Am I using DT correctly?
Posted: Mon Jun 10, 2013 11:20 pm
I've run into a simple problem that has left me extremely confused.
I program on a mid-range laptop, and frequently send demonstrations of my code to friends whom use higher end PCs. I understand the need for dt in running games identically on devices with different specs, but I think I may have been using it wrong. The code I have pasted below causes the player to jump to its own head height and drop down to the floor again when 'w' is pressed, but on a friend's gaming PC it flies off the screen and takes around 10 seconds to reappear. I'm convinced this is due to me using dt incorrectly.
The code:
Thanks for the help guys. This is a really friendly forum.
I program on a mid-range laptop, and frequently send demonstrations of my code to friends whom use higher end PCs. I understand the need for dt in running games identically on devices with different specs, but I think I may have been using it wrong. The code I have pasted below causes the player to jump to its own head height and drop down to the floor again when 'w' is pressed, but on a friend's gaming PC it flies off the screen and takes around 10 seconds to reappear. I'm convinced this is due to me using dt incorrectly.
The code:
Code: Select all
function love.load()
Player = {}
Player.X1, Player.Y1 = 100, 100
Player.W, Player.H = 50, 100
Player.X2, Player.Y2 = Player.X1 + Player.W
Player.XSpeed, Player.YSpeed = 0, 0
Player.Falling = true
FloorHeight = 480
end
function love.update(dt)
dt = math.min(dt, 1/60)
-- Updating the player's position and hitbox.
Player.X2, Player.Y2 = Player.X1 + Player.W, Player.Y1 + Player.H
Player.X1 = Player.X1 + (Player.XSpeed * dt)
Player.Y1 = Player.Y1 + (Player.YSpeed * dt)
-- Check if the player is falling.
if Player.Y2 > FloorHeight then
Player.Falling = false
else
Player.Falling = true
end
-- Falling.
if Player.Falling == true then
if Player.YSpeed < 500 then
Player.YSpeed = Player.YSpeed + 1.5
end
else
Player.YSpeed = 0
end
-- Jumping behaviour.
if love.keyboard.isDown("w") then
if Player.Falling == false then
Player.YSpeed = -600
end
end
-- Moving left and right.
if love.keyboard.isDown("a") then
Player.XSpeed = -200
elseif love.keyboard.isDown("d") then
Player.XSpeed = 200
else
Player.XSpeed = 0
end
end
function love.draw()
love.graphics.rectangle("fill", Player.X1, Player.Y1, Player.W, Player.H)
love.graphics.line(0, FloorHeight, 1000, FloorHeight)
if Player.Falling == false then
love.graphics.print("falling : FALSE", 10, 25)
else
love.graphics.print("falling : TRUE", 10, 25)
end
end