From 2823ddc3d7fdd27353656bd22c5df13238486827 Mon Sep 17 00:00:00 2001
From: En Yi <randomsity1@gmail.com>
Date: Sat, 7 Mar 2020 16:06:47 +0800
Subject: [PATCH] Make linked list functions more general

---
 include/header.h        |  7 ++-----
 main.c                  | 20 ++++++++++----------
 utilities/linked_list.c | 19 ++++++++-----------
 3 files changed, 20 insertions(+), 26 deletions(-)

diff --git a/include/header.h b/include/header.h
index 988f6d5..599ce59 100644
--- a/include/header.h
+++ b/include/header.h
@@ -88,8 +88,6 @@ struct squishy_square
     Vector2 right_vertices[BEZIER_POINTS+1];
 };
 
-
-
 // Object functions, kinematics.c
 struct kinematic_obj init_kinematic_obj(int width, int height);
 void move(struct kinematic_obj *obj, Vector2 acceleration);
@@ -105,11 +103,10 @@ Vector2 dir(Vector2 vec);
 void approach(double *val, double target, float f);
 
 // Linked list, linked_list.c
-extern struct kinematic_obj_node *kinematic_HEAD;
 void create_list(void);
-void add_node(struct kinematic_obj *obj);
+void add_node(struct kinematic_obj *obj, struct kinematic_obj_node **HEAD);
 //struct kinematic_obj_node **get_list();
-void free_list(void);
+void free_list(struct kinematic_obj_node **HEAD);
 void create_afterimage(struct player_obj *player, Color color);
 void remove_last_afterimage(struct player_obj *player);
 void free_afterimages(struct player_obj *player);
diff --git a/main.c b/main.c
index e85c5ea..9e64e1c 100644
--- a/main.c
+++ b/main.c
@@ -23,7 +23,7 @@
 */
 
 #include "header.h"
-extern struct kinematic_obj_node *kinematic_HEAD;
+struct kinematic_obj_node *kinematic_HEAD = NULL;
 int PLAYER_ACCEL = 1500;
 int JUMP_ACCEL = 15000;
 int JUMP_SPD = 350;
@@ -73,14 +73,14 @@ int main()
     struct squishy_square sqr = init_squishy_square(&player.kinematic, RED);
     player.image = &sqr;
 
-    add_node(&tile);
-    add_node(&tile2);
-    add_node(&tile3);
-    add_node(&tile4);
-    add_node(&tile5);
-    add_node(&tile6);
-    add_node(&tile7);
-    add_node(&player.kinematic);
+    add_node(&tile, &kinematic_HEAD);
+    add_node(&tile2, &kinematic_HEAD);
+    add_node(&tile3, &kinematic_HEAD);
+    add_node(&tile4, &kinematic_HEAD);
+    add_node(&tile5, &kinematic_HEAD);
+    add_node(&tile6, &kinematic_HEAD);
+    add_node(&tile7, &kinematic_HEAD);
+    add_node(&player.kinematic, &kinematic_HEAD);
     
     SetTargetFPS(60);               // Set our game to run at 60 frames-per-second
     //--------------------------------------------------------------------------------------
@@ -126,7 +126,7 @@ int main()
 
     // De-Initialization
     //--------------------------------------------------------------------------------------
-    free_list();
+    free_list(&kinematic_HEAD);
     free_afterimages(&player);
     CloseWindow();        // Close window and OpenGL context
     //--------------------------------------------------------------------------------------
diff --git a/utilities/linked_list.c b/utilities/linked_list.c
index c48b179..bed6933 100644
--- a/utilities/linked_list.c
+++ b/utilities/linked_list.c
@@ -3,28 +3,25 @@
 
 // Placeholder collision checking structure. Use linked list for now
 // Need to implement some sort of tree structure for efficient collision checking
-struct kinematic_obj_node *kinematic_HEAD = NULL;
 
-void add_node(struct kinematic_obj *obj){
+void add_node(struct kinematic_obj *obj, struct kinematic_obj_node **HEAD){
     struct kinematic_obj_node *node = malloc(sizeof(struct kinematic_obj_node));
     if (node){
         node->obj = obj;
         node->next = NULL;
     }
-    if (kinematic_HEAD == NULL){
-        kinematic_HEAD = node;
-    }else{
-        node->next = kinematic_HEAD;
-        kinematic_HEAD = node;
-    }
+    if (*HEAD != NULL)
+        node->next = *HEAD;
+    
+    *HEAD = node;
 }
 
 /**struct kinematic_obj_node **get_list(){
     return &kinematic_HEAD;
 }*/
 
-void free_list(){
-    struct kinematic_obj_node *current = kinematic_HEAD;
+void free_list(struct kinematic_obj_node **HEAD){
+    struct kinematic_obj_node *current = *HEAD;
     struct kinematic_obj_node *next;
     while(current){
         next = current->next;
@@ -32,7 +29,7 @@ void free_list(){
         free(current);
         current = next;
     }
-    kinematic_HEAD = NULL;
+    *HEAD = NULL;
 }
 
 void create_afterimage(struct player_obj *player, Color color){