VisualShaderNodeVaryingSetter in Godot – Complete Guide

Welcome to the mesmerizing world of shader programming in Godot 4! Shaders are a fantastic tool for developers and artists alike, allowing you to create stunning visual effects and manipulate how your game renders at a fundamental level. In this tutorial, we’ll dive into a specialized shader node called the VisualShaderNodeVaryingSetter. This node is part of Godot’s robust shading language and opens up new possibilities for your games’ visual potential. Join us as we unpack the features and functionalities of this class and demonstrate its power through practical examples.

What is the VisualShaderNodeVaryingSetter?

The VisualShaderNodeVaryingSetter is a component in Godot’s visual shader system. It serves as a conduit for passing values within your shader script.

What is it for?

This node primarily functions to input values to ‘varyings’. Varyings are special types of variables used in shaders to pass data from one stage of the rendering pipeline to another, especially from vertex to fragment shaders.

Why Should I Learn It?

Understanding the VisualShaderNodeVaryingSetter is key for more advanced shader work. Whether you are aiming to create complex visual effects or efficient shaders for your games, mastering this node can significantly enhance your shader’s flexibility and functionality. Let’s step through its usage to see how it can elevate your game’s visuals to the next level.

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Setting Up the VisualShaderNodeVaryingSetter

To get started with the VisualShaderNodeVaryingSetter, we need to set up a basic shader. In Godot 4, shaders are typically associated with materials that can be applied to any mesh.

var material = VisualShader.new()
var shader = VisualShaderNodeVaryingSetter.new()

# Configure your shader as needed
shader.varying_name = "custom_varying"

# Create and configure other necessary nodes
var input_node = VisualShaderNodeInput.new()
input_node.input_name = VisualShaderNodeInput.INPUT_VECTOR_VIEW

# Connect nodes (output_port, node_to, input_port)
material.connect_nodes(input_node, 0, shader, 0)

# Attach the shader to a material
material.set_shader(shader)

This code initializes the material and the VisualShaderNodeVaryingSetter node. We set the `varying_name` to “custom_varying,” which we’ll use to pass data within the shader. We also add an input node that provides the view vector as the data source. Finally, we connect the nodes and attach the shader to the material.

Passing Data to Fragment Shader

One of the primary use cases for VisualShaderNodeVaryingSetter is to pass vertex shader data to the fragment shader.

var output_node = VisualShaderNodeOutput.new()
var varying = shader.varying_name

# Establish connection from the varying setter to the output
material.connect_nodes(shader, 0, output_node, 0)

# Set up fragment category
output_node.shader_mode = VisualShaderNodeOutput.SHADER_MODE_FRAGMENT
output_node.set_input_port_value(0, varying)

# Set the material shader to output node
material.set_shader(output_node)

# Assuming you have a proper setup to render the material
mesh_instance.set_surface_material(0, material)

In this example, we pass the “custom_varying” data from the varying setter to the fragment shader’s output node. This will affect the fragment shader where the varying variable is used, allowing you to dynamically change the way pixels are rendered based on the vertex data.

Manipulating Varyings for Visual Effects

An exciting aspect of varying setters is their ability to manipulate visual output in real-time. For example, let’s say you want to create a waving effect on your mesh.

var time_node = VisualShaderNodeTime.new()
var sine_node = VisualShaderNodeScalarFunc.new()
sine_node.function = VisualShaderNodeScalarFunc.FUNC_SIN

# Connect time to sin function to get a value that changes over time
material.connect_nodes(time_node, 0, sine_node, 0)

# Combine the sine value with the original vertex position
var vertex_node = VisualShaderNodeInput.new()
vertex_node.input_name = VisualShaderNodeInput.INPUT_VECTOR_VERTEX

var add_node = VisualShaderNodeVectorOp.new()
add_node.operation = VisualShaderNodeVectorOp.OPERATION_ADD

material.connect_nodes(sine_node, 0, add_node, 0)
material.connect_nodes(vertex_node, 0, add_node, 1)

# Finally, assign the combined value to the varying setter
material.connect_nodes(add_node, 0, shader, 0)

In this code, we create a time variable that feeds into a sine function to generate a waving pattern. We then take the vertex position and add our sine function output to it. This manipulates the original vertex position on a per-frame basis, creating a dynamic waving effect across the surface of the mesh.

