Implement runner movement to lowest position

Changelog:
- Add new state for when runner reaches target position
- Skip movement if already on target position
- Add extra handling for spawning on solid tile
- Fix tile toggling bug on the same tile

scenes/engine/EC/EC.h

@@ -141,9 +141,20 @@ typedef struct _BFSTileMap {
     uint32_t len;
 }BFSTileMap_t;
 
+typedef enum _WaterRunnerState
+{
+    LOWEST_POINT_SEARCH = 0,
+    LOWEST_POINT_MOVEMENT,
+    SCANLINE_FILL,
+}WaterRunerState_t;
+
 typedef struct _CWaterRunner {
-    int32_t current_tile;
     BFSTileMap_t bfs_tilemap;
+    int32_t current_tile;
+    int32_t target_tile;
+    struct sc_queue_32 bfs_queue;
+    bool* visited;
+    WaterRunerState_t state;
 }CWaterRunner_t;
 
 // Credits to bedroomcoders.co.uk for this

scenes/engine/EC/entManager.c

@@ -37,7 +37,10 @@ void update_entity_manager(EntityManager_t* p_manager)
         if (!p_entity) continue;
         for (size_t i = 0; i < N_COMPONENTS; ++i)
         {
-            remove_component(p_entity, i);
+            if (p_entity->components[i] == MAX_COMP_POOL_SIZE) continue;
+            free_component_to_mempool(i, p_entity->components[i]);
+            sc_map_del_64v(&p_manager->component_map[i], e_idx);
+            p_entity->components[i] = MAX_COMP_POOL_SIZE;
         }
         sc_map_del_64v(&p_manager->entities_map[p_entity->m_tag], e_idx);
         free_entity_to_mempool(e_idx);

scenes/engine/collisions.h

@@ -15,6 +15,7 @@ typedef struct Tile {
     SolidType_t solid;
     uint8_t def;
     unsigned int water_level;
+    unsigned int max_water_level;
     struct sc_map_64v entities_set;
     Vector2 offset;
     Vector2 size;

scenes/water_flow.c

@@ -1,6 +1,6 @@
 #include "water_flow.h"
-
-
+#include "sc/queue/sc_queue.h"
+#include <stdio.h>
 Entity_t* create_water_runner(EntityManager_t* ent_manager, int32_t width, int32_t height, int32_t start_tile)
 {
     Entity_t* p_filler = add_entity(ent_manager, DYNMEM_ENT_TAG);
@@ -22,7 +22,11 @@ Entity_t* create_water_runner(EntityManager_t* ent_manager, int32_t width, int32
     p_crunner->bfs_tilemap.height = height;
     p_crunner->bfs_tilemap.len = total;
 
+    sc_queue_init(&p_crunner->bfs_queue);
+    p_crunner->visited = calloc(total, sizeof(bool));
+
     p_crunner->current_tile = start_tile;
+    p_crunner->target_tile = total;
 
     CTransform_t* p_ct = add_component(p_filler, CTRANSFORM_COMP_T);
     p_ct->movement_mode = KINEMATIC_MOVEMENT;
@@ -34,10 +38,11 @@ void free_water_runner(Entity_t* ent, EntityManager_t* ent_manager)
 {
     CWaterRunner_t* p_crunner = get_component(ent, CWATERRUNNER_T);
     free(p_crunner->bfs_tilemap.tilemap);
+    free(p_crunner->visited);
+    sc_queue_term(&p_crunner->bfs_queue);
     remove_entity(ent_manager, ent->m_id);
 }
 
