Backwards Compatibility - AlsoGhostglowDev/Ghost-s-Utilities GitHub Wiki

Backwards Compatibility handler. Used to handle backwards compatibility between outdated versions of Psych Engine.

^{Be reminded that these versions only uses GhostUtil's counterpart of said function if it's not supported there; Else it'll fallback to the original Psych Engine function. If GhostUtil's version of a function were to bug out, please contact @ghostglowdev in Discord.}

local bcompat = require 'ghostutil.backwards-compat'

startTween(tag: string, object: string, values: directory<string, dynamic>, ?duration: number, ?options: TweenOptions): void

Creates a tween of an object supporting multiple values for each respective fields.
^{(from Psych Engine 0.7.0)}

Parameters:

• tag: The tween's tag.
• object: The target object to tween.
• values: Directory containing values mapped to their corresponding field.
• duration (optional): Determines how long the tween will take, defaults to 1.
• options (optional): The tween's options; Refer to TweenOptions.

_{This function only uses GhostUtil's alternative way if the current Psych Engine version is under 0.7.0.}

-- tweens boyfriend's x position to 100 alongside his velocity.x to 200.
-- the tween runs for 2 seconds with the expoInOut ease.
bcompat.startTween('tweenTag', 'boyfriend', { x = 100, ['velocity.x'] = 200 }, 2, {
    ease = 'expoInOut',
    onComplete = 'coolFn'    
})

-- gets called when the tween is completed.
function coolFn(tag, object)
    -- debug prints "tweenTag" (tag) and "boyfriend" (object).
    debugPrint(tag)
    debugPrint(object)
end

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runHaxeFunction(funcToRun: string, ?args: table<dynamic>): dynamic

Calls a function from the current HScript / runHaxeCode instance.
^{(from Psych Engine 0.7.0)}

Parameters:

• funcToRun: The function to call.
• args (optional): The arguments for the function, defaulted to an empty table.

Returns: The called function's return value if there's any.

_{This function only uses GhostUtil's alternative way if the current Psych Engine version is under 0.7.0.}

runHaxeCode([[
    function coolFn(arg:String) {
        game.addTextToDebug(arg, 0xFF00FF00);
    }
]])

bcompat.runHaxeFunction('coolFn', {'oh look, its a green debug text!!'})

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setHealthBarColors(left: string, right: string): void

Sets the health bar's colors.
^{(from Psych Engine 0.7.0)}

Parameters:

• left: The color to apply on the left side. Inputted as a string hexadecimal.
• right: The color to apply on the right side. Inputted as a string hexadecimal.

_{This function only uses GhostUtil's alternative way if the current Psych Engine version is under 0.7.0.}

-- just like the old times where the opponent will have a red colored healthbar,
-- meanwhile the player will have a green one.
bcompat.setHealthBarColors('FF0000', '00FF00')

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setTimeBarColors(left: string, right: string): void

Sets the time bar's colors.
^{(from Psych Engine 0.7.0)}

Parameters:

• left: The color to apply on the left side. Inputted as a string hexadecimal.
• right: The color to apply on the right side. Inputted as a string hexadecimal.

_{This function only uses GhostUtil's alternative way if the current Psych Engine version is under 0.7.0.}

-- it's my color scheme!!
bcompat.setTimeBarColors('08FF9C', '10201A')

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instanceArg(instanceName: string, ?classVar: string): string

Fetches the "instance string" of an instance to be used in reflection functions of which that accepts it.
^{(Shortcut to helper.instanceArg, from Psych Engine 0.7.2h)
(reflection functions that accepts instance strings are callMethod, callMethodFromClass, createInstance, setProperty, setPropertyFromGroup, setPropertyFromGroup and setVar)}

Parameters:

• instanceName: The instance's name.
• classVar (optional): What class the instance is from, defaults to nil.

-- loads dad's graphic into my cool sprite
bcompat.callMethod('sprite.loadGraphicFromSprite', { bcompat.instanceArg('dad') })

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callMethod(method: string, ?args: table<dynamic>): dynamic

Calls a method from PlayState's instance.
^{(Shortcut to helper.callMethod, from Psych Engine 0.7.0)}

Parameters:

• method: The method to call.
• args (optional): The arguments to use for said method, defaults to an empty table.
  ^{(You may need to use {''} instead for an empty table/argument in some versions.)}

Returns: The called method's return value if there's any.

