Merge branch 'master' into pospos

6 files changed, 41 insertions, 23 deletions

diff --git a/README.md b/README.md
index 905be3c..4aa63d8 100644
--- a/README.md
+++ b/README.md
@@ -35,10 +35,12 @@ Also note that `-N` should always be used together with `-T`.
 	-t thread_multiplier Float > 0
 	                     Coefficient to multiply cores by in order to achieve
 	                     count of worker threads to use. (1)
-	-x left              position of left of image on the real axis (x+iy)
-	-y top               position of top of image on the imaginary axis (x+iy)
-	-z scale             width and height of image in units on the cartesian
-	                     plane
+	-x xval              Float
+	                     x value of centre of image on the real axis (x+iy)
+	-y yval              Float
+	                     y value of centre of image on the imaginary axis (x+iy)
+	-z scale             Float
+	                     width and height of image (units on cartesian plane)
 	-N cluster_id        0 <= Integer < cluster_total
 	                     A unique ID used to determine which sections of the
 	                     image this instance should work on.
@@ -108,4 +110,11 @@ Check out [pgm-interlace][pgm-interlace] for a tool to do this job.
    I'm working on an example tool to do this, but there are so many palettes
    you could use that you might as well write your own.
 
+### Areas of interest
+
+Use the `-x`, `-y` and `-z` parameters to see them.
+Have a play with the iteration count; as a general rule you will need more iterations when the scale is decreased
+
+ * Tiny lone mandelbrot (0.001643721971153 + 0.822467633298876i), scale = 0.00000000005
+
 [pgm-interlace]: https://github.com/phillid/pgm-interlace/
diff --git a/algorithms/burning-ship.c b/algorithms/burning-ship.c
index 7e27e4b..6f8c9d9 100644
--- a/algorithms/burning-ship.c
+++ b/algorithms/burning-ship.c
@@ -34,17 +34,21 @@ void
 	struct frame *f = &(d->parent_frame);
 	unsigned int x,y,i;
 	double a,b;
+	double left,top;
 	double complex z,c;
 
 	defaultsd(&d->parent_frame.scale, 3.5f);
-	defaultsd(&d->parent_frame.top, -2.2f);
-	defaultsd(&d->parent_frame.left, -2.2f);
+	defaultsd(&d->parent_frame.x, -0.45f);
+	defaultsd(&d->parent_frame.y, -0.45f);
+
+	left = d->parent_frame.x - (d->parent_frame.scale / 2);
+	top = d->parent_frame.y - (d->parent_frame.scale / 2);
 
 	/* FIXME document this */
-	b = clust_id*(f->scale/size)+f->top; /* FIXME document this */
+	b = clust_id*(f->scale/size)+top; /* FIXME document this */
 
 	for (y = clust_id; y < size; y += clust_total) {
-		a = d->core*(f->scale/size)+f->left;
+		a = d->core*(f->scale/size)+left;
 		for (x = d->core; x < size; x += cores) {
 			z = 0;
 			c = a+I*b;
diff --git a/algorithms/mandelbrot.c b/algorithms/mandelbrot.c
index 51d0c43..33d7cde 100644
--- a/algorithms/mandelbrot.c
+++ b/algorithms/mandelbrot.c
@@ -34,18 +34,21 @@ void
 	struct frame *f = &(d->parent_frame);
 	unsigned int x,y,i;
 	double a,b;
+	double left, top;
 	double complex z,c;
 
-	defaultsd(&d->parent_frame.top, -1.75f);
-	defaultsd(&d->parent_frame.left, -2.5f);
 	defaultsd(&d->parent_frame.scale, 3.5f);
+	defaultsd(&d->parent_frame.x, -0.75f);
+	defaultsd(&d->parent_frame.y, 0);
 
+	left = d->parent_frame.x - (d->parent_frame.scale / 2);
+	top = d->parent_frame.y - (d->parent_frame.scale / 2);
 
 	/* FIXME document this */
-	b = clust_id*(f->scale/size)+f->top; /* FIXME document this */
+	b = clust_id*(f->scale/size)+top; /* FIXME document this */
 
 	for (y = clust_id; y < size; y += clust_total) {
-		a = d->core*(f->scale/size)+f->left;
+		a = d->core*(f->scale/size)+left;
 		for (x = d->core; x < size; x += cores) {
 			z = 0;
 			c = a + I*b;
diff --git a/extra/burning-ship-lattice-gen.sh b/extra/burning-ship-lattice-gen.sh
index 1a39c0d..0cb66a1 100755
--- a/extra/burning-ship-lattice-gen.sh
+++ b/extra/burning-ship-lattice-gen.sh
@@ -1,3 +1,5 @@
 #!/bin/sh
 
-exec ./burning-ship-gen -x -1.8 -y -0.082 -z 0.09 $@
+ourdir="$(dirname $0)"
+
+exec "${ourdir}/../burning-ship-gen" -x -1.755 -y -0.037 -z 0.09 $@
diff --git a/fractal-gen.c b/fractal-gen.c
index 6531491..883ef2d 100644
--- a/fractal-gen.c
+++ b/fractal-gen.c
@@ -140,8 +140,8 @@ main(int argc, char **argv)
 		/* FIXME repetition */
 		sections[i].core = i;
 		sections[i].width = width;
-		sections[i].parent_frame.top = f.top;
-		sections[i].parent_frame.left = f.left;
+		sections[i].parent_frame.y = f.y;
+		sections[i].parent_frame.x = f.x;
 		sections[i].parent_frame.scale = f.scale;
 		sections[i].datasize = toalloc;
 		fprintf(stderr, " -> Thread %lu\r", i);
@@ -152,10 +152,10 @@ main(int argc, char **argv)
 
 	switch (child = fork()) {
 	case 0:
-		while((x = s->idx) < s->datasize) {
+		while(1) {
 			fprintf(stderr, "Thread %d: %.4f%%\r",
 					cores-1,
-					100.f*(double)x/s->datasize);
+					100.f*(double)s->idx/s->datasize);
 			sleep(1);
 		}
 		break;
@@ -207,8 +207,8 @@ parse_args(int argc, char **argv)
 	clust_id = 0;
 	clust_total = 1;
 
-	f.left = nan("");
-	f.top = nan("");
+	f.x = nan("");
+	f.y = nan("");
 	f.scale = nan("");
 
 	/* bail out early if no arguments are supplied */
@@ -228,8 +228,8 @@ parse_args(int argc, char **argv)
 			case 'N': clust_id = atoi(optarg); break;
 			case 'T': clust_total = atoi(optarg); break;
 
-			case 'x': f.left = atof(optarg); break;
-			case 'y': f.top = atof(optarg); break;
+			case 'x': f.x = atof(optarg); break;
+			case 'y': f.y = atof(optarg); break;
 			case 'z': f.scale = atof(optarg); break;
 
 			/* redundant case for '?', but explicitness is best */
diff --git a/fractal-gen.h b/fractal-gen.h
index a103d1f..210d50f 100644
--- a/fractal-gen.h
+++ b/fractal-gen.h
@@ -29,8 +29,8 @@
 #include <pthread.h>
 
 struct frame {
-	double top;
-	double left;
+	double x;
+	double y;
 	double scale;
 };