AnimationNodeBlendTree in Godot – Complete Guide

In the realm of game development, animation plays a critical role in bringing our virtual worlds to life. Whether it’s the gentle sway of leaves in the wind or the dynamic movements of a heroic character, animations are the soul of our game’s visual storytelling. Enter Godot 4’s AnimationNodeBlendTree, an incredibly powerful tool designed to help developers orchestrate complex animations with ease and precision. For those eager to delve into the art of animation in games, understanding this tool is essential. So, join us as we explore the capabilities of AnimationNodeBlendTree, where each node dances to the tune of your game’s rhythm, creating a mesmerizing spectacle for gamers to experience.

What is AnimationNodeBlendTree?

The AnimationNodeBlendTree is a feature within Godot 4, an open-source game engine loved for its user-friendly interface and powerful capabilities. As suggested by its name, AnimationNodeBlendTree is a versatile system that allows game developers to create and manage complex animations through a network of interconnected nodes. Think of it as a conductor orchestrating different instruments, where each node is an individual musician contributing to the overall harmony of your game’s animation score.

What is it for?

AnimationNodeBlendTree is the cornerstone for creating intricate animation sequences where multiple animations need to be blended or transitioned seamlessly. It’s designed to handle a variety of scenarios, from simple two-state blends to elaborate meshes of multiple animations. This system is tailor-made for scenarios where characters have a multitude of actions and states, like running, jumping, or interacting with the environment, ensuring fluid transitions without the need for cumbersome manual intervention.

Why Should I Learn It?

Embracing the AnimationNodeBlendTree can elevate the quality of your game’s animations exponentially. By mastering it, you’ll unlock:

– The ability to blend animations for smooth transitions and more realistic character movements.
– Versatility in managing complex animation states without overwhelming your codebase.
– A visual representation of your animations that can simplify the debugging and iteration process.

Dedicated both to novices taking their first steps and to seasoned veterans looking to polish their animation toolkit, learning the intricacies of AnimationNodeBlendTree is an investment in the quality and fluidity of your game animations. Let’s embark on this journey and see how the magic of animated storytelling comes to life in Godot 4.

FREE COURSES AT ZENVA

LEARN GAME DEVELOPMENT, PYTHON AND MORE

ACCESS FOR FREE

AVAILABLE FOR A LIMITED TIME ONLY

Setting Up Your AnimationNodeBlendTree

To begin adding animations to your characters in Godot 4, you need to set up an AnimationNodeBlendTree in an AnimationTree node. Start by creating an AnimationPlayer node and defining some animations. Here’s a quick setup example:

var animation_player = AnimationPlayer.new()
add_child(animation_player)
animation_player.add_animation("run", run_anim)
animation_player.add_animation("jump", jump_anim)

With some basic animations defined in your AnimationPlayer, let’s attach an AnimationTree node to your character and start blending:

var animation_tree = AnimationTree.new()
var blend_tree = AnimationNodeBlendTree.new()

animation_tree.set_process(true)
animation_tree.tree_root = blend_tree
add_child(animation_tree)

This code will initialize the AnimationTree and set the blend tree as its root. Now you’ve laid the groundwork to begin creating a blend tree!

Creating State Blends

When dealing with character movement, you’ll likely want to blend between a running and a walking animation depending on the character’s speed. Here’s how to create a simple state blend:

// Create a state machine within the blend tree
var state_machine = AnimationNodeStateMachine.new()

// Create states for running and walking
var walk_state = AnimationNodeAnimation.new()
walk_state.animation = "walk"
state_machine.add_node("walk", walk_state)

var run_state = AnimationNodeAnimation.new()
run_state.animation = "run"
state_machine.add_node("run", run_state)

// Add the state machine to the blend tree
blend_tree.add_node("StateMachine", state_machine)

Blending with Parameters

To dynamically blend between animations, you can use parameters. Let’s say you have a parameter “speed” that varies with your character’s movement speed. Here’s how you can create a blend based on this parameter:

var blend2 = AnimationNodeBlend2.new()
blend_tree.add_node("RunWalkBlend", blend2)
blend_tree.connect_node("walk", "", "RunWalkBlend", 0)
blend_tree.connect_node("run", "", "RunWalkBlend", 1)
blend_tree.connect("parameters/RunWalkBlend/blend_amount", "parameters/speed")

This code snippet creates a two-way blend node that mixes the “walk” and “run” animations based on the value of “speed”.

