Not finished. Need to commit.

Makefile

@@ -19,9 +19,7 @@ LIB_DIR := $(abspath libs/$(PLATFORM))
 CFLAGS  += -I$(LIB_DIR)
 LDFLAGS += -L$(LIB_DIR)
 
-ifeq ($(PLATFORM), linux)
-    LIBS += -lraylib -lm -lraygui
-endif
+LIBS += -lraylib -lm -lraygui
 
 SRC := $(shell find -L $(SRC_DIR) -type f -name '*.c')
 

README.md

@@ -1,5 +1,5 @@
 # snejk
-My take on the classic game "Snake". Can be played solo or with friends online.
+My take on the classic game "Snake". Can be played solo or with friends locally/online.
 
 So far, only Linux is supported.
 

src/game/instance/game_instance.c

@@ -2,20 +2,27 @@
 
 #include <assert.h>
 
-#define INPUT_QUEUE_CAPACITY 8
-
 void game_instance_init(Game_Instance *instance) {
-    instance->local_player_id = 0xFFFF;
-    // TODO: SS - Init input-queue.
+    instance->amount_of_local_players = 0;
     instance->simulation_accumulator = 0.0f; // TODO: SS - Should probably be moved to the Ingame context.
     instance->game_session = NULL;
     memset(&instance->game_networking, 0, sizeof(Game_Networking));
 
-    squeue_init(&instance->local_input_queue, 4, sizeof(Simulation_Game_Input));
+    for(uint8_t i = 0; i < MAX_LOCAL_PLAYERS; i++) {
+        Locally_Controlled_Player *locally_controlled_player = &instance->locally_controlled_players[i];
+        squeue_init(
+            &locally_controlled_player->input_queue,
+            MAX_INPUTS_IN_QUEUE_PER_LOCAL_PLAYER,
+            sizeof(Simulation_Game_Input)
+        );
+    }
 }
 
 void game_instance_dispose(Game_Instance *instance) {
-    squeue_free(&instance->local_input_queue);
+    for(uint8_t i = 0; i < MAX_LOCAL_PLAYERS; i++) {
+        Locally_Controlled_Player *locally_controlled_player = &instance->locally_controlled_players[i];
+        squeue_free(&locally_controlled_player->input_queue);
+    }
 }
 
 bool game_instance_host_session(Game_Instance *instance, const Game_Session_Settings settings) {
@@ -33,7 +40,7 @@ bool game_instance_host_session(Game_Instance *instance, const Game_Session_Sett
         return false;
     }
 
-    instance->game_session = (Game_Session *)calloc(1, sizeof(Game_Session)); // LEAK
+    instance->game_session = (Game_Session *)calloc(1, sizeof(Game_Session));
 
     if(settings.online) {
         if(instance->game_networking.api != NULL) {
@@ -46,19 +53,31 @@ bool game_instance_host_session(Game_Instance *instance, const Game_Session_Sett
         uint16_t host_player_id = 0xFFFF;
         if(!networking_try_host(&instance->game_networking, instance->game_session, settings, &host_player_id)) {
             printf("Failed to host session.\n");
+            
             free(instance->game_session);
             instance->game_session = NULL;
             return false;
         }
 
-        instance->local_player_id = host_player_id;
+        game_instance_clear_local_players(instance);
+        assert(game_instance_setup_local_player(instance, host_player_id));
     }
     else {
+        if(settings.max_players > MAX_LOCAL_PLAYERS) {
+            printf("Failed. Max amount of players (when playing locally) is %u. Max amount of players in the settings is %u.\n", MAX_LOCAL_PLAYERS, settings.max_players);
+            free(instance->game_session);
+            instance->game_session = NULL;
+            return false;
+        }
+        
         game_session_init(instance->game_session, settings);
 
+        // When playing locally/offline, create the player(s) here.
+        game_instance_clear_local_players(instance);
         for(uint32_t i = 0; i < settings.max_players; i++) {
-            // When playing locally/offline, create the player(s) here.
-            assert(game_session_create_player(instance->game_session, &instance->local_player_id)); // TODO: SS - Fix me! Always assigning the newest player to be the active 'local_player_id' which isn't correct.
+            uint16_t player_id = 0xFFFF;
+            assert(game_session_create_player(instance->game_session, &player_id));
+            assert(game_instance_setup_local_player(instance, player_id));
         }
 
         printf("Created %u local players.\n", settings.max_players);
@@ -82,10 +101,11 @@ bool game_instance_join_session(Game_Instance *instance, const char *session_id)
         return false;
     }
 
-    instance->game_session = (Game_Session *)calloc(1, sizeof(Game_Session)); // LEAK
+    instance->game_session = (Game_Session *)calloc(1, sizeof(Game_Session));
 
     if(!networking_try_join(&instance->game_networking, instance->game_session, session_id)) {
         free(instance->game_session);
+        instance->game_session = NULL;
         return false;
     }
 
@@ -114,13 +134,44 @@ void game_instance_stop_session(Game_Instance *instance) {
     instance->game_session = NULL;
 }
 
-bool game_instance_push_local_input(Game_Instance *instance, Simulation_Game_Input input) {
-    return squeue_push(&instance->local_input_queue, (void *)&input);
+void game_instance_clear_local_players(Game_Instance *instance) {
+    instance->amount_of_local_players = 0;
 }
 
-bool game_instance_pop_local_input(Game_Instance *instance, Simulation_Game_Input *out_input) {
+bool game_instance_setup_local_player(Game_Instance *instance, uint16_t player_id) {
+    if(instance->amount_of_local_players >= MAX_LOCAL_PLAYERS) {
+        return false;
+    }
+
+    Locally_Controlled_Player *locally_controlled_player = &instance->locally_controlled_players[instance->amount_of_local_players];
+    assert(locally_controlled_player != NULL);
+    instance->amount_of_local_players += 1;
+
+    locally_controlled_player->player_id = player_id;
+    squeue_clear(&locally_controlled_player->input_queue);
+
+    return true;
+}
+
+bool game_instance_push_local_input(Game_Instance *instance, uint8_t local_player_index, Simulation_Game_Input input) {
+    assert(local_player_index < MAX_LOCAL_PLAYERS);
+    assert(local_player_index < instance->amount_of_local_players);
+
+    Locally_Controlled_Player *locally_controlled_player = &instance->locally_controlled_players[local_player_index];
+    assert(locally_controlled_player != NULL);
+
+    return squeue_push(&locally_controlled_player->input_queue, (void *)&input);
+}
+
+bool game_instance_pop_local_input(Game_Instance *instance, uint8_t local_player_index, Simulation_Game_Input *out_input) {
+    assert(local_player_index < MAX_LOCAL_PLAYERS);
+    assert(local_player_index < instance->amount_of_local_players);
+
+    Locally_Controlled_Player *locally_controlled_player = &instance->locally_controlled_players[local_player_index];
+    assert(locally_controlled_player != NULL);
+    
     Simulation_Game_Input input = {0};
-    if(!squeue_pop(&instance->local_input_queue, (void *)&input)) {
+    if(!squeue_pop(&locally_controlled_player->input_queue, (void *)&input)) {
         return false;
     }
 

src/game/instance/game_instance.h

@@ -8,9 +8,17 @@
 
 #include "shared/squeue.h"
 
+#define MAX_LOCAL_PLAYERS 4
+#define MAX_INPUTS_IN_QUEUE_PER_LOCAL_PLAYER 4
+
 typedef struct {
-    uint16_t local_player_id; // TODO: SS - We need to modify this to support local multiplayer.
-    SQueue local_input_queue;
+    uint16_t player_id;
+    SQueue input_queue;
+} Locally_Controlled_Player;
+
+typedef struct {
+    Locally_Controlled_Player locally_controlled_players[MAX_LOCAL_PLAYERS];
+    uint8_t amount_of_local_players;
 
     double simulation_accumulator;
     
