Blobs in the Caves

Part of the Worlds section of Coddy's Pygame journey. Lesson 33 of 35.

Two blobs patrol the cave floor. Bring in the Blob class from Enemies That Patrol, with its walk cycle: it turns at walls and ledges and shows its two poses in turn.

Each E in the map adds a blob standing on that tile. Each frame, update the group, then test each blob against the player. A stomp removes the blob and bounces the player; any other touch is a danger, so it sets hurt like a spike:

blobs.update()
for blob in blobs:
    if player.colliderect(blob.rect):
        if vel_y > 0 and player.bottom < blob.rect.centery:
            blob.kill()
            vel_y = -8
        else:
            hurt = True

Draw each blob through the camera, with its image's bottom middle on its Rect's bottom middle:

spot = blob.image.get_rect(midbottom=(blob.rect.centerx - camera_x, blob.rect.bottom))
screen.blit(blob.image, spot)

Challenge

Hard

Load blob.png and blob_walk.png into blob_img and blob_walk_img, and add the Blob class with its patrol and walk cycle, after solid().
Make blobs = pygame.sprite.Group() before the map loop, and add a Blob(rect.midbottom) for each E.
Each frame, after the spikes, update blobs and stomp or set hurt as shown.
Draw the blobs after the spikes.

Try it yourself

import pygame

TILE = 36
WIDTH, HEIGHT = 576, 360
SPEED = 4
GRAVITY = 1
JUMP = -15
MAX_FALL = 12

LEVEL = [
    "................................................................",
    "................................................................",
    "................................................................",
    "................................................................",
    "#..............................................................#",
    "#....................C.........................#####...........#",
    "#......CC...C................CC.....CC.........#####.....CC....#",
    "#....................#.........................D...............#",
    "#.P.........#...E....#...^.......K......E......D.C....^......F.#",
    "#######..####################..##########################..#####",
]

pygame.init()
screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption("Moss Caves")
clock = pygame.time.Clock()
font = pygame.font.Font("assets/fonts/pixel.ttf", 24)


def load(name):
    return pygame.image.load("assets/images/" + name).convert_alpha()


background = pygame.image.load("assets/backgrounds/forest.png").convert_alpha()
grass_img = load("grass.png")
grass_left_img = load("grass_left.png")
grass_right_img = load("grass_right.png")
dirt_img = load("dirt.png")
player_img = load("player.png")
coin_img = load("coin.png")
spikes_img = load("spikes.png")
heart_img = load("heart.png")
heart_empty_img = load("heart_empty.png")


def solid(row, col):
    if row < 0 or row >= len(LEVEL) or col < 0 or col >= len(LEVEL[0]):
        return False
    return LEVEL[row][col] == "#"


walls = []
tiles = []
coins = []
spikes = []
for row, line in enumerate(LEVEL):
    for col, char in enumerate(line):
        rect = pygame.Rect(col * TILE, row * TILE, TILE, TILE)
        if char == "#":
            if solid(row - 1, col):
                image = dirt_img
            elif not solid(row, col - 1) and solid(row, col + 1):
                image = grass_left_img
            elif solid(row, col - 1) and not solid(row, col + 1):
                image = grass_right_img
            else:
                image = grass_img
            walls.append(rect)
            tiles.append((image, rect))
        elif char == "P":
            start = rect.midbottom
        elif char == "C":
            coins.append(rect)
        elif char == "^":
            spikes.append(pygame.Rect(rect.x, rect.y + 18, TILE, 18))

level_width = len(LEVEL[0]) * TILE
player = player_img.get_rect(midbottom=start)
vel_y = 0
on_ground = False
camera_x = 0
coins_collected = 0
lives = 3

running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.KEYDOWN and event.key in (pygame.K_SPACE, pygame.K_UP):
            if on_ground:
                vel_y = JUMP
        elif event.type == pygame.KEYUP and event.key in (pygame.K_SPACE, pygame.K_UP):
            if vel_y < -4:
                vel_y = -4

    keys = pygame.key.get_pressed()
    dx = 0
    if keys[pygame.K_LEFT]:
        dx -= SPEED
    if keys[pygame.K_RIGHT]:
        dx += SPEED

    player.x += dx
    for wall in walls:
        if player.colliderect(wall):
            if dx > 0:
                player.right = wall.left
            elif dx < 0:
                player.left = wall.right

    vel_y = min(vel_y + GRAVITY, MAX_FALL)
    player.y += vel_y
    on_ground = False
    for wall in walls:
        if player.colliderect(wall):
            if vel_y > 0:
                player.bottom = wall.top
                on_ground = True
            elif vel_y < 0:
                player.top = wall.bottom
            vel_y = 0

    hurt = False
    if player.top > HEIGHT:
        hurt = True

    for coin in coins[:]:
        if player.colliderect(coin):
            coins.remove(coin)
            coins_collected += 1
    for spike in spikes:
        if player.colliderect(spike):
            hurt = True

    if hurt:
        lives -= 1
        player.midbottom = start
        vel_y = 0

    camera_x = player.centerx - WIDTH // 2
    camera_x = max(0, min(camera_x, level_width - WIDTH))

    shift = camera_x // 3 % 72
    for y in range(0, HEIGHT, 72):
        for x in range(-shift, WIDTH, 72):
            screen.blit(background, (x, y))
    for image, rect in tiles:
        screen.blit(image, (rect.x - camera_x, rect.y))
    for coin in coins:
        screen.blit(coin_img, (coin.x - camera_x, coin.y))
    for spike in spikes:
        screen.blit(spikes_img, (spike.x - camera_x, spike.y - 18))
    screen.blit(player_img, (player.x - camera_x, player.y))
    for i in range(3):
        if i < lives:
            screen.blit(heart_img, (10 + i * 40, 8))
        else:
            screen.blit(heart_empty_img, (10 + i * 40, 8))
    text = font.render(f"Coins: {coins_collected}", True, (255, 255, 255))
    screen.blit(text, text.get_rect(topright=(WIDTH - 12, 14)))
    pygame.display.flip()
    clock.tick(60)

pygame.quit()