VisualShaderNodeDotProduct In Godot - Complete Guide

Welcome to our in-depth tutorial on the VisualShaderNodeDotProduct class within the Godot 4 engine. If you’re intrigued by the magic of shaders and want to understand how they contribute to the stunning visuals in games and simulations, then you’re in the right place. Mastering the dot product operation is a cornerstone in shader programming and is fundamental to many visual effects. So let’s dive into the world of visual shaders and discover how the ‘dot product’ can enhance your game development skills.

Table of contents

What is VisualShaderNodeDotProduct?

The VisualShaderNodeDotProduct is a node in the powerful Godot Engine’s visual shader graph that performs a mathematical operation known as the dot product on two vectors. This operation is a workhorse in computer graphics, used in lighting calculations, projection, and many more areas where understanding spatial relationships is key.

What is it Used For?

VisualShaderNodeDotProduct is typically used for:

Determining the angle between two vectors.
Calculating light intensity in shading languages.
Assisting in the generation of bump maps and reflections.

This functionality is instrumental in creating dynamic and realistic interactions between objects and light sources within a scene, which is crucial for any graphical application.

Why Should I Learn It?

Understanding and utilizing the VisualShaderNodeDotProduct can be critical to a game or graphical application as it:

Enhances rendering capabilities, allowing for more sophisticated visual effects.
Serves as a foundation for more complex shader operations that you’ll likely encounter as you develop your skills.
Is a valuable tool in the shader programmer’s toolkit, expanding your abilities to create visually compelling features.

By learning how to implement and manipulate the dot product within Godot’s visual shader graph, you can take your game visuals to the next level. This knowledge is not only practical but also opens the door to a deeper understanding of graphics programming, which is an increasingly valuable skillset in the industry.

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Creating a Basic Dot Product Shader

First, we’ll begin by creating a simple node setup that calculates the dot product of two static vectors in the Godot VisualShader environment. This will help us understand how to work with the VisualShaderNodeDotProduct node.

var dot_product_node = VisualShaderNodeDotProduct.new()
dot_product_node.input_port_1_default_value = Vector3(1, 0, 0)
dot_product_node.input_port_2_default_value = Vector3(0, 1, 0)

In this snippet, we create a new VisualShaderNodeDotProduct and set its default input values. The dot product of a vector facing the X-axis and a vector facing the Y-axis is 0 because they are perpendicular to each other.

Integrating User Input

Now let’s enhance the shader by allowing user input to dynamically change one of the vectors. We’ll connect a user-provided vector to the dot product node.

var user_vector_input = VisualShaderNodeVectorUniform.new()
user_vector_input.set_name("User Vector")

var dot_product_node = VisualShaderNodeDotProduct.new()
dot_product_node.set_input_port_value(1, user_vector_input)

Here, we created a VisualShaderNodeVectorUniform to accept user input and connected it to the second input of the dot product node. The user can now manipulate this vector through the shader parameters in the Godot editor.

Visualizing the Dot Product

To see the result of the dot product operation, we will set up a shader that changes the color of a mesh based on the dot product of two vectors. This can illustrate, for example, how the surface angle relative to a light source affects its brightness.

// User input for the dynamic vector, representing the light direction
var user_light_direction = VisualShaderNodeVectorUniform.new()
user_light_direction.set_name("Light Direction")

// Static normal map
var normalmap = VisualShaderNodeTexture.new()
normalmap.set_name("Normal Map")

// Dot Product Node
var dot_product = VisualShaderNodeDotProduct.new()

// Connect the normalmap to the first input
dot_product.set_input_port_value(0, normalmap)
// Connect the dynamic vector to the second input
dot_product.set_input_port_value(1, user_light_direction)

// Output the result to the color of a surface
var output = VisualShaderNodeOutput.new()
output.set_input_port_value(0, dot_product)

This setup uses a normal map and a vector uniform representing the light direction. The dot product between the surface’s normal and the light direction is then used as the output for the shader’s color, creating a simple lighting effect.

Adjusting Intensity with Dot Product

Sometimes, you may want to adjust the intensity of the effect based on the dot product. In this example, we’ll use the result to control the intensity of a diffuse texture on a surface.

// User input for intensity
var user_intensity_input = VisualShaderNodeScalarUniform.new()
user_intensity_input.set_name("Intensity")

// Diffuse texture
var diffuse_texture = VisualShaderNodeTexture.new()
diffuse_texture.set_name("Diffuse Texture")

// Dot Product Node
var dot_product = VisualShaderNodeDotProduct.new()

// Texture coordinate input
var uv_input = VisualShaderNodeUV.new()

dot_product.set_input_port_value(0, uv_input)
dot_product.set_input_port_value(1, user_intensity_input)

var output = VisualShaderNodeOutput.new()
output.set_input_port_value(0, dot_product)

In this snippet, we calculate the dot product between texture coordinates and an intensity value. The result is used to scale the diffuse texture color before it’s sent to the output, effectively controlling the texture’s visible intensity on the surface.