@@ -23,10 +31,12 @@ void game_instance_dispose(Game_Instance *instance);
 
 bool game_instance_host_session(Game_Instance *instance, const Game_Session_Settings settings);
 bool game_instance_join_session(Game_Instance *instance, const char *session_id);
-
 void game_instance_stop_session(Game_Instance *instance);
 
-bool game_instance_push_local_input(Game_Instance *instance, Simulation_Game_Input input);
-bool game_instance_pop_local_input(Game_Instance *instance, Simulation_Game_Input *out_input);
+void game_instance_clear_local_players(Game_Instance *instance);
+bool game_instance_setup_local_player(Game_Instance *instance, uint16_t player_id);
+
+bool game_instance_push_local_input(Game_Instance *instance, uint8_t local_player_index, Simulation_Game_Input input);
+bool game_instance_pop_local_input(Game_Instance *instance, uint8_t local_player_index, Simulation_Game_Input *out_input);
 
 #endif

src/game/presentation/states/state_ingame.c

@@ -26,7 +26,7 @@ static void state_enter(Presentation_State *state) {
         .offset     = (Vector2) { 0, 0 },
         .target     = (Vector2) { 0, 0 },
         .rotation   = 0.0f,
-        .zoom       = 3.0f
+        .zoom       = 2.0f
     };
 
     // TODO: SS - Maybe put the textures in an array and index them using an enum?
@@ -43,6 +43,39 @@ static void state_enter(Presentation_State *state) {
     assert(IsTextureValid(ctx->texture_snake_body));
 }
 
+static Simulation_Game_Input gather_input_for_local_player(uint8_t local_player_index) {
+    switch(local_player_index) {
+        case 0: {
+            return (Simulation_Game_Input) {
+                .right  = IsKeyPressed(KEY_D),
+                .left   = IsKeyPressed(KEY_A)
+            };
+        }
+        case 1: {
+            return (Simulation_Game_Input) {
+                .right  = IsKeyPressed(KEY_RIGHT),
+                .left   = IsKeyPressed(KEY_LEFT)
+            };
+        }
+        case 2: {
+            return (Simulation_Game_Input) {
+                .right  = IsKeyPressed(KEY_L),
+                .left   = IsKeyPressed(KEY_J)
+            };
+        }
+        case 3: {
+            return (Simulation_Game_Input) {
+                .right  = IsKeyPressed(KEY_H),
+                .left   = IsKeyPressed(KEY_F)
+            };
+        }
+        default: {
+            assert(false);
+            return (Simulation_Game_Input) {0};
+        }
+    }
+}
+
 static void state_tick(Presentation_State *state) {
     Presentation_State_Ingame_Context *ctx = (Presentation_State_Ingame_Context *)state->context;
     (void)ctx;
@@ -53,16 +86,23 @@ static void state_tick(Presentation_State *state) {
     assert(session != NULL);
 
     { // Push local input to queue.
-        Simulation_Game_Input input = (Simulation_Game_Input) { // NOTE: SS - This needs to be slightly modified to support N local players.
-            .up     = IsKeyDown(KEY_UP)     || IsKeyDown(KEY_W),
-            .down   = IsKeyDown(KEY_DOWN)   || IsKeyDown(KEY_S),
-            .right  = IsKeyDown(KEY_RIGHT)  || IsKeyDown(KEY_D),
-            .left   = IsKeyDown(KEY_LEFT)   || IsKeyDown(KEY_A)
-        };
+        if(instance->amount_of_local_players == 1) { // If playing alone (either singleplayer or online-multiplayer), more inputs are allowed.
+            Simulation_Game_Input input = (Simulation_Game_Input) {
+                .right  = IsKeyPressed(KEY_RIGHT)  || IsKeyPressed(KEY_D),
+                .left   = IsKeyPressed(KEY_LEFT)   || IsKeyPressed(KEY_A)
+            };
 
-        if(!simulation_input_equal(input, ctx->prev_local_input)) {            
-            game_instance_push_local_input(instance, input);
-            ctx->prev_local_input = input;
+            if(!simulation_input_empty(input)) {
+                game_instance_push_local_input(instance, 0, input);
+            }
+        }
+        else if(instance->amount_of_local_players > 1) {
+            for(uint8_t i = 0; i < instance->amount_of_local_players; i++) {
+                Simulation_Game_Input input = gather_input_for_local_player(i);
+                if(!simulation_input_empty(input)) {
+                    game_instance_push_local_input(instance, i, input);
+                }
+            }
         }
     }
 
@@ -72,24 +112,26 @@ static void state_tick(Presentation_State *state) {
     const double sim_dt = 1.0f / session->settings.tickrate;
 
     while (ctx->simulation_accumulator >= sim_dt) {
-        // Pop input from instance's local_input_queue and set the local player's input to it, if we have one.
-        Simulation_Game_Input input = {0};
-        if(game_instance_pop_local_input(instance, &input)) {
-            // TODO: SS - We should probably check if this input is invalid for the snake. (pressing "go right" when going left, for example.)
-            // If it is invalid, the next input in the queue should be tried.
-            game_session_set_player_input(session, instance->local_player_id, input);
+        for(uint16_t i = 0; i < instance->amount_of_local_players; i++) {
+            // Pop input from local-player's input_queue and set the player's input to it, if we have one.
+            Simulation_Game_Input input = {0};
+            game_instance_pop_local_input(instance, i, &input);
+            game_session_set_player_input(session, i, input);
         }
 
         game_session_tick(session);
         ctx->simulation_accumulator -= sim_dt;
     }
 
+    // TODO: SS - I believe that this is where we should send game-messages to the clients and the host.
+
     { // TEMP: SS
         if(IsKeyPressed(KEY_TAB)) {
             ctx->debug_draw_session_details = !ctx->debug_draw_session_details;
         }
 
         if(IsKeyPressed(KEY_ESCAPE)) {
+            // TODO: SS - Show pause-menu instead.
             presentation_state_machine_go_to(&presentation_state_main_menu);
         }
     }
@@ -99,6 +141,38 @@ uint32_t floor_texture_variant(uint32_t x, uint32_t y, uint32_t seed, uint32_t n
     return (wang_hash(x * 73856093u ^ y * 19349663u ^ seed)) % num_variants;
 }
 
+Color get_tint_for_player_id(uint16_t player_id) { // TODO: SS - Could get values from 'the active color-palette'.
+    switch(player_id) {
+        case 0: {
+            return (Color) { 255, 135, 102, 255 };
+        }
+        case 1: {
+            return (Color) { 230, 204, 138, 255 };
+        }
+        case 3: {
+            return (Color) { 240, 236, 226, 255 };
+        }
+        case 4: {
+            return (Color) { 77, 106, 148, 255 };
+        }
+        case 5: {
+            return (Color) { 36, 43, 74, 255 };
+        }
+        case 6: {
+            return (Color) { 153, 92, 149, 255 };
+        }
+        case 7: {
+            return (Color) { 245, 79, 79, 255 };
+        }
+        case 8: {
+            return (Color) { 53, 121, 133, 255 };
+        }
+        default: {
+            return (Color) { 82, 33, 110, 255 };
+        }
+    }
+}
+
 #define SHADOW_ALPHA 64
 
 static void state_render(Presentation_State *state) {
@@ -151,7 +225,21 @@ static void state_render(Presentation_State *state) {
 
                 switch(entity->type) {
                     case Entity_Type_Snake_Head: {
-                        Color tint = (Color) { 255, 135, 102, 255 }; // TODO: SS - Get tint based on player ID.
+
+                        Color tint = (Color) { 255, 255, 255, 255 };
+                        // Set the snake's tint based on player-index.
+                        for(uint16_t i = 0; i < world->max_players; i++) {
+                            Game_World_Player *player = &world->players[i];
+                            if(!player->active) {
+                                continue;
+                            }
+
+                            if(player->entity_id == entity->id) {
+                                tint = get_tint_for_player_id(i); // NOTE: SS - It's more like player-index. This needs to change if they're not sorted (but they are at the moment and I don't really plan on switching that up.)
+                                break;
+                            }
+                        }
+
                         Vector2 origin = (Vector2) { GRID_CELL_SIZE/2, GRID_CELL_SIZE/2 };
 
