X-Git-Url: http://git.itanic.dy.fi/?p=mandelbrot;a=blobdiff_plain;f=mandelbrot.c;h=9ca242101ae1bad4a2f98aa5e89387dee82f36f0;hp=624fcf2ebda615e2275021d1d50aa59b91624a30;hb=HEAD;hpb=ba47e789a437c348b1d0a1a3cfa2c91e517762c7

diff --git a/mandelbrot.c b/mandelbrot.c
index 624fcf2..9ca2421 100644
--- a/mandelbrot.c
+++ b/mandelbrot.c
@@ -2,6 +2,17 @@
 #include <unistd.h>
 #include <stdio.h>
 #include <time.h>
+#include <string.h>
+
+struct context {
+	struct SDL_Surface *screen;
+	long double origo_x, origo_y;
+	int motion_x, motion_y;		/* mouse motion */
+	int mx, my;			/* mouse position */
+	long double zoom;
+	int scroll_enabled;
+	int zooms;
+};
 
 static void putpixel(struct SDL_Surface *screen, const int x, const int y,
 		     const unsigned char r, const unsigned char g,
@@ -17,9 +28,9 @@ static void putpixel(struct SDL_Surface *screen, const int x, const int y,
 
 #define MAX_ITERATION 1000
 
-int get_mandelbrot_iterations(double x0, double y0)
+int get_mandelbrot_iterations(long double x0, long double y0)
 {
-	double x = 0, y = 0, xtemp;
+	long double x = 0, y = 0, xtemp;
 	int iteration = 0;
 
 	while ((x * x + y * y < 2 * 2) && iteration < MAX_ITERATION) {
@@ -34,16 +45,16 @@ int get_mandelbrot_iterations(double x0, double y0)
 	return iteration;
 }
 
-int draw_mandelbrot(struct SDL_Surface *screen, double x1, double x2,
-		double y1, double y2)
+int draw_mandelbrot(struct SDL_Surface *screen, long double x1, long double x2,
+		long double y1, long double y2)
 {
-	double x0, y0, xlen, ylen, xstep, ystep;
+	long double x0, y0, xlen, ylen, xstep, ystep;
 	int iteration, xs, ys;
 
 	xlen = x2 - x1;
 	ylen = y2 - y1;
-	xstep = xlen / (double)screen->w;
-	ystep = ylen / (double)screen->h;
+	xstep = xlen / (long double)screen->w;
+	ystep = ylen / (long double)screen->h;
 
 	y0 = y1;
 #pragma omp parallel for private(xs, ys, x0, y0)
@@ -67,12 +78,140 @@ int draw_mandelbrot(struct SDL_Surface *screen, double x1, double x2,
 	return 0;
 }
 