With these examples, you have seen how to create and manipulate dot product operations in visual shaders with Godot. Understanding and experimenting with these basics sets the foundation for crafting more complex shaders and exploring the full range of visual possibilities offered by the Godot Engine.

After exploring the basics of the VisualShaderNodeDotProduct and creating both static and dynamic setups, let’s advance our skills further. We’ll explore how we can use the dot product in combination with other nodes to produce some interesting visual effects!

Incorporating conditional logic with the dot product:

var dot_product = VisualShaderNodeDotProduct.new()
var if_node = VisualShaderNodeIf.new()

// Setup dot product as usual
// ...

// Connect the dot product to the condition of the 'if' node
if_node.set_input_port_value(VisualShaderNodeIf.CONDITION, dot_product)
if_node.set_input_port_value(VisualShaderNodeIf.A, Vector3(1.0, 1.0, 1.0)) // Color when true (e.g., light is facing the surface)
if_node.set_input_port_value(VisualShaderNodeIf.B, Vector3(0.0, 0.0, 0.0)) // Color when false (e.g., light is not facing the surface)

// Output the result
var output = VisualShaderNodeOutput.new()
output.set_input_port_value(0, if_node)

This code snippet shows how to change a mesh’s color based on whether the light is facing the surface. By adding the VisualShaderNodeIf, we create a conditional effect that changes color if the dot product is positive (indicating that surfaces are facing each other).

Let’s create a rim-lighting effect by using the dot product:

var light_dir = VisualShaderNodeVectorUniform.new()
light_dir.set_name("Light Direction")

var view_dir = VisualShaderNodeVectorUniform.new()
view_dir.set_name("View Direction")

var dot_product = VisualShaderNodeDotProduct.new()
dot_product.set_input_port_value(0, light_dir)
dot_product.set_input_port_value(1, view_dir)

var smoothstep_node = VisualShaderNodeScalarFunc.new()
smoothstep_node.function = VisualShaderNodeScalarFunc.FUNC_SMOOTHSTEP
smoothstep_node.set_input_port_value(0, 0.0) // edge0
smoothstep_node.set_input_port_value(1, 1.0) // edge1
smoothstep_node.set_input_port_value(2, dot_product) // T

// Output the result as an overlay to the base color
var output = VisualShaderNodeOutput.new()
output.set_input_port_value(0, smoothstep_node) // Assuming this is connected to an emission output for rim lighting

Here, we calculate the rim lighting effect which gives a glow on the edges of the object when the light is almost tangential to the surface. We utilize the VisualShaderNodeScalarFunc to apply a smoothstep function to the dot product result, enhancing the light’s edge effect.

Now, let’s use the dot product for environment mapping:

var reflection_vector = VisualShaderNodeReflect.new()
var camera_normal = VisualShaderNodeCamera.new()

reflection_vector.set_input_port_value(0, camera_normal)

var environment_texture = VisualShaderNodeTexture.new()
environment_texture.texture_type = VisualShaderNodeTexture.TYPE_CUBEMAP

var dot_product = VisualShaderNodeDotProduct.new()
dot_product.set_input_port_value(0, reflection_vector)
dot_product.set_input_port_value(1, environment_texture)

// Output result to the shader's color emission channel
var output = VisualShaderNodeOutput.new()
output.set_input_port_value(0, dot_product)

This code snippet demonstrates how the dot product, combined with a reflection vector and a cubemap texture of the environment, can simulate reflective surfaces. The resulting value modulates how the environment map affects the object’s appearance.

Finally, we use dot product for creating fake shadows underneath objects:

var ground_normal = VisualShaderNodeVectorUniform.new()
ground_normal.set_name("Ground Normal")
ground_normal.set_default_value(Vector3(0, 1, 0)) // Assuming ground plane is the XY plane

var object_position = VisualShaderNodeGlobalExpression.new()
object_position.global_expression = "WORLD_MATRIX"

var dot_product = VisualShaderNodeDotProduct.new()
// Calculate the dot product between the object's bottom position and the ground plane normal
dot_product.set_input_port_value(0, object_position)
dot_product.set_input_port_value(1, ground_normal)

var shadow_intensity = VisualShaderNodeScalarUniform.new()
shadow_intensity.set_name("Shadow Intensity")

// Combine dot product with a shadow intensity to modulate the darkness of the shadow
var multiply = VisualShaderNodeScalarOp.new()
multiply.operation = VisualShaderNodeScalarOp.OP_MUL
multiply.set_input_port_value(0, dot_product)
multiply.set_input_port_value(1, shadow_intensity)

// Output the shadow value
var output = VisualShaderNodeOutput.new()
output.set_input_port_value(0, multiply)

In this instance, we create the illusion of shadows under the objects by calculating the dot product between the object’s bottom position and the ground plane normal. By modulating this value with a shadow intensity parameter, we can simulate the effect of shadow softness.