                         Entity *e = entity;
@@ -276,6 +364,9 @@ static void state_render(Presentation_State *state) {
             }
         }
 
+        // TODO: SS - Let the main-camera follow the entity you're controlling?
+
+
         // TODO: SS - Switch on 'sim_world->match_state'.
 
         if(ctx->debug_draw_session_details) {
@@ -313,7 +404,7 @@ static void state_render(Presentation_State *state) {
                     networking->is_host ? "true" : "false",
                     networking->session_id,
                     networking->local_client_id,
-                    instance->local_player_id,
+                    instance->locally_controlled_players[0].player_id,
                     game_session_get_amount_of_active_players(session), sim_world->max_players
                 );
             }

src/game/presentation/states/state_ingame.h

@@ -10,7 +10,6 @@
 typedef struct {
     Game_Instance *game_instance;
     double simulation_accumulator;
-    Simulation_Game_Input prev_local_input;
 
     Camera2D main_camera;
 

src/game/presentation/states/state_main_menu.c

@@ -14,37 +14,48 @@ static void state_enter(Presentation_State *state) {
     (void)ctx;
 
     ctx->mode = Main_Menu_Mode_Home;
+
+    SetExitKey(KEY_ESCAPE);
 }
 
 static void state_tick(Presentation_State *state) {
     Presentation_State_Main_Menu_Context *ctx = (Presentation_State_Main_Menu_Context *)state->context;
 
-    { // DEBUG
-        if(IsKeyPressed(KEY_P)) {
-            printf("Shortcut to singleplayer.\n");
-            game_session_init_default_settings(false, &ctx->session_settings);
-            ctx->session_settings.max_players = 1;
+    switch(ctx->mode) {
+        case Main_Menu_Mode_Home: {
+            { // DEBUG
+                if(IsKeyPressed(KEY_P)) {
+                    printf("Shortcut to singleplayer.\n");
+                    game_session_init_default_settings(false, &ctx->session_settings);
+                    ctx->session_settings.max_players = 1;
                     
-            if(game_instance_host_session(ctx->game_instance, ctx->session_settings)) {
-                ctx->ingame_ctx->game_instance = ctx->game_instance;
-                presentation_state_machine_go_to(&presentation_state_ingame);
-            }
-            else {
-                printf("Failed to play.\n");
+                    if(game_instance_host_session(ctx->game_instance, ctx->session_settings)) {
+                        ctx->ingame_ctx->game_instance = ctx->game_instance;
+                        presentation_state_machine_go_to(&presentation_state_ingame);
+                    }
+                    else {
+                        printf("Failed to play.\n");
+                    }
+                }
+                else if(IsKeyPressed(KEY_L)) {
+                    printf("Shortcut to local multiplayer (2 players).\n");
+                    game_session_init_default_settings(false, &ctx->session_settings);
+                    ctx->session_settings.max_players = 2;
+                    
+                    if(game_instance_host_session(ctx->game_instance, ctx->session_settings)) {
+                        ctx->ingame_ctx->game_instance = ctx->game_instance;
+                        presentation_state_machine_go_to(&presentation_state_ingame);
+                    }
+                    else {
+                        printf("Failed to play.\n");
+                    }
+                }
             }
+            
+            break;
         }
-        else if(IsKeyPressed(KEY_L)) {
-            printf("Shortcut to local multiplayer (2 players).\n");
-            game_session_init_default_settings(false, &ctx->session_settings);
-            ctx->session_settings.max_players = 2;
-            
-            if(game_instance_host_session(ctx->game_instance, ctx->session_settings)) {
-                ctx->ingame_ctx->game_instance = ctx->game_instance;
-                presentation_state_machine_go_to(&presentation_state_ingame);
-            }
-            else {
-                printf("Failed to play.\n");
-            }
+        default: {
+            break;
         }
     }
 }
@@ -75,8 +86,6 @@ static void state_render(Presentation_State *state) {
         case Main_Menu_Mode_Singleplayer: {
             ctx->mode = Main_Menu_Mode_Game_Setup;
             game_session_init_default_settings(false, &ctx->session_settings);
-            ctx->ingame_ctx->game_instance = ctx->game_instance;
-            presentation_state_machine_go_to(&presentation_state_ingame);
 
             break;
         }
@@ -89,12 +98,7 @@ static void state_render(Presentation_State *state) {
                 ctx->mode = Main_Menu_Mode_Multiplayer_Join;
 
                 memset(&ctx->session_id_input, 0, sizeof(ctx->session_id_input));
-                ctx->session_id_input[0] = 'A';
-                ctx->session_id_input[1] = 'B';
-                ctx->session_id_input[2] = 'C';
-                ctx->session_id_input[3] = 'D';
-                ctx->session_id_input[4] = 'E';
-                ctx->session_id_input[5] = 'F';
+                // snprintf(&ctx->session_id_input[0], sizeof(ctx->session_id_input) + 1, "ABCDEF");
             }
             if (GuiButton((Rectangle){ 64, 64 + (BUTTON_HEIGHT * 2), 128, BUTTON_HEIGHT }, "Back to Main Menu")) {
                 ctx->mode = Main_Menu_Mode_Home;
@@ -125,7 +129,7 @@ static void state_render(Presentation_State *state) {
                 }
             }
             if (GuiButton((Rectangle){ 64, 64 + (BUTTON_HEIGHT * 1), 128, BUTTON_HEIGHT }, "Cancel")) {
-                ctx->mode = ctx->session_settings.max_players == 1 ? Main_Menu_Mode_Home : Main_Menu_Mode_Multiplayer;
+                ctx->mode = Main_Menu_Mode_Home;
             }
 
             break;
@@ -136,7 +140,7 @@ static void state_render(Presentation_State *state) {
             int pressed_button_index = GuiTextInputBox(
                 (Rectangle) { 64, 64, 256, 128 }, // Bounds
                 "Session-ID", // Title
-                NULL, // Message
+                "6 characters expected. (ABCDEF)", // Message
                 "Join", // Buttons
                 &ctx->session_id_input[0], // Text
                 sizeof(ctx->session_id_input) + 1, // Text max size
@@ -170,6 +174,8 @@ static void state_render(Presentation_State *state) {
 static void state_exit(Presentation_State *state) {
     (void)state;
     printf("Exited main menu\n");
+
+    SetExitKey(KEY_NULL);
 }
 
 Presentation_State presentation_state_main_menu;

src/game/session/game_session.c

@@ -43,7 +43,7 @@ void game_session_init_default_settings(bool online, Game_Session_Settings *out_
     out_settings->online       = online;
     out_settings->tickrate     = 10.0;
     out_settings->level_width  = 64;
-    out_settings->level_height = 32;
+    out_settings->level_height = 48;
     out_settings->max_players  = online ? 8 : 2;
 }
 

src/game/session/multiplayer_api.c

@@ -392,7 +392,7 @@ int mp_api_join(MultiplayerApi *api,
     return joinAccepted ? MP_API_OK : MP_API_ERR_REJECTED;
 }
 
-int mp_api_game(MultiplayerApi *api, json_t *data, const char* destination) {
+int mp_api_game(MultiplayerApi *api, json_t *data, const char* target_client_id) {
     if (!api || !data) return MP_API_ERR_ARGUMENT;
     if (api->sockfd < 0 || !api->session_id) return MP_API_ERR_STATE;
 
@@ -403,8 +403,8 @@ int mp_api_game(MultiplayerApi *api, json_t *data, const char* destination) {
     json_object_set_new(root, "session", json_string(api->session_id));
     json_object_set_new(root, "cmd", json_string("game"));
 