Using Filters for Directional Blending

Animations may also need to respond to directional input. For this, blending with filters can come in handy. Say your character can move sideways; you’ll need “strafe” animations as well as a filter parameter called “direction”:

var direction_blend = AnimationNodeBlend3.new()
blend_tree.add_node("DirectionalBlend", direction_blend)
blend_tree.connect_node("walk", "", "DirectionalBlend", 1)
blend_tree.connect_node("strafe_left", "", "DirectionalBlend", 0)
blend_tree.connect_node("strafe_right", "", "DirectionalBlend", 2)
blend_tree.connect("parameters/DirectionalBlend/blend_amount", "parameters/direction")

This code provides a three-way blend, allowing for left, right, and center (walk) states to be blended according to the “direction” parameter.

Remember, these examples are the basics to get you started; you’ll want to build and experiment with different nodes and parameters to fully realize your character’s animation potential. Next, we’ll delve deeper into transitional blending and how to use it to create even more dynamic animations.Now, as we deepen our exploration of the AnimationNodeBlendTree, let’s focus on managing transitions between our animation states. Smooth transitions are crucial for maintaining the illusion of a cohesive world and a lifelike character. Here we’ll see how Godot enables us to blend animation states effectively using transition nodes.

Transitional Blending and Travel

The AnimationNodeStateMachineTransition comes into play for managing transitions. It helps us define the rules under which our character moves from one animation state to another, such as from walking to running. Let’s set up a transition:

// Add a transition from walk to run
var walk_to_run_transition = AnimationNodeStateMachineTransition.new()
state_machine.add_transition("walk", "run", walk_to_run_transition)

This code creates a straightforward transition that will be triggered based on the conditions you set.

Moving on, we might want to start an animation after another one finishes, like playing a “jump” animation right after the “run” animation. For this, we’ll need to use the travel method of the state machine:

// Assuming we have a jump state already added to the state_machine

// Travel from run to jump
state_machine.travel("jump")

This code snippet tells the state machine to switch to the “jump” state after the “run” state, assuming the appropriate transitions are set.

Parameter-Based Blends

Now, let’s look at how parameters help us control the blend amounts in a more nuanced way. For instance, you might have a blend space that allows a character to aim their weapon at different angles. To demonstrate, you would use something like an AnimationNodeBlendSpace2D:

var aim_blend_space = AnimationNodeBlendSpace2D.new()
blend_tree.add_node("AimBlendSpace", aim_blend_space)

We’ll then add animation points to the blend space based on the direction the weapon should be aiming:

// Assume animation for aiming up, down, left, and right are made
aim_blend_space.add_blend_point(aim_up_anim, Vector2(0, -1))
aim_blend_space.add_blend_point(aim_down_anim, Vector2(0, 1))
aim_blend_space.add_blend_point(aim_left_anim, Vector2(-1, 0))
aim_blend_space.add_blend_point(aim_right_anim, Vector2(1, 0))

By manipulating the blend position within your BlendSpace2D, you can smoothly interpolate between these discrete aiming directions.

To control the aim dynamically, you may do something like:

// Connect the blend space to a Vector2 parameter
blend_tree.connect("parameters/AimBlendSpace/blend_position", "parameters/aim_direction")

In this case, we’re assuming that “aim_direction” is a Vector2 that changes based on player input or game logic.

Handling Animation Callbacks

Animations often need to trigger in-game events at specific times. For example, you might want an event to happen when a character’s foot touches the ground during a walk cycle. Godot’s AnimationPlayer provides a signal called animation_finished which we can connect to a method that will handle our event:

animation_player.connect("animation_finished", self, "_on_AnimationPlayer_animation_finished")

func _on_AnimationPlayer_animation_finished(anim_name):
    if anim_name == "walk":
        emit_signal("footstep")

With this setup, every time the “walk” animation ends, a “footstep” signal will be emitted, which you could connect to sound effects or other in-game reactions.

Transitions, parameter-based blending, and animation callbacks represent just a snippet of the possibilities with Godot 4’s AnimationNodeBlendTree. These examples provide a foundation for creating sophisticated and responsive character animations in your games, pushing the envelope of interactive storytelling and immersive gameplay.