Creating a Custom Color Gradient

VisualShaderNodeVaryingSetter can also be used to interpolate custom data, such as color gradients.

var color_start_node = VisualShaderNodeColorConstant.new()
color_start_node.constant = Color(1.0, 0.0, 0.0) # Red color

var color_end_node = VisualShaderNodeColorConstant.new()
color_end_node.constant = Color(0.0, 0.0, 1.0) # Blue color

var mix_node = VisualShaderNodeVectorInterp.new()

# Connect the color nodes and the varying setter to the mix node
material.connect_nodes(color_start_node, 0, mix_node, 0)
material.connect_nodes(color_end_node, 0, mix_node, 1)
material.connect_nodes(shader, 0, mix_node, 2)

# Connect mix node to fragment shader's albedo
material.connect_nodes(mix_node, 0, output_node, VisualShaderNodeOutput.PORT_ALBEDO)

In this example, we introduce two color nodes, one for the start and one for the end color of our gradient. We use the VisualShaderNodeVectorInterp to mix these two colors based on a value provided by our VisualShaderNodeVaryingSetter. This mix is then sent to the fragment shader’s albedo output, creating a color gradient across the surface.

These examples showcase the power and flexibility of the VisualShaderNodeVaryingSetter node in Godot 4, which can be a game-changer for those looking to push the limits of visual design in their projects. Stay tuned for the next part where we’ll delve into more complex uses and optimization strategies!

Implementing Custom Lighting Effects

Lighting can dramatically affect the mood and realism of your game’s environment. With the VisualShaderNodeVaryingSetter, you can implement custom lighting effects that tailor to your artistic vision.

Let’s create a basic custom lighting effect where the lighting intensity varies with the angle of incidence:

var light_node = VisualShaderNodeInput.new()
light_node.input_name = VisualShaderNodeInput.INPUT_LIGHT_VEC

var dot_node = VisualShaderNodeScalarFunc.new()
dot_node.function = VisualShaderNodeScalarFunc.FUNC_DOT

var normal_node = VisualShaderNodeInput.new()
normal_node.input_name = VisualShaderNodeInput.INPUT_NORMAL

# Connect the normal and the light direction to the dot product node
material.connect_nodes(normal_node, 0, dot_node, 0)
material.connect_nodes(light_node, 0, dot_node, 1)

# Use the dot product as input for varying to affect the lighting
material.connect_nodes(dot_node, 0, shader, 0)

This snippet computes the dot product between the light direction and the surface normal to determine the angle at which light strikes the surface. The result is then set through a varying variable to change the lighting intensity based on this angle.

Manipulating UV Coordinates

UV mapping is fundamental for texturing; however, by tweaking UV coordinates procedurally, we can create dynamic textural effects such as scrolling textures or distortion.

Let’s look at a simple scrolling effect:

var uv_node = VisualShaderNodeInput.new()
uv_node.input_name = VisualShaderNodeInput.INPUT_UV

var time_node = VisualShaderNodeTime.new()

var vec_const_node = VisualShaderNodeVectorConstant.new()
vec_const_node.constant = Vector3(1.0, 0.0, 0.0) # Direction of scrolling

var mult_node = VisualShaderNodeVectorOp.new()
mult_node.operation = VisualShaderNodeVectorOp.OPERATION_MUL

var add_node = VisualShaderNodeVectorOp.new()
add_node.operation = VisualShaderNodeVectorOp.OPERATION_ADD

# Multiply time by our direction vector to create the scroll effect
material.connect_nodes(time_node, 0, mult_node, 0)
material.connect_nodes(vec_const_node, 0, mult_node, 1)

# Add the time-based scroll effect to the UVs
material.connect_nodes(uv_node, 0, add_node, 0)
material.connect_nodes(mult_node, 0, add_node, 1)

# Pass the modified UVs to the varying setter
material.connect_nodes(add_node, 0, shader, 0)

The UVs are modified by adding a time-based offset, resulting in a scrolling texture effect in the direction defined by `vec_const_node`.

Creating a Wave Distortion Effect

For a more advanced example, consider a wave distortion effect on a sprite or texture:

var uv_node = VisualShaderNodeInput.new()
uv_node.input_name = VisualShaderNodeInput.INPUT_UV

var sine_node = VisualShaderNodeScalarFunc.new()
sine_node.function = VisualShaderNodeScalarFunc.FUNC_SIN

var time_node = VisualShaderNodeTime.new()

# Create a time-dependent wave pattern
material.connect_nodes(time_node, 0, sine_node, 0)

var mult_node = VisualShaderNodeVectorOp.new()
mult_node.operation = VisualShaderNodeVectorOp.OPERATION_MUL

# Amplify the wave effect by some factor, e.g., 0.1
var amplitude = VisualShaderNodeScalarConstant.new()
amplitude.constant = 0.1

material.connect_nodes(sine_node, 0, mult_node, 0)
material.connect_nodes(amplitude, 0, mult_node, 1)

# Modulate the UVs coordinates by the wave pattern
var uv_wave_node = VisualShaderNodeVectorOp.new()
uv_wave_node.operation = VisualShaderNodeVectorOp.OPERATION_ADD

material.connect_nodes(uv_node, 0, uv_wave_node, 0)
material.connect_nodes(mult_node, 0, uv_wave_node, 1)

# Assign the result to the varying setter
material.connect_nodes(uv_wave_node, 0, shader, 0)

Here, a sine wave pattern is generated over time and then scaled by a constant to control the intensity of the distortion. This pattern is then added to the original UV coordinates, creating a dynamic wave distortion as the texture is sampled by the fragment shader.