-	if(destination)
-		json_object_set_new(root, "destination", json_string(destination));
+	if(target_client_id)
+		json_object_set_new(root, "target_client_id", json_string(target_client_id));
 
     json_t *data_copy;
     if (json_is_object(data)) {
@@ -612,7 +612,7 @@ static void process_line(MultiplayerApi *api, const char *line) {
     }
 
     if (strcmp(cmd, "joined") != 0 &&
-        strcmp(cmd, "leaved") != 0 &&
+        strcmp(cmd, "left") != 0 &&
         strcmp(cmd, "game") != 0) {
         json_decref(root);
         return;

src/game/session/multiplayer_api.h

@@ -67,7 +67,7 @@ int mp_api_join(MultiplayerApi *api,
                 json_t **out_data);
 
 /* Skickar ett "game"‑meddelande med godtycklig JSON‑data till sessionen. */
-int mp_api_game(MultiplayerApi *api, json_t *data, const char* destination);
+int mp_api_game(MultiplayerApi *api, json_t *data, const char* target_client_id);
 
 /* Registrerar en lyssnare för inkommande events.
    Returnerar ett positivt listener‑ID, eller −1 vid fel. */

src/game/session/networking.c

@@ -17,7 +17,12 @@ static void listen_callback(
 
     (void)data;
 
-    printf("#%li :: Event: '%s' from '%s'.\n", messsage_id, event, client_id);
+    printf("%s * #%li :: Event: '%s' from '%s'.\n",
+        networking->is_host ? "Host" : "Client",
+        messsage_id,
+        event,
+        client_id
+    );
 
     assert(networking != NULL);
 
@@ -35,8 +40,17 @@ static void listen_callback(
         // TODO: SS - Send a 'game' message to the joinee with information about the session?
 
         printf("Added client-id '%s' (player-index: %u) to the map.\n", client_id, player_index);
+
+        { // TEMP: SS - Testing to see if the joinee gets a message.
+            json_t *gameData = json_object();
+            json_object_set_new(gameData, "temp", json_integer(4));
+            
+            mp_api_game(networking->api, gameData, NULL);
+
+            json_decref(gameData);
+        }
     }
-    else if(strcmp(event, "leaved") == 0) {
+    else if(strcmp(event, "left") == 0) {
         // TODO: SS - Index the hashmap using 'client_id' as the key and attempt to get the
         // player-index for that client. Run 'game_session_destroy_player()'.
 
@@ -82,11 +96,22 @@ static inline bool setup_api(Game_Networking *networking) {
     return true;
 }
 
+static inline bool shutdown_api(Game_Networking *networking) {
+    if(networking->api == NULL) {
+        return false;
+    }
+
+    mp_api_destroy(networking->api);
+    networking->api = NULL;
+
+    return true;
+}
+
 static bool start_listening(Game_Networking *networking) {
     assert(networking != NULL);
     assert(networking->api != NULL);
     
-    int listener_id = mp_api_listen(networking->api, listen_callback, (void *)networking); // TODO: SS - Change context.
+    int listener_id = mp_api_listen(networking->api, listen_callback, (void *)networking);
     if(listener_id < 0) {
         return false;
     }
@@ -118,19 +143,35 @@ bool networking_try_host(Game_Networking *networking, Game_Session *session, Gam
         return false;
     }
 
+    json_t *payload = json_object();
+	json_object_set_new(payload, "test", json_integer(settings.max_players));
+
+    json_t *data = json_object();
+	json_object_set_new(data, "name", json_string("My session")); // TODO: SS - Use 'settings.name'.
+	json_object_set_new(data, "private", json_boolean(false)); // TODO: SS - Use 'settings.private' or '!settings.public'.
+	json_object_set_new(data, "maxClients", json_integer(settings.max_players));
+	json_object_set_new(data, "payload", payload);
+
     char *session_id = NULL;
     char *local_client_id = NULL;
     json_t *response_data = NULL;
     int host_result = mp_api_host(
         networking->api,
-        NULL, // TODO: SS - Send data to server that contains the game-session's settings.
+        data,
         &session_id,
         &local_client_id,
         &response_data
     );
     if(host_result != MP_API_OK) {
         printf("Failed to host; Got result: %i.\n", host_result);
-        // TODO: SS - Shutdown API.
+        shutdown_api(networking);
+
+        if(response_data != NULL) {
+            char *response = json_dumps(response_data, 0);
+            printf("Response: '%s'.\n", response);
+            free(response);
+        }
+        
         return false;
     }
     
@@ -180,9 +221,10 @@ bool networking_try_join(Game_Networking *networking, Game_Session *session, con
     
     printf("Trying to join session using code: '%s' ...\n", session_id);
 
-    char *result_session_id;
-    char *local_client_id;
-    json_t *received_json;
+    char *result_session_id = NULL;
+    char *local_client_id = NULL;
+    json_t *received_json = NULL;
+
     int join_result = mp_api_join(
         networking->api, // API.
         session_id, // Session-code.
@@ -192,37 +234,70 @@ bool networking_try_join(Game_Networking *networking, Game_Session *session, con
         &received_json // Received JSON-data.
     );
     if(join_result != MP_API_OK) {
-        // TODO: SS - Shutdown API.
+        shutdown_api(networking);
         printf("Failed to join; Got result: %i.\n", join_result);
         return false;
     }
     assert(strcmp(result_session_id, session_id) == 0);
 
     printf("Joined session '%s', local_client_id is '%s'.\n", result_session_id, local_client_id);
-    networking->is_host = true;
+    networking->is_host = false;
     networking->game_session = session;
     networking->session_id = result_session_id;
     networking->local_client_id = local_client_id;
     
+    assert(start_listening(networking));
+    
     map_init(&networking->client_id_to_player_index);
 
     // TODO: SS - Decide how to network this..
     // Should we just receive the session's settings as well as a long list of commands of what has happened throughout the match (so far) - at least one per tick?
     // Or, should this client receive the current state of the session?
 
-    if(received_json != NULL) {
-        // TODO: SS - Read this json because it might contain valuable information.
-        json_decref(received_json);
-    }
-    
-    // TODO: SS - Stop listening.
-    assert(start_listening(networking));
     
     // TODO: SS - Set up session based on what we got in the json.
-    // game_session_init(
-    //     session,
-    //     settings
-    // );
+    Game_Session_Settings settings;
+    memset(&settings, 0, sizeof(Game_Session_Settings));
+    settings.online = true;
+    { // TEMP: SS - Get values from json.
+        settings.seed = 1337; // TODO: SS - Get from json.
+        settings.level_width = 64; // TODO: SS - Get from json.
+        settings.level_height = 48; // TODO: SS - Get from json.
+        settings.tickrate = 10.0f; // TODO: SS - Get from json.
+        settings.max_players = 8; // TODO: SS - Get from json.
+    }
+
+    if(received_json != NULL) {
+        // TODO: SS - Read this json. It should contain valuable information about the session.
+        printf("received_json is NOT NULL.\n");
+
+        char *recv_str = json_dumps(received_json, 0);
+        printf("Received JSON: '%s'.\n", recv_str);
+
+        printf("trying to get maxClients.\n");
+        json_t* max_clients_json = json_object_get(received_json, "maxClients");
+        if(max_clients_json != NULL) {
+            printf("found maxClients.\n");
+            if(json_is_integer(max_clients_json)) {
+                printf("maxClients is integer.\n");
+                long max_clients = json_integer_value(max_clients_json);
+                printf("Max clients is: '%lu'.\n", max_clients);
+            }
+            else {
+                printf("maxClients is NOT an integer.\n");
+            }
+        }
+        
+        json_decref(received_json);
+    }
+    else {
+        printf("received_json is NULL.\n");
+    }
+    
+    game_session_init(
+        session,
+        settings
+    );
 
     return true;
 }
@@ -242,8 +317,7 @@ bool networking_stop(Game_Networking *networking) {
     assert(stop_listening(networking));
     networking->listener_id = 0;
     
