From 3e6a53b0975208fe05106234154fc769c5a6d0c4 Mon Sep 17 00:00:00 2001
From: En Yi <en.yi@tutanota.com>
Date: Mon, 12 Dec 2022 20:29:51 +0800
Subject: [PATCH] Fix incorrect player input processing

Changelog:
- Store player dir input in LevelScene Data instead of pointer,
  to avoid use-after-free (non-fatal as mempool is used, but can cause
  unintended behaviour)
- Only process player movement in system update. This is done in the
  movement update system
- Normalise before apply acceleration, duh
---
 scene_impl.c | 27 ++++++++++++++++++---------
 scene_impl.h |  2 +-
 scene_test.c |  5 ++---
 3 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/scene_impl.c b/scene_impl.c
index ae57a8f..0a6191c 100644
--- a/scene_impl.c
+++ b/scene_impl.c
@@ -17,6 +17,19 @@ static void level_scene_render_func(Scene_t* scene)
 
 static void movement_update_system(Scene_t* scene)
 {
+    LevelSceneData_t *data = (LevelSceneData_t *)scene->scene_data;
+    float mag = Vector2Length(data->player_dir);
+    mag = (mag == 0)? 1 : mag;
+    Entity_t * p_player;
+    sc_map_foreach_value(&scene->ent_manager.entities_map[PLAYER_ENT_TAG], p_player)
+    {
+        CTransform_t* p_ctransform = get_component(&scene->ent_manager, p_player, CTRANSFORM_COMP_T);
+        p_ctransform->accel.x = data->player_dir.x * 200 * 1.0 / mag;
+        p_ctransform->accel.y = data->player_dir.y * 200 * 1.0 / mag;
+    }
+    data->player_dir.x = 0;
+    data->player_dir.y = 0;
+
     float delta_time = GetFrameTime();
     CTransform_t * p_ctransform;
     sc_map_foreach_value(&scene->ent_manager.component_map[CTRANSFORM_COMP_T], p_ctransform)
@@ -61,28 +74,24 @@ static void screen_bounce_system(Scene_t *scene)
 void level_do_action(Scene_t *scene, ActionType_t action, bool pressed)
 {
     LevelSceneData_t *data = (LevelSceneData_t *)scene->scene_data;
-    CTransform_t *p_ctransform = get_component(&scene->ent_manager, data->player, CTRANSFORM_COMP_T);
-    Vector2 dir = {0, 0};
     if (pressed)
     {
         switch(action)
         {
             case ACTION_UP:
-                dir.y -= 1;
+                data->player_dir.y = -1;
             break;
             case ACTION_DOWN:
-                dir.y += 1;
+                data->player_dir.y = 1;
             break;
             case ACTION_LEFT:
-                dir.x -= 1;
+                data->player_dir.x = -1;
             break;
             case ACTION_RIGHT:
-                dir.x += 1;
+                data->player_dir.x = 1;
             break;
         }
     }
-    p_ctransform->accel.x = dir.x * 500;
-    p_ctransform->accel.y = dir.y * 500;
 
 }
 
@@ -90,7 +99,7 @@ void init_level_scene(LevelScene_t *scene)
 {
     init_scene(&scene->scene, LEVEL_SCENE, &level_scene_render_func, &level_do_action);
     scene->scene.scene_data = &scene->data;
-    scene->data.player = NULL;
+    memset(&scene->data.player_dir, 0, sizeof(Vector2));
 
     // insert level scene systems
     sc_array_add(&scene->scene.systems, &movement_update_system);
diff --git a/scene_impl.h b/scene_impl.h
index 3d05d35..00d7544 100644
--- a/scene_impl.h
+++ b/scene_impl.h
@@ -20,7 +20,7 @@ typedef struct TileGrid
 
 typedef struct LevelSceneData
 {
-    Entity_t * player;
+    Vector2 player_dir;
     TileGrid_t tilemap;
 }LevelSceneData_t;
 
diff --git a/scene_test.c b/scene_test.c
index 28ad45e..57afc9c 100644
--- a/scene_test.c
+++ b/scene_test.c
@@ -19,14 +19,14 @@ int main(void)
     LevelScene_t scene;
     init_level_scene(&scene);
     Entity_t *p_ent = add_entity(&scene.scene.ent_manager, PLAYER_ENT_TAG);
-    scene.data.player = p_ent;
 
     CBBox_t *p_bbox = add_component(&scene.scene.ent_manager, p_ent, CBBOX_COMP_T);
     p_bbox->size.x = 30;
     p_bbox->size.y = 30;
     add_component(&scene.scene.ent_manager, p_ent, CTRANSFORM_COMP_T);
     update_entity_manager(&scene.scene.ent_manager);
-    for (size_t step = 0; step < 6000; step++)
+    //for (size_t step = 0; step < 6000; step++)
+    while(true)
     {
 
         // This entire key processing relies on the assumption that a pressed key will
@@ -68,7 +68,6 @@ int main(void)
             next_keybuf = tmp;
         }
 
-        printf("Step %lu\n", step);
         update_scene(&scene.scene);
         // This is needed to advance time delta
         BeginDrawing();