An educational retro game using only Python? Challenge Accepted!

How to make a game using OOP Python concepts for reuse of entities.

Transcript

1. @siloraptor Roberto.Rosario.Gonzalez@gmail.com https://github.com/rosarior http://robertorosario.com An educational retro game using only Python? Challenge Accepted!
2. Who am I?
3. Who am I?
4. Who am I?
5. Who am I?
6. Who am I? http://pythonlatino.com
11. Who am I? http://pythonlatino.com
12. Preamble
25. Original Problem
26. Problem
27. Problem http://elitedaily.com
28. Problem http://elitedaily.com
29. Problem
30. Problem
31. Problem
32. Problem
33. Problem
34. Problem
35. Doing bad in school in not such a big deal
37. Problem
38. Problem
39. Problem
40. Problem
41. Problem
42. Problem
43. Problem
44. Instant action, storylines are boring
45. Problem
46. The eye candy, pixel wars
47. And then...
54. Experiment
55. Experiment
56. Success!
58. One simple truth
59. “Content is king”
60. “A video game is just modern day storytelling, pixel perfect graphics, pitch perfect music are not requirements for that. Tell a story someone will want to spend time experiencing.”
61. Easiest part?
63. Hardest part?
65. Basic Game Elements
66. #1 Title screen #2 Introduction / Storyline #3 Progressive stages #4 Player #5 Bosses #6 Game over #7 Game win
68. #1 Title screen - Setting (static) #2 Introduction / Storyline - Setting (scripted) #3 Progressive stages - Setting (interactive) #4 Player - Entity (controllable) #5 Bosses - Entity (autonomous) #6 Game over - Setting (scripted) #7 Game win - Setting (scripted)
69. #1 Title screen - Setting (static) #2 Introduction / Storyline - Setting (scripted) #3 Progressive stages - Setting (interactive) #6 Game over - Setting (scripted) #7 Game win - Setting (scripted)
70. #4 Player - Entity (controllable) #5 Bosses - Entity (autonomous)
71. #1 Settings = Stages #2 Entities = Actors
72. This looks familiar
74. Story?
75. Monomyth or “Hero’s Journey”
77. Simplified monomyth #1 Major crisis #2 Choosen one #3 Behind enemy lines #4 Insurmountable odds #5 Return home victorious
78. Storyboard
82. Game mechanics
87. Dismissal
88. GameJam
89. Pygame
90. Scanlines
91. Scanlines Sprites
92. Scanlines Sprites Double buffering
93. Scanlines Sprites Double buffering Main loop
97. The Main Loop
98. The main loop VBlank Interrupt service: • Process input events • Update bad guys • Update good guys • Update environment • Paint screen • Update screen • Release control
99. The main loop BEGIN: • Process input events • Update bad guys • Update good guys • Update environment • Paint screen • Update screen • GOTO BEGIN
100. The main loop BEGIN: • Process input events • Update bad guys • Update good guys • Update environment • Paint screen • Update screen • GOTO BEGIN
102. Actual code
103. The main loop class Game(object): def on_setup(self): # Configure screen, resolution, sound, fonts def on_events(self): # Handle input events def on_update(self): # Update entities, movement, behaviour def on_blit(self): # Paint scene and actor in canvas def on_render(self): # Display canvas on screen
104. The main loop class Game(object): ... def run(self): self.on_setup() while not self.finish: self.on_events() self.on_update() self.on_blit() # Render pygame.display.flip()
105. Setup
106. The main loop def on_setup(self) self.clock = pygame.time.Clock() screen_mode = pygame.HWSURFACE | pygame.DOUBLEBUF if self.fullscreen: screen_mode |= pygame.FULLSCREEN self._screen = pygame.display.set_mode(DEFAULT_SCREENSIZE, screen_mode) self.surface = pygame.Surface(self._screen.get_size()) self.running = True self.font = pygame.font.Font(GAME_FONT, 15) self.pause_sound = pygame.mixer.Sound('assets/sounds/pause.wav') self.player = ActorPlayer(game=self) pygame.display.set_caption(GAME_TITLE) self._current_stage = None self.can_be_paused = self._can_be_paused = False self._exit_prompt = False self.ask_exit_confirm = False self.initial_stage = self.module.initial_stage post_event(event=EVENT_CHANGE_STAGE, stage=self.initial_stage)
107. Events