-    mp_api_destroy(networking->api);
-    networking->api = NULL;
+    shutdown_api(networking);
     networking->game_session = NULL;
     networking->is_host = false;
 

src/game/shared/entity.h

@@ -25,7 +25,7 @@ typedef enum {
 typedef struct {
     bool active;
 
-    // TODO: SS - Maybe add an ID here.
+    Entity_ID id;
 
     Entity_Type type;
     

src/game/shared/game_world.c

@@ -7,17 +7,23 @@
 #define MIN_LEVEL_WIDTH 8 // TODO: SS - Move these out of here.
 #define MIN_LEVEL_HEIGHT 8
 
-Game_World *game_world_create(uint32_t seed, uint16_t level_width, uint16_t level_height) {
+Game_World *game_world_create(uint32_t seed, uint16_t max_players, uint16_t level_width, uint16_t level_height) {
     assert(level_width >= MIN_LEVEL_WIDTH); // We should probably have failed earlier.
     assert(level_height >= MIN_LEVEL_HEIGHT);
 
     Game_World *w = (Game_World *)calloc(1, sizeof(Game_World));
     assert(w != NULL);
+
     w->seed = seed;
     random_init(&w->random_generator, w->seed);
 
+    w->max_players = max_players;
+    w->players = (Game_World_Player *)calloc(w->max_players, sizeof(Game_World_Player));
+    assert(w->players != NULL);
+
     w->max_entities = level_width * level_height;
     w->entities = (Entity *)calloc(w->max_entities, sizeof(Entity));
+    assert(w->entities != NULL);
 
     // Set up entity-id queue.
     assert(squeue_init(&w->entity_id_queue, w->max_entities, sizeof(Entity_ID)));
@@ -28,17 +34,20 @@ Game_World *game_world_create(uint32_t seed, uint16_t level_width, uint16_t leve
 
     grid_initialize(&w->grid, level_width, level_height);
 
-    { // TEMP: SS - Testing ..
-        for(uint16_t i = 0; i < 8; i++) {
-            Entity_ID entity_food;
-            assert(game_world_create_entity(
-                w,
-                Entity_Type_Food,
-                (uint16_t)random_u32_range(&w->random_generator, 0, level_width),
-                (uint16_t)random_u32_range(&w->random_generator, 0, level_height),
-                &entity_food
-            ));
-        }
+    // Spawn initial food(s). One per player.
+    for(uint16_t i = 0; i < w->max_players; i++) {
+        Entity_ID entity_food;
+
+        uint16_t x = 0;
+        uint16_t y = 0;
+        assert(game_world_find_position_to_spawn(w, &x, &y));
+        
+        assert(game_world_create_entity(
+            w,
+            Entity_Type_Food,
+            x, y,
+            &entity_food
+        ));
     }
     
     return w;
@@ -48,8 +57,15 @@ void game_world_destroy(Game_World *world) {
     assert(world != NULL);
     
     world->seed = 0;
+
+    world->max_players = 0;
+    free(world->players);
+    world->players = NULL;
+    
     world->max_entities = 0;
     free(world->entities);
+    world->entities = NULL;
+    
     grid_dispose(&world->grid);
     squeue_free(&world->entity_id_queue);
     
@@ -78,6 +94,7 @@ bool game_world_create_entity(Game_World *world, Entity_Type type, uint16_t x, u
     
     world->entities[id] = (Entity) {
         .active = true,
+        .id = id,
         .type = type,
         .child = INVALID_ENTITY_ID
     };
@@ -90,23 +107,285 @@ bool game_world_create_entity(Game_World *world, Entity_Type type, uint16_t x, u
     return true;
 }
 
-void game_world_destroy_entity(Game_World *world, Entity_ID entity_id) {
+void game_world_destroy_entity(Game_World *world, Entity_ID entity_id, bool destroy_children) {
     assert(world != NULL);
+    assert(entity_id != INVALID_ENTITY_ID);
 
-    Entity *entity = game_world_try_get_entity_by_id(
-        world,
-        entity_id
-    );
-    assert(entity != NULL);
-    entity->active = false;
+    Entity_ID id_to_remove = entity_id;
     
-    Grid_Cell *cell = grid_get_cell(&world->grid, entity->x, entity->y);
-    assert(cell != NULL);
-    assert(grid_try_remove_entity_from_cell(cell));
+    while(id_to_remove != INVALID_ENTITY_ID) {
+        Entity *e = game_world_try_get_entity_by_id(
+            world,
+            id_to_remove
+        );
+        assert(e != NULL);
 
-    squeue_push(&world->entity_id_queue, (void *)&entity_id);
+        Grid_Cell *cell = grid_get_cell(&world->grid, e->x, e->y);
+        assert(cell != NULL);
+        assert(grid_try_remove_entity_from_cell(cell));
+
+        squeue_push(&world->entity_id_queue, (void *)&e->id);
+        
+        id_to_remove = e->child;
+        memset(e, 0, sizeof(Entity));
+
+        if(!destroy_children) {
+            break;
+        }
+    }
 }
 
