24 replies to this topic

[MadBudderKing]

Hi,

Im a lot more experienced with lua now, and im creating my own OS now.
The thing I want to know is how to create windows that run programs, and mostly how to multitask programs, like a windowed multi-tasking OS.
A small example and explanation would be fine

Thanks - MadBudder

[Lyqyd]

This is not something that can be demonstrated with "a small example and explanation", just so you know. This is a relatively complex thing to do, as far as ComputerCraft is concerned.

[Zacklogan]

Hi. What I would recommend is to is watch these videos, they are very indepth and would be a good place to start: Building a UI / OS.

Hope this helps!

[oeed]

Zacklogan, on 04 May 2014 - 12:18 AM, said:

Hi. What I would recommend is to is watch these videos, they are very indepth and would be a good place to start: Building a UI / OS.

Hope this helps!

They're pretty good for getting the concept of how GUI work in CC, but it's not the best. Once you've watched those take a look at some of the OSs that use windowing, CraftBang, OneOS and LyqydOS (I'd recommend you look at them in that order, ranked by easiness to understand)

[MadBudderKing]

Zacklogan, on 04 May 2014 - 12:18 AM, said:

Hi. What I would recommend is to is watch these videos, they are very indepth and would be a good place to start: Building a UI / OS.

Hope this helps!

I've watched all of those before,
But thanks anyways!

oeed, on 04 May 2014 - 01:11 AM, said:

Zacklogan, on 04 May 2014 - 12:18 AM, said:

Hi. What I would recommend is to is watch these videos, they are very indepth and would be a good place to start: Building a UI / OS.

Hope this helps!

They're pretty good for getting the concept of how GUI work in CC, but it's not the best. Once you've watched those take a look at some of the OSs that use windowing, CraftBang, OneOS and LyqydOS (I'd recommend you look at them in that order, ranked by easiness to understand)

I was looking at craftbang, and it seems like theres a function that over rides the term API to suit it needs to put everything in the right position and everything, but I dont exactly understand 'how it does over rides the term API'.

[OczkoSX]

If you want to run multiple functions in one time, you can use parallel API

[oeed]

MadBudderKing, on 04 May 2014 - 03:00 AM, said:

I was looking at craftbang, and it seems like theres a function that over rides the term API to suit it needs to put everything in the right position and everything, but I dont exactly understand 'how it does over rides the term API'.

What it does, as does OneOS, although not quite to the same extent as OneOS which completely sandboxes everything, is it runs each program in it's own environment. This means that you can set the term API for each program to be your custom one. Take a look at setfenv, or the code I use to do this in OneOS. (the term API overriding is in TermRedirect in the same folder)

[viluon]

It's definitely good to learn from code of OSes here at the forums (as oeed mentioned). However, I don't recommend you to start your own project if you don't understand multitasking. Start with something less complicated, multitasking is the main part of OS's kernel and asking for the code would sound like copy paste (for me). Have a look on how others do it, then try yourself, then ask if you don't understand.

[oeed]

viluon, on 04 May 2014 - 08:58 AM, said:

It's definitely good to learn from code of OSes here at the forums (as oeed mentioned). However, I don't recommend you to start your own project if you don't understand multitasking. Start with something less complicated, multitasking is the main part of OS's kernel and asking for the code would sound like copy paste (for me). Have a look on how others do it, then try yourself, then ask if you don't understand.

Yea, there's no problem with looking at peoples code and learning from it.

I used the NDF-Jay tutorials to learn how CC OSs worked before making PearOS, then I used CraftBang to learn how to do shell based multitasking.

[MadBudderKing]

oeed, on 04 May 2014 - 07:35 AM, said:

MadBudderKing, on 04 May 2014 - 03:00 AM, said:

I was looking at craftbang, and it seems like theres a function that over rides the term API to suit it needs to put everything in the right position and everything, but I dont exactly understand 'how it does over rides the term API'.

What it does, as does OneOS, although not quite to the same extent as OneOS which completely sandboxes everything, is it runs each program in it's own environment. This means that you can set the term API for each program to be your custom one. Take a look at setfenv, or the code I use to do this in OneOS. (the term API overriding is in TermRedirect in the same folder)

Funny enough, I was just looking at this, but ill try it out.

[MadBudderKing]

local buffer =
{
setCursorPos = function(x, y)
term.native.setCursorPos(x+1, y+1)
end;
write = function(text)
term.native.write(text)
end
}
setmetatable(buffer, {__index = _G})
setfenv(1, buffer)
term.setCursorPos(1,1)
term.write("Hii!!")

