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help with movement
Posted: Fri Mar 17, 2017 3:06 am
by eqnox
So I was working on a bit of code for player movement and I wanted to add the option to be able to hold shift to sprint
Code: Select all
function love.update()
if love.keyboard.isDown("w") then
py = py - 1
end
if love.keyboard.isDown("s") then
py = py + 1
end
if love.keyboard.isDown("a") then
px = px - 1
end
if love.keyboard.isDown("d") then
px = px + 1
end
if love.keyboard.isDown("lshift" and "w") then
py = py - 10
elseif love.keyboard.isDown("lshift" and "s") then
py = py + 10
end
if love.keyboard.isDown("lshift" and "a") then
px = px - 10
elseif love.keyboard.isDown("lshift" and "d") then
px = px + 10
end
This results in the player always moving at sprint speeds.
Code: Select all
ws = false
ss = false
as = false
ds = false
function love.update()
while(ws == true) do
py = py - 10
end
while(ss == true) do
py = py + 10
end
while(as == true) do
px = px - 10
end
while(ds == true) do
px = px + 10
end
end
function love.keypressed(key)
if key == "right" then
if key == down then
px = px + 3
end
end
if key == "lshift" and key == "s" then
ss = true
end
if key == "lshift" and key == "a" then
as = true
end
if key == "lshift" and key == "d" then
ds = true
end
end
function love.keyreleased(key)
if key == "lshift" and "w" then
ws = false
end
if key == "lshift" and "s" then
ss = false
end
if key == "lshift" and "a" then
as = false
end
if key == "lshift" and "d" then
ds = false
end
end
I have also tried something like this and it doesn't seem to work either. I think I might be doing something wrong. Over all im out of ways I know to fix it or at least ones that I have thought of.
Re: help with movement
Posted: Fri Mar 17, 2017 3:38 am
by Sulunia
Did you try
checking if shift was pressed first before checking what direction the player wants to move? Like this:
Code: Select all
if love.keyboard.isDown("w") then
if love.keyboard.isDown("lshift") then
py = py - 5
else
py = py - 1
end
end
For some reason, I just like to check if the run key was pressed before the actual movement key.
Re: help with movement
Posted: Fri Mar 17, 2017 3:47 am
by eqnox
So I did this
Code: Select all
if love.keyboard.isDown("w") then
if love.keyboard.isDown("lshift") then
py = py - 3
end
else
py = py - 1
end
end
but my player just started going up without any key press
Re: help with movement
Posted: Fri Mar 17, 2017 3:55 am
by eqnox
Ah I saw my mistake in my last bit of code i posted
Code: Select all
function love.update()
if love.keyboard.isDown("w") then
if love.keyboard.isDown("lshift") then
py = py - 3
else
py = py - 1
end
end
if love.keyboard.isDown("s") then
if love.keyboard.isDown("lshift") then
py = py + 3
else
py = py +1
end
end
if love.keyboard.isDown("a") then
if love.keyboard.isDown("lshift") then
px = px - 3
else
px = px -1
end
end
if love.keyboard.isDown("d") then
if love.keyboard.isDown("lshift") then
px = px + 3
else
px = px +1
end
end
end
This is the revised version and it works great!
Thanks for your help!
Re: help with movement
Posted: Fri Mar 17, 2017 6:51 am
by ivan
Hello eqnox, the code needs work, I recommend the following changes:
1.Don't allow holding W/S or A/D at the same time.
Code: Select all
local vx, vy = 0, 0
if love.keyboard.isDown("w") then
vy = -1
elseif love.keyboard.isDown("s") then
vy = 1
end
if love.keyboard.isDown("a") then
vx = -1
elseif love.keyboard.isDown("d") then
vx = 1
end
2.There is another subtle thing happening,
the player will move faster diagonally -
sqrt(2) = 1.41421356237 times faster to be precise.
Code: Select all
local d = math.sqrt(vx^2 + vy^2)
if d > 0 then
-- normalize vx/vy so that its length equals 1
vx, vy = vx/d, vy/d
end
3.Use multiplication instead of several if-else statements
(this must be done after normalizing vx,vy as described in step 2):
Code: Select all
if love.keyboard.isDown("lshift") then
-- move x5 as fast when holding lshift
vx = vx*5
vy = vy*5
end
PS. It should be clarified that vx and vy is the
velocity which is later added to the position:
Code: Select all
player.x = player.x + vx*dt
player.y = player.y + vy*dt
Re: help with movement
Posted: Fri Mar 17, 2017 7:29 pm
by Le_juiceBOX
Use the suggestions above also use this:
Code: Select all
if love.keyboard.isDown('w') then
py = py - 1*dt
end
the dt makes the game run at the same speed for 'all' computers. Use dt with movement etc.
Re: help with movement
Posted: Tue Mar 21, 2017 1:04 pm
by NickRock
If you multiply by dt you need to change 1 with 100 since it makes your speed really slow
Re: help with movement
Posted: Tue Mar 21, 2017 1:12 pm
by zorg
NickRock wrote: ↑Tue Mar 21, 2017 1:04 pm
If you multiply by dt you need to change 1 with 100 since it makes your speed really slow
More correctly, with dt there, the number multiplied by it will basically have "pixels per second" as its unit, instead of pixels per "loop".