+static void kill_and_respawn_player(Game_World *world, Entity *entity) {
+    assert(world != NULL);
+    assert(entity != NULL);
+
+    // Loop over the players to find the owner of this entity.
+    Game_World_Player *owner_player = NULL;
+    for(uint16_t i = 0; i < world->max_players; i++) {
+        Game_World_Player *player = &world->players[i];
+        if(!player->active) {
+            continue;
+        }
+
+        if(player->entity_id == entity->id) {
+            owner_player = player;
+            break;
+        }
+    }
+    assert(owner_player != NULL);
+
+    game_world_destroy_entity(world, entity->id, true);
+    owner_player->entity_id = INVALID_ENTITY_ID;
+    
+    { // Respawn.
+        Entity_ID entity_snake_id;
+
+        uint16_t spawn_x = 0;
+        uint16_t spawn_y = 0;
+        assert(game_world_find_position_to_spawn(world, &spawn_x, &spawn_y));
+
+        assert(game_world_create_entity(
+            world,
+            Entity_Type_Snake_Head,
+            spawn_x, spawn_y,
+            &entity_snake_id
+        ));
+
+        owner_player->entity_id = entity_snake_id;
+
+        Entity *player_entity = game_world_try_get_entity_by_id(
+            world,
+            owner_player->entity_id
+        );
+
+        // Set initial move-direction for player-entities.
+        player_entity->move_direction = game_world_choose_initial_move_direction_based_on_coords(
+            world,
+            spawn_x, spawn_y
+        );
+    }
+}
+
+void game_world_tick(Game_World *world) {
+    // Game-logic! :)
+    
+    for(uint16_t i = 0; i < world->max_entities; i++) {
+        Entity *entity = &world->entities[i];
+        if(!entity->active) {
+            continue;
+        }
+
+        switch(entity->type) {
+            case Entity_Type_Snake_Head: {
+                { // Move entity
+                    int16_t dx = 0;
+                    int16_t dy = 0;
+        
+                    switch(entity->move_direction) {
+                        case Entity_Movement_Direction_None: {
+                            break;
+                        }
+                        case Entity_Movement_Direction_Up: {
+                            dy = -1;
+                            break;
+                        }
+                        case Entity_Movement_Direction_Down: {
+                            dy = 1;
+                            break;
+                        }
+                        case Entity_Movement_Direction_Right: {
+                            dx = 1;
+                            break;
+                        }
+                        case Entity_Movement_Direction_Left: {
+                            dx = -1;
+                            break;
+                        }
+                    }
+        
+                    if(dx != 0 || dy != 0) {
+                        // Try moving.
+        
+                        // Figure out what cell we're on and what cell we want to go to.
+                        Grid_Cell *current_cell = grid_get_cell(&world->grid, entity->x, entity->y);
+                        assert(current_cell != NULL);
+                        Grid_Cell *target_cell  = grid_get_cell(&world->grid, entity->x + dx, entity->y + dy);
+        
+                        if(target_cell == NULL) {
+                            // Target cell does not exist.
+
+                            // TODO: SS - Check the session's settings.
+                            // Maybe each session could decide whether the snake should "loop-around" or not.
+                            // If the snake shouldn't loop around, die. For now, we say that it's not okay to loop around.
+                            bool should_loop_around = false; 
+                            if(should_loop_around) {
+                                // TODO: SS - Implement looping around.
+                            }
+                            else {
+                                kill_and_respawn_player(world, entity);
+                            }
+                        }
+                        else {
+                            bool should_move_to_target_cell = false;
+                            bool snake_ate = false;
+        
+                            if(target_cell->entity != NULL) {
+                                // Target cell is occupied.
+        
+                                // Check what type of entity it is and determine what should happen.
+                                switch(target_cell->entity->type) {
+                                    case Entity_Type_Snake_Head: {
+                                        kill_and_respawn_player(world, entity);
+                                        break;
+                                    }
+                                    case Entity_Type_Snake_Body: {
+                                        kill_and_respawn_player(world, entity);
+                                        break;
+                                    }
+                                    case Entity_Type_Food: {
+                                        // Eat!
+                                        assert(grid_try_remove_entity_from_cell(target_cell));
+        
+                                        snake_ate = true;
+                                        should_move_to_target_cell = true;
+        
+                                        break;
+                                    }
+                                }
+                            }
+                            else {
+                                // Target cell is unoccupied and free to enter.
+                                should_move_to_target_cell = true;
+                            }
+                            
+                            if(should_move_to_target_cell) {
+                                { // Move snake recursively.
+                                    Entity *e = entity;
+                                    Grid_Cell *t = target_cell;
+                                    while(e != NULL) {
+                                        Grid_Cell *a = grid_get_cell(&world->grid, e->x, e->y);
+                                        assert(a != NULL);
+                                        
+                                        grid_move_entity_from_cell_to_cell(a, t);
+        
+                                        e = game_world_try_get_entity_by_id(world, e->child);
+                                        t = a;
+                                    }
+                                }
+        
+                                if(snake_ate) {
+                                    Entity *e = entity;
+                                    uint16_t child_index = 0;
+                                    while(e->child != INVALID_ENTITY_ID) {
+                                        e = game_world_try_get_entity_by_id(world, e->child);
+                                        child_index += 1;
+                                    }
+        
+                                    Entity_ID child_entity = INVALID_ENTITY_ID;
+                                    assert(game_world_create_entity(
+                                        world,
+                                        Entity_Type_Snake_Body,
+                                        e->prev_x,
+                                        e->prev_y,
+                                        &child_entity
+                                    ));
+        
+                                    assert(e->child == INVALID_ENTITY_ID);
+                                    e->child = child_entity;
+        
+                                    { // Spawn food.
+                                        uint16_t food_spawn_x = 0;
+                                        uint16_t food_spawn_y = 0;
+        
+                                        if(!game_world_find_position_to_spawn(world, &food_spawn_x, &food_spawn_y)) {
+                                            printf("Failed to find a position to spawn food.\n");
+                                        }
+                                        else {
+                                            Entity_ID entity_food;
+                                            assert(game_world_create_entity(
+                                                world,
+                                                Entity_Type_Food,
+                                                food_spawn_x, food_spawn_y,
+                                                &entity_food
+                                            ));
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+                break;
+            }
+            case Entity_Type_Snake_Body: {
+                // Skip.
+                break;
+            }
+            case Entity_Type_Food: {
+                // Skip (for now).
+                break;
+            }
+            default: {
+                printf("Unhandled entity-type %i.\n", entity->type);
+                break;
+            }
+        }
+
+    }
+}
+
+bool game_world_add_player(Game_World *world, Game_World_Player **out_gw_player) {
+    assert(world != NULL);
+    assert(out_gw_player != NULL);
+
+    for(uint16_t i = 0; i < world->max_players; i++) {
+        Game_World_Player *player = &world->players[i];
+        
+        if(player->active) {
+            continue;
+        }
+
+        // Found free player.
+        player->active = true;
+        *out_gw_player = player;
+        return true;
+    }
+    
+    return false;
+}
+
+bool game_world_remove_player(Game_World *world, Game_World_Player *player) {
+    assert(world != NULL);
+    assert(player != NULL);
+
+    game_world_destroy_entity(world, player->entity_id, true);
+
+    memset(player, 0, sizeof(Game_World_Player));
+
+    return true;
+}
+
+
 Entity *game_world_try_get_entity_by_id(Game_World *world, Entity_ID id) {
     assert(world != NULL);
 
@@ -116,3 +395,62 @@ Entity *game_world_try_get_entity_by_id(Game_World *world, Entity_ID id) {
 
     return &world->entities[id];
 }
+
+bool game_world_find_position_to_spawn(Game_World *world, uint16_t *out_x, uint16_t *out_y) {
+    assert(world != NULL);
+    assert(out_x != NULL);
+    assert(out_y != NULL);
+    
+    uint32_t attempts = world->grid.width * world->grid.height;
+    while(attempts > 0) {
+        uint16_t potential_x = random_u32_range(&world->random_generator, 0, (uint32_t) world->grid.width - 1);
+        uint16_t potential_y = random_u32_range(&world->random_generator, 0, (uint32_t) world->grid.height - 1);
+
+        Grid_Cell *cell = grid_get_cell(&world->grid, potential_x, potential_y);
+        assert(cell != NULL);
+
+        // Check if cell is free.
+        if(cell->entity == NULL) {
+            *out_x = potential_x;
+            *out_y = potential_y;
+            return true;
+        }
+
+        if(attempts > 0) {
+            attempts -= 1;
+        }
+        else {
+            break;
+        }
+    }
+    
+    *out_x = 0;
+    *out_y = 0;
+    return false;
+}
+
+Entity_Movement_Direction game_world_choose_initial_move_direction_based_on_coords(Game_World *world, uint16_t x, uint16_t y) {
+    assert(world != NULL);
+
+    Grid *grid = &world->grid;
+    
+    // TODO: SS - Consider potential obstacles in the grid (lava, walls etc) if we ever have them.
+
+    if (x == 0) {
+        return Entity_Movement_Direction_Right;
+    }
+
+    if (x == grid->width - 1) {
+        return Entity_Movement_Direction_Left;
+    }
+
+    if (y == 0) {
+        return Entity_Movement_Direction_Down;
+    }
+
+    if (y == grid->height - 1) {
+        return Entity_Movement_Direction_Up;
+    }
+
+    return Entity_Movement_Direction_Up;
+}

src/game/shared/game_world.h

@@ -6,11 +6,15 @@
 #include "grid.h"
 #include "shared/squeue.h"
 #include "shared/random.h"
+#include "game_world_player.h"
 
 typedef struct {
     uint32_t seed;
     Random_Generator random_generator;
 
+    Game_World_Player *players;
+    uint16_t max_players;
+    
     SQueue entity_id_queue;
     Entity *entities;
     uint16_t max_entities;
@@ -19,14 +23,20 @@ typedef struct {
 
 } Game_World;
 
-Game_World *game_world_create(uint32_t seed, uint16_t level_width, uint16_t level_height);
+Game_World *game_world_create(uint32_t seed, uint16_t max_players, uint16_t level_width, uint16_t level_height);
 void game_world_destroy(Game_World *world);
 
 bool game_world_create_entity(Game_World *world, Entity_Type type, uint16_t x, uint16_t y, Entity_ID *out_entity_id);
-void game_world_destroy_entity(Game_World *world, Entity_ID entity_id);
+void game_world_destroy_entity(Game_World *world, Entity_ID entity_id, bool destroy_children);
 
