Ved technical documentation

This page is intended to document Ved's internals as well as possible. The page is still being worked on, and more things are being added over time. If you'd like to know more about anything specific in Ved that I haven't explained yet here, or not well enough (except for the easter eggs :P), feel free to ask! If you'd like more information on how to make plugins, check this page. The repository is here.

Last updated: Sunday 18 November 2018 21:05 (UTC) (this is the last edit date of the file)

Files

First of all, the following source files are used in Ved:

States

Ved uses state numbers to represent different screens, menus and interfaces. Blue state numbers are not normally used anymore, and/or are not normally accessible, and many of them are leftover testing states.

State allocation

In Ved 1.1.4 and higher, plugins can allocate an amount of states for their own use, without using hardcoded state numbers, making it unnecessary to think of unique state numbers that won't interfere with any other plugins or future Ved updates. The following functions can be used:

allocate_states(name [, amount=1])

This function is used to allocate the given amount of flags with identifier name.

in_astate(name [, s=0])

This function returns true if the current state is s for identifier name. These state numbers start at 0.

to_astate(name [, new=0 [, dontinitialize=false]])

Change state to state number new for identifier name, and if dontinitialize is set, call hook func_loadstate.

For example, take a plugin called My First Plugin, which uses three states. Upon startup, like in hook love_load_start or love_load_end, the plugin calls allocate_states("my_1st_plug", 3). If this is the only plugin, or the first plugin to call allocate_states(), the allocated states will now, internally, be 100, 101 and 102. Let's say My First Plugin has three buttons to go to each of the allocated states. The first button, when clicked, would call to_astate("my_1st_plug", 0), the second would call to_astate("my_1st_plug", 1) and the third would call to_astate("my_1st_plug", 2). Hook love_draw_state, would contain something like this:

if in_astate("my_1st_plug", 0) then
	-- Insert drawing code for first state!
	statecaught = true
elseif in_astate("my_1st_plug", 1) then
	-- Insert drawing code for second state!
	statecaught = true
elseif in_astate("my_1st_plug", 2) then
	-- Insert drawing code for third state!
	statecaught = true
end

The hook func_loadstate could contain something similar for initialization code for all the states (but without statecaught = true)

The identifying name can be anything, but this name should be unique to one plugin. It's also possible to allocate multiple blocks of state numbers within the same plugin, if you use different names. If your plugin only has one state, you can leave out the number (allocate_states("my_1st_plug"), in_astate("my_1st_plug"), to_astate("my_1st_plug")). And of course, this means you can have multiple states that are only referred to by string names (I can see how in_astate("my_1st_plug_menu") and in_astate("my_1st_plug_display") can be more pleasing than in_astate("my_1st_plug", 0) and in_astate("my_1st_plug", 1)). It's up to you to choose whatever you like most, or whatever works best for your plugin.

LÖVE version compatibility

Ved is compatible with all revisions of LÖVE 0.9.x, 0.10.x and 11.x, but its code is written for 0.9.x. Compatibility with newer versions is mostly achieved by causing update changes to be undone; for example, LÖVE functions that were renamed or expect different arguments are redefined/hijacked and then called by those redefinitions if arguments or return values need to be passed differently, and callbacks that get "new-style" data from LÖVE get a bit of conversion code at the top. There are a few instances of conditionals depending on the version number in regular code, but that is not very common.

Debug mode

Debug mode is a special mode used to access certain features and information that can be useful for debugging and developing Ved. Enabling debug mode has the following effects:

• You can jump to any state by pressing F12
• The window title bar displays the FPS, state number, window size, cursor position and LÖVE version number.
• Entities have tooltips with their properties
• You can access the lua_debug console by pressing Ctrl+PageUp. Make sure you do have a console attached, this blocks the entire Ved window until you type cont in the console. This shortcut is always available on a crash screen, by the way, even outside debug mode.
• You can limit the framerate to 60, 30 or 15 by pressing Ctrl+PageDown
• Entity IDs/table keys are shown in the raw entity properties dialog
• The hidden tileset creator can be accessed by pressing LCtrl+\ in the main editor (I'm pretty sure I've written an explanation of it somewhere, but I'll document it here as well
• Pressing LCtrl+' in the main editor will print all tileset and tilecol numbers to the console
• Pressing F11 will print all global variables to the console
• Holding / in the main editor would display instead of all entities, but that key now jumps to the script editor.
• A visual indicator is added that displays when text input is being taken.
• On the loading screen, you can add a fake level to the list of levels by pressing Shift+F2, and (visually) remove the last level from the list by pressing Shift+F3. This is for testing the scrolling area and such.

Debug mode is enabled by the boolean variable allowdebug. It is possible to enable it in-app by going from the load screen to the Ved options, clicking and holding the OK button, and "dragging" over the Send Feedback button holding the right mouse button as well.