108. The main loop def on_event(self) for event in pygame.event.get(): try: self.on_event(event) except SwallowEvent: pass else: if self._current_stage: self.module.stages[self._current_stage].on_event(event)
109. The main loop def on_event(self) for event in pygame.event.get(): try: self.on_event(event) except SwallowEvent: pass else: if self._current_stage: self.module.stages[self._current_stage].on_event(event)
110. Updates
111. The main loop class Game(object): ... def run(self): self.on_setup() while not self.finish: self.on_events() self.module.stages[self._current_stage].on_update() self.on_blit() # Render pygame.display.flip()
112. The main loop class Game(object): ... def run(self): self.on_setup() while not self.finish: self.on_events() self.module.stages[self._current_stage].on_update() self.on_blit() # Render pygame.display.flip()
113. Blit
114. The main loop def on_blit(self): self.module.stages[self._current_stage].on_blit() if self._exit_prompt: self.exit_confirmation(self.font) if self.paused: self.display_pause_label(self.font) if self.shake_screen: self._screen.blit(self.surface, (randint(0, 10), randint(0, 10))) else: self._screen.blit(self.surface, (0, 0))
115. Screen refresh
116. The main loop class Game(object): ... def run(self): self.on_setup() while not self.finish: self.on_events() self.module.stages[self._current_stage].on_update() self.on_blit() # Render pygame.display.flip()
117. The main loop class Game(object): ... def run(self): self.on_setup() while not self.finish: self.on_events() self.module.stages[self._current_stage].on_update() self.on_blit() # Render pygame.display.flip()
118. Double buffering
119. Game code Screen
120. Game code Screen
121. Game code Screen
122. Scanlines
123. http://lea.hamradio.si/~s51kq/scan-lines.gif
126. Game code Screen Memory page 1 Memory page 2
127. Game code Screen Memory page 1 Memory page 2 Video generator pointer
128. Game code Screen Memory page 1 Memory page 2 Video generator pointer Draw on inactive page
129. Game code Screen Memory page 1 Memory page 2 Video generator pointer Draw on inactive page
130. Game code Screen Memory page 1 Memory page 2 Switch video generator pointer
131. Game code Screen Memory page 1 Memory page 2 Draw on inactive page
132. Game code Screen Memory page 1 Memory page 2 Switch video generator pointer
133. Stages
134. Stage class Stage(object): def __init__(self, next_stage=None): def add_actor(self, actor): def on_blit(self): def on_event(self, event): def on_level_exit(self): def on_setup(self, game): def on_start(self): def on_update(self):
135. Stage StageScripted StagePlayable StagePlayableBoss Stage
136. Stage class Stage(object): def __init__(self, next_stage=None): def add_actor(self, actor): def on_blit(self): def on_event(self, event): def on_level_exit(self): def on_setup(self, game): def on_start(self): def on_update(self):
137. class Stage(object): def add_actor(self, actor): if actor not in self.actors: actor.on_setup(stage=self) self.actors.append(actor) def on_blit(self): self.on_draw_background() for actor in self.actors: actor.on_blit() def on_update(self): if not self.game.paused: for actor in self.actors: actor.on_update(time_passed=self.game.time_passed) for time, entry in self._runtime_script.items(): if pygame.time.get_ticks() > self._start_time + time: entry = self._runtime_script.pop(time) entry.on_execute() Stage
138. Stage StageScripted StagePlayable StagePlayableBoss Stage
139. Stage StageScripted StagePlayable StagePlayableBoss Stage
140. class StageScripted(Stage): def on_setup(self, game): ... self.script = {} def on_start(self): self._start_time = pygame.time.get_ticks() self._runtime_script = self.script.copy() def on_update(self): if not self.game.paused: for actor in self.actors: actor.on_update(time_passed=self.game.time_passed) for time, entry in self._runtime_script.items(): if pygame.time.get_ticks() > self._start_time + time: entry = self._runtime_script.pop(time) entry.on_execute() Stage
