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Unreal Engine Developer Course - Section 5 - Testing Grounds

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In This Section

1 Testing Grounds Introduction

• Welcome, fresh start, new energy
• Did you go back and modify Building Escape?
• Most ambitious section yet
• Bookmark the live Google Slides
• Comment on the slides, especially typos
• Come say hi at community.gamedev.tv

Code Architecture Storing State

2 Testing Grounds GDD

• The concept of the game
• The rules of the game
• Some of the asset requirements for the game
• Identify possible technical challenges.

3 Using Git LFS (Large File Support)

• The distinction between Git vs GitHub
• Use Unreal’s toolbar & SourceTree
• Enable Git Large File Support (LFS)
• Setup on GitHub (no readme.md or initial commit)
• Push to GitHub and share
• Warning: may take a while on slow broadband.

4 Marketing & Markdown

• Limitations of Unreal’s connection to GitHub
• How to reset to previous commit to combine
• Presenting your public GitHub page well
• Using Markdown to enrich formatting.

5 Use git clean to Revert Project

• Upgrading my project to Unreal 4.13
• An overview of the scene
• How the First Person Character is composed
• Adding a spiral staircase.

6 First Person Character Overview

8 The Third Person Character

• Add a third person character to the scene
• Caution about tidying files at this stage
• Add a navmesh, and check it’s continuous.

9 Introducing AI Behaviour Trees

• Setup a Blueprint AI controller class
• Behaviour Trees controll AI execution flow
• Blackboards hold AI instance data
• How to associate a behaviour tree with an AI
• Testing that our behavior tree is running.

10 Introducing AI Blackboard Data

• Blackboard data is like member variables in code
• Using blackboard data to set patrol points
• Practice setting blackboard values in Blueprint
• Test simple AI patrol behaviour.

11 Target Points and Patrol Routes

• Add a variable to the NPC’s blueprint
• How to make a variable an array in blueprint
• Introducing Target Point actors
• Using target points to specify patrol routes.

12 Using Any Actor for Waypoints

• Actors are more general than target points
• How to select an actor from another actor
• Getting the AI Controller to set Blackboard data
• Testing our characters go to a set waypoint.

13 Options for Grouping Actors

• Use layers (usually used for visibility)
• Use groups as a simple multi-select tool
• Use tags, can be flexible but easy to forget
• Use a parent Empty Actor, or a Folder
• Group on game object (e.g. array on NPC)
• The key is to know the pros and cons.

14 Blueprint Behaviour Tree Tasks

• How to use Blackboard Key Selector variables
• Creating new Tasks in Behaviour Trees
• Pseudocode programming in Blueprint
• How to use the Execute AI node
• How to use the Finish Execute node.

15 Modular Arithmetic & Cycles

16 Performance Profiling 101

• The first rule of performance: “profile first”
• Access profiler from Window > Developer Tools
• Choose Session Front End
• Select your running game session
• Chose Profiler tab, and hit Data Preview
• Search for your function and double-click.

17 C++ AI Behaviour Tree Tasks

• Add “AIModule” and “GameplayTasks” to build
• Inherit C++ class from UBTTaskNode
• Override ExecuteTask()
• Return EBTNodeResult::Succeeded;
• Don’t try and extend in Blueprint
• Use Blueprint XOR C++ for a given task.

18 Reading Blackboard Data in C++

• Expose a blackboard key selector in C++
• #include “BehaviorTree/BlackboardComponent.h”
• OwnerComp.GetBlackboardComponent()
• Use GetValueAsInt() etc to get the value
• You can now access blackboard data in C++.

19 The Consequences of Inheritance

• We have coupled our AI ChoseNextWaypoint task to the Third Person Character.
• We have also specialised our Blueprint class with a variable, PatrolPoints.
• These dependencies are undesirable, but we will proceed with our conversion.

20 Converting Blueprint to C++

• OwnerComp.GetAIOwner() to get AI Controller
• If you’re casting, you’re probably coupling
• Use .Num() to get number of elements in TArray
• Use TODO for reminders, to help you FOCUS
• FOCUS = Follow One Course Until Successful.

21 Composition over Inheritance

• We created PatrollingGuard by inheritance
• How about if we want a patrolling tank?
• Another option is to use an actor component
• This is an age-old debate
• Let’s get some real-world experience of the two
• Convert to a component model.

21b Talking Head: What We've Covered So Far

• What we've covered recently
• What's coming up.

22 How to Delete a C++ Class

• Yes it should be easier than this, tell Epic!
• How to remove CPP files from browser in Unreal
• The process for deleting C++ classes.

23 Instanced Materials

• Also called Material Instances
• These allow modification with little overhead
• How to create an instanced material.

24 Introducing AI Perception

• Use AI Perception, it’s newer than Pawn Sensing
• How to add AI Perception to your controller
• Use the apostrophe key ‘ to enable AI debug
• Remember Shift + F1, F8, F11 etc.

25 OnTargetPerceptionUpdated Event

• Use the On Target Perception Updated event
• This reports the actor sensed
• And the class of the sense (e.g. sight, hearing)
• How to setup perception events.

26 AI Hearing Perception in Unreal

• Hearing is a sense that compliments sight
• How to set up AI Perception hearing sense
• How to get hearing perception to trigger
• Making your actor create a noise.

27 The Animation Starter Pack

• The skeleton comprises the bones
• Over the skeleton lays a skeletal mesh
• Each vertex of the mesh connects to bone(s)
• The animation tells the bones how to move
• The bones tell the mesh how to move
• The Animation BP controls the animations.

28 Changing a Character’s Animation

• How to change a mesh’s animation class
• Matching the animation’s mesh to…
• … the mesh selected on the character
• You can apply instance changes to blueprint
• However be careful what you take with you
• Solving “can’t save… graph is linked” error.

29 Customising a Character Blueprint

• You can start with a off-the-shelf blueprint
• We can then add our reusable components
• Another way of getting our desired character.

30 Sub Behaviour Trees

• Behaviour trees can get complex
• We want to keep a consistent level of abstraction
• Behaviour trees can run “sub” trees
• This helps us organise our project.

31 Talking Head - Introducing Sam

• Congratulations on getting this far in the course.
• Recapping the AI work we have done so far.
• Introducing the new instructor for the section: Sam.

31b Talking Head - Refactoring Superpowers

• Why refactoring is so important.
• Refactor skills give you the edge.
• What’s coming up in the next lectures.

32 Simplifying Our Project

• Deleting and Moving folders.
• Ensuring deletion on the file-system.
• Good file structure for Unreal.
• Viewing the dependencies of an object.
• How and when to fix redirectors.

33 Renaming & Moving CPP

• Renaming CPP files.
• How to deal with renaming blueprint parents.
• Refactor class names in CPP.
• Updating .generated.h files.

34 Solution: Renaming & Moving CPP

• Repeating the renaming process.
• Finishing our refactor.
• Fixing CDO Constructor errors.

35 Holding a Gun with Skeletal Sockets

• Reading existing source code for hints.
• Creating a socket on a skeletal mesh.
• Parenting a gun to that socket.
• Removing unused assets.

35b Understanding Animation Blueprints

• The major components.
• How to preview animations.
• Definition of an animation and pose.
• Understanding the AnimGraph.
• Playing a custom animation.

36 Creating Animation State Machines

• Why state machines?
• What are state machines?
• What’s inside a UE4 state?
• How to add transitions.
• Adding a shooting state.

37 Movement Blend Spaces

• What is a blend space?
• How to create a movement blend space.
• Examining the existing Jog blend space.
• Replicating for Ironsights.

38 Offset Animations

• Creating an offset animation.
• Applying an offset to a base.
• Conditional blend nodes.

39 Aiming Blend Spaces Offsets

• Aim offset assets.
• 1D vs 2D Aim offsets.
• Editing an existing animation sequence.

40 Rotating with SetFocalPoint()

• Revising Behaviour Tree tasks.
• Making our character face us.
• Using AIController’s SetFocalPoint()

41 Character Movement vs Rotation

• More code reading.
• Jumping between files in Visual Studio.
• Difference between movement and rotation.
• Mapping out complex systems.

42 Control Rotation for Aim

• Getting the control rotation.
• Focus Actor vs Focal Point
• Splitting rotators and setting pitch.
• Controlling Animation BP properties.

43 Behaviour Tree Decorators

• Creating a decorator.
• Sequence vs Select nodes.
• Aborting decorators early.
• Clearing blackboard keys from blueprint.
• Patrolling, agro and following.

44 Behaviour Tree Services

• Using decorators vs services.
• Creating a service.
• Deeper into behaviour tree states.
• How to implement suspicion.
• Giving our character breathing space.
• Comparing BP Validity and NULL.

45 Tweaking AI Behaviour

• Preventing Behaviour Tree flicker.
• Creating mutually exclusive states.

46 Debugging AI Behaviour

• Viewing behaviour while playing.
• Using tags on Actors.
• Revising interrupting tasks.
• Adding in multiple actors.

47 Refactoring to a Gun Actor

• Create a Gun actor.
• Move the firing code over.
• Revising refactoring.

48 Attaching Actors to Components

• Revise spawning child actors.
• Attaching actors to sub-components.
• Attachment rule to sockets.

