From 2b71a3c73cf7aa1c25e51d85843d165190a62e55 Mon Sep 17 00:00:00 2001
From: glenda <glenda@r51>
Date: Thu, 30 Jan 2025 23:47:24 +0000
Subject: [PATCH] spirals

---
 spiral.c | 60 ++++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 41 insertions(+), 19 deletions(-)

diff --git a/spiral.c b/spiral.c
index 53a211a283fe540fc21208abebd89d8435a12720..1da3bafd7d655cf0df970c10a3786f9f9205b81c 100644
--- a/spiral.c
+++ b/spiral.c
@@ -12,14 +12,14 @@ int frametime;
 double spr;
 int wings;
 double wingrads;
-double eccen;
+double turns;
 
 vlong starttime;
 
 void
 usage(void)
 {
-	fprint(2,"usage: %s [-f framerate] [-r rpm] [-w wings] [-e deg]\n", argv0);
+	fprint(2,"usage: %s [-f framerate] [-r rpm] [-w wings] [-t turns]\n", argv0);
 	exits("usage");
 }
 
@@ -62,29 +62,50 @@ vecpt(double radians, double radius)
 void
 drawframe(double ts)
 {
-	double radians, radius;
+	double radians, radius, spiralrads, spiralx, spiraly;
+	uint numpoints, iradius;
+	int i, j, k;
 	Point center;
-	Point wingpoints[6];
+	Point *wingpoints;
 
 	radians = fmod(ts / spr, spr) * RAD;
 	radius = imageradius(screen) * 1.4;
+	iradius = radius + 1;
 	center = imagecenter(screen);
+
+	numpoints = iradius + iradius;
+	wingpoints = malloc(sizeof(Point) * numpoints);
 	wingpoints[0] = center;
-	wingpoints[5] = addpt(center, Pt(1, 1));
+	wingpoints[numpoints - 1] = center;
 
 	draw(screen, screen->r, bg, nil, SPt(0, 0));
 
-	for(int i = 0; i < wings; i++)
-	{
-		wingpoints[1] = addpt(center, vecpt(radians + eccen, radius / 3));
-		wingpoints[2] = addpt(center, vecpt(radians, radius));
-		radians += wingrads;
-		wingpoints[3] = addpt(center, vecpt(radians, radius));
-		wingpoints[4] = addpt(center, vecpt(radians + eccen, radius / 3));
+	for(i = 0; i < wings; i++){
+		for(j = 0; j < iradius; j++){
+			spiralrads = (double)j / (double)iradius * turns * RAD;
+			spiralx = sin(radians + spiralrads) * j;
+			spiraly = cos(radians + spiralrads) * j;
+			k = j;
+			wingpoints[k] = addpt(center, Pt(spiralx, spiraly));
+		}
+
 		radians += wingrads;
 
-		fillbezspline(screen, wingpoints, 6, ~0, fg, Pt(0, 0));
+		for(j = 0; j < iradius; j++){
+			spiralrads = (double)(iradius - j) / (double)iradius * turns * RAD;
+			spiralx = sin(radians + spiralrads) * (iradius - j);
+			spiraly = cos(radians + spiralrads) * (iradius - j);
+			// weird syntax issue
+			k = j + iradius;
+			wingpoints[k] = addpt(center, Pt(spiralx, spiraly));
+		}
+
+		fillpoly(screen, wingpoints, numpoints, ~0, fg, Pt(0,0));
+
+		radians += wingrads;
 	}
+
+	free(wingpoints);
 }
 
 double
@@ -110,7 +131,7 @@ main(int argc, char* argv[])
 	frametime = 1.0 / 30.0 * 1000;
 	wings = 3;
 	spr = 2;
-	eccen = RAD / 6;
+	turns = 1.0 / 6.0;
 
 	ARGBEGIN{
 	case 'f':
@@ -122,12 +143,14 @@ main(int argc, char* argv[])
 	case 'w':
 		wings = atoi(EARGF(usage()));
 		break;
-	case 'e':
-		eccen = DEG * atof(EARGF(usage()));
+	case 't':
+		turns = atof(EARGF(usage()));
 		break;
 	default:
 		usage();
-	} ARGEND
+	}ARGEND
+
+	fprint(2,"turns: %f\n", turns);
 
 	if(wings < 1) wings = 1;
 	wingrads = PI / (double) wings;
@@ -148,8 +171,7 @@ main(int argc, char* argv[])
 	einit(Emouse);
 	timer = etimer(0, frametime);
 
-	for(;;)
-	{
+	for(;;){
 		etype = event(&e);
 
 		if (etype == timer)