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Moving a Sprite towards player in Pygame (using pygame vectors)

Tags:

python

pygame

I'm making a game and an opponent is supposed to shoot bullets at the player.

I want the bullets to go in the direction of where the player is when the bullet shoots (the player may move but the bullet goes in a constant direction.)

But the bullet just flickers on the opponent.

I use pygame's Vector2 to control the movement of the bullets.

Here's a bullet-spell example:

bulletspell = Spell(
    pygame.image.load("Sprites/lightblue-glowey.png"),
    ((0, pygame.Vector2(-0.5, 1) * 4), #these vectors show the bullet shooting pattern
     (0, pygame.Vector2(0, 1) * 4),
     (0, pygame.Vector2(0.5, 1) * 4)),
    10, 8, 340
    )

The vector I tried was (player.image.get_rect(topleft=(player.rect.x, player.rect.y)).x, 1)

I'm not looking for the whole code to be revised, I've had too many revisions and the code I have works, I just need help figuring out the vector.

Here's the code (just for reference):

import pygame

class Player(pygame.sprite.Sprite):
    sprite = pygame.image.load("Sprites/player.png")

    def __init__(self, *groups):
        super().__init__(*groups)
        self.image = Player.sprite
        self.rect = self.image.get_rect(topleft=(445, 550))
        self.pos = pygame.Vector2(self.rect.topleft)

    def update(self):
        key = pygame.key.get_pressed()
        dist = 3
        if key[pygame.K_DOWN]:
            self.rect.y += dist
        elif key[pygame.K_UP]:
            self.rect.y -= dist
        if key[pygame.K_RIGHT]:
            self.rect.x += dist
        elif key[pygame.K_LEFT]:
            self.rect.x -= dist
class Spell:

    def __init__(self, bullet, pattern, speed, loop, tick_delay):
        self.bullet = bullet
        self.pattern = pattern
        self.speed = speed
        self.loop = loop
        self.tick_delay = tick_delay


class Opponent(pygame.sprite.Sprite):

    def __init__(self, sprite, sequence, *groups):
        super().__init__(*groups)
        self.image = sprite
        self.rect = self.image.get_rect(topleft=(425, 30))
        self.start_time = pygame.time.get_ticks()
        self.sequence = sequence
        self.spellno = 0
        self.currentspell = sequence[self.spellno]

    def update(self):
        time_gone = pygame.time.get_ticks() - self.start_time

        if self.currentspell is not None and time_gone > self.currentspell.tick_delay:
            self.start_time = pygame.time.get_ticks()
            for bullet in self.currentspell.pattern:
                if bullet[0] <= time_gone:
                    Bullet(self.rect.center, bullet[1], self.currentspell.bullet, sprites, bullets)

            self.currentspell.loop -= 1
            if self.currentspell.loop <= 0:
                self.spellno += 1
                if self.spellno >= len(self.sequence):
                    self.currentspell = None
                else:
                    self.currentspell = self.sequence[self.spellno]


class Bullet(pygame.sprite.Sprite):

    def __init__(self, pos, direction, image, *groups):
        super().__init__(*groups)
        self.image = image
        self.rect = self.image.get_rect(topleft=pos)
        self.direction = direction
        self.pos = pygame.Vector2(self.rect.topleft)

    def update(self):
        self.pos += self.direction
        self.rect.topleft = (self.pos.x, self.pos.y)
        if not screen.get_rect().colliderect(self.rect):
            self.kill()


sprites = pygame.sprite.Group()
bullets = pygame.sprite.Group()

opponentgroup = pygame.sprite.Group()


img3 = pygame.image.load("Sprites/minty.png")
player = Player(sprites)

#I tried:    
mi3 = Spell(
    pygame.image.load("Sprites/purple-glowey.png"),
    ((0, pygame.Vector2(player.image.get_rect(topleft=(player.rect.x, player.rect.y)).x, 1) * 4),
    ), 4, 8, 340)

minty_spells = [mi1, mi3]

Minty = Opponent(img3, minty_spells, opponentgroup)
sprites.add(Minty)

pygame.init()
SCREENWIDTH = 1000
SCREENHEIGHT = 650
screen = pygame.display.set_mode([SCREENWIDTH, SCREENHEIGHT])
screen.fill((255, 123, 67))
pygame.draw.rect(screen, (0, 255, 188), (50, 50, 900, 575), 0)
background = screen.copy()
clock = pygame.time.Clock()

#main loop goes here

Any help would be appreciated

Thanks :)

like image 887
Eleeza the Other World Wizard Avatar asked Dec 31 '18 12:12

Eleeza the Other World Wizard


1 Answers

At the moment a bullet is instantiated its direction needs to be:

(Player.pos - Opponent.pos).normalise()

This will give you a unit vector (a vector of length 1) pointing from Opponent to Player at the moment the bullet is fired. You'll need to add this to the bullet's position at each update.

like image 71
westgarthw Avatar answered Oct 08 '22 10:10

westgarthw