As you can see, by delving into the capabilities of the VisualShaderNodeDotProduct node within Godot, you have at your fingertips a versatile tool for enhancing the visual appeal of your game environments. Whether you’re a beginner or an experienced shader programmer, Godot offers user-friendly visual tools to craft detailed and complex graphical effects. These examples are just the tip of the iceberg, and as you experiment with these nodes, you’ll begin to uncover even more creative uses for the dot product in shading.

Let’s further explore how the dot product can be used within Godot’s visual shaders to achieve different effects, focusing on practical applications that can elevate your game development skills.

Creating a Specular Highlight Effect:

// Assuming we have normals, camera direction, and light direction set up

var light_direction = VisualShaderNodeVectorUniform.new()
var camera_direction = VisualShaderNodeVectorUniform.new()
var normal = VisualShaderNodeVectorUniform.new()

light_direction.set_name("LightDirection")
camera_direction.set_name("CameraDirection")
normal.set_name("Normal")

// Calculate halfway vector
var add_node = VisualShaderNodeVectorOp.new()
add_node.operation_type = VisualShaderNodeVectorOp.OP_ADD
add_node.set_input_port_value(0, light_direction)
add_node.set_input_port_value(1, camera_direction)

var normalize_node = VisualShaderNodeVectorFunc.new()
normalize_node.function_type = VisualShaderNodeVectorFunc.FUNC_NORMALIZE
normalize_node.set_input_port_value(0, add_node)

// Specular calculation using dot product
var dot_product = VisualShaderNodeDotProduct.new()
dot_product.set_input_port_value(0, normal)
dot_product.set_input_port_value(1, normalize_node)

// Raise to power for size of specular highlight
var specular_power = VisualShaderNodeScalarUniform.new()
specular_power.set_name("SpecularPower")

var pow_node = VisualShaderNodeScalarFunc.new()
pow_node.function_type = VisualShaderNodeScalarFunc.FUNC_POW
pow_node.set_input_port_value(0, dot_product)
pow_node.set_input_port_value(1, specular_power)

// Output the specular highlight
var output = VisualShaderNodeOutput.new()
output.set_input_port_value(0, pow_node)

Here, we’ve calculated the halfway vector between the light direction and camera direction, normalized it, and then used the dot product to find the specular highlight. The specular power determines the size of the highlight.

Using Dot Product for Height-based Fog:

var world_position = VisualShaderNodeGlobalExpression.new()
world_position.global_expression = "WORLD_MATRIX * vec4(VERTEX, 1.0)"

var fog_height = VisualShaderNodeScalarUniform.new()
fog_height.set_name("FogHeight")

// Dot product height with fog height control
var dot_product = VisualShaderNodeDotProduct.new()
dot_product.set_input_port_value(0, world_position)
dot_product.set_input_port_value(1, fog_height)

var fog_intensity_node = VisualShaderNodeScalarInterp.new()
fog_intensity_node.set_input_port_value(0, dot_product)
fog_intensity_node.set_input_port_value(1, fog_height)

// Combine interpolated fog intensity with base color
var base_color = VisualShaderNodeVectorUniform.new()
base_color.set_name("BaseColor")

var mix_node = VisualShaderNodeVectorInterp.new()
mix_node.set_input_port_value(0, base_color)
mix_node.set_input_port_value(1, fog_intensity_node)

// Output the color with fog effect
var output = VisualShaderNodeOutput.new()
output.set_input_port_value(0, mix_node)

This snippet demonstrates how to create a height-based fog effect by manipulating the dot product between world position and fog height. The fog intensity interpolates between the object’s base color and the fog strength to provide a smooth transition.

