Issues with smooth 2D movement in python

The objective I’m trying to reach is to make smooth, 2-D movement in processing’s python mode. I understand that python processing isn’t nearly as popular as Java, but I need to do it for a school project.

I don’t know Java at all, and because python is so unpopular on processing, I wasn’t able to find much help on legacy forum posts. My movement, while fishy, still works in the X and Y axis, but diagonals are a complete no-go, and overall is really uncomfortable to use.

I’m aiming for something like this:
http://studio.processingtogether.com/sp/pad/export/ro.91tcpPtI9LrXp

If you want to try my code: have a look for yourself!

PlayX = 1280 / 2
PlayY = 720 / 2

def setup():
    size(1280, 720)
    background(255)
    frameRate(60)

def draw():
    global PlayX, PlayY
    if keyPressed:
        if key == 'w':    
            PlayY -= 10
            pushMatrix() # activating translation grid
            background(255) # painting over previous circle
            ellipse(PlayX, PlayY, 55, 55) #drawing the player 
            translate(10, 0) # translation
            popMatrix() # deactivating translation grid
        if key == 'a':
            PlayX -= 10
            pushMatrix()
            background(255)
            ellipse(PlayX, PlayY, 55, 55) 
            translate(-10, 0)
            popMatrix()
        if key == 's':
            PlayY += 10
            pushMatrix()
            background(255)
            ellipse(PlayX, PlayY, 55, 55) 
            translate(0, 10)  
            popMatrix()
        if key == 'd':
            PlayX += 10
            pushMatrix()
            background(255)
            ellipse(PlayX, PlayY, 55, 55) 
            translate(0, -10)
            popMatrix()

Any help would be really appreciated.

1 Like

Hi @webbm1,

How about storing the directions in a dictionary and having a toggle function to activate them when triggered.

Interactive demo

W, H = 1280, 720

p = PVector(W>>1, H>>1) #similar to (W/2, H/2)

D = {'w': [0, PVector(0, -10)], #0 means False
     'a': [0, PVector(-10, 0)], 
     's': [0, PVector(0, 10)], 
     'd': [0, PVector(10, 0)]}


def setup():
    size(W, H, P2D)


def draw():
    background('#FFFFFF')

    controls()    
    
    pushMatrix() # activating translation grid
    translate(p.x, p.y)
    ellipse(0, 0, 55, 55) #drawing the player 
    popMatrix() # deactivating translation grid

    
    
def keyPressed():
    toggle(key)

            
def keyReleased():  
    toggle(key)



def toggle(k):
    
    if k in D:
        D[k][0] = not D[k][0]
        

def controls():
    
    for k in D:
        b, dir = D[k] #boolean (is it activated ?), direction
        if b:
            p.add(dir)
4 Likes

Thanks! I’ll try this solution out, and if it works, I’ll mark it as answer. Really appreciate the help, @solub

That’s a very old sketch of mine. :innocent:

BtW, I did a followup w/ 2 players instead of 1 both for Java Mode & p5js flavors: :sunglasses:

And now I’ve decided to do a Python Mode version as well. Check it out: :snake:


#!/bin/python2

"""
Players Movement (v1.1.0)
by GoToLoop (2020/Mar/11)

Discourse.Processing.org/t/issues-with-smooth-2d-movement-in-python/18556/4

GoToLoop.Trinket.io/sites/players-movement
Trinket.io/processing/62fab051ed

Reddit.com/r/processing/comments/bshqa8/
how_would_i_make_a_keypressed_function_support/eor5epo/

OpenProcessing.org/sketch/718355
OpenProcessing.org/sketch/717760

Studio.ProcessingTogether.com/sp/pad/export/ro.91tcpPtI9LrXp
"""

original_set = set # Save Python's builtin set() before Processing's import

from processing import *

ONLINE = '__papplet__' not in globals()

W = 750 if ONLINE else 1200
H = 450 if ONLINE else 600

PLAYERS = 2 # Number of players
BG = 0xff00FFFF # Cyan background

DIAMS = 50, 40 # Diameters
SPDS = 4, 5 # Speeds
INKS = 0xff0000FF, 0xffFF0000 # Blue, Red

KEYS = (
    tuple(ord(k) for k in 'WSAD'), # Player 1's keys
    (UP, DOWN, LEFT, RIGHT)) # Player 2's keys

players = PLAYERS * [ None ]
keysDown = original_set()

def setup():
    size(W, H)

    stroke(Player.OUTLINE)
    strokeWeight(Player.BOLD)
    ellipseMode(Player.MODE)

    for i in range(PLAYERS):
        d = DIAMS[i]
        dd = d << i
        players[i] = Player(dd, dd, d, SPDS[i], INKS[i], KEYS[i])


def draw():
    background(BG)
    for p in players: p.move().display()


def keyPressed(): keysDown.add(keyCode)

def keyReleased(): keysDown.discard(keyCode)


class Player:
    OUTLINE, BOLD, MODE = 0, 2, CENTER
    UP, DOWN, LEFT, RIGHT = range(4)

    def __init__(p, x, y, d, v, ink, keys):
        p.x = x
        p.y = y
        p.d = d
        p.v = v
        p.ink = color(ink)
        p.keys = keys


    def display(p):
        fill(p.ink)
        ellipse(p.x, p.y, p.d, p.d)
        return p


    def move(p):
        r = p.d >> 1
        v = p.v
        k = p.keys

        hor = (k[p.RIGHT] in keysDown) - (k[p.LEFT] in keysDown)
        ver = (k[p.DOWN]  in keysDown) - (k[p.UP]   in keysDown)

        p.x = constrain(p.x + v*hor, r, width  - r)
        p.y = constrain(p.y + v*ver, r, height - r)

        return p



ONLINE and run()
3 Likes

(me when I see GoToLoop posting in Python: … :male_detective:‍♂ :thinking: :open_mouth::grey_exclamation::writing_hand:t2: :man_technologist:t2: :ok_hand:t2: :smirk: :shushing_face:…)

Joke aside:

hor = (k[p.RIGHT] in keysDown) - (k[p.LEFT] in keysDown)
ver = (k[p.DOWN]  in keysDown) - (k[p.UP]   in keysDown)

p.x = constrain(p.x + v*hor,...
p.y = constrain(p.y + v*ver,...

I like that.

3 Likes