Editor-related variables

Current room

Selected tool

Selected tileset

Undo/redo stacks

Other things

Level-related variables and functions

Level metadata

metadata["Creator"]
metadata["Title"]
metadata["Created"]
metadata["Modified"]
metadata["Modifiers"]
metadata["Desc1"]
metadata["Desc2"]
metadata["Desc3"]
metadata["website"]
metadata["mapwidth"]
metadata["mapheight"]
metadata["levmusic"]

Room tiles

Entities

{
	x = 12,
	y = 34,
	t = 17,
	p1 = 0,
	p2 = 0,
	p3 = 0,
	p4 = 0,
	p5 = 320,
	p6 = 240,
	data = "Roomtext or script name"
}

Room metadata

{
	tileset = 0,
	tilecol = 0,
	platx1 = 0,
	platy1 = 0,
	platx2 = 320,
	platy2 = 240,
	platv = 4,
	enemyx1 = 0,
	enemyy1 = 0,
	enemyx2 = 320,
	enemyy2 = 240,
	enemytype = 0,
	directmode = 0,
	warpdir = 0,
	roomname = "Roomname",
	auto2mode = 0,
}

Scripts

scriptnames = {
	[1] = "mynewscript",
	[2] = "mynewscript_load"
}
scripts = {
	mynewscript_load = {
		[1] = "ifflag(2,stop)",
		[2] = "flag(2,on)",
		[3] = "iftrinkets(0,mynewscript)"
	},
	mynewscript = {
		[1] = "reply(3)",
		[2] = "I probably don't really need it,",
		[3] = "but it might be nice to take it",
		[4] = "back to the ship to study..."
	}
}

Counts

	local mycount = {trinkets = 0, crewmates = 0, entities = 0, startpoint = nil, FC = 0}  -- FC = Failed Checks

Metadata entity (level notes, flag names)

The metadata entity is used by Ved to store data that is specific to a certain level. It is a roomtext entity at x=800 y=600, which means it's in room 21,21 (1-indexed). The data is formatted with several levels of separation characters:

For example, one of the "tables" contains level notes. Each level note is separated by $, and inside a level note, the name and the contents of the note are separated by @.

Accent grave (`) is the escape character; if the real versions of certain characters need to be represented, they are escaped as follows:

The function despecialchars(text) encodes the raw characters to escaped format, undespecialchars(text) decodes escaped characters back to raw characters.

As said, | is the primary separator, which separates the following items:

(more coming soon)

Clipboard room format

Currently, when you copy a room to the clipboard, it's stored in a comma-separated format. It consists of 1215 values separated by commas, and it's structured as follows (indices start at 1, as in Lua):

In the room name, commas are replaced by the character ´ (U+00B4 ACUTE ACCENT).

In this format, entities are not copied. I'm planning to replace this CSV system by an XML format, which will also contain entities. Data in the old format will still be pasteable, and I'll probably also leave in a way to copy as CSV.

Dialogs

dialog.create(message, buttons, handler, title, fields, noclosechecker, identifier)

message is the body of the dialog box. This is the only required argument.
buttons speaks for itself as to what it is (but see below), if not specified, only an OK button will be present.
handler is a function that will be called when the dialog is closed, and will be provided with the button that was pressed and the dialog fields.
title is the title text of the dialog. Setting this to an empty string is not needed anymore.
fields defines the input fields that the dialog has, see below. If not given, the dialog has no input fields.
noclosechecker is a function of which the main purpose is to check whether a button shouldn't actually close the dialog, and should return true if so - think of apply buttons
identifier is just an extra internal label indicating the type of dialog, rarely used (it's used for the quit dialog to know that a quit dialog is already on top)

Buttons

Strictly speaking, the buttons parameter accepts a list/table of buttons. For each element, if that element is a string, that string will be displayed as-is. But if possible, it should be an integer, representing one of the built-in buttons. A list of buttons is available as DB, so for example, DB.YES is a "Yes" button. The list is as follows:

There's also built-in lists of buttons available as DBS, like DBS.YESNO, which stands for {DB.YES, DB.NO}, meaning a Yes and No button.

Handler

The purpose of the handler function is to take action after closing a dialog. For example, if a question is asked whether the user wants to destroy something, then that should be done if (and only if) the user chooses DB.YES.

The handler is a function that can take up to four arguments:

• The first is the returned button (an element of the buttons list provided to dialog.create).
• The second argument is a table with all the contents of the input fields, where input field keys are the keys, and their inputs are the values.
• Optionally, the "identifier" of the dialog, if given when creating the dialog
• A boolean that is true if closing the dialog has been closed by the no-close checker (more below)

Dialog handlers as used in Ved's code can be found in the file dialog_uses.lua, starting with dialog.callback. An example handler is the following. Assume the buttons for this dialog are DBS.YESNOCANCEL. In this example, users press Yes if they want a new dialog to be created showing what they entered in a field with the key name, press No if they still want a dialog but don't want to know their input, and press Cancel if they want no new dialog.

function(button, fields)
	if button == DB.YES then
		dialog.create("You pressed Yes, and the input with key \"name\" is " .. fields.name)
	elseif button == DB.NO then
		dialog.create("You pressed No! Apparently you don't want to know what you entered, but you still want a dialog.")
	end
end

No-close checker

No-close checkers are similar to handlers, but they are called before the dialog closes. This function can stop the dialog from being closed by returning true, and thus are useful for creating error messages if the user puts in invalid input. They can also be used to not close the dialog if an Apply button is pressed, for example.