-- sets dad's position to (X: 200, Y: 300) 
bcompat.callMethod('dad.setPosition', {200, 300})

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callMethodFromClass(className: string, method: string, ?args: table<dynamic>): dynamic

Calls a method from a class.
^{(Shortcut to helper.callMethodFromClass, from Psych Engine 0.7.0)}

Parameters:

• className: Class based on the source folder structure.
• method: The method to call from said class.
• args (optional): The arguments to use for said method, defaults to an empty table.
  ^{(You may need to use {''} instead for an empty table/argument in some versions.)}

Returns: The called method's return value if there's any.

-- loads up a youtube video on your default browser
bcompat.callMethodFromClass('backend.CoolUtil', 'browserLoad', {'https://www.youtube.com/watch?v=dQw4w9WgXcQ'})

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createInstance(tag: string, className: string, ?args: table<dynamic>): dynamic

Creates an instance of the provided class with the specified arguments. The instance can later be used with other functions like setProperty.
^{(Shortcut to helper.createInstance, from Psych Engine 0.7.0)}

Parameters:

• tag: The tag to save the variable as.
• className: Class based on the source folder structure.
• args (optional): The arguments to use for the class' constructor, defaults to an empty table.
  

-- creates a new character instance with tag "pico"
bcompat.createInstance('pico', 'objects.Character', {100, 200, 'pico-player', true})

-- adds pico to the game
bcompat.addInstance('pico', true)

-- modifying the instance's properties
setProperty('pico.alpha', 0.2)

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addInstance(tag: string, ?inFront: boolean): void

Adds the created instance to the game.
^{(Shortcut to helper.addInstance, from Psych Engine 0.7.0)}

Parameters:

• tag: The tag of the instance to add.
• inFront (optional): If the instance should be infront of everything, defaults to false.

-- creates a new character instance with tag "pico"
bcompat.createInstance('pico', 'objects.Character', {100, 200, 'pico-player', true})

-- adds pico to the game
bcompat.addInstance('pico', true)

-- modifying the instance's properties
setProperty('pico.alpha', 0.2)

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setProperty(variable: string, value: dynamic, ?allowMaps: boolean, ?allowInstances: boolean): void

Sets the property of the given variable in PlayState to value.
^{(Shortcut to helper.setProperty, instance support from Psych Engine 1.0)}

Parameters:

• variable: The variable to change.
• value: The value to set the property to.
• allowMaps (optional): Allows for map access in properties, disabled by default for optimization.
• allowInstances (optional): Allows usage of instanceArg for properties, disabled by default for optimization.

-- applies a sprite's shader to boyfriend
bcompat.setProperty('boyfriend.shader', bcompat.instanceArg('sprite.shader'), false, true)

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setPropertyFromGroup(group: string, index: number, variable: string, value: dynamic, ?allowMaps: boolean, ?allowInstances: boolean): void

Sets the property of the given group/array in PlayState to value.
^{(Shortcut to helper.setPropertyFromGroup, instance support from Psych Engine 1.0)}

Parameters:

• group: The variable's object group.
• index: The index to the variable's object.
• variable: The variable to change.
• value: The value to set the property to.
• allowMaps (optional): Allows for map access in properties, disabled by default for optimization.
• allowInstances (optional): Allows usage of instanceArg for properties, disabled by default for optimization.

-- sets the first note's multAlpha to 0.5.
bcompat.setPropertyFromGroup('unspawnNotes', 0, 'multAlpha', 0.5)

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setPropertyFromClass(className: string, variable: string, value: dynamic, ?allowMaps: boolean, ?allowInstances: boolean): void

Sets the property of the variable in the provided class to value.
^{(Shortcut to helper.setPropertyFromClass, instance support from Psych Engine 1.0)}

Parameters:

• className: The classpath of where the variable is from.
• variable: The variable to change.
• value: The value to set the property to.
• allowMaps (optional): Allows for map access in properties, disabled by default for optimization.
• allowInstances (optional): Allows usage of instanceArg for properties, disabled by default for optimization.

-- sets isPixelStage to true.

--[[
  Q: Why can't this be done in setProperty instead?
  A: isPixelStage is a static variable, only exists within the class itself.
]]
bcompat.setPropertyFromClass('states.PlayState', 'isPixelStage', true)

<sub>GhostUtil 3.0.0 • Docs 3.0.0, Revision 1

a Lua Library made by GhostglowDev; for Psych Engine
© 2025 GhostglowDev — Ghost's Utilities
Licensed under the MIT License.</sub>