LÖVE

Posted: **Mon Jun 18, 2018 6:01 pm**

Hi! I'm new to GD and I am trying to implement smooth sliding of a block and simulate friction to stop object slowly. The problem is, when object almost completely stops, you can notice freezes in his movement. What can cause it? Thank you!

Here's the code.

Code: Select all

push = require 'push'

WINDOW_WIDTH = 1280
WINDOW_HEIGHT = 720

VIRTUAL_WIDTH = 256
VIRTUAL_HEIGHT = 144

BLOCK_SIZE = 10

GRAVITY = 10

function love.load()
  love.graphics.setDefaultFilter('nearest', 'nearest')

  push:setupScreen(VIRTUAL_WIDTH, VIRTUAL_HEIGHT, WINDOW_WIDTH, WINDOW_HEIGHT, {
    fullscreen = false,
    resizable = false,
    vsync = true
  })

  x = VIRTUAL_WIDTH / 2 - BLOCK_SIZE
  y = VIRTUAL_HEIGHT / 2 - BLOCK_SIZE

  dx = 0
  dy = 0

  jumping = true
end

function love.update(dt)
  if love.keyboard.isDown('d') then
      dx = dx + 50
  end

  if love.keyboard.isDown('a') then
      dx = dx - 50
  end

  if love.keyboard.isDown('w') and jumping == false then
    dy = -200
    jumping = true
  end

  dy = dy + GRAVITY

  x = x + dx * dt
  y = y + dy * dt

  --friction
  dx = dx * 0.9
  --dy = dy * 0.9

  if(y > VIRTUAL_HEIGHT - BLOCK_SIZE) then
    y = VIRTUAL_HEIGHT - BLOCK_SIZE
    dy = 0
    jumping = false
  end

  if(x > VIRTUAL_WIDTH) then
    x = 0
  elseif (x + BLOCK_SIZE < 0) then
    x = VIRTUAL_WIDTH
  end
end

function displayFPS()
    love.graphics.setColor(0, 255, 0, 255)
    love.graphics.print('FPS: ' .. tostring(love.timer.getFPS()), 10, 10)
end

function love.draw()
  push:apply('start')
  --love.graphics.setColor(123, 43, 15, 255)
    love.graphics.setColor(0, 255, 0, 255)
  love.graphics.rectangle('fill', x, y, BLOCK_SIZE, BLOCK_SIZE)
  displayFPS()
  push:apply('end')
end

Posted: **Mon Jun 18, 2018 9:26 pm**

you should really not make others to find the libraries:
https://github.com/Ulydev/push/blob/master/push.lua

i noticed not dt applied to friction

i could not debug you sorry, good luck, bump lol

Posted: **Mon Jun 18, 2018 9:44 pm**

never came across the issue as i use the box 2D, also lerping wouldn't have such behaviour as it always makes the sum from start to finish

sorta want to now, this code exhibits less issue, i think it might be a known thing to oldschool vid game devs

Code: Select all

x = 30
y = 30

x_vel = 300

function love.update(dt)
    x = x + (dt * x_vel)
    x_vel = x_vel * 0.99
    if x_vel < 20 then --simply added a point of rest
        x_vel = 0
    end
end

function love.draw()
    love.graphics.rectangle('fill', x, y, 50, 50)
end

<shouts> FORUM!!!

Posted: **Mon Jun 18, 2018 9:57 pm**

hows this smooth your boat, yeah i know that looks a bit weird but surely you can do the rest, i will keep this for myself now, i need a custom physics comparison for my framework

Code: Select all

x = 30
y = 30

x_vel = 300

x_acceleration = -100

function love.update(dt)
    x = x + (dt * x_vel)
    -- x_vel = x_vel * 0.99 --friction
    if x_vel < 1 then --simply added a point of rest
        -- x_vel = 0
        x_acceleration = 0
        x_vel = 0
    end
    
    x_vel = x_vel + x_acceleration * dt
end

function love.draw()
    love.graphics.rectangle('fill', x, y, 50, 50)
end

someone really needs to hire me (yeah like maybe just to actually make sense of the answer sure...)

edit: so i think your code was MATH correct, mine is applying a constant deceleration, which doesn't screw up when it is applied frame by frame, or something like that

edit2: my cv:
beer
telesales

Posted: **Tue Jun 19, 2018 4:17 am**

You may be interested in this great library: https://github.com/kikito/tween.lua

Code: Select all

-- make some text fall from the top of the screen, bouncing on y=300, in 4 seconds
local label = { x=200, y=0, text = "hello" }
local labelTween = tween.new(4, label, {y=300}, 'outBounce')
labelTween:update(dt)

It provides Tweening/Easing/Interpolating functions, allowing you to move between 2 values gradually over a specified time duration, using an easing function for different effects. I use it within my game for gradual deceleration like you describe.

Posted: **Tue Jun 19, 2018 12:41 pm**

Link wrote: ↑Tue Jun 19, 2018 4:17 am You may be interested in this great library: https://github.com/kikito/tween.lua
Code: Select all
-- make some text fall from the top of the screen, bouncing on y=300, in 4 seconds
local label = { x=200, y=0, text = "hello" }
local labelTween = tween.new(4, label, {y=300}, 'outBounce')
labelTween:update(dt)
It provides Tweening/Easing/Interpolating functions, allowing you to move between 2 values gradually over a specified time duration, using an easing function for different effects. I use it within my game for gradual deceleration like you describe.

perhaps he doesn't know the destination, or do you have some other idea on this?

Posted: **Tue Jun 19, 2018 5:30 pm**

Thank you, guys, that helped a lot!

LÖVE

Object freezes when stops

Object freezes when stops

Re: Object freezes when stops

Re: Object freezes when stops

Re: Object freezes when stops

Re: Object freezes when stops

Re: Object freezes when stops

Re: Object freezes when stops