added shape_new_square to construct a square collision shape

src/shape.c

@@ -83,6 +83,15 @@ Shape* shape_new(const Vector* points, size_t points_len) {
     return self;
 }
 
+Shape* shape_new_square(Vector size) {
+    return shape_new((Vector[4]){
+        ZeroVector,
+        (Vector){0.f, size.y},
+        size,
+        (Vector){size.x, 0.f}
+    }, 4);
+}
+
 Shape* shape_clone(const Shape* source) {
     Shape* self = malloc(sizeof(Shape));
     ASSERT_RETURN(self != NULL, NULL, "Failed to allocate space for shape object.");

src/shape.h

@@ -7,6 +7,7 @@
 typedef struct Shape Shape;
 
 extern Shape* shape_new(const Vector* points, size_t points_len);
+extern Shape* shape_new_square(Vector size);
 extern Shape* shape_clone(const Shape* source);
 extern void shape_destroy(Shape* self);