""" ════════════════════════════════════════════════════════════ MODULE 5 — Script 02: Scene Transitions ════════════════════════════════════════════════════════════ What this demonstrates: • Transition layer that runs independently of scenes • Fade-out → swap scene → fade-in • Slide transition (left/right wipe) • Crossfade between scene snapshots • How to keep scenes decoupled from transition logic Controls: • 1 / 2 / 3: switch scene (fade) • LEFT / RIGHT arrows: slide transition • F: crossfade transition • ESC: quit ════════════════════════════════════════════════════════════ """ import pygame import sys import math import random pygame.init() WIDTH, HEIGHT = 900, 600 FPS = 60 BLACK = (0, 0, 0) WHITE = (255, 255, 255) GRAY = (80, 80, 80) GRAY_LT = (160, 160, 160) DARK_BG = (10, 10, 20) screen = pygame.display.set_mode((WIDTH, HEIGHT)) pygame.display.set_caption("Module 5 — Scene Transitions") clock = pygame.time.Clock() F_SMALL = pygame.font.SysFont("monospace", 13) F_MED = pygame.font.SysFont("monospace", 17) F_LARGE = pygame.font.SysFont("monospace", 26, bold=True) F_TITLE = pygame.font.SysFont("monospace", 44, bold=True) def blit_centered(surf, txt, y, color=WHITE, font=None): s = (font or F_MED).render(txt, True, color) surf.blit(s, (WIDTH // 2 - s.get_width() // 2, y)) def blit_text(surf, txt, pos, color=WHITE, font=None): s = (font or F_MED).render(txt, True, color) surf.blit(s, pos) # ── SCENE DEFINITIONS ───────────────────────────────────── SCENES_DATA = [ {"title": "Scene 1 — Menu", "bg": (15, 10, 30), "accent": (120, 80, 220), "icon": "🏠"}, {"title": "Scene 2 — Gameplay", "bg": (10, 20, 15), "accent": (50, 200, 100), "icon": "🎮"}, {"title": "Scene 3 — Settings", "bg": (25, 15, 10), "accent": (220, 150, 50), "icon": "⚙️"}, ] def render_scene(index, t=0.0): """Render a scene to an offscreen surface.""" data = SCENES_DATA[index % len(SCENES_DATA)] surf = pygame.Surface((WIDTH, HEIGHT)) surf.fill(data["bg"]) # Background pattern accent = data["accent"] for i in range(8): ang = t + i * math.pi / 4 cx = int(WIDTH // 2 + math.cos(ang) * 160) cy = int(HEIGHT // 2 + math.sin(ang) * 100) r = int(30 + 20 * math.sin(t * 2 + i)) pygame.draw.circle(surf, (*accent, 40) if False else accent, (cx, cy), r, 2) blit_centered(surf, data["title"], HEIGHT // 2 - 40, WHITE, F_TITLE) blit_centered(surf, f"Scene index: {index}", HEIGHT // 2 + 30, accent, F_LARGE) return surf # ── TRANSITION ENGINE ────────────────────────────────────── class TransitionEngine: """ Manages transitions between scene renders. The current and next scene are pre-rendered to surfaces, then blended over `duration` seconds using the chosen mode. """ FADE = "fade" SLIDE_L = "slide_left" SLIDE_R = "slide_right" CROSSFADE = "crossfade" def __init__(self): self.active = False self.mode = self.FADE self.progress = 0.0 # 0.0 → 1.0 self.duration = 0.5 # seconds self.surf_from = None self.surf_to = None self.on_complete = None # callback when done def start(self, surf_from, surf_to, mode=FADE, duration=0.5, on_complete=None): self.surf_from = surf_from.copy() self.surf_to = surf_to.copy() self.mode = mode self.duration = duration self.progress = 0.0 self.active = True self.on_complete = on_complete def update(self, dt): if not self.active: return self.progress += dt / self.duration if self.progress >= 1.0: self.progress = 1.0 self.active = False if self.on_complete: self.on_complete() def draw(self, surface): p = self.progress # Ease in-out cubic p_ease = p * p * (3 - 2 * p) if self.mode == self.FADE: # Fade through black if p_ease < 0.5: # First half: fade out current alpha_out = int(255 * (1 - p_ease * 2)) self.surf_from.set_alpha(alpha_out) surface.fill(BLACK) surface.blit(self.surf_from, (0, 0)) else: # Second half: fade in next alpha_in = int(255 * ((p_ease - 0.5) * 2)) self.surf_to.set_alpha(alpha_in) surface.fill(BLACK) surface.blit(self.surf_to, (0, 0)) elif self.mode == self.CROSSFADE: # Blend both surfaces simultaneously surface.blit(self.surf_from, (0, 0)) overlay = self.surf_to.copy() overlay.set_alpha(int(255 * p_ease)) surface.blit(overlay, (0, 0)) elif self.mode == self.SLIDE_L: # New scene slides in from the right offset = int((1 - p_ease) * WIDTH) surface.blit(self.surf_from, (-offset, 0)) surface.blit(self.surf_to, (WIDTH - offset, 0)) elif self.mode == self.SLIDE_R: # New scene slides in from the left offset = int((1 - p_ease) * WIDTH) surface.blit(self.surf_from, (offset, 0)) surface.blit(self.surf_to, (offset - WIDTH, 0)) # ── MAIN LOOP ───────────────────────────────────────────── engine = TransitionEngine() current_idx = 0 t = 0.0 log = [] MAX_LOG = 5 def do_transition(next_idx, mode, duration=0.5): global current_idx if engine.active: return surf_from = render_scene(current_idx, t) surf_to = render_scene(next_idx, t) def on_done(): global current_idx current_idx = next_idx log.append(f"→ Scene {next_idx} [{mode}]") if len(log) > MAX_LOG: log.pop(0) engine.start(surf_from, surf_to, mode=mode, duration=duration, on_complete=on_done) while True: dt = clock.tick(FPS) / 1000.0 t += dt for event in pygame.event.get(): if event.type == pygame.QUIT: pygame.quit(); sys.exit() if event.type == pygame.KEYDOWN: if event.key == pygame.K_ESCAPE: pygame.quit(); sys.exit() # Number keys → fade to that scene if event.key == pygame.K_1: do_transition(0, TransitionEngine.FADE) if event.key == pygame.K_2: do_transition(1, TransitionEngine.FADE) if event.key == pygame.K_3: do_transition(2, TransitionEngine.FADE) # Arrow keys → slide if event.key == pygame.K_LEFT: do_transition((current_idx - 1) % 3, TransitionEngine.SLIDE_R) if event.key == pygame.K_RIGHT: do_transition((current_idx + 1) % 3, TransitionEngine.SLIDE_L) # F → crossfade if event.key == pygame.K_f: do_transition((current_idx + 1) % 3, TransitionEngine.CROSSFADE, 0.8) engine.update(dt) # ── Draw ──────────────────────────────────────────────── if engine.active: engine.draw(screen) else: screen.blit(render_scene(current_idx, t), (0, 0)) # ── HUD overlay ───────────────────────────────────────── hud = pygame.Surface((WIDTH, 110), pygame.SRCALPHA) hud.fill((0, 0, 0, 180)) screen.blit(hud, (0, HEIGHT - 110)) pygame.draw.line(screen, GRAY, (0, HEIGHT - 110), (WIDTH, HEIGHT - 110), 1) blit_text(screen, f"Current: {current_idx} | Transitioning: {engine.active} " f"| Progress: {engine.progress:.2f}", (20, HEIGHT - 104), GRAY_LT, F_SMALL) controls = "1/2/3: fade | ←→: slide | F: crossfade | ESC: quit" blit_text(screen, controls, (20, HEIGHT - 82), GRAY, F_SMALL) # Log for i, entry in enumerate(log): blit_text(screen, entry, (20, HEIGHT - 60 + i * 16), (200 - i * 30,) * 3, F_SMALL) # Progress bar bar_w = int(engine.progress * (WIDTH - 40)) pygame.draw.rect(screen, GRAY, (20, HEIGHT - 18, WIDTH - 40, 8)) pygame.draw.rect(screen, (100, 180, 255), (20, HEIGHT - 18, bar_w, 8)) # Mode label if engine.active: blit_text(screen, f"MODE: {engine.mode.upper()}", (WIDTH - 220, HEIGHT - 104), (100, 180, 255), F_SMALL) pygame.display.flip()