game.c

#include <stdbool.h>
#include <stdlib.h>
#include <rand.h>
#include <stdio.h>
#include <libetc.h>

#include "game.h"
#include "fixed.h"
#include "math.h"
#include "vec2.h"
#include "mem.h"
#include "gfx.h"
#include "audio.h"
#include "input.h"
#include "ship.h"
#include "bullet_ship.h"
#include "asteroid.h"

static bool game_started = false;

static uint32_t game_title_count = 0;
static uint32_t game_cleared_count = 0;
static uint32_t ship_destroyed_count = 0;
static uint32_t go_count = 0;
static uint32_t game_over_count = 0;

static uint32_t score = 0;

static uint8_t lives = 3;

static Entity center_space_check_entity;

static void reset_ship()
{
    Entity *ship = ship_create();
    entity_add_after(ship_tag_start, ship);
    ship_destroyed_count = 0;
}

static void reset_level()
{
    const ASTEROID_SIZE asteroid_sizes[] = { SIZE_SMALL, SIZE_SMALL, SIZE_LARGE };
    const uint8_t asteroid_nums[] = { 5, 2, 2 };
    for (size_t s = 0; s < 3; s++)
    {
        for (uint32_t i = 0; i < asteroid_nums[s]; i++)
        {
            // ensure the spawned asteroid does not hit ship at center of screen
            int32_t px = center_space_check_entity.radius_collision;
            px += asteroid_sizes[s];
            px += rand() % 64;
            px = (px << 12);
            Vec2 position = vec2_init(px, 0);
            fixed angle = rand() % 4096;
            position = vec2_rotate(angle, &position);
            position.x += center_space_check_entity.position.x;
            position.y += center_space_check_entity.position.y;
            angle = rand() % 4096;
            asteroid_spawn(asteroid_sizes[s], &position, angle);
        }
    }
}

static void start_title()
{
    audio_play_music(MUSIC_ID_TITLE);
    entity_remove_all();
    reset_level();
    game_title_count = 0;
    game_started = false;
    lives = 3;
    score = 0;
}

static void start_new_game()
{
    srand(VSync(-1));
    audio_play_music(MUSIC_ID_PLAYING);
    audio_pause_music();
    audio_play_sound(SOUND_ID_START);
    VSync(60);
    audio_resume_music();
    entity_remove_all();
    reset_ship();
    reset_level();
    game_started = true;
    game_cleared_count = 0;
    game_over_count = 0;
    lives = 3;
    score = 0;
}

static void next_level()
{
    entity_remove_all();
    reset_ship();
    reset_level();
    game_started = true;
    game_cleared_count = 0;
    game_over_count = 0;
}

static void handle_title()
{
    game_title_count++;
    gfx_print("\n\n\n\n\n\n\n\n               ASTEROIDS");
    if (game_title_count % 30 < 20)
    {
        gfx_print("\n\n\n\n\n\n\n         - PUSH START BUTTON -");
    }
    else {
        gfx_print("\n\n\n\n\n\n\n");
    }
    gfx_print("\n\n\n\n\n\n\n\n           (C)2023 danx2016");

    if (!game_started && input_is_action_just_pressed(0, START))
    {
        start_new_game();
    }
}

// check if there is a large empty space enough at center of screen where the ship can respawn
static bool can_ship_respawn()
{
    Entity *next_asteroid = asteroid_tag_start->next_entity;
    while (next_asteroid != NULL && next_asteroid != asteroid_tag_end)
    {
        if (entity_check_collision(&center_space_check_entity, next_asteroid))
        {
            return false;
        }
        next_asteroid = next_asteroid->next_entity;
    }
    return true;
}

static void handle_playing()
{
    Entity *ship = entity_find_first_type(SHIP);

    // check level cleared (all asteroids was destroyed?)
    if (ship != NULL && asteroid_tag_start->next_entity == asteroid_tag_end)
    {
        gfx_print("\n\n\n\n\n\n\n\n\n\n            LEVEL CLEARED!");
        game_cleared_count++;
    }

    if (game_cleared_count >= 360)
    {
        next_level();
    }

    if (ship == NULL)
    {
        ship_destroyed_count++;
    }
    else if (ship->is_invincible)
    {
        gfx_print("\n\n\n\n\n\n\n\n\n                READY?");
        go_count = 30;
    }
    else if (!ship->is_invincible && go_count > 0)
    {
        gfx_print("\n\n\n\n\n\n\n\n\n                 GO!");
        go_count--;
    }

    if (ship_destroyed_count >= 180)
    {
    
        if (lives > 0)
        {
            if (!can_ship_respawn())
            {
                return;
            }

            reset_ship();
            lives--;
        }
        else {
            audio_stop_music();
            gfx_print("\n\n\n\n\n\n\n\n\n\n               GAME OVER");
            game_over_count++;
            if (game_over_count >= 540)
            {
                start_title();
            }
        }
    }
}

void game_add_score(uint32_t points)
{
    score += points;
}

static void game_init_all()
{
    mem_init();
    gfx_init();
    audio_init();
    math_init();
    input_init();
    entity_init();
    ship_init();
    asteroid_init();
}

void game_start()
{
    game_init_all();
    
    center_space_check_entity.radius_collision = 40;
    center_space_check_entity.position = vec2_init(160 << 12, 128 << 12);

    start_title();

    uint8_t hud_info[128];

    while (true)
    {
        input_update();
        entity_update_all();
        entity_render_all();

        // show lives and score
        sprintf(hud_info, "\n\n\n LIVES: %d               SCORE: %06d\n", lives, score);
        gfx_print(hud_info);

        // handle title & playing states
        if (!game_started)
        {
            handle_title();
        }
        else
        {
            handle_playing();
        }
        gfx_swap_buffers();
    }    
}