Question

我已经看过很多关于在2D侧滚动游戏中实现简单相机的不同方法的文章。我的解决方法是，只要播放器位于屏幕中央而不是屏幕末端，就可以制作一个使所有位置都偏移的对象。

这绝对可以，但是我想更大一点。

因此，我想知道如何添加“平滑的摄像机运动”，即播放器不总是一直停留在屏幕中间，而是摄像机实际上在跟随播放器。为了寻找答案，我找到了仅在Java中有效的示例。我不确定如何在pygame中添加此功能。如果您认为可以向我解释如何实施，那将很有帮助。

即使您不了解“平稳的相机运动”的意思，也可以浏览this video，以了解我在说什么。正如我已经提到的，您可以给我的任何提示或起点都将非常有帮助。

Answer 1

您可以使用矢量进行此操作。我只是在这里使用矢量作为相机，使其跟随玩家。首先从camera中减去player.pos，以获得另一个向量（此处称为heading），该向量从摄像机指向播放器。然后将矢量缩放到所需的速度（长度的一小部分），并将其用作相机的速度。

from random import randrange

import pygame as pg
from pygame.math import Vector2


class Player(pg.sprite.Sprite):

    def __init__(self, pos, *groups):
        super().__init__(*groups)
        self.image = pg.Surface((30, 30))
        self.image.fill(pg.Color('dodgerblue1'))
        self.rect = self.image.get_rect(center=pos)
        self.pos = Vector2(pos)
        self.vel = Vector2(0, 0)

    def handle_event(self, event):
        if event.type == pg.KEYDOWN:
            if event.key == pg.K_d:
                self.vel.x = 5
            elif event.key == pg.K_a:
                self.vel.x = -5
            elif event.key == pg.K_w:
                self.vel.y = -5
            elif event.key == pg.K_s:
                self.vel.y = 5
        elif event.type == pg.KEYUP:
            if event.key == pg.K_d and self.vel.x > 0:
                self.vel.x = 0
            elif event.key == pg.K_a and self.vel.x < 0:
                self.vel.x = 0
            elif event.key == pg.K_w:
                self.vel.y = 0
            elif event.key == pg.K_s:
                self.vel.y = 0

    def update(self):
        # Move the player.
        self.pos += self.vel
        self.rect.center = self.pos


def main():
    pg.init()
    screen = pg.display.set_mode((800, 600))

    clock = pg.time.Clock()
    all_sprites = pg.sprite.Group()
    camera = Vector2(400, 300)
    player = Player((400, 300), all_sprites)

    background_rects = [pg.Rect(randrange(-3000, 3001), randrange(-3000, 3001), 20, 20)
                        for _ in range(500)]

    while True:
        for event in pg.event.get():
            if event.type == pg.QUIT:
                return

            player.handle_event(event)

        all_sprites.update()
        # A vector that points from the camera to the player.
        heading = player.pos - camera
        # Follow the player with the camera.
        # Move the camera by a fraction of the heading vector's length.
        camera += heading * 0.05
        # The actual offset that we have to add to the positions of the objects.
        offset = -camera + Vector2(400, 300)  # + 400, 300 to center the player.

        screen.fill((30, 30, 30))
        # Blit all objects and add the offset to their positions.
        for background_rect in background_rects:
            topleft = background_rect.topleft + offset
            pg.draw.rect(screen, (200, 50, 70), (topleft, background_rect.size))

        screen.blit(player.image, player.rect.topleft+offset)
        pg.display.flip()
        clock.tick(60)


if __name__ == '__main__':
    main()
    pg.quit()

我将如何在pygame中创建流畅的相机运动？

1 个答案: