VisualShaderNodeCurveTexture in Godot – Complete Guide

VisualShaderNodeCurveTexture is an intriguing class in Godot 4 that allows for advanced visual effects within the shader graph through curve textures. Understanding how to use this class can deeply enhance your visual shaders, giving you control over interpolations and transitions that can add depth and nuance to your game.

What is VisualShaderNodeCurveTexture?

The VisualShaderNodeCurveTexture class in Godot 4 is a component of the visual shader graph that provides the functionality to perform lookups based on a CurveTexture. This means that it can take a curve that’s been defined in the engine and use it to manipulate the output of textures in various ways, potentially creating dynamic visual effects.

What is it for?

This node is mainly used to control interpolations within shaders based on predefined curves. By adjusting the curve, developers can create complex transitions or effects that can be applied to objects or scenes. It’s a versatile tool for fine-tuning how shades and colors transition within various parts of a texture.

Why should I learn it?

Learning how to utilize the VisualShaderNodeCurveTexture can significantly benefit game developers seeking more control over their game’s visual aspect. Whether you’re a beginner wanting to expand your toolkit or an experienced coder looking to delve deeper into Godot’s capabilities, mastering this node will empower you to create more polished and visually interesting games.

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Setting Up Your VisualShaderNodeCurveTexture

Before delving into complex shaders, let’s start by setting up a VisualShaderNodeCurveTexture. This will be our foundation for manipulating textures based on curves within Godot 4.

var shader = VisualShader.new()
var curve_texture = VisualShaderNodeCurveTexture.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, curve_texture, Vector2(0, 0))

This snippet shows how to create a new VisualShader instance, adds a VisualShaderNodeCurveTexture to it, and places it at the origin of the shader graph (Vector2(0, 0)).

var curve = Curve.new()
curve.add_point(Vector2(0, 0), 0, 1, Curve.TANGENT_FREE, 1)
curve.add_point(Vector2(1, 1), 0, 1, Curve.TANGENT_FREE, 1)
curve_texture.curve = curve

Here, we initialized a Curve resource, added two points to it to create a basic linear curve, and then assigned it to our VisualShaderNodeCurveTexture instance.

Using the Curve for Color Interpolation

Next, we’ll use our VisualShaderNodeCurveTexture to interpolate colors on a shader. We’ll be adjusting a simple color transition from one end of the spectrum to another.

var color_interpolation = VisualShaderNodeVectorInterp.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, color_interpolation, Vector2(200, 100))

var color_from = Color(1, 0, 0) # Red
var color_to = Color(0, 0, 1) # Blue
color_interpolation.inputs[0].default_value = color_from.to_vector()
color_interpolation.inputs[1].default_value = color_to.to_vector()

var output_node = VisualShaderNodeOutput.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, output_node, Vector2(400, 100))

shader.node_connect(curve_texture.get_output_port_index("output"), color_interpolation.get_input_port_index("ratio"))
shader.node_connect(color_interpolation.get_output_port_index("output"), output_node.get_input_port_index("albedo"))

This script creates a node for color interpolation and an output node, connecting our curve texture’s output to control the ratio of color transition between red and blue. The outcome is a gradient controlled by the curve shape.

Manipulating Textures with Curves

Now let’s see how the VisualShaderNodeCurveTexture can be used to manipulate an existing texture, like distorting it based on our curve for unique visual effects.

var texture_sampler = VisualShaderNodeTexture.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, texture_sampler, Vector2(-200, -100))

var uv_map = VisualShaderNodeUV.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, uv_map, Vector2(-400, -100))

shader.node_connect(uv_map.get_output_port_index("uv"), texture_sampler.get_input_port_index("uv"))
shader.node_connect(texture_sampler.get_output_port_index("rgb"), curve_texture.get_input_port_index("texture"))

In this example, we’re taking a UV map and the sample of a texture, then passing the texture through our curve texture node to dynamically change the rendering of this texture according to the curve.

shader.node_connect(curve_texture.get_output_port_index("output"), output_node.get_input_port_index("albedo"))

Finally, we connect the distorted texture to the output, resulting in the texture being displayed with the distortions we’ve defined with our curve.