141. class StageTitle(StageScripted): def on_setup(self, *args, **kwargs): super(...) text_press_enter = DisplayText(string=, position=, font_file=, size=, effect=, horizontal_align=, vertical_align=) text_credit = text_version = self.game.can_be_pause = False self.game.ask_exit_confirm = False self.script = { 0000: Background(image_file=, fit=), 0001: PlayMusic(filename=, loop=True), 0002: ActorCommand(text_press_enter, lambda x: x.show()), 0003: ActorCommand(text_credit, lambda x: x.show()), 0004: ActorCommand(text_version, lambda x: x.show()), } Stage
142. def on_event(self, event): if event.type == pygame.KEYDOWN: post_event(event=EVENT_CHANGE_STAGE, stage=self.next_stage) Stage
143. class StoryStage(StageScripted): def on_setup(self, *args, **kwargs): ... evil_spaceship = ActorSpaceship(game=self.game) tractor_beam = ActorTracktorBeam(game=self.game) book_01 = ActorBook01(game=self.game) book_02 = ActorBook02(game=self.game) book_03 = ActorBook03(game=self.game) book_04 = ActorBook04(game=self.game) book_05 = ActorBook05(game=self.game) human_ship = ActorHumanShip(game=self.game) text_time = DisplayText(string=TEXT_YEAR, position=(0, 400), effect=TypeWriter (150, 'assets/sounds/08.ogg'), horizontal_align=CenterAlign) text_book_1 = DisplayText(string=TEXT_STEAL_BOOKS_1, position=(0, 350), effect=TypeWriter(50), horizontal_align=CenterAlign) text_book_2 = DisplayText(string=TEXT_STEAL_BOOKS_2, position=(0, 380), effect=TypeWriter(50), horizontal_align=CenterAlign) text_hero = DisplayText(string=TEXT_HERO, position=(0, 350), effect=TypeWriter (50), horizontal_align=CenterAlign) Stage
144. class StoryStage(StageScripted): def on_setup(self, *args, **kwargs): ... self.script = { 0000: Background(image_file='assets/backgrounds/earth.png'), 0001: PlayMusic('assets/music/LongDarkLoop.ogg'), 1000: ActorCommand(text_time, lambda x: x.show()), 6000: ActorCommand(text_time, lambda x: x.hide()), 6500: ActorCommand(text_book_1, lambda x: x.show()), 9000: ActorCommand(text_book_2, lambda x: x.show()), 15000: ActorCommand(text_book_1, lambda x: x.hide()), 15001: ActorCommand(text_book_2, lambda x: x.hide()), 16500: ActorCommand(evil_spaceship, lambda x: x.set_position(220, -65)), 16501: ActorCommand(evil_spaceship, lambda x: x.show()), 16502: ActorCommand(evil_spaceship, lambda x: x.set_destination(235, 30, 0.04)), 17500: ActorCommand(evil_spaceship, lambda x: x.set_destination(235, 30, 0.03)), 19000: ActorCommand(evil_spaceship, lambda x: x.set_destination(235, 30, 0.01)),
145. class StoryStage(StageScripted): def on_setup(self, *args, **kwargs): ... self.script = … 21000: ActorCommand(tractor_beam, lambda x: x.set_position(253, 70)), 21001: ActorCommand(tractor_beam, lambda x: x.show()), 21200: ActorCommand(tractor_beam, lambda x: x.strobe_start()), 22100: ActorCommand(book_01, lambda x: x.set_destination(240, 40, 0.02)), 22101: ActorCommand(book_01, lambda x: x.set_position(253, 170)), 22102: ActorCommand(book_01, lambda x: x.show()),
146. Actors
147. Actors class Actor(object): animation_death_file = None animation_death_fps = 8 animation_loop = True animation_normal_files = [] attack_points = 1 total_hit_points = 100 invincible = False fps = 1 sound_hit_file = None sound_die_file = None speed = 0.05 team = None scale = 1 rotation = 0 flip_x = False flip_y = False can_overflow = True
148. Actors def __init__(self, game): def change_animation(self, images): def destroy(self): def hide(self): def is_alive(self): def set_animation_fps(self, fps): def set_destination(self, x_position, y_position, speed): def set_direction(self, vector): def set_flip_x(self, flip): def set_flip_y(self, flip): def set_invincible(self, offset): def set_position(self, x_position, y_position): def set_rotation(self, degrees): def set_scale(self, scale): def show(self): def strobe_start(self): def strobe_stop(self):
149. Actors @staticmethod def load_sliced_sprites(width, height, filename, origin_y=0): File Memory self.images = []
150. Actors
151. Actors def set_animation_fps(self, fps): self._animation_delay = 1000 / fps def on_animate(self): if self.animation_active or force: t = pygame.time.get_ticks() if t - self._last_update > self._animation_delay: self._frame += 1 if self._frame >= len(self.images): if self.animation_loop: self._frame = 0 else: self._frame -= 1 self.on_animation_finished() self.image = self.images[self._frame] self._last_update = t
