VisualShaderNodeVaryingGetter in Godot – Complete Guide

Welcome to our deep dive into the realm of visual shaders within Godot Engine! If you’ve dabbled with Godot’s robust shading system or are interested in adding a touch of visual appeal to your games, you’re in the right place. Today, we’ll untangle the intricacies of the `VisualShaderNodeVaryingGetter` class in Godot 4, a feature that can unlock new dimensions in your game’s visual fidelity. So buckle up as we embark on a journey to master this powerful tool, and by the end, you’ll be well-equipped to enhance your projects with stunning shader effects.

What is VisualShaderNodeVaryingGetter?

The `VisualShaderNodeVaryingGetter` is a highly specialized node within Godot’s visual shader system. A varying, in shading terms, is a variable that is interpolated between stages of the rendering pipeline. In simpler words, it carries and modifies data from one shader step to the next – a critical functionality for creating dynamic visual effects.

What is it for?

This node specifically retrieves the value of a varying that has been previously defined and can be used within different shading functions of your game. For example, if you want a custom lighting effect or a unique texture movement on a character, `VisualShaderNodeVaryingGetter` comes into play by fetching the necessary varying value created explicitly for that purpose.

Why should I learn it?

Understanding how to utilize the `VisualShaderNodeVaryingGetter` can elevate your game’s visuals to professional levels. Godot’s visual shaders offer a node-based interface, which means you get to work with a more intuitive visual representation of your shaders. This unlocks immense creative potential without the steep learning curve typically associated with shader programming. If you’re eager to give your games that extra aesthetic edge, mastering this node is an essential step in your development toolkit.

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Creating a Basic Varying with VisualShaderNodeVaryingSetter

Before we delve into retrieving varying values, it’s crucial to understand how to create a varying in the first place. Let’s start with a simple example of setting up a varying to pass a value from the vertex shader to the fragment shader.

// Create a varying using VisualShaderNodeVaryingSetter
var varying_setter = VisualShaderNodeVaryingSetter.new()
varying_setter.data_type = VisualShaderNode.VAR_TYPE_VEC3
varying_setter.varying_name = "myVec3"

// Attach your varying_setter to graph
visual_shader.add_node(varying_setter, Vector2(0, 0))

This code block shows how you instantiate a `VisualShaderNodeVaryingSetter`, set its data type, and give it a name. Remember to attach the node to your shader graph in the position you want.

Defining a Varying Value

Next, you’ll assign a value to the varying. In a vertex shader, this could be something like the vertex’s position or normal which you want to pass to the fragment shader.

// Connect a position output to varying_setter
var output_node = VisualShaderNodeOutput.new()
visual_shader.add_node(output_node, Vector2(300, 0))

var position_port = output_node.get_input_port_by_name("vertex")
visual_shader.connect_nodes(output_node.shader, position_port, varying_setter.shader, 0)

We’re connecting the position output of a `VisualShaderNodeOutput` node to the `varying_setter`. The position is now set to be passed down the shader pipeline.

Using Varying Getter to Retrieve the Value

With the varying set, you can now retrieve its value in the fragment shader using a `VisualShaderNodeVaryingGetter`.

// Retrieve the value with VisualShaderNodeVaryingGetter
var varying_getter = VisualShaderNodeVaryingGetter.new()
varying_getter.varying_name = "myVec3"

// Attach the varying_getter to graph
visual_shader.add_node(varying_getter, Vector2(600, 0))

The `varying_getter` is retrieving the value from the varying we previously defined.

Using the Varying in a Fragment Shader

Now, let’s use the varying value in a fragment shader to change the fragment color based on the vertex position.

// Create a color operation using the varying
var color_node = VisualShaderNodeVectorInterp.new()
visual_shader.add_node(color_node, Vector2(900, 0))

visual_shader.connect_nodes(varying_getter.shader, 0, color_node.shader, 0)

var fragment_output = VisualShaderNodeOutput.new()
fragment_output.set_output_port_for_preview(VisualShaderNodeOutput.PORT_TYPE_VEC4)
visual_shader.add_node(fragment_output, Vector2(1200, 0))

visual_shader.connect_nodes(color_node.shader, 0, fragment_output.shader, fragment_output.get_input_port_by_name("albedo"))

Here, we’re using `VisualShaderNodeVectorInterp` to interpolate between colors based on the varying value we get from the vertex shader. The interpolated value is passed to the fragment’s output resulting in variation of colors across the surface.In our continued exploration of visual shaders in Godot 4, we’re going to enhance our example by incorporating texture sampling and light direction into our shader. This will demonstrate the power of varyings to create visually compelling effects fully.