-
 void update_water_runner_system(Scene_t* scene)
 {
     // The core of the water runner is to:
@@ -45,17 +50,158 @@ void update_water_runner_system(Scene_t* scene)
     //  - Scanline fill
     // A runner is given an amount of movement cost
     // Within the movement cost, do the following logic
-    // Perform a modified DFS to find the lowest point:
+    // Perform a modified BFS to find the lowest point:
     //  - Solid tiles are not reachable
     //  - If bottom tile is non-solid, that is the only reachable tile,
     //  - If bottom tile is filled with water fully, down+left+right are reachable
     //  - If bottom tile is solid, left+right are reachable
     //  - If bottom tile is OOB, terminate
-    // Use a LIFO to deal with this.
+    // Use a FIFO to deal with this.
     // On DFS completion, find the path to the lowest point. Keep track of this 
     // The DFS should have figured out all reachable tiles, start scanline filling at the lowest point.
     // On completion, move up update tile reachability by DFS on the current level. (repeat first step)
     //  - No need to recheck already reachable tiles
     //  - If current tile is solid, scan left and right for reachable tile and start from there
     // Repeat scanline fill
+    LevelSceneData_t* data = &(CONTAINER_OF(scene, LevelScene_t, scene)->data);
+    TileGrid_t tilemap = data->tilemap;
+
+    CWaterRunner_t* p_crunner;
+    unsigned int ent_idx;
+    sc_map_foreach(&scene->ent_manager.component_map[CWATERRUNNER_T], ent_idx, p_crunner)
+    {
+        Entity_t* ent = get_entity(&scene->ent_manager, ent_idx);
+        if (tilemap.tiles[p_crunner->current_tile].solid == SOLID)
+        {
+            CTileCoord_t* p_tilecoord = get_component(
+                ent, CTILECOORD_COMP_T
+            );
+            for (size_t i = 0;i < p_tilecoord->n_tiles; ++i)
+            {
+                // Use previously store tile position
+                // Clear from those positions
+                unsigned int tile_idx = p_tilecoord->tiles[i];
+                sc_map_del_64v(&(tilemap.tiles[tile_idx].entities_set), ent_idx);
+            }
+            free_water_runner(ent, &scene->ent_manager);
+            continue;
+        }
+
+        static uint8_t delay = 5;
+        switch (p_crunner->state)
+        {
+            case LOWEST_POINT_SEARCH:
+            {
+                for (size_t i = 0; i < p_crunner->bfs_tilemap.len; ++i)
+                {
+                    p_crunner->bfs_tilemap.tilemap[i].from = -1;
+                    p_crunner->bfs_tilemap.tilemap[i].reachable = false;
+                }
+                memset(p_crunner->visited, 0, p_crunner->bfs_tilemap.len * sizeof(bool));
+                int32_t lowest_tile = p_crunner->current_tile;
+                sc_queue_add_last(&p_crunner->bfs_queue, p_crunner->current_tile);
+                while (!sc_queue_empty(&p_crunner->bfs_queue))
+                {
+                    unsigned int curr_idx = sc_queue_peek_first(&p_crunner->bfs_queue);
+                    sc_queue_del_first(&p_crunner->bfs_queue);
+
+                    unsigned int curr_height = curr_idx / p_crunner->bfs_tilemap.width;
+                    unsigned int curr_low = lowest_tile / p_crunner->bfs_tilemap.width;
+                    if (curr_height > curr_low)
+                    {
+                        lowest_tile = curr_idx;
+                    }
+
+                    p_crunner->visited[curr_idx] = true;
+                    p_crunner->bfs_tilemap.tilemap[curr_idx].reachable = true;
+                    // Possible optimisation to avoid repeated BFS, dunno how possible
+
+                    unsigned int next = curr_idx + p_crunner->bfs_tilemap.width;
+                    if (next >= p_crunner->bfs_tilemap.len) continue;
+
+                    Tile_t* next_tile = tilemap.tiles + next;
+                    if (
+                        next_tile->solid != SOLID
+                        && next_tile->water_level < next_tile->max_water_level
+                        && !p_crunner->visited[next]
+                    )
+                    {
+                        sc_queue_add_last(&p_crunner->bfs_queue, next);
+                        p_crunner->bfs_tilemap.tilemap[next].from = curr_idx;
+                    }
+                    else
+                    {
+                        next = curr_idx - 1;
+                        if (next % p_crunner->bfs_tilemap.width != 0)
+                        {
+                            next_tile = tilemap.tiles + next;
+                            if (
+                                next_tile->solid != SOLID
+                                && next_tile->water_level < next_tile->max_water_level
+                                && !p_crunner->visited[next]
+                            )
+                            {
+                                sc_queue_add_last(&p_crunner->bfs_queue, next);
+                                p_crunner->bfs_tilemap.tilemap[next].from = curr_idx;
+                            }
+                        }
+                        next = curr_idx + 1;
+                        if (next % p_crunner->bfs_tilemap.width != 0)
+                        {
+                            next_tile = tilemap.tiles + next;
+                            if (
+                                next_tile->solid != SOLID
+                                && next_tile->water_level < next_tile->max_water_level
+                                && !p_crunner->visited[next]
+                            )
+                            {
+                                sc_queue_add_last(&p_crunner->bfs_queue, next);
+                                p_crunner->bfs_tilemap.tilemap[next].from = curr_idx;
+                            }
+                        }
+                    }
+                }
+                p_crunner->target_tile = lowest_tile;
+
+                if (p_crunner->target_tile == p_crunner->current_tile)
+                {
+                    p_crunner->state = SCANLINE_FILL;
+                    break;
+                }
+                // Trace path from lowest_tile
+                unsigned int prev_idx = lowest_tile;
+                unsigned int curr_idx = p_crunner->bfs_tilemap.tilemap[prev_idx].from;
+                while (p_crunner->bfs_tilemap.tilemap[prev_idx].from >= 0)
+                {
+                    p_crunner->bfs_tilemap.tilemap[curr_idx].to = prev_idx;
+                    prev_idx = curr_idx;
+                    curr_idx = p_crunner->bfs_tilemap.tilemap[prev_idx].from;
+                }
+                delay = 5;
+                p_crunner->state = LOWEST_POINT_MOVEMENT;
+            }
+            break;
+            case LOWEST_POINT_MOVEMENT:
+                delay--;
+                if (delay == 0)
+                {
+                    p_crunner->current_tile = p_crunner->bfs_tilemap.tilemap[p_crunner->current_tile].to;
+                    CTransform_t* p_ct = get_component(ent, CTRANSFORM_COMP_T);
+                    p_ct->position.x = (p_crunner->current_tile % tilemap.width) * tilemap.tile_size; 
+                    p_ct->position.y = (p_crunner->current_tile / tilemap.width) * tilemap.tile_size; 
+                    if (p_crunner->current_tile == p_crunner->target_tile)
+                    {
+                        p_crunner->state = SCANLINE_FILL;
+                    }
+                    delay = 5;
+                }
+            break;
+            default:
+            break;
+        }
+    }
+}
+
+void init_water_runner_system(void)
+{
 }

