BaseStateMachineState

BaseStateMachineState

Description

A base, abstract state to be used with an implementation of the StateMachine class.

Functions

• addTransition
• caclulateDebugScreenBounds
• calculateIfShouldBeForced
• calculateIfValidEntryState
• createTransitions
• debugDraw
• new
• onStateEntered
• onStateExited
• trySwitchToValidTransition
• updateAsCurrent
• updateAsInactive

addTransition

Description

Adds a transition to the given targetState whenever the given condition is true.

Definition

addTransition(function conditionFunction, BaseStateMachineState targetState, table contextObject)

Arguments

function	conditionFunction	The condition function that must return true for the target state to be switched to.
BaseStateMachineState	targetState	The state that will be transitioned to if the condition is true.
table	contextObject	The object used as the context to fire the condition function, if this is nil then the given targetState is used.

Code

function BaseStateMachineState:addTransition(conditionFunction, targetState, contextObject)

    --#debug Assert.isType(conditionFunction, "function", "Transition must have a valid condition function!")
        --#debug Assert.isClass(targetState, BaseStateMachineState, "Transition's target state must inherit from BaseStateMachineState!")

        -- Add the transition object to the transitions table.
        self.transitions[targetState] = { context = contextObject or targetState, conditionFunction = conditionFunction }
        return self.transitions[targetState]
    end

caclulateDebugScreenBounds

Description

Calculates the bounds in screen-space of the debug draw.

Definition

caclulateDebugScreenBounds(float x, float y, float width, float height)

Arguments

float	x	The x position on the screen to begin drawing the values.
float	y	The y position on the screen to begin drawing the values.
float	width	The total width of the whole state machine on the screen.
float	height	The total height of the whole state machine on the screen.

Code

function BaseStateMachineState:caclulateDebugScreenBounds(x, y, width, height)

    -- No drawing can happen if there are no debug bound properties.
        if self.debugPositionX = = nil or self.debugPositionY = = nil or self.debugWidth = = nil or self.debugHeight = = nil then
            return nil , nil , nil , nil
        end

        return x + ( self.debugPositionX * width), y + ( self.debugPositionY * height), self.debugWidth * width, self.debugHeight * height
    end

calculateIfShouldBeForced

Description

Calculates if this state should be forced as the current state.

Definition

calculateIfShouldBeForced()

Return Values

float	isValid	True if this state is valid and can be forced to be made current; otherwise false. False by default.

Code

function BaseStateMachineState:calculateIfShouldBeForced()
    return false
end

calculateIfValidEntryState

Description

Calculates if this state is a valid state to enter back in on after a forced state.

Definition

calculateIfValidEntryState()

Return Values

float	isValid	True if this state is valid and can be made current; otherwise false. False by default.

Code

function BaseStateMachineState:calculateIfValidEntryState()
    return false
end

createTransitions

Description

Called just after the creation of all states, so that other states can be used to create transitions.

Definition

createTransitions()

Code

function BaseStateMachineState:createTransitions()

end

debugDraw

Description

Draws debug information for this state.

Definition

debugDraw(float x, float y, float width, float height, float textSize, )

Arguments

float	x	The x position on the screen to begin drawing the values.
float	y	The y position on the screen to begin drawing the values.
float	width	The total width of the whole state machine on the screen.
float	height	The total height of the whole state machine on the screen.
float	textSize	The height of the text.
any	color

Code

function BaseStateMachineState:debugDraw(x, y, width, height, textSize, color)

    local frameX, frameY, frameWidth, frameHeight = self:caclulateDebugScreenBounds(x, y, width, height)
    if frameX = = nil then
        return nil , nil , nil , nil
    end

    if color = = nil then
        color = self.stateMachine.currentState = = self and Color.PRESETS.GREEN or Color.PRESETS.GRAY
    end

    drawFilledRect(frameX, frameY, frameWidth, frameHeight, color:unpack())

    return frameX, frameY, frameWidth, frameHeight
end

new

Description

Creates a base state machine state. This should only be done within a derived class, as this is an abstract class.

Definition

new(StateMachine stateMachine, table custom_mt)

Arguments

StateMachine	stateMachine	The state machine that manages this state.
table	custom_mt	The derived metatable to use.

Return Values

table	instance	The created instance.

Code

function BaseStateMachineState.new(stateMachine, custom_mt)

    -- Create the instance.
    local self = setmetatable( { } , custom_mt or BaseStateMachineState _mt)

    -- Set the state machine.
    self.stateMachine = stateMachine

    -- Create the transitions table.
    self.transitions = { }

    -- The bounds of the state when debug-drawn to the screen.
    self.debugPositionX = nil
    self.debugPositionY = nil
    self.debugWidth = nil
    self.debugHeight = nil

    -- Return the created instance.
    return self
end

onStateEntered

Description

Fired when this state is entered.

Definition

onStateEntered(BaseStateMachineState previousState)

Arguments

BaseStateMachineState	previousState	The previous state the machine was in before entering this one.

Code

function BaseStateMachineState:onStateEntered(previousState)

end

onStateExited

Description

Fired when this state is exited.

Definition

onStateExited(BaseStateMachineState nextState)

Arguments

BaseStateMachineState	nextState	The state the machine will be in after exiting this one.

Code

function BaseStateMachineState:onStateExited(nextState)

end

trySwitchToValidTransition

Description

Goes through each transition and runs the condition function. The first function that returns true will cause the state machine to switch to the associated state, and the state will be returned.

Definition

trySwitchToValidTransition()

Return Values

BaseStateMachineState	newState	The state whose associated condition function returned true, and was successfully switched to in the state machine; otherwise nil.

Code

function BaseStateMachineState:trySwitchToValidTransition()

    -- Go over each transition pair and check for validity.
        for state, binding in pairs( self.transitions) do

            -- If the condition passes, switch the state machine's current state to the state, if it successfully changes then return the state.
                if binding.conditionFunction(binding.context) then
                    self.stateMachine:changeState(state)
                    return state
                end
            end

            -- If no state was switched to, return nil.
            return nil
        end

updateAsCurrent

Description

Updates this state when it is currently the state machine's current state.

Definition

updateAsCurrent(float dt)

Arguments

float	dt	Delta time in ms.

Code

function BaseStateMachineState:updateAsCurrent(dt)

    -- Do nothing if the state machine is passive.
        if self.stateMachine:getIsPassive() then
            return
        end

        -- Go through the transitions and see if any are valid.
            self:trySwitchToValidTransition()
        end

updateAsInactive

Description

Updates this state when it is currently NOT the state machine's current state.

Definition

updateAsInactive(float dt)

Arguments

float	dt	Delta time in ms.

Code

function BaseStateMachineState:updateAsInactive(dt)

end