Hello, I need help with collision detection in my game,

I tried to do collision detection on based on some scrolling platformer detection method but I coded it over and over again because something was still wrong, collision does work but it's still jittery and buggy,

1. It could only fix collisions when you walk into a wall until you slide into the wall multiple times!
keep sliding and holding arrow keys at the same time towards the wall until the player glitches through the wall or dies and you'll see what I mean.

2. the green vertical hitbox thinks the player is deep in the ground and tries to move vertically of the floor, then it thinks that the player was crushed by something then the collision detection fails,

I still don't believe it's working 100% for that reason

Any ideas on how to fix this?
find this script,

define Move speed: (Speed) Input (Input)
go to x: ((Input) * (Speed)) y: (y position)
switch costume to (X-hitbox v)
WALL check ::custom block
set [current input v] to (Input)
change [P1 scroll x v] by ((Speed) * (Input)
if <<touching [ Level v] ?> or <(Touching?) > [0]>> then
set [last value v] to (direction)
set [moving? v] to [Scene-moving]
change [P1 scroll x v] by ((([floor v] of (() - (Speed))::operators)) * ((last input) * (1)))
point in direction (last value)
set [moving? v] to [true]
end
set [last input v] to (current input)

the script is in the Megaman//MegamanHitbox sprite.
It's responsible for scrolling colliding



the project is the link: https://scratch.mit.edu/projects/1137901998/.

Help would be appreciated, thanks!

I was gonna try and fix it but your code is hurting my brain abit, might try later when the sun's actually up

Koamodo975 wrote:

I was gonna try and fix it but your code is hurting my brain abit, might try later when the sun's actually up

Ok, what part of the code were you struggling with?

You've made some mistakes that make it really hard for others to understand your code:
1. You have left a lot of hatless scripts.
2. Scripts overlap a lot.
3. You've made the engine while not testing it during the process.
All this makes the code barely readable and hard to remake from scratch.

And a cool fact: use ::type to change the type of a block in Scratchblocks:

move (2) steps ::events

snip block lol ::grey

custom block ::custom

OrangeFlyingCat wrote:

You've made some mistakes that make it really hard for others to understand your code:
1. You have left a lot of hatless scripts.
2. Scripts overlap a lot.
3. You've made the engine while not testing it during the process.
All this makes the code barely readable and hard to remake from scratch.

And a cool fact: use ::type to change the type of a block in Scratchblocks:

move (2) steps ::events

snip block lol ::grey

custom block ::custom

I can understand the overlapping scripts and hatless script it's because I might put the code to the side because it might be useful and then I forget it and forgot to clean it up before sharing it., I've also spent too much time testing each part of the engine most important before I got stuck on scrolling collision detection. thanks for clarifying, I'll clean it up now.
(the jittery collision detection problem is still not solved though and we are going a bit off topic.)

Bump.

Bump

DNQ_brwn wrote:

Bump.

DNQ_brwn wrote:

Bump

Have you fixed this?

OrangeFlyingCat wrote:

DNQ_brwn wrote:

Bump.

DNQ_brwn wrote:

Bump

Have you fixed this?

No I cannot even fix the collision myself because,
1. the way I coded it is to prevent the vertical hitbox from being inside a wall that it cannot move vertically out of, that's for the ground,

2. moving the player out of the wall by negative value without input and repeating it until the player moves out the wall sends the player out of bounds.

this is the only way I know how to do horizontal scrolling collision, by subtracting movement. even if I disable the vertical collision you're in the wall for 5 milliseconds then you slowly move out the wall if you keep sliding and walking into the wall.

So, the collisions and movement should work like this (though, most probably, your ones work differently):

switch costume to (Hitbox v) //just a rectangle that somewhat represents the player's size
change [world x v] by (speed x)
position
if <touching (Level v) ?> then
fix collision x
end
change [world y v] by (speed y)
position
if <touching (Level v) ?> then
fix collision y
end

define position
go to x: ((round (world x)) - (round (Camera X))) y: ((round (world y)) - (round (Camera Y)))

define fix collision x
set [i v] to [1]
repeat (5) //checking if we hit just a small step
change [world y v] by (i)
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world y v] by ((-2) * (i))
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world y v] by (i)
change [i v] by (1)
end
position
repeat until <not <touching (Level v) ?>>
if <(speed x) > (0)> then 
change [world x v] by (-1)
else
change [world x v] by (1)
end
position
end
set [speed x v] to [0]

define fix collision y
set [i v] to [1]
repeat (5) //checking if we hit just a small step
change [world x v] by (i)
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world x v] by ((-2) * (i))
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world x v] by (i)
change [i v] by (1)
end
position
repeat until <not <touching (Level v) ?>>
if <(speed y) > (0)> then 
change [world y v] by (-1)
else
change [world y v] by (1)
end
position
end
set [speed y v] to [0]

.

