Turbo Loader

/* Coded By JD(2026) */
#error "Reference listing only — not provided as build-ready source."
#include "turbo_loader.h"

#include "c64_colors.h"
#include "game_graphics.h"
#include "PET2001_font.h"

#include <stdio.h>

#define TURBO_LOADER_DURATION_MS 1100U
#define TURBO_LOADER_BAR_HEIGHT  4
#define TURBO_LOADER_BAR_SPACING 8
#define TURBO_LOADER_WINDOW_WIDTH 256
#define TURBO_LOADER_WINDOW_HEIGHT 128

static bool loader_active;
static screen_id_t loader_screen = SCREEN_MENU;
static uint32_t loader_started_ms;

// Bright C64 colours only: black remains the Turbo Tape background.
static const uint16_t turbo_colours[] = {
    C64_COLOR_RED,
    C64_COLOR_CYAN,
    C64_COLOR_PURPLE,
    C64_COLOR_GREEN,
    C64_COLOR_BLUE,
    C64_COLOR_YELLOW,
    C64_COLOR_ORANGE_BROWN,
    C64_COLOR_ORANGE,
    C64_COLOR_SALMON,
    C64_COLOR_LIGHT_GREEN,
    C64_COLOR_LIGHT_PURPLE,
    C64_COLOR_LIGHT_GREY,
};

static bool is_game_screen(screen_id_t screen)
{
    return screen == SCREEN_CHECKERS || screen == SCREEN_OTHELLO ||
           screen == SCREEN_CONNECT_FOUR || screen == SCREEN_BATTLESHIPS ||
           screen == SCREEN_BATTLE_ZONE || screen == SCREEN_BOULDER_DASH ||
           screen == SCREEN_YAHTZEE || screen == SCREEN_BLACKJACK ||
           screen == SCREEN_POKER || screen == SCREEN_POKER_DICE ||
           screen == SCREEN_PIG || screen == SCREEN_ASTEROIDS ||
           screen == SCREEN_TEMPEST || screen == SCREEN_INVADERS ||
           screen == SCREEN_MISSILE_COMMAND || screen == SCREEN_SCRAMBLE ||
           screen == SCREEN_BREAKOUT || screen == SCREEN_CRAWLER ||
           screen == SCREEN_MAZE_CHASE || screen == SCREEN_SIMON ||
           screen == SCREEN_DEFENDER || screen == SCREEN_GALAGA ||
           screen == SCREEN_DUNGEON;
}

static const char *loader_screen_name(screen_id_t screen)
{
    switch (screen) {
        case SCREEN_CHECKERS: return "CHECKERS";
        case SCREEN_OTHELLO: return "OTHELLO";
        case SCREEN_CONNECT_FOUR: return "CONNECT 4";
        case SCREEN_BATTLESHIPS: return "BATTLESHIPS";
        case SCREEN_BATTLE_ZONE: return "BATTLE ZONE";
        case SCREEN_BOULDER_DASH: return "BOULDER DASH";
        case SCREEN_YAHTZEE: return "YAHTZEE";
        case SCREEN_BLACKJACK: return "BLACKJACK";
        case SCREEN_POKER: return "POKER";
        case SCREEN_POKER_DICE: return "POKER DICE";
        case SCREEN_PIG: return "PIG";
        case SCREEN_ASTEROIDS: return "ASTEROIDS";
        case SCREEN_TEMPEST: return "TEMPEST";
        case SCREEN_INVADERS: return "INVADERS";
        case SCREEN_MISSILE_COMMAND: return "MISSILE COMMAND";
        case SCREEN_SCRAMBLE: return "SCRAMBLE";
        case SCREEN_BREAKOUT: return "BREAKOUT";
        case SCREEN_CRAWLER: return "CRAWLER";
        case SCREEN_MAZE_CHASE: return "MAZE CHASE";
        case SCREEN_SIMON: return "SIMON";
        case SCREEN_DEFENDER: return "DEFENDER";
        case SCREEN_GALAGA: return "GALAGA";
        case SCREEN_DUNGEON: return "DUNGEON";
        default: return "GAME";
    }
}

void turboLoaderUpdate(screen_id_t requested_screen, uint32_t now_ms)
{
    if (!is_game_screen(requested_screen)) {
        loader_active = false;
        loader_screen = SCREEN_MENU;
        return;
    }

    if (requested_screen != loader_screen) {
        loader_screen = requested_screen;
        loader_started_ms = now_ms;
        loader_active = true;
    }

    if (loader_active && now_ms - loader_started_ms >= TURBO_LOADER_DURATION_MS) {
        loader_active = false;
    }
}

bool turboLoaderActive(void)
{
    return loader_active;
}

static uint32_t stripe_noise(uint32_t value)
{
    value ^= value << 13;
    value ^= value >> 17;
    value ^= value << 5;
    return value;
}

void drawTurboLoader(uint16_t *frame, uint32_t now_ms)
{
    // Full horizontal colour bands match the C64 Ocean/Turbo Tape display.
    clear(frame, C64_COLOR_BLACK);

    const uint32_t phase = now_ms / 80U;
    const uint16_t band_colour = turbo_colours[stripe_noise(phase) %
        (sizeof(turbo_colours) / sizeof(turbo_colours[0]))];
    for (int y = 0; y < LCD_HEIGHT; y += TURBO_LOADER_BAR_SPACING) {
        fill_rect(frame, 0, y, LCD_WIDTH, TURBO_LOADER_BAR_HEIGHT, band_colour);
    }

    const int window_x = (LCD_WIDTH - TURBO_LOADER_WINDOW_WIDTH) / 2;
    const int window_y = (LCD_HEIGHT - TURBO_LOADER_WINDOW_HEIGHT) / 2;
    char loading_text[32];
    snprintf(loading_text, sizeof(loading_text), "LOADING - %s", loader_screen_name(loader_screen));
    fill_rect(frame, window_x, window_y, TURBO_LOADER_WINDOW_WIDTH,
              TURBO_LOADER_WINDOW_HEIGHT, C64_COLOR_BLACK);
    drawPet2001TextCentredTransparent(frame, LCD_WIDTH / 2,
                                       window_y + (TURBO_LOADER_WINDOW_HEIGHT - PET2001_FONT_GLYPH_HEIGHT) / 2,
                                       loading_text,
                                       C64_COLOR_ORANGE, 1);
}