152. Actors def is_alive(self): return self.hit_points > 0 def change_animation(self, images): self.images = images self._frame = -1 self._last_update = 0 self.rect = self.images[0].get_rect() self.size = self.images[0].get_size() self.image = self.images[0]
153. Actors def on_hit(self, attack_points): self.hit_points -= attack_points if self.sound_hit: self.sound_hit.play() if self.hit_points <= 0: self.hit_points = 0 self.on_death() def on_death(self): self.hit_points = 0 self.direction = vec2d(0, 0) if self.sound_die: self.sound_die.play() self.animation_loop = False if self.animation_death_fps: self.set_animation_fps(self.animation_death_fps) if self.animation_death: self.change_animation(self.animation_death)
154. Actors def on_animate(self, time_passed, force=False): def on_animation_finished(self): def on_blit(self): def on_calculate_movement(self): def on_collision(self, foreign_actor): def on_death(self): def on_execute(self): def on_event(self, event): def on_hit(self, attack_points): def on_setup(self, stage): def on_update(self, time_passed, force=False):
155. Actors def on_animate(self, time_passed, force=False): def on_animation_finished(self): def on_blit(self): def on_calculate_movement(self): def on_collision(self, foreign_actor): def on_death(self): def on_execute(self): def on_event(self, event): def on_hit(self, attack_points): def on_setup(self, stage): def on_update(self, time_passed, force=False):
158. Displacement (how much movement) Position (where)
159. Position (where) Direction vector * time Displacement (how much movement)
160. Position (where)
161. Direction vector
162. Direction vector
163. Vec2D
164. new_position = old_position + vector * speed * time_delta time_delta = current_time - last_calculation_time
165. new_position = old_position + vector * speed * time_delta time_delta = [given by pygame]
166. new_position = old_position + vector * speed * time_delta
167. new_position = old_position + vector * speed
168. vector * speed
169. vector
170. Player = Moves by keyboard Enemy = Follows player Boss = Bounces
171. class Actor(object): def set_direction(self, vector): self.direction = vector def on_update(self, time_passed, force=False): if self.is_alive(): self.on_calculate_movement() displacement = vec2d( self.direction.x * self.speed * time_passed, self.direction.y * self.speed * time_passed ) self.pos += displacement
172. class ActorPlayer(Actor): def on_calculate_movement(self): super(ActorPlayer, self).on_calculate_movement() if self.game.running and self.is_alive(): keys_pressed = pygame.key.get_pressed() direction_y = 0 direction_x = 0 if keys_pressed[pygame.K_LEFT]: direction_x = -1 if keys_pressed[pygame.K_RIGHT]: direction_x = 1 if keys_pressed[pygame.K_UP]: direction_y = -1 if keys_pressed[pygame.K_DOWN]: direction_y = 1 self.set_direction(vec2d(direction_x, direction_y).normalized())
173. class ActorEnemy(Actor): def on_calculate_movement(self): # Follow player self.set_direction((self.game.player.pos - self.pos).normalized())
174. 5 * -1 = -5 -5 * -1 = 5 -1 ~ NOT
175. from libraries.vec2d import vec2d >>> vec2d(1, 0) * vec2d(-1, 1) # Moves right, invert (x) vec2d(-1, 0) # Now moves left >>> vec2d(-1, 0) * vec2d(-1, 1) # Moves left, invert (x) vec2d(1, 0) # Now moves right >>> vec2d(0, -1) * vec2d(-1, 1) # Moves up, invert (x) vec2d(0, -1) # Keeps moving up
176. class ActorBoss(Actor): def on_calculate_movement(self): bounds_rect = self.game.surface.get_rect() if self.rect.left <= bounds_rect.left: self.direction.x *= -1 elif self.rect.right >= bounds_rect.right: self.direction.x *= -1 elif self.rect.top <= bounds_rect.top: self.direction.y *= -1 elif self.rect.bottom >= bounds_rect.bottom: self.direction.y *= -1
177. Demo
179. Questions? @siloraptor Roberto.Rosario.Gonzalez@gmail.com https://github.com/rosarior http://robertorosario.com
180. Thank you! @siloraptor Roberto.Rosario.Gonzalez@gmail.com https://github.com/rosarior http://robertorosario.com