-// TODO: SS - "void game_world_spawn_player(Game_World *world, ..)"
+void game_world_tick(Game_World *world);
+
+bool game_world_add_player(Game_World *world, Game_World_Player **out_gw_player);
+bool game_world_remove_player(Game_World *world, Game_World_Player *player);
 
 Entity *game_world_try_get_entity_by_id(Game_World *world, Entity_ID id);
 
+bool game_world_find_position_to_spawn(Game_World *world, uint16_t *out_x, uint16_t *out_y);
+Entity_Movement_Direction game_world_choose_initial_move_direction_based_on_coords(Game_World *world, uint16_t x, uint16_t y);
+
 #endif

src/game/shared/game_world_player.h

@@ -0,0 +1,10 @@
+#ifndef GAME_WORLD_PLAYER_H
+#define GAME_WORLD_PLAYER_H
+
+typedef struct {
+    bool active;
+    
+    Entity_ID entity_id; // The entity that this player is controlling. Can be INVALID_ENTITY_ID.
+} Game_World_Player;
+
+#endif

src/game/shared/squeue.c

@@ -55,3 +55,8 @@ bool squeue_peek(const SQueue *q, void *out) {
     memcpy(out, src, q->element_size);
     return true;
 }
+
+void squeue_clear(SQueue *q) {
+    void *t = NULL;
+    while(squeue_pop(q, t)) {}
+}

src/game/shared/squeue.h

@@ -24,4 +24,6 @@ bool squeue_push(SQueue *q, const void *elem);
 bool squeue_pop(SQueue *q, void *out);
 bool squeue_peek(const SQueue *q, void *out);
 
+void squeue_clear(SQueue *q);
+
 #endif

src/game/simulation/input.h

@@ -2,24 +2,15 @@
 #define SIM_GAME_INPUT_H
 
 typedef struct {
-    // Movement can probably just be one byte. For a traditional snake-game, only one directional-input is OK.
-    bool up;
-    bool down;
     bool right;
     bool left;
 } Simulation_Game_Input;
 
-static inline bool simulation_input_equal(Simulation_Game_Input a, Simulation_Game_Input b) {
-    if(a.up != b.up) {
+static inline bool simulation_input_empty(Simulation_Game_Input input) {
+    if(input.right) {
         return false;
     }
-    if(a.down != b.down) {
-        return false;
-    }
-    if(a.right != b.right) {
-        return false;
-    }
-    if(a.left != b.left) {
+    if(input.left) {
         return false;
     }
 

src/game/simulation/player.h

@@ -6,8 +6,10 @@
 typedef struct {
     bool active;
     
-    Entity_ID entity_id;
+    Game_World_Player *game_world_player;
+    
     Simulation_Game_Input input;
+    
     // score, name etc.
 
 } Simulation_Player;

src/game/simulation/simulation_world.c

@@ -14,7 +14,7 @@ Simulation_World simulation_create_world(uint32_t seed, bool online, uint8_t max
     
     w.online = online;
     
-    w.game_world    = game_world_create(seed, width, height);
+    w.game_world    = game_world_create(seed, max_players, width, height);
     assert(w.game_world != NULL);
     
     w.match_state   = Simulation_Match_State_Waiting_To_Start;
@@ -49,6 +49,9 @@ void simulation_world_tick(Simulation_World *simulation_world) {
 
     // printf("TICK: %lu.\n", simulation_world->tick);
 
+    Game_World *gw = simulation_world->game_world;
+    assert(gw != NULL);
+
     for(uint16_t i = 0; i < simulation_world->command_count; i++) {
         Simulation_Command *cmd = &simulation_world->commands[i];
         // printf("Command type: %i, player id: %i.\n", cmd->type, cmd->player_id);
@@ -62,18 +65,28 @@ void simulation_world_tick(Simulation_World *simulation_world) {
                 assert(!player->active);
                 player->active = true;
 
+                assert(game_world_add_player(gw, &player->game_world_player));
+
+                Game_World_Player *gwp = player->game_world_player;
+
+                uint16_t spawn_x = 0;
+                uint16_t spawn_y = 0;
+                assert(game_world_find_position_to_spawn(gw, &spawn_x, &spawn_y));
+                
                 assert(game_world_create_entity(
-                    simulation_world->game_world,
+                    gw,
                     Entity_Type_Snake_Head,
-                    i+6, 15, // NOTE: SS - Hardcoded spawn-position.
-                    &player->entity_id
+                    spawn_x, spawn_y,
+                    &gwp->entity_id
                 ));
 
-                Entity *player_entity = game_world_try_get_entity_by_id(simulation_world->game_world, player->entity_id);
+                Entity *player_entity = game_world_try_get_entity_by_id(gw, gwp->entity_id);
 
                 // Set initial move-direction for player-entities.
-                // The initial direction should probably take the spawn-position in to account.
-                player_entity->move_direction = Entity_Movement_Direction_Up;
+                player_entity->move_direction = game_world_choose_initial_move_direction_based_on_coords(
+                    gw,
+                    spawn_x, spawn_y
+                );
 
                 break;
             }
@@ -82,8 +95,7 @@ void simulation_world_tick(Simulation_World *simulation_world) {
                 assert(player->active);
                 player->active = false;
 
-                game_world_destroy_entity(simulation_world->game_world, player->entity_id);
-                
+                assert(game_world_remove_player(gw, player->game_world_player));                
                 break;
             }
             case Simulation_Command_Type_Set_Player_Input: {
@@ -126,44 +138,75 @@ void simulation_world_tick(Simulation_World *simulation_world) {
         
                 // Loop over all players in the simulation.
                 for(uint16_t i = 0; i < simulation_world->max_players; i++) {
-                    Simulation_Player *player = &simulation_world->players[i];
-                    if(!player->active) {
+                    Simulation_Player *sim_player = &simulation_world->players[i];
+                    if(!sim_player->active) {
                         continue;
                     }
 
-                    // printf("* Input for player %i - up: %i, down: %i, right: %i, left: %i.\n",
+                    Game_World_Player *gw_player = sim_player->game_world_player;
+                    assert(gw_player != NULL);
+                    if(!gw_player->active) {
+                        continue;
+                    }
+                    
+                    // NOTE: SS - Not sure if this should be moved to game-world.. This is input that comes from the simulation.
+    
+                    // printf("* Input for player %i - right: %i, left: %i.\n",
                     //     i,
-                    //     player->input.up, player->input.down, player->input.right, player->input.left
+                    //     player->input.right, player->input.left
                     // );
     
-                    Entity *player_entity = game_world_try_get_entity_by_id(gw, player->entity_id);
-                    assert(player_entity != NULL);
+                    Entity *player_entity = game_world_try_get_entity_by_id(gw, gw_player->entity_id);
+                    if(player_entity == NULL) {
+                        // No entity to control. No entity to apply input on.
+                        continue;
+                    }
 
                     // Snakes can't go backwards. They have to turn.
 
