gzclose(file);
+			return 1;
+		}
+		for (element = 0; element < 3; element++)
+		{
+			accum = 0;
+			while (isblank(*cidx))
+				cidx++;
+			if (!isdigit(*cidx))
+			{
+				fprintf(stderr, "%s: palette file format fault on color %d -- expected digit, got `%c'\n", name, idx, *cidx);
+				gzclose(file);
+				return;
+			}
+			while (isdigit(*cidx))
+			{
+				accum *= 10;
+				accum += *cidx - '0';
+				cidx++;
+			}
+			switch(element)
+			{
+			case 0:	origpalette[idx].r = palette[idx].r = accum; break;
+			case 1: origpalette[idx].g = palette[idx].g = accum; break;
+			case 2: origpalette[idx].b = palette[idx].b = accum; break;
+			default: abort();
+			}
+		}
+	}
+	gzclose(file);
+	set_palette();
+	return 1;
+}
+
+void usage(char* me)
+{
+	printf(
+		"Usage: %s [OPTION]...\n"
+		"Renders the Mandelbrot set.\n"
+		"\n"
+		"Mandatory arguments to long options are mandatory for short options too.\n"
+		"  -x, --width=PIXELS           sets the output width\n"
+		"  -y, --height=PIXELS          sets the output height\n"
+		"  -m, --maxiters=ITERATIONS    sets the maximum number of iterations\n"
+		"  -s, --sdl                    enables SDL as an output device (default)\n"
+		"  -S, --no-sdl                 disables SDL as an output device (implies -q)\n"
+		"  -p, --ppm                    enables .ppm to stdout as an output device (implies -q)\n"
+		"  -P, --no-ppm                 disables .ppm as an output device (default)\n"
+		"  -q, --quit-immediately       exits immediately after rendering\n"
+		"  -l, --location=XMIN,XMAX,YMIN,YMAX\n"
+		"                               sets the starting location\n"
+		"  -t, --palette=FILENAME       sets the palette\n"
+		"      --help                   shows this help\n"
+		"\n"
+		"Written by Joshua Wise <joshua@joshuawise.com>.\n"
+		, me
+		);
+	exit(2);
+}
+
+struct option longopts[] = {
+	{"x", required_argument, NULL, 'x'},
+	{"width", required_argument, NULL, 'x'},
+	{"y", required_argument, NULL, 'y'},
+	{"height", required_argument, NULL, 'y'},
+	{"maxiters", required_argument, NULL, 'm'},
+	{"sdl", no_argument, NULL, 's'},
+	{"ppm", no_argument, NULL, 'p'},
+	{"no-sdl", no_argument, NULL, 'S'},
+	{"no-ppm", no_argument, NULL, 'P'},
+	{"help", no_argument, NULL, 'h'},
+	{"location", required_argument, NULL, 'l'},
+	{"palette", required_argument, NULL, 't'},
+	{"quit-immediately", no_argument, NULL, 'q'},
+	{0,0,0,0}
+};
+
+int main(int argc, char** argv)
+{
+        SDL_Event event;
+        int startx, starty;
+        int buttondown = 0;
+        int dragged = 0;
+        int arg;
+        int custompalette = 0;
+        int quitimmediately = 0;
+        double yctr, ysz;
+        
+        while ((arg = getopt_long(argc, argv, "x:y:m:l:t:sSpPq", longopts, NULL)) != -1)
+        {
+        	switch(arg)
+        	{
+		case 'x':
+			xres = atoi(optarg);
+			if (!xres)
+			{
+				printf("%s: option `%c' requires an integer argument\n", argv[0], arg);
+				printf("Try `%s --help' for more information.\n", argv[0]);
+				exit(2);
+			}
+			break;
+		case 'y':
+			yres = atoi(optarg);
+			if (!yres)
+			{
+				printf("%s: option `%c' requires an integer argument\n", argv[0], arg);
+				printf("Try `%s --help' for more information.\n", argv[0]);
+				exit(2);
+			}
+			break;
+		case 'm':
+			maxiters = atoi(optarg);
+			if (!maxiters)
+			{
+				printf("%s: option `%c' requires an integer argument\n", argv[0], arg);
+				printf("Try `%s --help' for more information.\n", argv[0]);
+				exit(2);
+			}
+			break;
+		case 's':
+			sdl = 1;
+			break;
+		case 'p':
+			ppm = 1;
+			quitimmediately = 1;
+			break;
+		case 'S':
+			sdl = 0;
+			break;
+		case 'P':
+			ppm = 0;
+			break;
+		case 'h':
+			usage(argv[0]);
+			break;
+		case 'l':
+			{
+			float f1,f2,f3,f4;
+				if (sscanf(optarg, "%f,%f,%f,%f", &f1, &f2, &f3, &f4) != 4)
+				{
+					printf("%s: incorrect syntax for option `%c'\n", argv[0], arg);
+					printf("Try %s --help' for more information.\n", argv[0]);
+					exit(2);
+				}
+				xmin = f1; xmax = f2; ymin = f3; ymax = f4;
+			}
+			break;
+		case 't':
+			custompalette = load_palette(optarg);
+			break;
+		case 'q':
+			quitimmediately = 1;
+			break;
+		case '?':
+		case ':':
+			printf("Try `%s --help' for more information.\n", argv[0]);
+			exit(2);
+			break;
+		default:
+			printf("Oh God I am not good with computers how did this get here?\n");
+			exit(127);
+        	}
+        }
+        
+	if (sdl)