Dot Product for Stylized Water Waves:

// Time node to animate the wave
var time = VisualShaderNodeTime.new()

// Wave parameters
var wave_speed = VisualShaderNodeScalarUniform.new()
wave_speed.set_name("WaveSpeed")

var wave_height = VisualShaderNodeScalarUniform.new()
wave_height.set_name("WaveHeight")

// Calculate moving waves over time using sine function
var multiply_node_time = VisualShaderNodeScalarOp.new()
multiply_node_time.operation_type = VisualShaderNodeScalarOp.OP_MUL
multiply_node_time.set_input_port_value(0, time)
multiply_node_time.set_input_port_value(1, wave_speed)

var sine_node = VisualShaderNodeScalarFunc.new()
sine_node.function_type = VisualShaderNodeScalarFunc.FUNC_SIN
sine_node.set_input_port_value(0, multiply_node_time)

// Calculate wave height using dot product with wave direction
var wave_direction = VisualShaderNodeVectorUniform.new()
wave_direction.set_name("WaveDirection")

var dot_product = VisualShaderNodeDotProduct.new()
dot_product.set_input_port_value(0, sine_node)
dot_product.set_input_port_value(1, wave_direction)

var multiply_node_height = VisualShaderNodeScalarOp.new()
multiply_node_height.operation_type = VisualShaderNodeScalarOp.OP_MUL
multiply_node_height.set_input_port_value(0, dot_product)
multiply_node_height.set_input_port_value(1, wave_height)

// Output the wave height to the vertex position
var output = VisualShaderNodeOutput.new()
output.set_input_port_value(VisualShaderNodeOutput.VERTEX, multiply_node_height)

In this example, a simple sine function creates an animated wave effect. By multiplying the sine result with a wave direction vector using the dot product, we can move the vertices of a water mesh to simulate waves.

Using Dot Product for Drawing Outlines:

// Normal from mesh
var normal = VisualShaderNodeInput.new()
normal.input_name = "NORMAL"

// Negate the camera normal for the outline
var camera_normal = VisualShaderNodeVectorFunc.new()
camera_normal.function_type = VisualShaderNodeVectorFunc.FUNC_NEGATE
camera_normal.set_input_port_value(0, VisualShaderNodeInput.new("CAMERA_NORMAL"))

// Calculate the edge factor using dot product
var edge_factor = VisualShaderNodeDotProduct.new()
edge_factor.set_input_port_value(0, normal)
edge_factor.set_input_port_value(1, camera_normal)

// Output the edge factor for further use
var output = VisualShaderNodeOutput.new()
output.set_input_port_value(0, edge_factor)

This basic setup shows how the dot product can be used to create an outline effect around objects, by calculating the edge factor between the normal of the mesh and the camera normal. The result can be utilized to create a post-processing effect that highlights object edges.

Dot Product in Cel Shading:

// Light direction for cel shading
var light_direction = VisualShaderNodeVectorUniform.new()
light_direction.set_name("LightDirection")

// Normal vector
var normal = VisualShaderNodeInput.new()
normal.input_name = "NORMAL"

// Dot product for light intensity on surface
var dot_product = VisualShaderNodeDotProduct.new()
dot_product.set_input_port_value(0, normal)
dot_product.set_input_port_value(1, light_direction)

// Output the light intensity
var output = VisualShaderNodeOutput.new()
output.set_input_port_value(VisualShaderNodeOutput.ALBEDO, dot_product)

Here, the basic principle of cel shading is shown, using the dot product to calculate the intensity of light on a surface. This value can be quantized to create the characteristic ‘banding’ effect of cel-shaded graphics.

These are just a few more examples of how the dot product can be used within Godot’s visual shader graph to affect a game’s graphics. Whether you’re looking to enhance the realism of your game environment or add a stylistic touch, mastering the dot product through the VisualShaderNodeDotProduct class is a vital skill. By experimenting with these nodes and understanding their effects on your meshes, you can develop vibrant and lively worlds for your players to immerse themselves in.

Where to Go Next in Your Godot Journey

Mastering the VisualShaderNodeDotProduct within the Godot engine opens up a universe of possibilities for creating stunning visual effects in your games. If you’ve enjoyed tinkering with the mechanics of shader programming and want to further expand your game development skills, we have just the right pathways for you to continue your journey.

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Conclusion

Exploring the VisualShaderNodeDotProduct is just the beginning of what you can achieve with Godot’s robust shader system. As you’ve seen, this versatile node can be the backbone of many unique visual effects, giving your games that extra polish and making them stand out in a crowded market. Shaders can be daunting, but with Godot’s user-friendly interface and our comprehensive tutorials and courses, you have all the tools you need to become a shader wizard.

Take the next step and consolidate your knowledge with our Godot Game Development Mini-Degree. We at Zenva are proud to accompany you on your game development journey, providing guidance and resources at every level. Whether you’re aiming to create the next indie hit or simply want to expand your skillset, mastering Godot with Zenva’s high-quality content is a game-changer. So why wait? Unlock your potential and start crafting those amazing game experiences today!

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