The arguments for the no-close checker are the same as for the main handler, except the fourth argument doesn't exist. If the no-close checker returns true (and thus stops the dialog from closing) the handler will still be called, and its fourth argument will be set to true as well. Here's an example of how a no-close checker can be used to give an error message in case someone enters a value for the field with key inp that is empty or above 20 characters:

function(button, fields)
	if button == DB.OK and (fields.inp == "" or fields.inp:len() > 20) then
		dialog.create("Your input must not be empty or longer than 20 characters.")
		return true
	end
end

function(button, fields, identifier, notclosed)
	if notclosed then
		return
	end

	if button == DB.OK then
		-- Save your fields.inp here.
	end
end

Fields

• Key (its identifier, like name in a HTML input field)
• X position in characters (blocks of 8)
• Y position in characters (blocks of 8)
• Width of input field in characters (so in blocks of 8 again)
• Default value (like value in HTML)
• Type (optional, by default 0, a text field)

The X and Y positions for the field both start at 0, which is the position the regular dialog text also starts.
These are the different types of input fields:

More information about how the different types work:

0 - Text input

1 - Dropdown

• A list of items shown in the dropdown menu
• An optional table that converts a value to a displayable "current selection" if you want to hide how the value is passed. If not given, set this to false if you also want to supply the next argument.
• An optional function that gets called whenever a selection is made from the dropdown. Think of an onchange event in HTML/JS. Gets passed the selection from the dropdown as text, and may return a substitute to fill into the input field behind the scenes.

Basically, there's two forms: first the simpler one. In the simpler form, you only need a list of items that will appear in the dropdown, and whenever the user selects an item, the value of the input field is set to the text of the option that the user selected. This means what's readable as an option will be passed. You may want to set the default value to an option in the list.
An example: {"drop", 0, 0, 30, "Option A", 1, {"Option A", "Option B", "Option C"}}
The width is set to 30 because that's how wide dropdown menus are (currently). If you want a function to be called every time an option is selected in this case, there'd be two more arguments: false (as a filler for the second table) and then the function.

For the second form, let's take the example of a user selecting between percentages, let's say 50%, 100% and 200%. You want to pass this as a number instead, so if the user selects 50%, you want the actual value to be 0.5. When the user does select 50%, the "onchange" function is called, and converts the "50%" into 0.5, and returns that. The second table that was mentioned (the one that converts a value to a displayable "current selection") has this 0.5 background value as a key, and that maps to a value of "50%".
So this is that example:

{
	"drop2", 0, 2, 30, "1", 1, {"50%", "100%", "200%"}, {[0.5] = "50%", [1] = "100%", [2] = "200%"},
	function(picked)
		if picked == "50%" then
			return 0.5
		elseif picked == "100%" then
			return 1
		elseif picked == "200%" then
			return 2
		end
	end
}

2 - Plain text label

This is just a bit of text that can be displayed anywhere in the dialog you want. It can therefore be used to label other input fields without having to include those labels in the dialog contents.

The "default value" will be used as text, but it can also be a function that returns the text dynamically.

An example for a plain-text label is as follows: {"", 0, 5, 10, "Label", 2}
The key is left empty, because it has not much use. But we can't set it to nil, otherwise Lua might think the table ends there. It is positioned on the start of the 6th line. The width is 10 characters, which means it will merely wrap beyond that point. Then the label is just a string, and will be displayed. 2 is the type.

Here's an example of a label that keeps changing: {"", 0, 5, 40, function() return love.math.random() end, 2}
This will continuously display a different random number between 0 and 1. Note that the key and the table of fields are passed to the function, but it's not used here.

3 - Checkbox

{"option", 0, 5, 2+font8:getWidth(OPTIONLABEL), true, 3},
{"", 2, 5, 40, OPTIONLABEL, 2}

Dialogs (old, deprecated system)

dialog.new(message, title, showbar, buttons, questionid)

message is the body of the text box.
title will be shown in the title bar (if the title bar is shown by setting showbar to 1, which is always done in Ved. In fact, as of 1.4.0, the showbar parameter has no effect anymore). The title is often set to an empty string in Ved.
buttons decides what buttons are shown, and questionid decides what to do with the button that is pressed, 0 to take no action. The question ID system is not optimized for plugins, but the new dialog system allows plugins to specify their own question handlers for dialogs.

Dialog buttons

The fourth argument of dialog.new (called buttons above) can be set to one of the following values V:

(6 has been added in Ved 1.3.0)

Text input

General text input can be started by a single call to startinput(). There's also a function startinputonce(), which can be used if you decide to do it in update/drawing code, but expect me to remove that sooner or later. Input can be stopped (or locked) by calling stopinput(). The text input to the left of the cursor can be found in input, and text to the right of the cursor can be found in input_r. The variable __ (two underscores) contains the text cursor and the text to the right of it. So, to display the input field, you can concatenate input and __ (input .. __).

It's also possible to include text boxes in dialogs, see the above part on fields in dialogs.

Easter eggs