Sampling a Texture

Textures add richness to surfaces in games. Let’s sample a texture and modify it using our varying value.

// Sample a texture with VisualShaderNodeTexture
var texture_node = VisualShaderNodeTexture.new()
visual_shader.add_node(texture_node, Vector2(0, 200))

// Combine texture color with varying value
var mix_node = VisualShaderNodeVectorMix.new()
visual_shader.add_node(mix_node, Vector2(300, 200))

visual_shader.connect_nodes(texture_node.shader, 0, mix_node.shader, 0)
visual_shader.connect_nodes(varying_getter.shader, 0, mix_node.shader, 1)

Here, `VisualShaderNodeTexture` is used to sample a texture, and `VisualShaderNodeVectorMix` mixes the texture color with the varying value obtained from the `VisualShaderNodeVaryingGetter`.

Next, you’ll see how to pass the light direction from the vertex to the fragment shader, a common requirement for lighting effects in 3D games.

Passing Light Direction

Let’s create a new varying to pass the light direction:

// Create a varying for light direction
var light_dir_setter = VisualShaderNodeVaryingSetter.new()
light_dir_setter.data_type = VisualShaderNode.VAR_TYPE_VEC3
light_dir_setter.varying_name = "light_direction"

visual_shader.add_node(light_dir_setter, Vector2(0, 400))

Now that the varying is set, we will connect the light direction value to it in the vertex shader.

// Connect light direction to varying_setter
var light_node = VisualShaderNodeLight.new()
visual_shader.add_node(light_node, Vector2(300, 400))

visual_shader.connect_nodes(light_node.shader, 0, light_dir_setter.shader, 0)

At this point, the light direction is stored in the varying and can be used in the fragment shader.

Utilizing Light Direction in Fragment Shader

Here’s how you might employ the light direction in your fragment shader:

// Get light direction in fragment shader
var light_dir_getter = VisualShaderNodeVaryingGetter.new()
light_dir_getter.varying_name = "light_direction"

visual_shader.add_node(light_dir_getter, Vector2(600, 400))

And then this light direction can be used to calculate diffuse light as a simple example:

// Calculate diffuse lighting
var diffuse_node = VisualShaderNodeVectorDot.new()
visual_shader.add_node(diffuse_node, Vector2(900, 400))

visual_shader.connect_nodes(light_dir_getter.shader, 0, diffuse_node.shader, 0)
visual_shader.connect_nodes(varying_getter.shader, 0, diffuse_node.shader, 1)

This snippet computes the dot product between the light direction and the vertex normal, providing us with a basic diffuse light effect.

Finally, let’s combine the texture and lighting to get the final color for our fragment:

// Output the final color
visual_shader.connect_nodes(mix_node.shader, 0, fragment_output.shader, fragment_output.get_input_port_by_name("albedo"))
visual_shader.connect_nodes(diffuse_node.shader, 0, fragment_output.shader, fragment_output.get_input_port_by_name("emission"))

Now, the mixed texture color and the light information have been combined and directed to the fragment output. This gives us an object whose surface not only features a dynamic textured appearance but also reacts to light in a basic yet visually appealing way.

By providing these varied and detailed examples, we’ve illustrated how `VisualShaderNodeVaryingGetter` and `VisualShaderNodeVaryingSetter` can be harnessed to craft custom visual effects in Godot 4, thereby enhancing your game development skills and your game’s visual arts.Implementing complex visual effects often involves modifying and controlling factors such as the passage of time, surface curvature, and the object’s position in the world. Let’s go a step further and enrich our shader by incorporating these elements into our visual nodes setup.

Animating with Time

Time is an essential factor in creating effects like pulsing lights or animated surfaces. Here’s how we incorporate time into our visual shader:

// Add a time node to animate the effect
var time_node = VisualShaderNodeTime.new()
visual_shader.add_node(time_node, Vector2(0, 600))

// Modulate the varying value with time
var sine_node = VisualShaderNodeScalarFunc.new()
sine_node.function = VisualShaderNodeScalarFunc.FUNC_SIN

visual_shader.add_node(sine_node, Vector2(300, 600))
visual_shader.connect_nodes(time_node.shader, 0, sine_node.shader, 0)

We’re using the `VisualShaderNodeTime` node to get the shader’s internal time. The `VisualShaderNodeScalarFunc` node applies a sine function to animate our varying over time smoothly.