49 Configuring the Gun

• Playing montage animations.
• Connecting to actors in code.
• Finishing our refactor.

50 Moving Files from LFS to Git

• The pros and cons of LFS.
• How to move files from LFS.
• Tracking folder instead of extensions.
• Where tracking happens.

51 To LFS or Not to LFS?

• The pros and cons of LFS.
• Organising your project for clarity.
• How to deal with .umap assets.

52 Child Actor Components

• Previewing the gun with the skeleton.
• Positioning the gun.
• Child actors with Blueprint.
• Using Child Actor Components.

52b Introduction to Inverse Kinematics

• Local vs component-space poses.
• Understanding bone-space.
• The principles of IK.
• End effectors and Joint targets.
• Mapping to the Two Bone IK node.

53 Inverse Kinematics with Animations

• Using the Two Bone IK node.
• Effectors vs Joint targets

54 Comparing Blueprints with Diffs

• Using UE4 built-in version control.
• Diffing blueprints.
• LFS vs Git assets in editor.

55 Boolean Blending for Aim States

• Boolean blending in Unreal.
• Setting variables in animation BP.
• Making the AI aim.

56 Adding Firing Animations

• When to use additive identities.
• Blending additive animations.
• Creating an additive firing animation.
• Controlling firing from the AI.

57 Animation Notify Events

• Synchronising sound and animation.
• Creating custom notify events.
• Hooking up our gun trigger to AI.

58 Taking Damage in Blueprint

• Applying damage from a projectile.
• Taking damage in a BP character.
• Detaching a controller from a Pawn.

59 Death Animations and Refactors

• Revision of BP refactoring.
• Making our Animation BP clean.
• Death animations on the AI.

60 Switching 1st and 3rd Person

• Swapping out a 1st to 3rd person character.
• Wrapping rotations.

61 Owner Invisible Meshes

• Own See vs Owner no see meshes.
• Why 1st person Meshes.
• Hooking up Fire input in TPCharacter.

62 Separating Firing from Gun Meshes

• Why we need two gun meshes.
• Creating Blueprint components.
• Scene components vs Actor components.
• Camera rotation with control rotation.

63 Aiming Our 1st Person Camera

• Local vs Global rotation.
• UE4 optimizations for unpossesed characters.

64 Architecture of Infinite Runners

• Using the Arrow component.
• How to architect an infinite runner.
• Overview of how we want our levels to work.

65 Spawning Terrain in the GameMode

• GameMode BP vs Level BP
• Creating a blueprint GameMode
• How to spawn tiled terrain.
• Using a blueprint for-loop.

66 Level Gating for Testing Grounds

• Why we need level gating.
• Our approach to gating.
• Enabling/disabling collisions.

67 Swapping Materials in Blueprint

• Creating material instances.
• Exposing material parameters.
• Swapping materials in blueprint.
• Adding affordance to our barriers.

68 Garbage Collecting Previous Tiles

• When to delete previous tiles.
• How to get hold of the Game Mode.
• Spawning new tiles when needed.
• Keeping the minimal tiles in memory.

69 Merging Our TP and FP Files

• Fix camera glitch while strafing.
• Merge the NPC and Player folders.
• Revise redirectors.
• Revise folder movement and deletion.

70 Hit vs Overlap Events

• Debug a projectile spawn issue.
• Overview the collision system.
• Understand hit and overlap notifications.
• Review different Collision Presets

71 Dynamically Calculating NavMesh

• NavMesh and procedural terrain.
• Dynamic NavMesh generation.
• When LFS shouldn’t be used.

72 Keep It Simple Stupid

• Make the player tough for testing.
• Deeply understand the AI system.
• When is code too complex to debug?
• Write high level pseudo code.

73 Parallel Behaviour Tree Tasks

• Parallel actions in Behaviour Trees.
• Pseudocode-lead refactoring.
• Aborting lower priority with decorators.
• Organising conditional Behaviour Trees.

74 Custom BT Tasks and Decorators

• Implementing a conditional decorator.
• Custom task nodes.
• Clean up when task node is aborted.

75 External Build Data in 4.14+

• Updating to 4.15.0
• Storing build data outside of .umaps.

76 Physical Gun Architecture

• Renaming to style guide
• Problems of our existing architecture
• Improved gun-centric architecture
• Challenge: reinstating the gun actor.

77 Converting a Character BP to C++

• Creating and reparenting a character
• Challenge: Converting the component hierarchy
• Reviewing my Mannequin.cpp

78 Who’s Pulled the Trigger?

• Reviewing the architecture
• Revision: binding input in C++
• Challenge
• Remove firing from Animation BP
• Control trigger from AI

79 Cooldown Nodes & Gameplay Tags

• How cooldown nodes work.
• Adding gameplay tags.
• Challenge: Let the AI Cooldown
• Randomised burst of fire.
• Separated into sub-behaviour trees.