+#define ZOOM_FACTOR	1.5
+
+static int read_events(struct context *ctx)
+{
+	SDL_Event event;
+	int wait = 1, ret, exit = 0, delayed_exit = 0;
+
+	while (!exit) {
+		if (wait) {
+			SDL_WaitEvent(&event);
+			wait = 0;
+		} else {
+			ret = SDL_PollEvent(&event);
+			if (!ret) {
+				wait = 1;
+				exit = delayed_exit;
+			}
+		}
+
+		switch (event.type) {
+		case SDL_KEYDOWN:
+			switch (event.key.keysym.sym) {
+			case SDLK_ESCAPE:
+				goto quit;
+			default:
+				break;
+			}
+			break;
+		case SDL_KEYUP:
+			switch (event.key.keysym.sym) {
+			default:
+				break;
+			}
+			break;
+		case SDL_MOUSEBUTTONDOWN:
+			if (event.button.button == 4) {
+				ctx->zooms++;
+				delayed_exit++;
+			} else if (event.button.button == 5) {
+				ctx->zooms--;
+				delayed_exit++;
+			} else {
+				ctx->scroll_enabled = 1;
+			}
+			break;
+		case SDL_MOUSEBUTTONUP:
+			ctx->scroll_enabled = 0;
+			delayed_exit++;
+			break;
+		case SDL_MOUSEMOTION:
+			ctx->mx = event.motion.x;
+			ctx->my = event.motion.y;
+			if (!ctx->scroll_enabled)
+				break;
+
+			ctx->motion_x -= event.motion.xrel;
+			ctx->motion_y -= event.motion.yrel;
+			delayed_exit++;
+			break;
+		case SDL_VIDEORESIZE:
+			ctx->screen =
+				SDL_SetVideoMode(event.resize.w,
+						 event.resize.h,
+						 32,
+						 ctx->screen->flags);
+			exit++;
+			break;
+		case SDL_QUIT:
+			goto quit;
+		}
+	}
+
+	return 0;
+quit:
+	printf("\nExiting. Good bye!\n");
+	return 1;
+}
+
+static void loop(struct context *ctx)
+{
+	long double aspect_ratio;
+	long double x1, x2, y1, y2;
+	int last_zoom;
+
+	do {
+		aspect_ratio = ctx->screen->w / (long double)ctx->screen->h;
+		ctx->origo_x += ctx->motion_x / ctx->zoom / ctx->screen->w;
+		ctx->origo_y += ctx->motion_y / ctx->zoom / ctx->screen->h;
+		ctx->motion_x = ctx->motion_y = 0;
+
+		if (ctx->zooms != last_zoom) {
+			int dx, dy;
+
+			dx = ctx->mx - ctx->screen->w / 2;
+			dy = ctx->my - ctx->screen->h / 2;
+
+			if (ctx->zooms > last_zoom) {
+				ctx->zoom *= ZOOM_FACTOR;
+				ctx->origo_x += dx / ctx->zoom /
+					(long double) ctx->screen->w;
+				ctx->origo_y += dy / ctx->zoom /
+					(long double) ctx->screen->h;
+			} else {
+				ctx->origo_x -= dx / ctx->zoom /
+					(long double) ctx->screen->w;
+				ctx->origo_y -= dy / ctx->zoom /
+					(long double) ctx->screen->h;
+				ctx->zoom /= ZOOM_FACTOR;
+			}
+
+			last_zoom = ctx->zooms;
+		}
+
+		x1 = ctx->origo_x - aspect_ratio / ctx->zoom;
+		x2 = ctx->origo_x + aspect_ratio / ctx->zoom;
+		y1 = ctx->origo_y - 1 / ctx->zoom;
+		y2 = ctx->origo_y + 1 / ctx->zoom;
+
+		printf("Drawing area (%LF, %LF)(%LF, %LF), zoom %d\n",
+			x1, y1, x2, y2, ctx->zooms);
+
+		draw_mandelbrot(ctx->screen, x1, x2, y1, y2);
+	} while (!read_events(ctx));
+}
+
 int main(int argc, char *argv[])
 {
-	SDL_Surface *screen;
+	struct context ctx;
 	int flags = SDL_DOUBLEBUF | SDL_HWSURFACE | SDL_RESIZABLE;
 	int xres = 800, yres = 600;
 
+	memset(&ctx, 0, sizeof(ctx));
+	ctx.zoom = 1;
+
 	if (SDL_Init(SDL_INIT_VIDEO) != 0) {
 		fprintf(stderr, "Unable to initialize SDL: %s\n",
 			SDL_GetError());
@@ -81,8 +220,8 @@ int main(int argc, char *argv[])
 	}
 	atexit(SDL_Quit);
 
-	screen = SDL_SetVideoMode(xres, yres, 32, flags);
-	if (screen == NULL) {
+	ctx.screen = SDL_SetVideoMode(xres, yres, 32, flags);
+	if (ctx.screen == NULL) {
 		fprintf(stderr, "Unable to set video mode: %s\n",
 			SDL_GetError());
 		return 2;
@@ -90,9 +229,7 @@ int main(int argc, char *argv[])
 
 	SDL_WM_SetCaption(argv[0], NULL);
 
-	draw_mandelbrot(screen, -2.5, 1, -1, 1);
-
-	yres = read(0, &xres, 1);
+	loop(&ctx);
 
 	return 0;
 }