Initial implementation of camera system

Changelog:
- Implement effectively a PI controller

scenes/constants.h

@@ -15,6 +15,7 @@
 #define VIEWABLE_MAP_HEIGHT 16
 #endif
 
+#define DELTA_T 0.017
 #define GRAV_ACCEL 1500
 #define JUMP_SPEED 70
 #define MOVE_ACCEL 1300

scenes/editor_scene.c

@@ -86,13 +86,13 @@ static void level_scene_render_func(Scene_t* scene)
     TileGrid_t tilemap = data->tilemap;
 
     Entity_t* p_ent;
-    Vector2 min = GetScreenToWorld2D((Vector2){data->game_rec.x, data->game_rec.y}, data->cam);
+    Vector2 min = GetScreenToWorld2D((Vector2){data->game_rec.x, data->game_rec.y}, data->camera.cam);
     Vector2 max = GetScreenToWorld2D(
         (Vector2){
             data->game_rec.x + data->game_rec.width,
             data->game_rec.y + data->game_rec.height
         },
-        data->cam
+        data->camera.cam
     );
     min = Vector2Scale(min, 1.0f/tilemap.tile_size);
     max = Vector2Scale(max, 1.0f/tilemap.tile_size);
@@ -103,7 +103,7 @@ static void level_scene_render_func(Scene_t* scene)
 
     BeginTextureMode(data->game_viewport);
         ClearBackground(WHITE);
-        BeginMode2D(data->cam);
+        BeginMode2D(data->camera.cam);
         for (int tile_y = min.y; tile_y <= max.y; tile_y++)
         {
             for (int tile_x = min.x; tile_x <= max.x; tile_x++)
@@ -533,7 +533,7 @@ static void toggle_block_system(Scene_t* scene)
         && raw_mouse_pos.y < data->game_rec.height
     ) 
     {
-        Vector2 mouse_pos = GetScreenToWorld2D(raw_mouse_pos, data->cam);
+        Vector2 mouse_pos = GetScreenToWorld2D(raw_mouse_pos, data->camera.cam);
         unsigned int tile_idx = get_tile_idx(mouse_pos.x, mouse_pos.y, &tilemap);
         if (tile_idx >= (tilemap.n_tiles - tilemap.width)) return;
         if (tile_idx == last_tile_idx) return;

scenes/game_scene.c

@@ -19,7 +19,7 @@ static void level_scene_render_func(Scene_t* scene)
 
     BeginTextureMode(data->game_viewport);
         ClearBackground(WHITE);
-        BeginMode2D(data->cam);
+        BeginMode2D(data->camera.cam);
         for (size_t i = 0; i < tilemap.n_tiles; ++i)
         {
             char buffer[6] = {0};

scenes/game_systems.c

@@ -1125,7 +1125,7 @@ void movement_update_system(Scene_t* scene)
     LevelSceneData_t* data = &(CONTAINER_OF(scene, LevelScene_t, scene)->data);
     TileGrid_t tilemap = data->tilemap;
     // Update movement
-    float delta_time = 0.017; // TODO: Will need to think about delta time handling
+    float delta_time = DELTA_T; // TODO: Will need to think about delta time handling
     CTransform_t * p_ctransform;
     unsigned long ent_idx;
     sc_map_foreach(&scene->ent_manager.component_map[CTRANSFORM_COMP_T], ent_idx, p_ctransform)
@@ -1795,29 +1795,59 @@ void sprite_animation_system(Scene_t* scene)
 
 void camera_update_system(Scene_t* scene)
 {
-    LevelScene_t* lvl_scene = CONTAINER_OF(scene, LevelScene_t, scene);
+    LevelSceneData_t* data = &CONTAINER_OF(scene, LevelScene_t, scene)->data;
     Entity_t* p_player;
-    const int width = lvl_scene->data.game_rec.width;
+    const int width = data->game_rec.width;
-    const int height = lvl_scene->data.game_rec.height;
+    const int height =data->game_rec.height;
+    data->camera.cam.offset = (Vector2){ width/2.0f, height/2.0f };
+
+    Vector2 target_pos = {0};
+    Vector2 target_vel = {0};
     sc_map_foreach_value(&scene->ent_manager.entities_map[PLAYER_ENT_TAG], p_player)
     {
         CTransform_t* p_ctransform = get_component(p_player, CTRANSFORM_COMP_T);
-        lvl_scene->data.cam.offset = (Vector2){ width/2.0f, height/2.0f };
+        target_pos = p_ctransform->position;
-        lvl_scene->data.cam.target = p_ctransform->position;
+        target_vel = p_ctransform->velocity;
+        CMovementState_t* p_movement = get_component(p_player, CMOVEMENTSTATE_T);
+        target_pos.x += (p_movement->x_dir == 1) ? width/4: -width/4;
     }
+    
+    // Mass-Spring damper update
+    Vector2 x = Vector2Subtract(target_pos, data->camera.cam.target);
+    Vector2 v = Vector2Subtract(data->camera.current_vel, target_vel); 
+    //Vector2 F = Vector2Scale(x, data->camera.k);
+    Vector2 F = 
+        Vector2Subtract(
+            Vector2Scale(x, data->camera.k),
+            Vector2Scale(v, data->camera.c)
+        );
+
+    // Kinematics update
+    const float dt = DELTA_T;
+    Vector2 a_dt = Vector2Scale(F, dt/data->camera.mass);
+    data->camera.cam.target =
+        Vector2Add(
+            data->camera.cam.target,
+                Vector2Add(
+                    Vector2Scale(data->camera.current_vel, dt),
+                    Vector2Scale(a_dt, dt*0.5f)
+                )
+        );
+    data->camera.current_vel = Vector2Add(data->camera.current_vel, a_dt);
+
     Vector2 max = GetWorldToScreen2D(
         (Vector2){
-            fmax(lvl_scene->data.tilemap.width * TILE_SIZE, lvl_scene->data.game_rec.width),
+            fmax(data->tilemap.width * TILE_SIZE, data->game_rec.width),
-            fmax(lvl_scene->data.tilemap.height * TILE_SIZE, lvl_scene->data.game_rec.height)
+            fmax(data->tilemap.height * TILE_SIZE, data->game_rec.height)
         },
-        lvl_scene->data.cam
+        data->camera.cam
     );
-    Vector2 min = GetWorldToScreen2D((Vector2){0, 0}, lvl_scene->data.cam);
+    //Vector2 min = GetWorldToScreen2D((Vector2){0, 0}, data->camera.cam);
 
