Randomly Move Player on Pressing X Key

Question

I am an amateur programmer and very new at Pygame. This is my program written in Pygame, something akin to Minecraft. For the past hour, I've been trying to set up a code that would make my player move to a random tile on pressing X key. I've exhausted most if not all web sites and search engines looking. I have manages to accomplish half of my task; when X key is pressed, the avatar moves to a random tile but it moves out of the window/display. Please, could you take a look at my code and see what I can do to improve it?

import pygame, sys, random

from pygame.locals import *

LTBLUE = (125, 221, 255)
GREEN = (42, 106, 24)
YELLOW = (247, 243, 59)
GREY = (150, 150, 150)
WHITE = (255, 255, 255)
PINK = (251, 175, 224)


WATER = 0
SEAWEED = 1
SAND = 2
ROCKS = 3
PEARL = 4
CORAL = 5

PLAYER = pygame.image.load("mermaid.gif")
playerPos=[0,0]


#colors = {SAND: YELLOW, SEAWEED: GREEN, WATER: LTBLUE,  PEARL: WHITE, ROCKS: GREY, CORAL: PINK}

textures = { WATER: pygame.image.load("water.png"),
             SEAWEED: pygame.image.load("seaweed.png"),
             SAND: pygame.image.load("sand.png"),
             ROCKS: pygame.image.load("rocks.png"),
             PEARL: pygame.image.load("pearl.png"),
             CORAL: pygame.image.load("coral3.png")



TILESIZE = 40
MAPWIDTH = 15
MAPHEIGHT = 15

resources = [SAND, WATER, SEAWEED, PEARL, ROCKS, CORAL]
tilemap=[]
for h in range(MAPHEIGHT):
        myrow=[]
        for w in range(MAPWIDTH):
            if(h==0 or h==14 or w==0 or w==14):
                    myrow.append(CORAL);
            else:
                randomindex = random.randint(0,5)
                myrow.append(randomindex);
        tilemap.append(myrow)
        print(tilemap)

pygame.init()



DISPLAYSURF = pygame.display.set_mode((MAPWIDTH*TILESIZE, MAPHEIGHT*TILESIZE))
while True:
    for event in pygame.event.get():
        if event.type == QUIT:
            pygame.quit()
            sys.exit()
        if event.type == KEYDOWN:
                #rmove = random.randint(0,15)
                if event.key == K_RIGHT:
                        playerPos[0]+=1
                elif event.key == K_LEFT:
                        playerPos[0]-=1
                elif event.key == K_UP:
                        playerPos[1]-=1
                elif event.key == K_DOWN:
                        playerPos[1]+=1
                elif event.key == K_x:
                        if(movex<14 and movey<14):
                                playerPos[0]-=movex
                                playerPos[0]+=movex
                                playerPos[1]-=movey
                                playerPos[1]+=movey




    for row in range(MAPHEIGHT):
        for column in range(MAPWIDTH):
           DISPLAYSURF.blit(textures[tilemap[row][column]],(column*TILESIZE, row*TILESIZE))
           DISPLAYSURF.blit(PLAYER, (playerPos[0]*TILESIZE, playerPos[1]*TILESIZE))`

  pygame.display.update()

Lornioiz Lornioiz · Accepted Answer · 2015-11-22T11:39:27

I think you left out a small part of code after the x event, something like:

movex = random.randint(0,14)
movey = random.randint(0,14)

Anyway, as far as I understand your question, and guessing that movex and movey are random numbers from 0 to 14, the problem should be here:

if(movex<14 and movey<14):
    playerPos[0]-=movex
    playerPos[0]+=movex
    playerPos[1]-=movey
    playerPos[1]+=movey

If you extract a random number from 0 14 and sum/subtract to the player position, you have no guarantee that the new position is inside the grid. You should add some logic to prevent that the player disappear out of visible screen. You can see the problm in action even using the other control keys: your caracter is going to disappear if you press the left button while your caracter is on the left border of the screen (because the position become (-1,0)). I would suggest starting with a simple condition after the event.key.K_*:

if event.key == K_RIGHT:
    if playerPos[14] == 14:
        playerPos[0]= playerPos[0]
    else:
        playerPos[0]+=1

if event.key == K_LEFT:
    if playerPos[0] == 0:
        playerPos[0]= playerPos[0]
    else:
        playerPos[0]-=1

You should be able to sort put the rest.

P.S.

To be clearer, you want to assign a number from 0 to 14 NOT subtract/add to the current position.

Randomly Move Player on Pressing X Key

1 Answers