water_test.c

@@ -85,6 +85,28 @@ static void level_scene_render_func(Scene_t* scene)
             unsigned int x = ((p_runner->current_tile) % tilemap.width) * tilemap.tile_size; 
             unsigned int y = ((p_runner->current_tile) / tilemap.width) * tilemap.tile_size; 
             DrawCircle(x+16, y+16, 8, ColorAlpha(BLACK, 0.2));
+            if (p_runner->target_tile < p_runner->bfs_tilemap.len)
+            {
+                unsigned int x = ((p_runner->target_tile) % tilemap.width) * tilemap.tile_size; 
+                unsigned int y = ((p_runner->target_tile) / tilemap.width) * tilemap.tile_size; 
+                DrawCircle(x+16, y+16, 8, ColorAlpha(BLUE, 0.2));
+            }
+
+            if (p_runner->state == LOWEST_POINT_MOVEMENT)
+            {
+                unsigned int curr_idx = p_runner->current_tile;
+                unsigned int next_idx = p_runner->bfs_tilemap.tilemap[curr_idx].to;
+                while(curr_idx != p_runner->target_tile)
+                {
+                    unsigned int x1 = (curr_idx % tilemap.width) * tilemap.tile_size + tilemap.tile_size / 2; 
+                    unsigned int y1 = (curr_idx / tilemap.width) * tilemap.tile_size + tilemap.tile_size / 2; 
+                    unsigned int x2 = (next_idx % tilemap.width) * tilemap.tile_size + tilemap.tile_size / 2; 
+                    unsigned int y2 = (next_idx / tilemap.width) * tilemap.tile_size + tilemap.tile_size / 2; 
+                    DrawLine(x1, y1, x2, y2, BLACK);
+                    curr_idx = next_idx;
+                    next_idx = p_runner->bfs_tilemap.tilemap[curr_idx].to;
+                }
+            }
         }
 
         char buffer[64] = {0};
@@ -173,6 +195,10 @@ static void toggle_block_system(Scene_t* scene)
     Vector2 raw_mouse_pos = {GetMouseX(), GetMouseY()};
     raw_mouse_pos = Vector2Subtract(raw_mouse_pos, (Vector2){data->game_rec.x, data->game_rec.y});
 
+    if (IsMouseButtonReleased(MOUSE_LEFT_BUTTON))
+    {
+        last_tile_idx = MAX_N_TILES;
+    }
     if (
         raw_mouse_pos.x < data->game_rec.width
         && raw_mouse_pos.y < data->game_rec.height
@@ -189,6 +215,11 @@ static void toggle_block_system(Scene_t* scene)
             if (new_type == SOLID_TILE) tilemap.tiles[tile_idx].water_level = 0;
             change_a_tile(&tilemap, tile_idx, new_type);
             last_tile_idx = tile_idx;
+            CWaterRunner_t* p_crunner;
+            sc_map_foreach_value(&scene->ent_manager.component_map[CWATERRUNNER_T], p_crunner)
+            {
+                p_crunner->state = LOWEST_POINT_SEARCH;
+            }
         }
         else if (IsMouseButtonReleased(MOUSE_RIGHT_BUTTON))
         {
@@ -309,6 +340,7 @@ int main(void)
         all_tiles[i].solid = NOT_SOLID;
         all_tiles[i].tile_type = EMPTY_TILE;
         all_tiles[i].moveable = true;
+        all_tiles[i].max_water_level = 1;
         sc_map_init_64v(&all_tiles[i].entities_set, 16, 0);
         all_tiles[i].size = (Vector2){TILE_SIZE, TILE_SIZE};
     }
@@ -330,9 +362,12 @@ int main(void)
     sc_array_add(&scene.scene.systems, &simple_friction_system);
     sc_array_add(&scene.scene.systems, &movement_update_system);
     sc_array_add(&scene.scene.systems, &update_tilemap_system);
+    sc_array_add(&scene.scene.systems, &update_water_runner_system);
     sc_array_add(&scene.scene.systems, &toggle_block_system);
     sc_array_add(&scene.scene.systems, &camera_update_system);
     sc_array_add(&scene.scene.systems, &player_dir_reset_system);
+
+
     sc_map_put_64(&scene.scene.action_map, KEY_R, ACTION_RESTART);
     sc_map_put_64(&scene.scene.action_map, KEY_UP, ACTION_UP);
     sc_map_put_64(&scene.scene.action_map, KEY_DOWN, ACTION_DOWN);