Animating Curves for Dynamic Shaders

Lastly, let’s look at how we can animate a curve to make dynamic shaders. This involves modifying the curve’s points in real-time to alter the visual output on the fly.

func _process(delta):
    var points = curve.get_point_count()
    for i in range(points):
        var point_pos = curve.get_point_position(i)
        point_pos.y = sin(point_pos.x * 2.0 * PI + delta)
        curve.set_point_position(i, point_pos)

    curve_texture.texture.update()

By altering the Y position of each point in the curve within the `_process` function, which updates every frame, we create animated effects. This could be used to create pulsating glows, waves, or other time-varying effects within your shaders.

Remember to run `update` on the curve texture after changing the curve points to reflect the changes in the shader.

These examples should give you a solid foundation for working with VisualShaderNodeCurveTexture in Godot 4. As you become familiar with these basics, you can start experimenting to create even more complex and visually stunning effects in your games.

To further explore the capabilities of the VisualShaderNodeCurveTexture, let’s delve into more complex use cases. You will see how you can leverage this powerful node to create nuanced and intricate visual effects that can truly differentiate your game’s aesthetic.

Combining Textures with Curve Modulation

First, we’ll consider combining two textures together using a curve to modulate their blend. This can create dynamic transition effects or be used for stylized rendering.

var texture1_sampler = VisualShaderNodeTexture.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, texture1_sampler, Vector2(-200, -150))

var texture2_sampler = VisualShaderNodeTexture.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, texture2_sampler, Vector2(-200, -50))

var blend = VisualShaderNodeMix.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, blend, Vector2(0, -100))

shader.node_connect(texture1_sampler.get_output_port_index("rgb"), blend.get_input_port_index("color1"))
shader.node_connect(texture2_sampler.get_output_port_index("rgb"), blend.get_input_port_index("color2"))
shader.node_connect(curve_texture.get_output_port_index("output"), blend.get_input_port_index("cubic"))
shader.node_connect(blend.get_output_port_index("output"), output_node.get_input_port_index("albedo"))

Here, we connected two texture samples to a blend node and then used our curve texture output to control the mix ratio. The curve’s form will dictate how each texture contributes to the final blend.

Adjusting the Texture Offset with Curves

Another practical application is adjusting the offset of a texture in real-time. Our curve can dynamically adjust how much of the texture is offset based on the curve’s value at a given point.

var offset = VisualShaderNodeVecOp.new()
offset.operator = VisualShaderNodeVecOp.OPERATOR_ADD
shader.add_node(VisualShader.TYPE_FRAGMENT, offset, Vector2(0, -250))

shader.node_connect(uv_map.get_output_port_index("uv"), offset.get_input_port_index("a"))
shader.node_connect(curve_texture.get_output_port_index("output"), offset.get_input_port_index("b"))
shader.node_connect(offset.get_output_port_index("vec_output"), texture_sampler.get_input_port_index("uv"))

This code snippet applies the curve output as an additional vector to our texture’s UV coordinates, moving the texture according to the curve values.

Creating a Heightmap-Based Displacement

Using VisualShaderNodeCurveTexture, you can also simulate a heightmap for pseudo-3D displacement effects on a surface.

var displacement = VisualShaderNodeVecOp.new()
displacement.operator = VisualShaderNodeVecOp.OPERATOR_MUL
shader.add_node(VisualShader.TYPE_VERTEX, displacement, Vector2(0, 0))

shader.node_connect(curve_texture.get_output_port_index("output"), displacement.get_input_port_index("a"))
shader.node_connect(uv_map.get_output_port_index("uv"), displacement.get_input_port_index("b"))
shader.node_connect(displacement.get_output_port_index("vec_output"), output_node.get_input_port_index("vertex"))

In this example, we’re using the curve’s output to manipulate the vertices of our mesh in the vertex shader stage, simulating relief based on the curve’s values mapped over the UVs of the mesh.