Remember, trial and error is part of the learning process. Experiment with these nodes, parameters, and transitions to discover the full range of dynamic animations you can achieve with Godot 4. With practice, the AnimationNodeBlendTree could become an indispensable tool in your game development toolkit.Continuing our journey through Godot 4’s animation system, let’s delve into more advanced techniques that can be employed using the AnimationNodeBlendTree. These techniques will give you even greater control over your animations, allowing your games to stand out with polished and interactive character movements.

It’s important to note that when animations get complex, you might need to mix different types of animations. Let’s see how you would handle a situation where your character can run, but also has the ability to shoot while running.

Mixing Actions with Additive Animations

In a situation where two separate actions need to take place simultaneously, such as running and shooting, you would use an AnimationNodeAdd2. This node allows you to add the effects of one animation on top of another, layering them together.

First, make sure both animations exist within your AnimationPlayer:

// Add a running and shooting animation to your AnimationPlayer
animation_player.add_animation("run", run_anim)
animation_player.add_animation("shoot", shoot_anim)

Next, set up your AnimationNodeAdd2 in the blend tree:

// Create an additive animation node
var run_shoot_additive = AnimationNodeAdd2.new()
blend_tree.add_node("RunShootAdditive", run_shoot_additive)
blend_tree.connect_node("run", "", "RunShootAdditive", 0)
blend_tree.connect_node("shoot", "", "RunShootAdditive", 1)

This piece of code sets “run” as the base and “shoot” as the animation to be added on top.

Blend Trees and Animation Layers

To further enhance the power of your AnimationNodeBlendTree, you can utilize layers. Layers are useful when you want animations to affect certain parts of your character independently from others, like the upper body reacting differently than the lower body.

Here’s how you could create and manage an AnimationNodeBlendTree’s layers:

// Create a blend tree for the upper body independent of the lower body
var upper_body_blend_tree = AnimationNodeBlendTree.new()
animation_tree.add_layer("UpperBodyLayer")
animation_tree.set_layer_tree("UpperBodyLayer", upper_body_blend_tree)

With this set up, you can have an upper body animation layer that can play a “shoot” animation without interfering with the lower body’s “run” animation.

Utilizing One-Shot Animations

There may be cases where an animation should only play once and not loop, like a character’s jump or an explosion effect. This is where one-shot animations are used. Let’s add a one-shot node to our blend tree:

// Create and set up a one-shot animation for the jump animation
var jump_one_shot = AnimationNodeOneShot.new()
jump_one_shot.set_animation("jump")
blend_tree.add_node("JumpOneShot", jump_one_shot)
blend_tree.connect_node("StateMachine", "JumpState", "JumpOneShot")

Controlling Playback with AnimationNodeTimescale

Sometimes, you may need to control the speed at which an animation plays. This could be used for slow-motion effects, or to sync the animation speed with character velocity. This is done with AnimationNodeTimescale:

// Set up a timescale node to adjust animation speed
var run_timescale = AnimationNodeTimescale.new()
run_timescale.set_scale(1.0) // Normal speed
blend_tree.add_node("RunTimescale", run_timescale)
blend_tree.connect_node("run", "", "RunTimescale", -1)

With this setup, you can now adjust the playback speed of your “run” animation in real-time by setting the scale on the RunTimescale node.

Animating Based on Custom Logic with AnimationNodeScript

Lastly, Godot 4 enables developers to execute custom logic within the animation system through AnimationNodeScript. You can use this for complex situations like procedural animations:

// Create a custom script node
var custom_animation_script = AnimationNodeScript.new()

// Imagine you have predefined a method that provides a custom blend amount
custom_animation_script.set("blend_amount", custom_method_for_calculating_blend())

blend_tree.add_node("CustomScriptNode", custom_animation_script)

This example would allow you to use a custom method to determine the blend amount dynamically, offering highly tailored animation controls.

These advanced techniques further demonstrate the flexibility and control provided by Godot 4’s AnimationNodeBlendTree. By utilizing these nodes and methods, you can craft detailed animation sequences that not only look great but are also responsive to the gameplay, delivering a rich and immersive experience to your players.

With the right combination of nodes, parameters, and scripts, your game’s characters will move and interact with their environment in lifelike and engaging ways. Remember, the more you experiment with Godot’s animation tools, the more you’ll appreciate the depth and power they bring to your game development arsenal. Dive in, get creative, and animate away!

FREE COURSES

FINAL DAYS: Unlock coding courses in Unity, Unreal, Python, Godot and more.

ACCESS FOR FREE