Implement simple animation system

Changelog:
- Add sprite map for player
- Add an animation system
- Add a placeholder player sprite transition function

engine/CMakeLists.txt

@@ -2,6 +2,7 @@ add_subdirectory(EC)
 add_library(lib_scenes STATIC
     engine.c
     assets.c
+    assets_maps.c
     editor_scene.c
     menu_scene.c
     game_systems.c

engine/EC/components.h

@@ -2,6 +2,7 @@
 #define __COMPONENTS_H
 #include "raylib.h"
 #include <stdint.h>
+#include "entity.h"
 // TODO: Look at sc to use macros to auto generate functions
 
 #define N_COMPONENTS 10
@@ -125,10 +126,14 @@ typedef struct Sprite
     char* name;
 }Sprite_t;
 
+typedef unsigned int (*sprite_transition_func_t)(Entity_t *ent); // Transition requires knowledge of the entity
 typedef struct _CSprite_t
 {
+    const char * const *sprites_map; //Array of all sprite names associated
     Sprite_t* sprite;
+    sprite_transition_func_t transition_func;
     Vector2 offset;
+    unsigned int current_idx;
 }CSprite_t;
 
 static inline void set_bbox(CBBox_t* p_bbox, unsigned int x, unsigned int y)

engine/assets_maps.c

@@ -0,0 +1,8 @@
+#include "assets_maps.h"
+
+
+const char * const player_sprite_map[N_PLAYER_SPRITES] =
+{
+    "plr_stand",
+    "plr_run",
+};

engine/assets_maps.h

@@ -0,0 +1,13 @@
+#ifndef __ASSETS_MAPS_H
+#define __ASSETS_MAPS_H
+
+#define N_PLAYER_SPRITES 2
+enum PlayerSpriteEnum
+{
+    SPR_PLAYER_STAND = 0,
+    SPR_PLAYER_RUN
+};
+
+extern const char * const player_sprite_map[N_PLAYER_SPRITES];
+
+#endif // __ASSETS_MAPS_H

engine/editor_scene.c

@@ -1,6 +1,7 @@
 #include "scene_impl.h"
 #include "game_systems.h"
 #include "constants.h"
+#include "assets_maps.h"
 #include "raylib.h"
 #include "raymath.h"
 #include <stdio.h>
@@ -212,6 +213,8 @@ static void spawn_player(Scene_t *scene)
     };
     CSprite_t* p_cspr = add_component(&scene->ent_manager, p_ent, CSPRITE_T);
     p_cspr->sprite = get_sprite(&scene->engine->assets, "plr_stand");
+    p_cspr->sprites_map = player_sprite_map;
+    p_cspr->transition_func = &player_sprite_transition_func;
 }
 
 static void toggle_block_system(Scene_t *scene)
@@ -336,6 +339,7 @@ void init_level_scene(LevelScene_t *scene)
     //sc_array_add(&scene->scene.systems, &update_tilemap_system);
     sc_array_add(&scene->scene.systems, &state_transition_update_system);
     sc_array_add(&scene->scene.systems, &player_ground_air_transition_system);
+    sc_array_add(&scene->scene.systems, &sprite_animation_system);
     sc_array_add(&scene->scene.systems, &toggle_block_system);
 
     // This avoid graphical glitch, not essential

engine/game_systems.c

@@ -1,6 +1,7 @@
 #include "game_systems.h"
 #include "AABB.h"
 #include "constants.h"
+#include "assets_maps.h"
 #include <stdio.h>
 
 static const Vector2 TILE_SZ = {TILE_SIZE, TILE_SIZE};
@@ -888,6 +889,39 @@ void hitbox_update_system(Scene_t *scene)
     }
 }
 
+void sprite_animation_system(Scene_t *scene)
+{
+    unsigned int ent_idx;
+    CSprite_t* p_cspr;
+    sc_map_foreach(&scene->ent_manager.component_map[CSPRITE_T], ent_idx, p_cspr)
+    {
+        Entity_t *p_ent =  get_entity(&scene->ent_manager, ent_idx);
+        // Update animation state
+        if (p_cspr->transition_func != NULL)
+        {
+            unsigned int spr_idx = p_cspr->transition_func(p_ent);
+            if (p_cspr->current_idx != spr_idx)
+            {
+                Sprite_t* new_spr = get_sprite(&scene->engine->assets, p_cspr->sprites_map[spr_idx]);
+                if (new_spr != NULL)
+                {
+                    p_cspr->sprite = new_spr;
+                    p_cspr->current_idx = spr_idx;
+                    p_cspr->sprite->current_frame = 0;
+                }
+            }
+        }
+        // Animate it (handle frame count)
+        p_cspr->sprite->elapsed++;
+        if (p_cspr->sprite->elapsed == p_cspr->sprite->speed)
+        {
+            p_cspr->sprite->current_frame++;
+            p_cspr->sprite->current_frame %= p_cspr->sprite->frame_count;
+            p_cspr->sprite->elapsed = 0;
+        }
+    }
+}
+
 void init_level_scene_data(LevelSceneData_t *data)
 {
     sc_map_init_32(&data->collision_events, 128, 0);
@@ -897,3 +931,8 @@ void term_level_scene_data(LevelSceneData_t *data)
 {
     sc_map_term_32(&data->collision_events);
 }
+
+unsigned int player_sprite_transition_func(Entity_t* ent)
+{
+    return SPR_PLAYER_RUN;
+}

engine/game_systems.h

@@ -14,4 +14,7 @@ void player_ground_air_transition_system(Scene_t* scene);
 void state_transition_update_system(Scene_t *scene);
 void update_tilemap_system(Scene_t *scene);
 void hitbox_update_system(Scene_t *scene);
+void sprite_animation_system(Scene_t *scene);
+
+unsigned int player_sprite_transition_func(Entity_t* ent);
 #endif // __GAME_SYSTEMS_H