Using Varying Setters for Gradient Mapping

Finally, consider gradient mapping: a technique where you map the luminance of an image to a gradient to recolor it dynamically.

var luminance_node = VisualShaderNodeVectorFunc.new()
luminance_node.function = VisualShaderNodeVectorFunc.FUNC_GRAYSCALE

var texture_node = VisualShaderNodeTexture.new()

# Convert the texture to grayscale to get luminance
material.connect_nodes(texture_node, 0, luminance_node, 0)

# Use the grayscale value to interpolate along a gradient texture
var gradient_texture_node = VisualShaderNodeTexture.new()
gradient_texture_node.texture = preload("res://gradient.png") # Your gradient texture

var uv_node = VisualShaderNodeInput.new()
uv_node.input_name = VisualShaderNodeInput.INPUT_UV

var uv_interp_node = VisualShaderNodeVectorOp.new()
uv_interp_node.operation = VisualShaderNodeVectorOp.OPERATION_VECTOR_SCALAR

material.connect_nodes(uv_node, 0, uv_interp_node, 0)
material.connect_nodes(luminance_node, 0, uv_interp_node, 1)

# Factor the interpolated UV by varying
material.connect_nodes(uv_interp_node, 0, shader, 0)

This code maps the grayscale value of a texture to a UV coordinate for a gradient texture, effectively recoloring the original texture according to the gradient. The VisualShaderNodeVaryingSetter passes this mapping from the vertex to the fragment shader where the final color is calculated.

These examples illustrate how the VisualShaderNodeVaryingSetter is an essential tool for crafting custom shaders in Godot 4. It allows unprecedented control over the rendering pipeline, enabling developers and artists to bring their creative visions to life. With these techniques in your toolkit, the graphical possibilities are nearly limitless. Enjoy experimenting with shaders and enhancing the visual fidelity of your games!

Performing Screen-Space Transformations

Sometimes, we want to influence how elements appear on the screen, regardless of their position in the world. Screen-space transformations can be valuable for creating post-processing effects, like vignettes or screen overlays.

Here’s an example of how you might adjust the UVs to create a screen-space ripple effect:

var screen_uv_node = VisualShaderNodeInput.new()
screen_uv_node.input_name = VisualShaderNodeInput.INPUT_SCREEN_UV

var time_node = VisualShaderNodeTime.new()

var sin_node = VisualShaderNodeScalarFunc.new()
sin_node.function = VisualShaderNodeScalarFunc.FUNC_SIN

# Create a periodic pattern with time
material.connect_nodes(time_node, 0, sin_node, 0)

var uv_mult_node = VisualShaderNodeVectorOp.new()
uv_mult_node.operation = VisualShaderNodeVectorOp.OPERATION_MUL

# Multiply the sine wave with the UVs to create the ripple pattern
material.connect_nodes(screen_uv_node, 0, uv_mult_node, 0)
material.connect_nodes(sin_node, 0, uv_mult_node, 1)

material.connect_nodes(uv_mult_node, 0, shader, 0)

This code will distort the screen space slightly, creating a ripple as if the screen were a pool of water. By wiring up the `screen_uv_node` directly instead of the `uv_node`, we ensure that this effect appears on top of the rendered scene, like a post-process effect.

Implementing a Dissolve Shader Effect

Dissolve effects are a visually engaging way to make objects appear or disappear. Typically, this involves using a noise texture to dictate where an object transitions from solid to transparent.

Here’s some basic code to implement a dissolve effect using a VisualShaderNodeVaryingSetter:

var gradient_texture_node = VisualShaderNodeTexture.new()
gradient_texture_node.texture = preload("res://noise_texture.png")

var threshold_node = VisualShaderNodeScalarUniform.new()

var step_node = VisualShaderNodeScalarFunc.new()
step_node.function = VisualShaderNodeScalarFunc.FUNC_STEP

var uv_node = VisualShaderNodeInput.new()
uv_node.input_name = VisualShaderNodeInput.INPUT_UV

# Sample the noise texture
material.connect_nodes(uv_node, 0, gradient_texture_node, 0)

# Create a step function to threshold the noise texture
material.connect_nodes(threshold_node, 0, step_node, 0)
material.connect_nodes(gradient_texture_node, 0, step_node, 1)

# Connect to varying setter to pass to fragment shader
material.connect_nodes(step_node, 0, shader, 0)

The noise texture is sampled, and a step function gets applied, which determines the cutoff (threshold) for dissolve. As the threshold changes, it looks like the object is dissolving or forming.

