commit d451c04331529a8595fcb9d4a717b1c0b473c007
Author: davidovski <david@davidovski.xyz>
Date:   Sun Dec 5 21:30:29 2021 +0000

    added a loop

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..c133749
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,14 @@
+PROG=rope
+CC=gcc
+FLAGS=-lm -lraylib 
+
+.DEFAULT_GOAL := build
+
+install: ${PROG}
+	cp ${PROG} ~/.local/bin/
+
+build: ${PROG}.c
+	${CC} ${PROG}.c -o ${PROG} ${FLAGS}
+
+clean: ${PROG}
+	rm ${PROG}
diff --git a/rope.c b/rope.c
new file mode 100755
index 0000000..b4561bc
--- /dev/null
+++ b/rope.c
@@ -0,0 +1,120 @@
+#include <raylib.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+
+const int radius = 8;
+const int size[] = {800, 450};
+const float t = 0.2;
+const int distance = 64;
+
+int holding = -1;
+
+typedef struct point {
+    Vector2 pos;
+    Vector2 vel;
+    int next;
+} Point;
+
+Point points[64]; 
+
+int populatePoints() {
+    int count = sizeof(points) / sizeof(Point);
+    for (int i = 0; i < count; i++) {
+        points[i] = (Point){rand() % size[0], rand() % size[1], (i+1) % count};
+    }
+}
+
+float magnitude(Vector2 a) {
+    return sqrt(a.x*a.x + a.y*a.y);
+}
+
+
+int distanceSquared(Vector2 a, Vector2 b) {
+    int dx = (a.x - b.x);
+    int dy = (a.y - b.y);
+    return dx*dx + dy*dy;
+}
+
+Vector2 add(Vector2 a, Vector2 b) {
+    return (Vector2){a.x + b.x, a.y + b.y};
+}
+
+Vector2 mul(Vector2 a, float v) {
+    return (Vector2){a.x * v, a.y * v};
+}
+
+Vector2 normalize(Vector2 a) {
+    float m = magnitude(a);
+    return (Vector2){a.x / m, a.y / m};
+}
+
+int physics(Point *p, Point *n) {
+    Vector2 d = (Vector2){(n->pos.x - p->pos.x), (n->pos.y - p->pos.y)};
+    Vector2 f = mul(normalize(d), t * (magnitude(d) - distance));
+
+    p->vel.x += f.x;
+    p->vel.y += f.y;
+
+}
+
+int draw(void) {
+    Vector2 mouse = (Vector2){GetMouseX(), GetMouseY()};
+
+    BeginDrawing();
+    ClearBackground(LIGHTGRAY);
+
+    int count = sizeof(points) / sizeof(Point);
+
+    if (holding > -1) {
+        Point *p = &points[holding];
+        p->pos = mouse;
+    }
+
+    for (int i = 0; i < count; i++) {
+        Point *p = &points[i]; 
+        Point *n = &points[(i+1)% count];
+        Point *m = &points[(i-1)% count];
+
+        p->vel.x = 0;
+        p->vel.y = 0;
+
+        physics(p, n);
+        physics(p, m);
+
+        p->pos.x += p->vel.x;
+        p->pos.y += p->vel.y;
+
+        if (IsMouseButtonDown(0)) {
+            if (distanceSquared(p->pos, mouse) < radius*radius) {
+                holding = i;
+            }
+        } else {
+            holding = -1;
+        }
+
+        DrawCircle(p->pos.x, p->pos.y, radius, DARKGRAY);
+
+        DrawLineEx(p->pos, n->pos, radius / 2, DARKGRAY);
+    }
+
+
+    EndDrawing();
+}
+
+int main(void) {
+
+
+    InitWindow(size[0], size[1], "Rope");
+
+    SetTargetFPS(60);
+
+    populatePoints();
+    while (!WindowShouldClose()) {
+        draw();
+    }
+
+    CloseWindow();
+
+    return 0;
+}