-    if (max.x < width) lvl_scene->data.cam.offset.x = width - (max.x - width/2.0f);
+    //if (max.x < width) data->camera.cam.offset.x = width - (max.x - width/2.0f);
-    if (max.y < height) lvl_scene->data.cam.offset.y = height - (max.y - height/2.0f);
+    //if (max.y < height) data->camera.cam.offset.y = height - (max.y - height/2.0f);
-    if (min.x > 0) lvl_scene->data.cam.offset.x = width/2.0f - min.x;
+    //if (min.x > 0) data->camera.cam.offset.x = width/2.0f - min.x;
-    if (min.y > 0) lvl_scene->data.cam.offset.y = height/2.0f - min.y;
+    //if (min.y > 0) data->camera.cam.offset.y = height/2.0f - min.y;
 }
 
 void level_end_detection_system(Scene_t* scene)

scenes/scene_impl.h

@@ -27,11 +27,22 @@ typedef struct CoinCounter
     uint16_t total;
 }CoinCounter_t;
 
+typedef struct LevelCamera {
+    Camera2D cam;
+    Vector2 target_pos;
+    //Vector2 prev_pos;
+    Vector2 current_vel;
+    float mass;
+    float c; // damping factor
+    float k; // spring constant
+}LevelCamera_t;
+
 typedef struct LevelSceneData {
     TileGrid_t tilemap;
     RenderTexture2D game_viewport;
     Rectangle game_rec;
-    Camera2D cam;
+    //Camera2D cam;
+    LevelCamera_t camera;
     Sprite_t* tile_sprites[MAX_TILE_SPRITES];
     LevelPack_t* level_pack;
     unsigned int current_level;

scenes/scene_systems.c

@@ -10,9 +10,13 @@ void init_level_scene_data(LevelSceneData_t* data, uint32_t max_tiles, Tile_t* t
     //data->game_rec = (Rectangle){25, 25, VIEWABLE_MAP_WIDTH*TILE_SIZE, VIEWABLE_MAP_HEIGHT*TILE_SIZE};
     data->game_viewport = LoadRenderTexture(view_zone.width, view_zone.height);
     data->game_rec = view_zone;
-    data->cam = (Camera2D){0};
+    //data->camera.cam = (Camera2D){0};
-    data->cam.rotation = 0.0f;
+    memset(&data->camera, 0, sizeof(LevelCamera_t));
-    data->cam.zoom = 1.0f;
+    data->camera.cam.rotation = 0.0f;
+    data->camera.cam.zoom = 1.0f;
+    data->camera.mass = 0.6f;
+    data->camera.c = 2.4f;
+    data->camera.k = 0.1f;
 
     data->tilemap.max_tiles = max_tiles;
     if (tiles != NULL)

water_test.c

@@ -34,7 +34,7 @@ static void level_scene_render_func(Scene_t* scene)
 
     BeginTextureMode(data->game_viewport);
         ClearBackground(WHITE);
-        BeginMode2D(data->cam);
+        BeginMode2D(data->camera.cam);
         for (size_t i = 0; i < tilemap.n_tiles; ++i)
         {
             char buffer[6] = {0};
@@ -240,7 +240,7 @@ static void toggle_block_system(Scene_t* scene)
         && raw_mouse_pos.y < data->game_rec.height
     ) 
     {
-        Vector2 mouse_pos = GetScreenToWorld2D(raw_mouse_pos, data->cam);
+        Vector2 mouse_pos = GetScreenToWorld2D(raw_mouse_pos, data->camera.cam);
         unsigned int tile_idx = get_tile_idx(mouse_pos.x, mouse_pos.y, &tilemap);
         if (tile_idx >= MAX_N_TILES) return;
         if (tile_idx == last_tile_idx) return;