Add sierpinski fractal triangle, lots of thin strokes

3 files changed, 162 insertions, 1 deletions

diff --git a/.gitignore b/.gitignore
index 6b32d65..4801e15 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,6 +6,7 @@ gears-demo
 gradient-demo
 poppler-demo
 pythagoras-demo
+sierpinski-demo
 slideshow-demo
 spinner-demo
 spiral-demo
diff --git a/Makefile b/Makefile
index a3cfedd..fc7cd29 100644
--- a/Makefile
+++ b/Makefile
@@ -38,7 +38,7 @@ else
 DEFINES+=-DHAVE_COGL=0
 endif
 
-all: spinner-demo spiral-demo slideshow-demo tiger-demo fish-demo flowers-demo gears-demo gradient-demo chart-demo waterfall-demo dragon-demo pythagoras-demo wave-demo
+all: spinner-demo spiral-demo slideshow-demo tiger-demo fish-demo flowers-demo gears-demo gradient-demo chart-demo waterfall-demo dragon-demo pythagoras-demo wave-demo sierpinski-demo
 
 ifeq ($(shell pkg-config --exists poppler-glib && echo 1), 1)
 all: poppler-demo
@@ -78,6 +78,8 @@ pythagoras-demo: pythagoras-demo.c $(SOURCES) demo.h Makefile
 	$(CC) $(DEFINES) $(CFLAGS) -o $@ pythagoras-demo.c $(SOURCES) $(LIBS)
 wave-demo: wave-demo.c $(SOURCES) demo.h Makefile
 	$(CC) $(DEFINES) $(CFLAGS) -o $@ wave-demo.c $(SOURCES) $(LIBS)
+sierpinski-demo: sierpinski-demo.c $(SOURCES) demo.h Makefile
+	$(CC) $(DEFINES) $(CFLAGS) -o $@ sierpinski-demo.c $(SOURCES) $(LIBS)
 clean:
 	rm -f *-demo
 
diff --git a/sierpinski-demo.c b/sierpinski-demo.c
new file mode 100644
index 0000000..5bd78a2
--- /dev/null
+++ b/sierpinski-demo.c
@@ -0,0 +1,158 @@
+#include "demo.h"
+#include <string.h>
+#include <sys/time.h>
+#include <math.h>
+
+static const double m_1_sqrt_3 = 0.577359269;
+
+static void
+T (cairo_t *cr, int size, int iterations)
+{
+	if (iterations-- == 0)
+		return;
+
+	cairo_move_to (cr, 0, 0);
+	cairo_line_to (cr, size, 0);
+	cairo_line_to (cr, size/2, size*m_1_sqrt_3);
+	cairo_close_path (cr);
+
+	size /= 2;
+	if (size >= 4) {
+		T (cr, size, iterations);
+		cairo_save (cr); {
+			cairo_translate (cr, size, 0);
+			T (cr, size, iterations);
+		} cairo_restore (cr);
+		cairo_save (cr); {
+			cairo_translate (cr, size/2, size*m_1_sqrt_3);
+			T (cr, size, iterations);
+		} cairo_restore (cr);
+	}
+}
+
+static void
+draw (cairo_t *cr, int width, int height, int iterations, double theta)
+{
+    cairo_set_source_rgb (cr, 1, 1, 1);
+    cairo_paint (cr);
+
+    cairo_save (cr);
+    cairo_set_source_rgb (cr, 0, 0, 0);
+    cairo_set_line_width (cr, 1.);
+
+    cairo_translate (cr, width/2, height/2);
+    cairo_rotate (cr, theta);
+    cairo_translate (cr, -width/2, -height/2);
+
+    T (cr, width, iterations);
+    cairo_stroke (cr);
+
+    cairo_restore (cr);
+}
+
+static int done;
+static void signal_handler(int sig)
+{
+	done = sig;
+}
+
+int main (int argc, char **argv)
+{
+	struct device *device;
+	struct timeval start, last_tty, last_fps, now;
+	int iterations = 1, step = 1, tick = 10;
+
+	double delta;
+	int frame = 0;
+	int frames = 0;
+	int show_fps = 1;
+	int benchmark;
+	const char *version;
+	enum clip clip;
+	double theta = 0;
+
+	int n;
+
+	device = device_open(argc, argv);
+	version = device_show_version(argc, argv);
+	clip = device_get_clip(argc, argv);
+	benchmark = device_get_benchmark(argc, argv);
+	if (benchmark == 0)
+		benchmark = 20;
+	if (benchmark > 0)
+		show_fps = 0;
+
+	signal(SIGHUP, signal_handler);
+
+	for (n = 1; n < argc; n++) {
+		if (strcmp (argv[n], "--hide-fps") == 0)
+			show_fps = 0;
+	}
+
+	gettimeofday(&start, 0); now = last_tty = last_fps = start;
+	do {
+		struct framebuffer *fb = device->get_framebuffer (device);
+		cairo_t *cr = cairo_create(fb->surface);
+
+		draw(cr, device->width, device->height, iterations, theta);
+		if (--tick == 0){
+			iterations += step;
+			tick = 10;
+			if (iterations < 1) {
+				iterations = 1;
+				step = -step;
+			} else if (iterations > log2(device->width)) {
+				iterations = log(device->width);
+				step = -step;
+			}
+		}
+		theta += 0.1 / 180. * M_PI;
+
+		gettimeofday(&now, NULL);
+		if (show_fps && last_fps.tv_sec) {
+			fps_draw(cr, device->name, version, &last_fps, &now);
+		}
+		last_fps = now;
+
+		cairo_destroy(cr);
+
+		fb->show (fb);
+		fb->destroy (fb);
+
+		if (benchmark < 0 && 0) {
+			delta = now.tv_sec - last_tty.tv_sec;
+			delta += (now.tv_usec - last_tty.tv_usec)*1e-6;
+			frames++;
+			if (delta >  5) {
+				printf("%.2f fps\n", frames/delta);
+				last_tty = now;
+				frames = 0;
+			}
+		}
+
+		frame++;
+		if (benchmark > 0) {
+			delta = now.tv_sec - start.tv_sec;
+			delta += (now.tv_usec - start.tv_usec)*1e-6;
+			if (delta > benchmark) {
+				printf("sierpinski: %.2f fps\n", frame / delta);
+				break;
+			}
+		}
+	} while (!done);
+
+	if (benchmark < 0) {
+		struct framebuffer *fb = device->get_framebuffer (device);
+		cairo_t *cr = cairo_create(fb->surface);
+
+		draw(cr, device->width, device->height, 2048, 0);
+		cairo_destroy(cr);
+
+		fps_finish(fb, device->name, version);
+		fb->show (fb);
+		fb->destroy (fb);
+		pause();
+	}
+
+	return 0;
+}