Hello there. I am far into Slimeith's quest 3 development when I went to finally work on the game's basic movement system. However I can not get it to work. A project with what I have of the broken system is here .

I am trying to make a scrolling game engine where the game stops scrolling where there is no more tiles left, then Slimeith starts scrolling until he hits the edge of the screen, or goes back to the center letting the stage scroll again. Slimeith scrolling on his own works perfectly in isolation, however when it activates in the going left script the game starts lagging to a screeching halt.

Other notes: The locations of the tiles in this are stored as a 12 digit number. The first and sixth digit telling whether it is positive or negative and the rest telling where it should go. All tiles are in a 480 by 360 grid. However in the borders the first and fifth digits tell whether it is positive or negative since the second and seventh digits were always 0 in Level one. Every NPC in the game depends on StageX and Y to tell where they should go. In area border a tile's number times two is it's Y position item on the list, and the Y item's number minus one is the X position item on the list.

Thank you if you can fix this. This means a lot to me and I will be eternally thankful as this is a important part of the game. I worked really hard on the rest of the game, and it wouldn't be complete until this is fixed.

See if this helps https://scratch.mit.edu/projects/51479882/

I think it helps to think of scrolling as a ‘window’ onto a real world. The coordinates of things in the real world don't change but the position of the window does. In your case the window cannot go beyond certain bounds. In most cases the window is centred on the player's character but that doesn't have to be the case as @gtoal says.

I made a test script that uses a “camera” sprite that handles all the scrolling (that also acts as a border so you can't see the sprites piling up at the sides). I made a “scroll align” block (run without screen refresh) that essentially moves the camera back into reasonable bounds that you input.

define scroll align (x bound) (y bound)
if <(scroll x) < [0]> then
repeat until <not <(scroll x) < [0]>>
change [scroll x v] by (1)//Do this again for scroll Y
end
end
if <(scroll x) > (x bound)> then
repeat until <not <(scroll x) > (x bound)>>
change [scroll x v] by (-1)//Do this again for scroll Y + Y bound
end
end

forever//Game loop stuff
...
scroll align (some bound) (some other bound)
end

As long as the block is run without screen refresh, it should work. You could also modify it so that there's an upper and lower bound instead of the lower bound always being 0 if you want.

While I'm still confused if I'm understanding correctly I should move the scripts that control scroll X and Y to the stage. I will also make an extra list for the current border taken from the border list I have now to make the code shorter. When moving a direction such as right it checks everything in the border list, first making sure that the tile it's checking is the same Y then checking to see if there is any acceptable Xs that would let it move. If there is an acceptable X it changes the X position. If no Xs are acceptable it sends a broadcast (or should it be a variable) that tells Slimeith that it can move and keeps moving by changing it's own X position until it is zero, then it sends another broadcast telling the background it should start scrolling X again(or should the stage check for when Slimeith's X position is zero). Then do the same thing but for the Y value. I'm just asking here first before it turns out I didn't understand correctly, and made the coding worse.

@DaEpikDude
Thank for trying to give me a script for this, however it won't work (unless I'm not understanding something) because most of my areas are not squares or rectangles. My biggest room's layout iswith the green and yellow pixels being the tiles. (Also by combining Powercon5's sizing script with adding mostly transparent pixels to the outer sides of the costumes my sprites don't pile up on the sides.)

I tried what I said, and I am stuck again. I updated the first post with my updated code.

I tried adding in allowing Slimeith to move, and it is very laggy(and probably glitchy). I have edited the first post to include this, and the going left for Slimeith is fully commented.

I still have no idea what to do. My two biggest problems right now is that going left out of bounds where Slimeith moves on his own lags tremendously, and I have no idea what to check for the scroll being in scroll bounds.

I am working on fixing it. I hope I can do it.

You have a bunch of stuff scattered around so it's hard to tell whats doing what. I made a quick experiment just of going to the edge of the scrolling then going to the edge of the screen and back to the center before going back the other way. Basically used and and or's to determine when it should move based on world size, x position and scrollX but not collisions. I'll try to add a collision if I have time.

https://scratch.mit.edu/projects/178140718/

Uniquename1 wrote:

You have a bunch of stuff scattered around so it's hard to tell whats doing what. I made a quick experiment just of going to the edge of the scrolling then going to the edge of the screen and back to the center before going back the other way. Basically used and and or's to determine when it should move based on world size, x position and scrollX but not collisions. I'll try to add a collision if I have time.

https://scratch.mit.edu/projects/178140718/

I organized my code so hopefully it is easier to understand. One of my main problems making this engine is that I have no idea what to put for when it check if you can scroll or not. It would be easier if it was just positive numbers, but there are, also negative coordinates for tiles too. I have areas where you would be able to scroll up when your Y position is 70 when your X is -200, but you can't scroll up when your X is 400. I have no idea how to code that. All I know is that I want the game to read from the borders list which areas it can scroll in.

Okay I tried to fix the left which turns out didn't work, and it is still having problems. Mostly with the downwards tiles.

Okay I managed to perfect scrolling left for the stage! However I have came across a new problem. Whenever Slimeith scrolls on his own. Slimeith scrolling on his own works perfectly in isolation, however when it activates in the going left script the game starts lagging to a screeching halt.

I am still stuck. My main problem is that the engine lags badly and stops working when you go to a part where Slimeith is suppost to scroll. I believe this may have something to do with it being a broadcast and wait block inside of a custom block however I am not sure.