VisualShaderNodeMultiplyAdd in Godot – Complete Guide

Welcome to this insightful dive into the world of visual shaders in Godot 4, specifically focusing on the `VisualShaderNodeMultiplyAdd` class. This tutorial is not just for those well-versed in Godot’s shader system, but also for anyone curious about adding powerful visual effects to their games. Shaders can seem daunting, but the truth is, understanding their basic principles opens up a world of graphical possibilities that can elevate your game development skills.

What is VisualShaderNodeMultiplyAdd?

Understanding VisualShaderNodeMultiplyAdd

The `VisualShaderNodeMultiplyAdd` class in Godot Engine is a fundamental component when working with visual shaders. It enables developers to create more complex visual effects in a more efficient and optimized manner. Shaders are incredibly powerful tools that allow you to manipulate the graphics pipeline to render graphics in a personalized way. They can control how objects are drawn on the screen, down to the pixel level.

The Purpose of Multiply-Add in Shaders

The multiply-add operation used by `VisualShaderNodeMultiplyAdd` takes three inputs – let’s call them a, b, and c – and computes them into a single expression: (a * b + c). This operation is common in graphics programming and is especially useful for optimizing performance and achieving various visual effects.

Why Should I Learn It?

Grasping the `VisualShaderNodeMultiplyAdd` concept is essential because it not only helps you understand how shaders work but also serves as a building block for creating complex visual representations. This knowledge can be a game-changer when looking to implement special effects or optimize graphical computations in your project. Whether you’re an aspiring indie developer or an experienced coder, mastering visual shaders is a valuable asset in the realm of game development.

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Creating a Basic Multiply-Add Shader

Let’s start by creating a basic multiply-add shader in Godot using the VisualShaderNodeMultiplyAdd class. This will involve creating a new visual shader and adding the multiply-add node to it.

var shader = VisualShader.new()
var multiply_add_node = VisualShaderNodeMultiplyAdd.new()

shader.add_node(VisualShader.TYPE_FRAGMENT, multiply_add_node, Vector2(0, 0))

This code snippet establishes a new shader, then a multiply-add node, and finally, adds the node to the shader’s fragment function at the specified coordinates on the visual shader editor grid.

Inputs and Outputs

In shaders, it’s essential to connect the inputs properly to see the desired outcome. For the multiply-add node, we’ll need to set the inputs ‘a’, ‘b’, and ‘c’ in order to compute the expression (a * b + c). Here’s how you can set up the inputs:

var input_a = VisualShaderNodeScalarConstant.new()
input_a.constant = 2.0

var input_b = VisualShaderNodeScalarConstant.new()
input_b.constant = 5.0

var input_c = VisualShaderNodeScalarConstant.new()
input_c.constant = 3.0

shader.add_node(VisualShader.TYPE_FRAGMENT, input_a, Vector2(-200, 0))
shader.add_node(VisualShader.TYPE_FRAGMENT, input_b, Vector2(-200, 100))
shader.add_node(VisualShader.TYPE_FRAGMENT, input_c, Vector2(-200, 200))

shader.connect_nodes(VisualShader.TYPE_FRAGMENT, input_a.get_output_port_by_name("value"), multiply_add_node.get_input_port_by_name("a"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, input_b.get_output_port_by_name("value"), multiply_add_node.get_input_port_by_name("b"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, input_c.get_output_port_by_name("value"), multiply_add_node.get_input_port_by_name("c"))

The scalar constants created as input_a, input_b, and input_c have been assigned the values of 2, 5, and 3, respectively. These are then connected to the corresponding inputs on the multiply-add node.

Applying the Shader

Now that we have our inputs linked, we must apply the shader to a material to see the effect on a mesh or sprite. The code below shows how to create a shader material and set our visual shader as its shader.

var material = ShaderMaterial.new()
material.shader = shader

# Assuming you have a MeshInstance or Sprite you want to apply the shader to:
var mesh_instance = MeshInstance.new()
mesh_instance.material_override = material

Once applied, you would see the effect this has on your chosen object within the engine’s viewport.

Modifying Inputs Dynamically

Let’s say you want to be able to modify the values of input_a, input_b, and input_c during runtime. You can set these values dynamically by referencing the index of the input port and changing the default value like so:

# Changing the constant of input_a to 10 during runtime
input_a.set_constant(0, 10.0)

# Updating the shader material to reflect the changes
material.set_shader_param('input_a', input_a.constant)
material.set_shader_param('input_b', input_b.constant)
material.set_shader_param('input_c', input_c.constant)

With these modifications, you can animate or adjust the values in response to gameplay or user interaction, making your visual effects more dynamic.