Ive tried this, but it just prints at 1,1. As its supposed to at 2,2. I might not be getting something, anything Im doing wrong here?

[MKlegoman357]

You are defining global 'setCursorPos' and 'write' functions, not 'term.setCursorPos' and 'term.write'. This might work (not tested):

local env = setmetatable({
  term = setmetatable({
    setCursorPos = function (x, y)
      _G.term.native.setCursorPos(x + 1, y + 1)
    end
  }, {__index = _G.term.native})
}, {__index = _G})

setfenv(1, env)
term.setCursorPos(1,1)
term.write("Hii!!")

Don't forget that in CC 1.6 and above 'term.native' was changed from a table to a function.

[MadBudderKing]

MKlegoman357, on 04 May 2014 - 02:35 PM, said:

You are defining global 'setCursorPos' and 'write' functions, not 'term.setCursorPos' and 'term.write'. This might work (not tested):

local env = setmetatable({
  term = setmetatable({
	setCursorPos = function (x, y)
	  _G.term.native.setCursorPos(x + 1, y + 1)
	end
  }, {__index = _G.term.native})
}, {__index = _G})

setfenv(1, env)
term.setCursorPos(1,1)
term.write("Hii!!")

Don't forget that in CC 1.6 and above 'term.native' was changed from a table to a function.

Ya, It errors.
Line 4, attempt to index ? (a function value)

Edited by MadBudderKing, 04 May 2014 - 02:40 PM.

[MKlegoman357]

MadBudderKing, on 04 May 2014 - 02:40 PM, said:

Ya, It errors.
Line 4, attempt to index ? (a function value)

MKlegoman357, on 04 May 2014 - 02:35 PM, said:

Don't forget that in CC 1.6 and above 'term.native' was changed from a table to a function.

Here's a fixed example (for CC 1.6+):

local env = setmetatable({
  term = setmetatable({
    setCursorPos = function (x, y)
      _G.term.setCursorPos(x + 1, y + 1)
    end
  }, {__index = _G.term})
}, {__index = _G})

local function func ()
  term.setCursorPos(1, 1)
  term.write("Hii!!")
end

setfenv(func, env)

func()

Edited by MKlegoman357, 04 May 2014 - 03:00 PM.

[MadBudderKing]

Thanks, it works. Now, what If I want to run it on another program?
Running shell.run after the setfenv errors; Line 11 (Line w/ the shell.run on it), attempt to index ? (a nil value)

[CometWolf]

Shell is not indexed in _G by default. So unless you put it in there, you won't be able to acess it through the index meta to _G. I would suggest putting it in the new environment.

[MadBudderKing]

I might get you entirly, but something like this?

local env = setmetatable({
  term = setmetatable({
    setCursorPos = function (x, y)
	  _G.term.setCursorPos(x + 1, y + 1)
    end
  }, {__index = _G.term}),
  shell = setmetatable({
    run = function (prg)
	  shell.run(prg)
    end
  }, {__index = _G.shell})
}, {__index = _G})
function func()
shell.run("firewolf")
end
setfenv(func, env)
func()

When ran, firewolf will stay at 1,1

[CometWolf]

I was thinkin more along the lines of just sticking the shell table in there, instead of putting the run function in there. Also as i noted earlier, there is no _G.shell. Anyways, i believe shell.run sets the environment to the environment of the shell, not the environment of the function calling it. Therefore, you're overrides won't work with shell.run unless you replace the global functions. You'll have to use os.run instead.

[MadBudderKing]

Yay, it works!
Im pretty much using this code:

local env = setmetatable({
  term = setmetatable({
	setCursorPos = function (x, y)
	  _G.term.setCursorPos(x + 1, y + 1)
	end
  }, {__index = _G.term}),
}, {__index = _G})
function func()
os.run(env, "ptest")
end
setfenv(func, env)
func()

ptest just has a simple term.setCursorPos(2,2) and write("hi") in it.

Now, to implement all the other drawing functions (paintutils.drawLine, drawPixel image, etc)

Oh, and while im doing that, what about multitasking?
No-one talked about that, really in here yet

Edited by MadBudderKing, 04 May 2014 - 05:18 PM.

[CometWolf]

function func()
os.run(env, "ptest")
end
setfenv(func, env)
func()

This, is pointless. os.run sets the environment of the called program to the first argument anyways, so you might aswell just do just

os.run(env, "ptest")