Considering Surface Curvature

Visual cues such as curvature can greatly assist in making an object’s surface look more dynamic. To implement this, we can calculate the Fresnel effect:

// Calculate the Fresnel effect
var fresnel_node = VisualShaderNodeFresnel.new()
visual_shader.add_node(fresnel_node, Vector2(0, 800))

visual_shader.connect_nodes(light_dir_getter.shader, 0, fresnel_node.shader, 0)
visual_shader.connect_nodes(varying_getter.shader, 0, fresnel_node.shader, 1)

The `VisualShaderNodeFresnel` reflects how much light is reflected off a surface based on the viewing angle. It’s a great way to simulate the curvature effect on shiny surfaces.

World Position Influence

The object’s position in the world can also play a crucial role in shading. To demonstrate this, we will use the world position to create a triplanar texture mapping effect:

// Get object's world position
var world_pos_node = VisualShaderNodeGlobalExpression.new()
world_pos_node.expression = "WORLD_MATRIX"

visual_shader.add_node(world_pos_node, Vector2(0, 1000))

// Use world position for triplanar mapping
var triplanar_node = VisualShaderNodeTriplanar.new()
visual_shader.add_node(triplanar_node, Vector2(300, 1000))

visual_shader.connect_nodes(world_pos_node.shader, 0, triplanar_node.shader, 0)
visual_shader.connect_nodes(texture_node.shader, 0, triplanar_node.shader, 1)

Here, `VisualShaderNodeGlobalExpression` fetches the global world matrix, which gives us the object’s position in world space. The `VisualShaderNodeTriplanar` uses this to map the texture onto the object seamlessly, regardless of its geometry.

Combining Effects

It’s when you combine all these elements that you truly start to see the power of Godot’s VisualShaders. Let’s put it all together:

// Modulate the Fresnel effect with time
var fresnel_time_mix = VisualShaderNodeVectorMix.new()
visual_shader.add_node(fresnel_time_mix, Vector2(600, 800))

visual_shader.connect_nodes(fresnel_node.shader, 0, fresnel_time_mix.shader, 0)
visual_shader.connect_nodes(sine_node.shader, 0, fresnel_time_mix.shader, 1)

// Apply triplanar mapping to diffuse color
visual_shader.connect_nodes(triplanar_node.shader, 0, fragment_output.shader, fragment_output.get_input_port_by_name("albedo"))

// Apply animated Fresnel to emission for a cool edge glow effect
visual_shader.connect_nodes(fresnel_time_mix.shader, 0, fragment_output.shader, fragment_output.get_input_port_by_name("emission"))

This setup modulates the Fresnel effect using our time-based sine wave, creating a pulsing edge glow. The triplanar mapping ensures the texture looks good from all angles.

Through this tutorial, we’ve showcased the boundless creativity Godot’s visual shader system offers. Remember that visual shaders are a playground for creativity, and the more you experiment, the more you harness their true potential. Keep crafting, keep iterating, and most importantly, have fun making your game world visually stunning!

Continuing Your Game Development Journey with Zenva

The world of visual shaders in Godot is just the beginning of a thrilling adventure in game development. To continue expanding your skills and to delve deeper into the vast capabilities of Godot 4, our Godot Game Development Mini-Degree is the perfect next step. This comprehensive collection of courses will equip you with the knowledge to build engaging, cross-platform games, and give you hands-on experience with a variety of game development aspects.

Whether you’re just starting out or looking to enhance your current skill set, our Mini-Degree caters to all levels, offering a flexible learning path that includes video lessons, interactive components, and lots of coding practice. What’s more, with Godot’s powerful and user-friendly features, you can create visually stunning games that stand out.

For those interested in a broader range of instruction, we also offer an extensive selection of Godot courses that cover various topics and levels of expertise. Dive into these resources and join the growing community of game developers who have found value in our curriculum. Your journey to becoming a pro developer awaits, and we at Zenva are excited to be a part of it!

Conclusion

Embarking on the quest to master visual shaders with Godot 4 is a testament to your commitment to becoming a well-rounded game developer. As you’ve seen through our tutorials, the power and flexibility of Godot’s visual shaders can add exceptional depth and professionalism to your games. By harnessing this knowledge, you are now equipped to transform your creative visions into tangible experiences for players around the world.

Remember, the learning doesn’t stop here. We at Zenva encourage you to continue exploring, experimenting, and honing your skills with our Godot Game Development Mini-Degree. This is your gateway to not just learning, but mastering the art of game creation. So go forth, create with confidence, and let your newfound shader prowess be the brush with which you paint your gaming masterpiece.

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