Time-Based Curve Manipulation for Effects

Animating the VisualShaderNodeCurveTexture allows us to create time-based effects. Let’s look at how to animate the curve’s points based on elapsed time.

func _process(delta):
    for i in range(curve.get_point_count()):
        var y_offset = sin(TIME + curve.get_point_position(i).x * PI) * 0.5 + 0.5
        curve.set_point_position(i, Vector2(curve.get_point_position(i).x, y_offset))

    curve_texture.texture.update()

This code modifies each curve point’s y-position with a sine wave function that takes into account the elapsed time (`TIME`), creating an animation effect. The curve texture is then updated to reflect these changes. This could be used, for example, to simulate water waves or other environmental effects.

Utilizing Curves for Color Correction

A final example illustrates how you can use curves to perform basic color correction by mapping color channels through different curves.

var red_curve_texture = VisualShaderNodeCurveTexture.new()
var green_curve_texture = VisualShaderNodeCurveTexture.new()
var blue_curve_texture = VisualShaderNodeCurveTexture.new()

# Assume red_curve, green_curve, and blue_curve are predefined Curve resources

red_curve_texture.curve = red_curve
green_curve_texture.curve = green_curve
blue_curve_texture.curve = blue_curve

shader.node_connect(texture_sampler.get_output_port_index("r"), red_curve_texture.get_input_port_index("value"))
shader.node_connect(texture_sampler.get_output_port_index("g"), green_curve_texture.get_input_port_index("value"))
shader.node_connect(texture_sampler.get_output_port_index("b"), blue_curve_texture.get_input_port_index("value"))

var color_corrected = VisualShaderNodeVecOp.new()
color_corrected.operator = VisualShaderNodeVecOp.OPERATOR_VEC_BUILD
shader.add_node(VisualShader.TYPE_FRAGMENT, color_corrected, Vector2(200, 200))

shader.node_connect(red_curve_texture.get_output_port_index("output"), color_corrected.get_input_port_index("x"))
shader.node_connect(green_curve_texture.get_output_port_index("output"), color_corrected.get_input_port_index("y"))
shader.node_connect(blue_curve_texture.get_output_port_index("output"), color_corrected.get_input_port_index("z"))
shader.node_connect(color_corrected.get_output_port_index("vec_output"), output_node.get_input_port_index("albedo"))

By connecting each color channel from a texture to its own curve texture, and then combining them again, we’re able to apply custom color correction curves to our textures, which is a staple in image processing.

With these examples, you can see how VisualShaderNodeCurveTexture can be an incredibly powerful tool in your game development process. These are just jumping-off points – the potential applications are as broad as your imagination. We hope you’ll explore these techniques and continue to push the boundaries of visual design in your Godot projects.

Now, let’s expand on the previous examples and venture into more dynamic and artistic territory. You’ll see how to animate your visual effects, integrate user input, and create versatile shaders that can respond to gameplay.

Animating the Curve Itself:

func _process(delta):
    var t = fmod(TIME, 10) / 10  # Cycle between 0 and 1 over 10 seconds
    curve.set_point_position(1, Vector2(t, curve.get_point_position(1).y))
    curve_texture.texture.update()

In this example, the curve animates by moving the x position of its second point across the 0-1 range in a repeating cycle, giving us a dynamic effect in how the curve modulates our textures or shader parameters over time.

Reacting to User Input:

func _input(event):
    if event is InputEventMouseMotion:
        var height = event.relative.y / OS.window_size.y
        curve.set_point_position(1, Vector2(curve.get_point_position(1).x, height))
        curve_texture.texture.update()

This code snippet allows the curve to react to the vertical motion of the user’s mouse. The height of the second curve point is adjusted based on the mouse’s movement, offering real-time visual feedback within the game environment.

