From: Timo Kokkonen <kaapeli@itanic.dy.fi>
Date: Sun, 1 May 2011 16:01:02 +0000 (+0300)
Subject: Factor out iteration calculation
X-Git-Url: http://git.itanic.dy.fi/?p=mandelbrot;a=commitdiff_plain;h=10394fae32c1a947bc2e000003c87b41599571ea

Factor out iteration calculation

Signed-off-by: Timo Kokkonen <kaapeli@itanic.dy.fi>
---

diff --git a/mandelbrot.c b/mandelbrot.c
index ef17b9e..ae05fbd 100644
--- a/mandelbrot.c
+++ b/mandelbrot.c
@@ -17,28 +17,34 @@ 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)
+{
+	double x = 0, y = 0, xtemp;
+	int iteration = 0;
+
+	while ((x * x + y * y < 2 * 2) && iteration < MAX_ITERATION) {
+
+		xtemp = x * x - y * y + x0;
+		y = 2 * x * y + y0;
+
+		x = xtemp;
+		iteration++;
+	}
+
+	return iteration;
+}
+
 int draw_mandelbrot(struct SDL_Surface *screen)
 {
-	double x, y, x0, y0, xtemp;
+	double x0, y0;
 	int iteration, xs,ys;
 
 	for (ys = 0, y0 = -1; ys < screen->h;
 	     y0 += 2 / (double)screen->h, ys++) {
 		for (xs = 0, x0 = -2.5; xs < screen->w;
 		     x0 += 3 / (double)screen->w, xs++) {
-			iteration = 0;
-			x = 0;
-			y = 0;
-
-			while (x * x + y * y < 2 * 2 &&
-				iteration < MAX_ITERATION) {
-
-				xtemp = x*x - y*y + x0;
-				y = 2*x*y + y0;
 
-				x = xtemp;
-				iteration++;
-			}
+			iteration = get_mandelbrot_iterations(x0, y0);
 
 			if (iteration == MAX_ITERATION)
 				putpixel(screen, xs, ys, 255, 255, 255);