+                    // We only have input 'right' and 'up'.
+                    Simulation_Game_Input input = sim_player->input;
+
+                    // Turn relative to the player's current move_direction.
                     switch(player_entity->move_direction) {
                         case Entity_Movement_Direction_None: {
                             break;
                         }
-                        case Entity_Movement_Direction_Up:
-                        case Entity_Movement_Direction_Down: // Snakes can only go right/left if it's currently moving up/down.
-                        {
-                            if(player->input.right) {
+                        case Entity_Movement_Direction_Up: {
+                            if(input.right) {
                                 player_entity->move_direction = Entity_Movement_Direction_Right;
                             }
-                            else if(player->input.left) {
+                            else if(input.left) {
                                 player_entity->move_direction = Entity_Movement_Direction_Left;
                             }
                             
                             break;
                         }
-                        case Entity_Movement_Direction_Right:
-                        case Entity_Movement_Direction_Left: // Snakes can only go up/down if it's currently moving right/left.
-                        {
-                            if(player->input.up) {
+                        case Entity_Movement_Direction_Down: {
+                            if(input.right) {
+                                player_entity->move_direction = Entity_Movement_Direction_Left;
+                            }
+                            else if(input.left) {
+                                player_entity->move_direction = Entity_Movement_Direction_Right;
+                            }
+                            
+                            break;
+                        }
+                        case Entity_Movement_Direction_Right: {
+                            if(input.right) {
+                                player_entity->move_direction = Entity_Movement_Direction_Down;
+                            }
+                            else if(input.left) {
                                 player_entity->move_direction = Entity_Movement_Direction_Up;
                             }
-                            else if(player->input.down) {
+
+                            break;
+                        }
+                        case Entity_Movement_Direction_Left: {
+                            if(input.right) {
+                                player_entity->move_direction = Entity_Movement_Direction_Up;
+                            }
+                            else if(input.left) {
                                 player_entity->move_direction = Entity_Movement_Direction_Down;
                             }
 
@@ -172,156 +215,7 @@ void simulation_world_tick(Simulation_World *simulation_world) {
                     }
                 }
                 
-                // Game-logic! :)
-    
-                for(uint16_t i = 0; i < gw->max_entities; i++) {
-                    Entity *entity = &gw->entities[i];
-                    if(!entity->active) {
-                        continue;
-                    }
-
-                    switch(entity->type) {
-                        case Entity_Type_Snake_Head: {
-
-                            break;
-                        }
-                        case Entity_Type_Snake_Body: {
-                            // Skip.
-                            break;
-                        }
-                        case Entity_Type_Food: {
-                            // Skip (for now).
-                            break;
-                        }
-                        default: {
-                            printf("Unhandled entity-type %i.\n", entity->type);
-                            break;
-                        }
-                    }
-    
-                    { // Move entity
-                        int16_t dx = 0;
-                        int16_t dy = 0;
-    
-                        switch(entity->move_direction) {
-                            case Entity_Movement_Direction_None: {
-                                break;
-                            }
-                            case Entity_Movement_Direction_Up: {
-                                dy = -1;
-                                break;
-                            }
-                            case Entity_Movement_Direction_Down: {
-                                dy = 1;
-                                break;
-                            }
-                            case Entity_Movement_Direction_Right: {
-                                dx = 1;
-                                break;
-                            }
-                            case Entity_Movement_Direction_Left: {
-                                dx = -1;
-                                break;
-                            }
-                        }
-    
-                        if(dx != 0 || dy != 0) {
-                            // Try moving.
-    
-                            // Figure out what cell we're on and what cell we want to go to.
-                            Grid_Cell *current_cell = grid_get_cell(&gw->grid, entity->x, entity->y);
-                            assert(current_cell != NULL);
-                            Grid_Cell *target_cell  = grid_get_cell(&gw->grid, entity->x + dx, entity->y + dy);
-    
-                            // { // Debug-logging.
-                            //     printf("Current cell = (x: %u, y: %u, entity: %p).\n", current_cell->x, current_cell->y, current_cell->entity);
-                            //     if(target_cell != NULL) {
-                            //         printf("Target cell = (x: %u, y: %u, entity: %p).\n", target_cell->x, target_cell->y, target_cell->entity);
-                            //     }
-                            //     else {
-                            //         printf("Target cell = NULL!\n");
-                            //     }
-                            // }
-    
-                            if(target_cell == NULL) {
-                                // Target cell does not exist.
-                                // TODO: SS - Check the session's settings.
-                                // Maybe each session could decide whether the snake should "loop-around" or not.
-                                // If the snake shouldn't loop around, die.
-                            }
-                            else {
-                                bool should_move_to_target_cell = false;
-                                bool snake_should_grow = false;
-
-                                if(target_cell->entity != NULL) {
-                                    // Target cell is occupied.
-    
-                                    // Check what type of entity it is and determine what should happen.
-                                    switch(target_cell->entity->type) {
-                                        case Entity_Type_Snake_Head: {
-                                            // TODO: SS - Die.
-                                            break;
-                                        }
-                                        case Entity_Type_Snake_Body: {
-                                            // TODO: SS - Die.
-                                            break;
-                                        }
-                                        case Entity_Type_Food: {
-                                            // Eat!
-                                            assert(grid_try_remove_entity_from_cell(target_cell));
-
-                                            snake_should_grow = true;
-                                            should_move_to_target_cell = true;
-
-                                            break;
-                                        }
-                                    }
-                                }
-                                else {
-                                    // Target cell is unoccupied and free to enter.
-                                    should_move_to_target_cell = true;
-                                }
-                                
-                                if(should_move_to_target_cell) {
-                                    { // Move snake recursively.
-                                        Entity *e = entity;
-                                        Grid_Cell *t = target_cell;
-                                        while(e != NULL) {
-                                            Grid_Cell *a = grid_get_cell(&gw->grid, e->x, e->y);
-                                            assert(a != NULL);
-                                            
-                                            grid_move_entity_from_cell_to_cell(a, t);
-
-                                            e = game_world_try_get_entity_by_id(gw, e->child);
-                                            t = a;
-                                        }
-                                    }
-
-                                    if(snake_should_grow) {
-                                        Entity *e = entity;
-                                        uint16_t child_index = 0;
-                                        while(e->child != INVALID_ENTITY_ID) {
-                                            e = game_world_try_get_entity_by_id(gw, e->child);
-                                            child_index += 1;
-                                        }
-
-                                        Entity_ID child_entity = INVALID_ENTITY_ID;
-                                        assert(game_world_create_entity(
-                                            gw,
-                                            Entity_Type_Snake_Body,
-                                            e->prev_x,
-                                            e->prev_y,
-                                            &child_entity
-                                        ));
-
-                                        assert(e->child == INVALID_ENTITY_ID);
-                                        e->child = child_entity;
-                                    }
-                                }
-                            }
-                        }
-                    }
-                }
+                game_world_tick(gw);
             }
             
             break;

src/main.c

@@ -46,9 +46,9 @@ int main() {
             presentation_state_machine.current->tick(presentation_state_machine.current);
         }
 
-        if(IsKeyPressed(KEY_F)) {
-            ToggleFullscreen();
-        }
+        // if(IsKeyPressed(KEY_F)) { // TODO: SS - Add this back, but not 'F'.
+        //     ToggleFullscreen();
+        // }
         
         // Render.
         BeginDrawing();

src/todo.md

@@ -0,0 +1,28 @@
+# TODO
+- [x] find_good_position_to_spawn()
+    - A lot of gameplay-functionality depends on this.
+- [x] Set initial move-direction based on where you spawn.
+    - Can be improved and take more things in to account.
+    - Right now it's only considering the size of of the grid, but what if we want to have obstacles in the grid?
+    - We also don't take if two players spawn one cell from each other in to consideration.
+- Add player-death.
+    - [x] Went out of bounds.
+    - [x] Hit other snake's head.
+    - [x] Hit yours/other snake's body.
+- Spawn players at a random position.
+    - [x] When initially joining.
+    - [x] When dead and should respawn.
+- [x] Spawn a new food when one was eaten.
+- [x] When a player disconnects, all children should recursively be destroyed too. Not just the head.
+- [ ] Send networked input.
+- [ ] Set up session when joining the host.
+- [x] Change player-movement?
+    - Only inputs needed are RIGHT and LEFT. Turn relative to your head.
+        - Right now we're moving relative to world-up.
+        - This would fix issues with invalid inputs, for example when the player inputs RIGHT when going LEFT.
+    - Make this an option later?
+- [ ] Customize the session.
+- [ ] Replays.
+- [ ] Sound effects + music.
+- [ ] Options menu.
+- [ ] Scoreboard.