Masking Textures with Curves:

var mask = VisualShaderNodeTexture.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, mask, Vector2(-200, 0))

var mask_curve = VisualShaderNodeCurveTexture.new()
mask_curve.curve = mask_curve_resource  # Assume mask_curve_resource is predefined

shader.node_connect(mask.get_output_port_index("rgba"), mask_curve.get_input_port_index("value"))
shader.node_connect(mask_curve.get_output_port_index("output"), output_node.get_input_port_index("albedo"))

Here, we’re using a curve to mask a texture, which can produce effects similar to those in image editing software. The alpha channel of a texture is used as input for the curve, allowing for smooth transitions and feathering effects.

Manipulating Light with Curves:

var light_amount = VisualShaderNodeDotProduct.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, light_amount, Vector2(400, 200))

var light_curve = VisualShaderNodeCurveTexture.new()
light_curve.curve = light_curve_resource  # Assume light_curve_resource is predefined

shader.node_connect(light_amount.get_output_port_index("dot"), light_curve.get_input_port_index("value"))
shader.node_connect(light_curve.get_output_port_index("output"), output_node.get_input_port_index("emission"))

In this script, the dot product of two vectors (which could represent light direction and surface normal) is fed into a curve. The resulting value is then used to control emission strength, simulating a more complex light interaction.

Responding to Gameplay:

func update_curve_based_on_health(health_percentage):
    var y_value = max(0.0, health_percentage / 100.0)
    curve.set_point_position(1, Vector2(curve.get_point_position(1).x, y_value))
    curve_texture.texture.update()

This function would be called with the player’s health percentage. The curve then adjusts accordingly, translating gameplay mechanics into visual changes. For example, as the player’s health decreases, the visual intensity of a shader effect could diminish, reinforcing the game’s feedback loop.

Creating a Waveform Visualizer:

func update_waveform(samples):
    for i in range(min(samples.size(), curve.get_point_count())):
        var normalized_sample = (samples[i] + 1.0) / 2.0  # Normalize the sample between 0 and 1
        curve.set_point_position(i, Vector2(i * 1.0 / curve.get_point_count(), normalized_sample))
    curve_texture.texture.update()

Given an array of audio samples, this function dynamically modifies the curve to reflect the waveform, essentially creating a real-time audio visualizer that could be used to animate a texture or other visual elements within your game.

These code examples should inspire you to think beyond static shaders and textures and towards a more interactive and dynamic gaming experience. By coupling the VisualShaderNodeCurveTexture with Godot’s scripting capabilities, the creative potential is immense. As you incorporate these techniques into your own Godot projects, remember that experimentation is key. Happy coding and creating!

Continue Your Game Development Journey

The world of game development is vast and ever-evolving, and there’s always something new to learn. If you’ve found the tutorials on VisualShaderNodeCurveTexture enlightening and wish to delve deeper into Godot and game development, we have an excellent path for you to continue your learning journey.

Check out our Godot Game Development Mini-Degree, a complete suite of courses designed to take you from a beginner to a confident game developer using the Godot engine. This Mini-Degree is a gateway to mastering 2D and 3D game development, GDScript, and many more key concepts that will empower you to bring your game ideas to life.

For those seeking a broader spectrum of courses on various topics and aspects of game development with Godot, our wide range of Godot courses is the perfect resource. Whether you’ve just started learning the ropes or you’re looking to add new tools to your developer’s toolkit, Zenva’s courses offer the versatility and depth to cater to your needs. Step into our virtual classroom and let’s turn your game development aspirations into reality.

Conclusion

As we’ve seen, the VisualShaderNodeCurveTexture in Godot 4 can revolutionize the way you create shaders, unlocking a plethora of possibilities for dynamic and responsive visual effects. From animating textures to responding to gameplay mechanics, the flexibility it offers can give your games a unique and professional polish. We hope that these insights inspire you to experiment with Godot’s powerful tools, and remember, the most important step in becoming a skilled game developer is continuous learning and creativity.

Don’t stop here—your game development adventure is just beginning. Whether you’re aiming to become a jack-of-all-trades in game creation or focusing on mastering the intricate art of shaders, our Godot Game Development Mini-Degree is the fuel you need for your journey. Join us at Zenva and get started on creating the games you’ve always dreamt of. Let’s code, create, and share your vision with the gaming world!

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