0
votes

The Problem:

So I'm making this 2D platformer game and have run into a problem. When the player jumps onto a platform and goes of it gravity doesn't affect it and it won't fall down until you press the jump key again, it's like it thinks it's still on ground until you update him. I've narrowed the problem down to either the gravity or the collision but can't find the problem. Can anyone help? I've attached the code below.

Code:

import pygame, sys, time, random, math
from pygame.locals import *

BACKGROUNDCOLOR = (255, 255, 255)

WINDOWW = 800 
WINDOWH = 600
PLAYERW = 66
PLAYERH = 22
FPS = 60
MOVESPEED = 3
YACCEL = 0.13
GRAVITY = 2
BLOCKSIZE = 30

pygame.init()
screen = pygame.display.set_mode((WINDOWW, WINDOWH), 0, 32)
mainClock = pygame.time.Clock()

testLevel = [
            (1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,),
            (1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,)]

def createblock(length, height, color):
    tmpblock = pygame.Surface((length, height))
    tmpblock.fill(color)
    tmpblock.convert()
    return tmpblock

def terminate(): # Used to shut down the software
    pygame.quit()
    sys.exit()

def add_level(lvl, bSize): # Creates the level based on a map (lvl) and the size of blocks
    bList = [] # List of every block
    bListDisp = [] # List of every block to display    
    bTypeList = [] # List with corresponding type of block(wall, air, etc.)

    for y in range(len(lvl)): 
        for x in range(len(lvl[0])):

            if lvl[y][x] == 0: # If the block type on lvl[y][x] is '0', write "air" down in the type list
                bTypeList.append("air")
            elif lvl[y][x] == 1: # If the block type on lvl[y][x] is '1', write "wall" down in the type list
                bTypeList.append("solid")

            bList.append(pygame.Rect((bSize * x), (bSize * y), bSize, bSize)) #Append every block that is registered
            bListDisp.append(pygame.Rect((bSize * x), (bSize * y), bSize, bSize)) #Append every block to display that is registered

    return bList, bListDisp, bTypeList

player = pygame.Rect((WINDOWW/2), (WINDOWH - BLOCKSIZE*3), PLAYERW, PLAYERH)
wallblock = createblock(BLOCKSIZE, BLOCKSIZE,(20,0,50))

lastTime = pygame.time.get_ticks()
isGrounded = False

vx = 0
vy = 0

allLevels = [testLevel] # A list containing all lvls(only one for now)
maxLevel = len(allLevels) # Checks which level is the last
currLevel = allLevels[0] # Current level(start with the first lvl)
blockList, blockListDisp, blockTypeList = add_level(currLevel, BLOCKSIZE) # A list with every block and another list with the blocks types

thrusters = True
jumping = False
falling = True
while True:
    """COLLISION"""
    for i in range(len(blockTypeList)): # Go through every block...
        if blockTypeList[i] == "solid": # ...and check what kind of block it is
            if player.colliderect(blockList[i]): #Apply necessary influences from the block(e.g. a solid block prevents the player from moving into it)
                if vx > 0 and not falling:
                    player.right = blockListDisp[i].left
                    print 'Collide Right'
                if vx < 0 and not falling:
                    player.left = blockListDisp[i].right
                    print 'Collide Left'
                if vy > 0:
                    player.bottom = blockListDisp[i].top
                    isGrounded = True
                    falling = False
                    vy = 0
                    print 'Collide Bottom'
                if vy < 0:
                    player.top = blockListDisp[i].bottom
                    print 'Collide Top'
    # Input
    pressedKeys = pygame.key.get_pressed() # Checks which keys are being pressed
    timeDiff = pygame.time.get_ticks() - lastTime # Calculates time difference 
    lastTime +=  timeDiff # Last time checked reset to current time

    # Shut-down if the ESC-key is pressed or the window is "crossed down"
    for event in pygame.event.get():
        if event.type == QUIT or event.type == KEYDOWN and event.key == K_ESCAPE:
            terminate()    

    """X-axis control"""
    if pressedKeys[ord('a')]:
        vx = -MOVESPEED
    if pressedKeys[ord('d')]:
        vx = MOVESPEED
    if not pressedKeys[ord('d')] and not pressedKeys[ord('a')]:
        vx = 0

    """Y-axis control"""
    # Controls for jumping
    if pressedKeys[ord('w')] and thrusters == True:
            vy -= YACCEL * timeDiff; # Accelerate along the y-xis when "jumping", but not above/below max speed
            if vy <= -4:
                vy = -4
            isGrounded = False # You are airborne
            jumping = True # You are jumping

    if event.type == KEYUP: # If you let go of the "jump"-button, stop jumping
        if event.key == ord('w') and vy < 0 and not isGrounded:
            jumping = False
            falling = True

    player.x += vx
    player.y += vy

    # Gravity
    if not isGrounded or falling:
        vy += 0.3
        if vy > 80:
            vy = 80

    screen.fill(BACKGROUNDCOLOR)

    for i in range(len(blockTypeList)):
        if blockTypeList[i] == "solid":
            screen.blit(wallblock, (blockListDisp[i].x, blockListDisp[i].y)) #blit the wall-block graphics

    pygame.draw.rect(screen, (0, 0, 0), player)

    pygame.display.update()
    mainClock.tick(FPS)
1
I didn't take the time to go through your code and find the location of the problem, but it probably has something to do with you not turning on gravity when he walks off the platform. Put a test in the game loop to check if the player is off the platform. - ThisIsAQuestion
Yes that is what I was thinking too, but I can't figure out how to do it. - user2274889
since you make it so the player collides only once with the platform, there is no way to know when he comes off of it. You still need to test for collision even, when he isGrounded. - Bartlomiej Lewandowski

1 Answers

0
votes

A checklist that may help you out.

create self.min_height:

  • min_height initialized to lowest possible level (for example, the floor)
  • if player is not colliding with anything, then min_height remains to be the floor
  • if player collides with platform, then his min_height becomes that of the platform
  • player CAN JUMP if distance_between(min_height, current_y) is close to JUMP_SENSITIVITY(you may need a way to figure out if he is going to collide soon, but leave it for later)
  • Player continues to Fall as long as min_height hasn't been reached.

EDIT: This may help you get rid of Jumping/Falling flags