80 Animation Montages and Slots

• What is an animation slot?
• How to blend by root bone.
• "Caching" a pose.
• Challenge: Create and Play Firing Montage

81 Reattaching the Gun

• Attach gun to correct mesh if player
• Reattach gun when player dies
• Challenge: Play Two Montages

82 Procedural Level Generation

• Importing asset pack.
• Introduction to procedural terrain.
• Creating ground mesh from BSP.
• Challenge: creating spawnable props.

83 Generating Random Numbers

• Create a Tile C++ class.
• Expose a UFunction to spawn actors.
• Functions to generate random data.
• Challenge: generate a random spawn point.

84 Spawning Actors in the Tile

• Spawn an actor.
• Randomise the number of actors.
• Challenge: place the actors correctly.

85 Sphere Casting in C++

• What is a Sweep?
• How to Sphere Cast in C++.
• Challenge: visualise the cast.

86 Configure Custom Trace Channels

• Creating a Trace Channel.
• Where to configure presets.
• Challenge: make it trace green.

87 Spawning into Free Space

• Writing an actor spawning algorithm.
• Challenge: generate empty space.
• Converting from local to global positions.

88 Randomising Rotation & Scale

• Adding randomised rotation.
• Challenge: add randomised scale.
• Tweaking the spawn radii.

89 Flyweight Pattern for Foliage

• Flyweight pattern for rendering
• Adding LOD for foliage.
• Challenge: spawn grass instances.
• Reviewing my code.
• Configuring my component.

90 Choosing Waypoint with EQS

• Outline of EQS.
• Enabling EQS.
• Creating and testing queries.
• CHALLENGE: Create a Waypoint Query.

91 Find Actors of Type from C++

• Overviewing the navigation issue.
• Getting hold of existing objects.
• CHALLENGE: Finding NavMeshBoundsVolumes

92 Plumbing an Actor Pool Setup

• Actor Pool architecture.
• Creating the Actor Pool Component.
• CHALLENGE: Plumb the Pool.

93 Using the Pool API

• Using the Checkout API
• Overview of object lifecycle
• CHALLENGE: Return to Pool
• Populate the initial pool.

94 Using TArray for Pools

• Implementing checkout.
• Challenge: Implement return and add.

95 Rebuilding Navigation Meshes

• Rebuilding the Navigation.
• Offset the NavMeshBoundsVolumes.
• CHALLENGE: Spawn on destroy.

96 Structs to Simplify Function Args

• The AI spawning problem.
• Combining parameters as structs.
• CHALLENGE: SpawnPosition Generator Function.

97 Spawning AI from C++

• How to spawn AI.
• PlaceAIPawns definition.
• CHALLENGE: spawn AI in the world.

98 Keeping Score

• Adding a GameMode Score.
• CHALLENGE: Notify on Tile Conquered

98b Understanding Function Templates

• What is a template.
• When would you use one?
• What is the syntax for functions.

98c Template Specialization

• When copy and paste isn’t enough.
• How to handle tricky types.

98d Fixing Double Spawning

• Fixing out spawn issue.
• When static polymorphism isn't enough.
• How to use templates in classes.
• Caveats to using templates in C++

99 Using the HUD Class

• Extending the HUD class
• Why use the HUD class
• CHALLENGE: Create the scoring UI

100 Post Processing for Tunnel Vision

• Adding PostProcessing Effects
• CHALLENGE: Ease in on Damage

101 Recruiting Play Testers

• Sharing your game
• CHALLENGE: Recruit Some Testers
• Changing the lighting
• Firing lasers
• Improving score UI
• Shorter blackout effect

102 Smooth Blending the Camera

• Making death easier
• How the camera works
• Overview of SetViewTargetWithBlend
• CHALLENGE: Smooth Blend the Camera

103 Possessing and the View Target

• Unpossing with View Targets
• Auto managed View Targets
• CHALLENGE: Manually Manage the View Target

104 The Calm Before The Storm

• Peace before the storm
• CHALLENGE 1: Fix the crashing issue
• CHALLENGE 2: Make the Actors spawn
• Parametrise the enemy count
• BONUS: Fixing multiple camera transitions

XXX Testing Grounds Wrap-up

• WELL DONE, over 50h of content
• You've got a great understanding of Unreal
• Your C++ knowledge is transferrable
• Improve with: more weapons, pick-ups, progression
• Please share screenshots / 20s video with community.