Creating a Heat Haze Distortion

Heat haze or heat distortion is a shimmering effect caused by temperature variations in the air. We can simulate this in Godot 4 using shader programming.

Below is an example of how you might implement a simple heat haze effect:

var time_node = VisualShaderNodeTime.new()

var noise_texture_node = VisualShaderNodeTexture.new()
noise_texture_node.texture = preload("res://noise_texture.png") # Your noise texture

var screen_uv_node = VisualShaderNodeInput.new()
screen_uv_node.input_name = VisualShaderNodeInput.INPUT_SCREEN_UV

# Sample noise texture at screen UV
material.connect_nodes(screen_uv_node, 0, noise_texture_node, 0)

var uv_time_node = VisualShaderNodeVectorOp.new()
uv_time_node.operation = VisualShaderNodeVectorOp.OPERATION_ADD

# Add time to the UVs for animation
material.connect_nodes(screen_uv_node, 0, uv_time_node, 0)
material.connect_nodes(time_node, 0, uv_time_node, 1)

# Use noise to distort UV based on time
material.connect_nodes(uv_time_node, 0, noise_texture_node, 0)

# The noise texture lookup controls the varying
material.connect_nodes(noise_texture_node, 0, shader, 0)

Here, we create a shimmering distortion by animating a noise texture across the screen. The distorted UVs are passed to the varying setter and then used to sample the final image in the fragment shader.

Using Varyings for Vertex Animation

Vertex animation can lend extra life to static meshes. With shaders, we can achieve dynamic motion without the need for rigged skeletons or animated models. Here’s an example:

var height_map_node = VisualShaderNodeTexture.new()
height_map_node.texture = preload("res://height_map.png") # Replacement for an actual heightmap

var vertex_position_node = VisualShaderNodeInput.new()
vertex_position_node.input_name = VisualShaderNodeInput.INPUT_VERTEX

var time_node = VisualShaderNodeTime.new()

# Get the time-dependent height value
var time_mult_node = VisualShaderNodeVectorOp.new()
time_mult_node.operation = VisualShaderNodeVectorOp.OPERATION_SCALAR_MULTIPLY

material.connect_nodes(time_node, 0, time_mult_node, 1)

# Apply heightmap based on time to vertex position
material.connect_nodes(height_map_node, 0, time_mult_node, 0)
material.connect_nodes(time_mult_node, 0, vertex_position_node, 0)

# Forward the displaced vertex to a varying for further processing
material.connect_nodes(vertex_position_node, 0, shader, 0)

In this snippet, the vertices of the mesh are displaced over time based on a height map texture, resulting in a dynamic, undulating surface. By using the VisualShaderNodeVaryingSetter, the modified vertex positions are injected into the pipeline for further processing.

Using these examples and many more like them, you can explore the capabilities of the shader system in Godot 4, particularly when augmented with the flexibility of the VisualShaderNodeVaryingSetter. The potential for creativity in shader programming is vast. From subtle visual enhancements to dramatic, eye-catching effects, shaders empower you to bring an additional layer of polish and uniqueness to your games.

Continuing Your Game Development Journey with Godot

Embarking on the journey of game development is an exhilarating quest that continually evolves. If the concepts of shaders and visual effects in Godot 4 have sparked a creative flame within you, your path to mastery is just beginning. To cement and grow your newfound skills, consider delving deeper with our comprehensive Godot Game Development Mini-Degree. This robust series of courses will guide you through the intricacies of building cross-platform games, encompassing everything from 2D and 3D assets to complex gameplay systems.

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Conclusion

With the power of the VisualShaderNodeVaryingSetter in Godot 4 now at your fingertips, the stage is set for you to unleash a torrent of creativity into your games. Shader programming is an art form in itself, and with these tools, your virtual worlds will not just be played; they’ll be felt, experienced, and remembered. We encourage you to keep experimenting, learning, and sharing your unique visual tales.

Remember that your journey through the rich landscape of game development is never a solitary one. Our Godot Game Development Mini-Degree is here to accompany you every step of the way, offering the knowledge and inspiration you need to transform your game development dreams into reality. Keep pushing the boundaries, and join us at Zenva, where your capacity to create knows no bounds.

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