OrangeFlyingCat wrote:

So, the collisions and movement should work like this (though, most probably, your ones work differently):

switch costume to (Hitbox v) //just a rectangle that somewhat represents the player's size
change [world x v] by (speed x)
position
if <touching (Level v) ?> then
fix collision x
end
change [world y v] by (speed y)
position
if <touching (Level v) ?> then
fix collision y
end

define position
go to x: ((round (world x)) - (round (Camera X))) y: ((round (world y)) - (round (Camera Y)))

define fix collision x
set [i v] to [1]
repeat (5) //checking if we hit just a small step
change [world y v] by (i)
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world y v] by ((-2) * (i))
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world y v] by (i)
change [i v] by (1)
end
position
repeat until <not <touching (Level v) ?>>
if <(speed x) > (0)> then 
change [world x v] by (-1)
else
change [world x v] by (1)
end
position
end
set [speed x v] to [0]

define fix collision y
set [i v] to [1]
repeat (5) //checking if we hit just a small step
change [world x v] by (i)
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world x v] by ((-2) * (i))
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world x v] by (i)
change [i v] by (1)
end
position
repeat until <not <touching (Level v) ?>>
if <(speed y) > (0)> then 
change [world y v] by (-1)
else
change [world y v] by (1)
end
position
end
set [speed y v] to [0]

It does do it's job, but when it's done without screen refresh,you walk straight into the wall, It still pushes the player too far off the map.
https://scratch.mit.edu/projects/1137901998/editor

DNQ_brwn wrote:

.

OrangeFlyingCat wrote:

So, the collisions and movement should work like this (though, most probably, your ones work differently):

switch costume to (Hitbox v) //just a rectangle that somewhat represents the player's size
change [world x v] by (speed x)
position
if <touching (Level v) ?> then
fix collision x
end
change [world y v] by (speed y)
position
if <touching (Level v) ?> then
fix collision y
end

define position
go to x: ((round (world x)) - (round (Camera X))) y: ((round (world y)) - (round (Camera Y)))

define fix collision x
set [i v] to [1]
repeat (5) //checking if we hit just a small step
change [world y v] by (i)
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world y v] by ((-2) * (i))
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world y v] by (i)
change [i v] by (1)
end
position
repeat until <not <touching (Level v) ?>>
if <(speed x) > (0)> then 
change [world x v] by (-1)
else
change [world x v] by (1)
end
position
end
set [speed x v] to [0]

define fix collision y
set [i v] to [1]
repeat (5) //checking if we hit just a small step
change [world x v] by (i)
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world x v] by ((-2) * (i))
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world x v] by (i)
change [i v] by (1)
end
position
repeat until <not <touching (Level v) ?>>
if <(speed y) > (0)> then 
change [world y v] by (-1)
else
change [world y v] by (1)
end
position
end
set [speed y v] to [0]

It does do it's job, but when it's done without screen refresh,you walk straight into the wall, It still pushes the player too far off the map.
https://scratch.mit.edu/projects/1137901998/editor

The top scripts should not be done without screen refresh
I'll be sharing a scrolling platformer example soon, I'll give you a link when I will (it's not an advertisement because you can always use TurboWarp to play the project anonymously without giving it a “view”)

OrangeFlyingCat wrote:

DNQ_brwn wrote:

.

OrangeFlyingCat wrote:

So, the collisions and movement should work like this (though, most probably, your ones work differently):

switch costume to (Hitbox v) //just a rectangle that somewhat represents the player's size
change [world x v] by (speed x)
position
if <touching (Level v) ?> then
fix collision x
end
change [world y v] by (speed y)
position
if <touching (Level v) ?> then
fix collision y
end

define position
go to x: ((round (world x)) - (round (Camera X))) y: ((round (world y)) - (round (Camera Y)))

define fix collision x
set [i v] to [1]
repeat (5) //checking if we hit just a small step
change [world y v] by (i)
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world y v] by ((-2) * (i))
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world y v] by (i)
change [i v] by (1)
end
position
repeat until <not <touching (Level v) ?>>
if <(speed x) > (0)> then 
change [world x v] by (-1)
else
change [world x v] by (1)
end
position
end
set [speed x v] to [0]

define fix collision y
set [i v] to [1]
repeat (5) //checking if we hit just a small step
change [world x v] by (i)
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world x v] by ((-2) * (i))
position
if <not <touching (Level v) ?>> then
stop [this script v]
end
change [world x v] by (i)
change [i v] by (1)
end
position
repeat until <not <touching (Level v) ?>>
if <(speed y) > (0)> then 
change [world y v] by (-1)
else
change [world y v] by (1)
end
position
end
set [speed y v] to [0]

It does do it's job, but when it's done without screen refresh,you walk straight into the wall, It still pushes the player too far off the map.
https://scratch.mit.edu/projects/1137901998/editor

The top scripts should not be done without screen refresh
I'll be sharing a scrolling platformer example soon, I'll give you a link when I will (it's not an advertisement because you can always use TurboWarp to play the project anonymously without giving it a “view”)

that's good news.

Scratch link:
https://scratch.mit.edu/projects/1141999320/
TurboWarp link:
https://turbowarp.org/1141999320
Hope you will not need to redo the whole engine.

,

OrangeFlyingCat wrote:

Scratch link:
https://scratch.mit.edu/projects/1141999320/
TurboWarp link:
https://turbowarp.org/1141999320
Hope you will not need to redo the whole engine.

Thanks for your help. I really appreciate the dedication to fixing this problem.