DemoBots/Components/InputComponent.swift

/*
    Copyright (C) 2016 Apple Inc. All Rights Reserved.
    See LICENSE.txt for this sample’s licensing information
    
    Abstract:
    A `GKComponent` that enables an entity to accept control input from device-specific sources.
*/
 
import SpriteKit
import GameplayKit
 
class InputComponent: GKComponent, ControlInputSourceDelegate {
    // MARK: Types
    
    struct InputState {
        var translation: MovementKind?
        var rotation: MovementKind?
        var beamIsTriggered = false
        var allowsStrafing = false
        
        static let noInput = InputState()
    }
    
    // MARK: Properties
    
    /**
        `InputComponent` has the ability to ignore input when disabled.
 
        This is used to prevent the player from moving or firing while
        being attacked.
    */
    var isEnabled = true {
        didSet {
            if isEnabled {
                // Apply the current input state to the movement and beam components.
                applyInputState(state: state)
            }
            else {
                // Apply a state of no input to the movement and beam components.
                applyInputState(state: InputState.noInput)
            }
        }
    }
    
    var state = InputState() {
        didSet {
            if isEnabled {
                applyInputState(state: state)
            }
        }
    }
    
    // MARK: ControlInputSourceDelegate
    
    func controlInputSource(_ controlInputSource: ControlInputSourceType, didUpdateDisplacement displacement: float2) {
        state.translation = MovementKind(displacement: displacement)
    }
    
    func controlInputSource(_ controlInputSource: ControlInputSourceType, didUpdateAngularDisplacement angularDisplacement: float2) {
        state.rotation = MovementKind(displacement: angularDisplacement)
    }
    
    func controlInputSource(_ controlInputSource: ControlInputSourceType, didUpdateWithRelativeDisplacement relativeDisplacement: float2) {
        /*
            Create a `MovementKind` instance indicating whether the displacement
            should translate the entity forwards or backwards from the direction
            it is facing.
        */
        state.translation = MovementKind(displacement: relativeDisplacement, relativeToOrientation: true)
    }
    
    func controlInputSource(_ controlInputSource: ControlInputSourceType, didUpdateWithRelativeAngularDisplacement relativeAngularDisplacement: float2) {
        /*
            Create a `MovementKind` instance indicating whether the displacement
            should rotate the entity clockwise or counter-clockwise from the direction
            it is facing.
        */
        state.rotation = MovementKind(displacement: relativeAngularDisplacement, relativeToOrientation: true)
    }
    
    func controlInputSourceDidBeginAttacking(_ controlInputSource: ControlInputSourceType) {
        state.allowsStrafing = controlInputSource.allowsStrafing
        state.beamIsTriggered = true
    }
    
    func controlInputSourceDidFinishAttacking(_ controlInputSource: ControlInputSourceType) {
        state.beamIsTriggered = false
    }
    
    // MARK: Convenience
    
    func applyInputState(state: InputState) {
        if let movementComponent = entity?.component(ofType: MovementComponent.self) {
            movementComponent.allowsStrafing = state.allowsStrafing
            movementComponent.nextRotation = state.rotation
            movementComponent.nextTranslation = state.translation
        }
        
        if let beamComponent = entity?.component(ofType: BeamComponent.self) {
            beamComponent.isTriggered = state.beamIsTriggered
        }
    }
}


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