Pygame中基于Mask的像素级碰撞检测：处理不同颜色形状的高效策略

import pygame

# 假设 SURFACE 是主屏幕 Surface
# circle_color = (0,255,0)
# polygon_color = (255,0,0)

# 绘制绿色圆形
# pygame.draw.circle(SURFACE, circle_color, (x1, y1), radius)
# 绘制红色多边形 (可能覆盖绿色圆形)
# pygame.draw.polygon(SURFACE, polygon_color, points)

# 尝试从主 Surface 生成 Mask
# circle_mask = pygame.mask.from_threshold(SURFACE, circle_color)
# polygon_mask = pygame.mask.from_threshold(SURFACE, polygon_color)

# if circle_mask.overlap(polygon_mask, offset=(0,0)):
#    print("collision")

import pygame

pygame.init()

# 屏幕设置
SCREEN_WIDTH = 800
SCREEN_HEIGHT = 600
screen = pygame.display.set_mode((SCREEN_WIDTH, SCREEN_HEIGHT))
pygame.display.set_caption("Pygame Mask Collision Demo")

WHITE = (255, 255, 255)
GREEN = (0, 255, 0)
RED = (255, 0, 0)
BLUE = (0, 0, 255)

class GameObject:
    def __init__(self, color, shape_type, pos, size, points=None):
        self.color = color
        self.shape_type = shape_type
        self.pos = list(pos) # 使用列表方便修改位置
        self.size = size # 对于圆形是半径，对于矩形是(width, height)

        # 创建对象自身的Surface
        if shape_type == "circle":
            surf_size = size * 2 # 直径
            self.image = pygame.Surface((surf_size, surf_size), pygame.SRCALPHA)
            pygame.draw.circle(self.image, self.color, (size, size), size)
        elif shape_type == "polygon":
            # 计算多边形边界，确定Surface大小
            min_x = min(p[0] for p in points)
            max_x = max(p[0] for p in points)
            min_y = min(p[1] for p in points)
            max_y = max(p[1] for p in points)

            width = max_x - min_x
            height = max_y - min_y
            self.image = pygame.Surface((width, height), pygame.SRCALPHA)

            # 绘制多边形到其自身Surface，需要调整点坐标
            adjusted_points = [(p[0] - min_x, p[1] - min_y) for p in points]
            pygame.draw.polygon(self.image, self.color, adjusted_points)
            self.pos[0] += min_x # 调整对象位置以匹配多边形左上角
            self.pos[1] += min_y

        self.rect = self.image.get_rect(topleft=self.pos)
        self.mask = pygame.mask.from_surface(self.image)

    def move(self, dx, dy):
        self.pos[0] += dx
        self.pos[1] += dy
        self.rect.topleft = self.pos

    def draw(self, surface):
        surface.blit(self.image, self.rect)

# 创建两个游戏对象
# 绿色圆形
circle_obj = GameObject(GREEN, "circle", (100, 200), 50) 
# 红色多边形
polygon_points = [(0, 0), (100, 20), (80, 80), (20, 100)] # 相对坐标
polygon_obj = GameObject(RED, "polygon", (300, 200), None, polygon_points)

# 游戏主循环
running = True
clock = pygame.time.Clock()

while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        if event.type == pygame.MOUSEMOTION:
            # 鼠标控制圆形移动
            circle_obj.pos = list(event.pos)
            circle_obj.rect.center = event.pos

    screen.fill(WHITE)

    # 绘制对象
    circle_obj.draw(screen)
    polygon_obj.draw(screen)

    # 碰撞检测
    # 1. AABB 包围盒检测
    if circle_obj.rect.colliderect(polygon_obj.rect):
        # 2. 如果包围盒碰撞，进行像素级 Mask 碰撞检测
        # 计算相对偏移量
        offset_x = polygon_obj.rect.x - circle_obj.rect.x
        offset_y = polygon_obj.rect.y - circle_obj.rect.y

        # 使用 mask.overlap 进行像素级检测
        if circle_obj.mask.overlap(polygon_obj.mask, (offset_x, offset_y)):
            pygame.draw.rect(screen, BLUE, circle_obj.rect, 2) # 碰撞时绘制蓝色边框
            pygame.draw.rect(screen, BLUE, polygon_obj.rect, 2)
            # print("Pixel-perfect Collision Detected!")
        else:
            pygame.draw.rect(screen, GREEN, circle_obj.rect, 1) # 未像素碰撞时绘制绿色边框
            pygame.draw.rect(screen, RED, polygon_obj.rect, 1)
    else:
        pygame.draw.rect(screen, GREEN, circle_obj.rect, 1) # 未包围盒碰撞时绘制绿色边框
        pygame.draw.rect(screen, RED, polygon_obj.rect, 1)

    pygame.display.flip()
    clock.tick(60)

pygame.quit()