+		start_sdl();
+	yctr = ymin + (ymax - ymin) / 2.0;
+	// get y in proportion
+	ysz = (xmax-xmin)*((double)yres)/((double)xres);
+	ymax = yctr+ysz/2; ymin = yctr-ysz/2;
+
+	if (!custompalette)
+		init_palette();
+	set_palette();
+	render();
+	if (quitimmediately)
+		exit(0);
+	while ( SDL_WaitEvent(&event) ) {
+                switch (event.type) {
+                	case SDL_KEYDOWN:
+                		if (event.key.keysym.sym == SDLK_c)
+                		{
+                			if (!cycling)
+                			{
+                				SDL_WM_SetCaption("Mandelbrot Set [color cycling]", "Mandelbrot");
+                				SDL_SetTimer(50, cycle_colors_cbk);
+					} else {
+						SDL_WM_SetCaption("Mandelbrot Set", "Mandelbrot");
+						SDL_SetTimer(0, NULL);
+					}
+                			cycling = !cycling;
+                		} else if (event.key.keysym.sym == SDLK_r) {
+                			int i;
+                			for (i=0;i<256;i++)
+                			{
+                				palette[i].r = origpalette[i].r;
+                				palette[i].g = origpalette[i].g;
+                				palette[i].b = origpalette[i].b;
+					}
+					set_palette();
+                		} else if (event.key.keysym.sym == SDLK_ESCAPE ||
+					   event.key.keysym.sym == SDLK_q) {
+					exit(0);
+				} else if (event.key.keysym.sym == SDLK_p) {
+					ppm = 1;
+					render();
+					ppm = 0;
+				} else if (event.key.keysym.sym == SDLK_RETURN) {
+					render();
+				} else if (event.key.keysym.sym == SDLK_i) {
+					printf("mandelbrot by Joshua Wise\n");
+					printf("2005-06-19, Little Cayman\n");
+					printf("\n");
+					printf("Current settings:\n");
+					printf("  xmin: %f, xmax: %f\n", xmin, xmax);
+					printf("  ymin: %f, ymax: %f\n", ymin, ymax);
+					printf("  maxiters: %d, bailout: %f\n", maxiters, BAILOUT);
+					printf("  xres: %d, yres: %d\n", xres, yres);
+					printf("Recreate with:\n");
+					printf("  %s -x%d -y%d -l%f,%f,%f,%f -m%d\n", argv[0], xres,yres,xmin,xmax,ymin,ymax,maxiters);
+				}
+                		break;
+			case SDL_MOUSEBUTTONDOWN:
+				if (event.button.button == 1)
+					buttondown = 1;
+				startx = event.button.x;
+				starty = event.button.y;
+				break;
+			case SDL_MOUSEMOTION:
+				if (buttondown)
+					dragged = 1;
+				break;
+			case SDL_MOUSEBUTTONUP:
+				if (event.button.button == 1)
+					buttondown = 0;
+				if (!dragged)
+				{
+					if (event.button.button == 1 || event.button.button == 3)
+					{
+						double xsz = xmax-xmin, ysz = ymax-ymin;
+						double x,y;
+						double scalar;
+						if (event.button.button == 1)
+							scalar = 1.0/2.0;
+						else
+							scalar = 2.0/1.0;
+						xsz *= scalar;
+						ysz *= scalar;
+						x = pxltofltx(event.button.x);
+						y = pxltoflty(event.button.y);
+						xmax = x + xsz / 2;
+						xmin = x - xsz / 2;
+						ymax = y + ysz / 2;
+						ymin = y - ysz / 2;
+						render();
+					} else if (event.button.button == 2) {
+						xmax = ymax = 2;
+						xmin = ymin = -2;
+						render();
+					}
+					dragged = 0;
+					break;
+				} else {
+					double newmaxx, newminx, newmaxy, newminy;
+					if (event.button.x > startx)
+					{
+						newmaxx = pxltofltx(event.button.x);
+						newminx = pxltofltx(startx);
+					} else {
+						newminx = pxltofltx(event.button.x);
+						newmaxx = pxltofltx(startx);
+					}
+					if (event.button.y > starty)
+					{
+						newmaxy = pxltoflty(event.button.y);
+						newminy = pxltoflty(starty);
+					} else {
+						newminy = pxltoflty(event.button.y);
+						newmaxy = pxltoflty(starty);
+					}
+					yctr = newminy + (newmaxy - newminy) / 2.0;
+					// get y in proportion
+					ysz = (newmaxx-newminx)*((double)yres)/((double)xres);
+					ymax = yctr+ysz/2; ymin = yctr-ysz/2;
+					xmax = newmaxx; xmin = newminx;
+					render();
+					dragged = 0;
+					break;
+				}
+			case SDL_VIDEORESIZE:
+			{
+				screen = SDL_SetVideoMode(event.resize.w, event.resize.h,
+							  screen->format->BitsPerPixel,
+							  videoflags);
+				if (!screen)
+				{
+					fprintf(stderr, "Couldn't resize screen\n");
+					exit(1);
+				}
+				SDL_SetColors(screen, palette, 0, 256);
+				xres = event.resize.w;
+				yres = event.resize.h;
+				yctr = ymin + (ymax - ymin) / 2.0;
+				// get y in proportion
+				ysz = (xmax-xmin)*((double)yres)/((double)xres);
+				ymax = yctr+ysz/2; ymin = yctr-ysz/2;
+				render();
+				break;
+			}
+			case SDL_QUIT:
+				return;
+		}
+	}
+	return 1;
+}
-- 
2.39.2