By following these examples, you now possess the foundational knowledge to start experimenting with the VisualShaderNodeMultiplyAdd class in Godot. Remember, the key to mastery is practice and experimentation, so don’t hesitate to tweak these examples and discover the myriad of effects you can produce.

Stay tuned for our next section, where we’ll expand on these concepts and create even more intricate shader effects!

Expanding upon our knowledge of the VisualShaderNodeMultiplyAdd, let’s delve into how we can use this powerful node in different contexts to achieve a variety of visual effects. We can apply it to alter colors, combine textures, and even manipulate vertices. Here are several practical applications and their corresponding code examples:

Color Correction

We can use the multiply-add operation to adjust the color output of a shader. Let’s say you want to brighten a texture’s color and add a tint to it:

var color_adjust = VisualShaderNodeMultiplyAdd.new()
var texture_input = VisualShaderNodeTexture.new()
var color_tint = VisualShaderNodeColorConstant.new()
var brightness_factor = VisualShaderNodeScalarConstant.new()

color_tint.constant = Color(1.0, 0.5, 0.5) # A reddish tint
brightness_factor.constant = 1.2 # Increase brightness by 20%

shader.add_node(VisualShader.TYPE_FRAGMENT, texture_input, Vector2(-400, 0))
shader.add_node(VisualShader.TYPE_FRAGMENT, color_tint, Vector2(-400, 100))
shader.add_node(VisualShader.TYPE_FRAGMENT, brightness_factor, Vector2(-400, 200))

shader.connect_nodes(VisualShader.TYPE_FRAGMENT, texture_input.get_output_port_by_name("color"), color_adjust.get_input_port_by_name("a"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, color_tint.get_output_port_by_name("color"), color_adjust.get_input_port_by_name("b"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, brightness_factor.get_output_port_by_name("value"), color_adjust.get_input_port_by_name("c"))

In this instance, the texture’s color will be multiplied by the reddish tint and then made brighter, providing a customized color effect.

Combining Textures

The multiply-add operation can also be used creatively for layering textures, such as adding a detail map onto a base texture:

var base_texture = VisualShaderNodeTexture.new()
var detail_texture = VisualShaderNodeTexture.new()
var detail_factor = VisualShaderNodeScalarConstant.new()

detail_factor.constant = 0.5 # controls the intensity of the detail layer

shader.add_node(VisualShader.TYPE_FRAGMENT, base_texture, Vector2(-400, 0))
shader.add_node(VisualShader.TYPE_FRAGMENT, detail_texture, Vector2(-400, 100))
shader.add_node(VisualShader.TYPE_FRAGMENT, detail_factor, Vector2(-400, 200))

shader.connect_nodes(VisualShader.TYPE_FRAGMENT, base_texture.get_output_port_by_name("color"), color_adjust.get_input_port_by_name("c"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, detail_texture.get_output_port_by_name("color"), color_adjust.get_input_port_by_name("a"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, detail_factor.get_output_port_by_name("value"), color_adjust.get_input_port_by_name("b"))

Here, the base texture’s color is added to the detail texture’s color (which is controlled by the detail_factor) to add more visual richness to your surface.

Manipulating Vertices

Moving beyond textures and colors, you can also use the multiply-add operation to manipulate vertex positions. This could be used to create a waving effect:

var vertex_position = VisualShaderNodeVertexPosition.new()
var time_input = VisualShaderNodeTime.new()
var wave_intensity = VisualShaderNodeScalarConstant.new()

wave_intensity.constant = 2.0 # The intensity of the wave effect

shader.add_node(VisualShader.TYPE_VERTEX, vertex_position, Vector2(-400, 0))
shader.add_node(VisualShader.TYPE_VERTEX, time_input, Vector2(-400, 100))
shader.add_node(VisualShader.TYPE_VERTEX, wave_intensity, Vector2(-400, 200))

# Modifying the y component of the vertex position to create a wave pattern
shader.connect_nodes(VisualShader.TYPE_VERTEX, time_input.get_output_port_by_name("time"), color_adjust.get_input_port_by_name("a"))
shader.connect_nodes(VisualShader.TYPE_VERTEX, wave_intensity.get_output_port_by_name("value"), color_adjust.get_input_port_by_name("b"))
shader.connect_nodes(VisualShader.TYPE_VERTEX, vertex_position.get_output_port_by_name("vertex"), color_adjust.get_input_port_by_name("c"))

This code will result in vertices of a mesh moving up and down over time, generating a dynamic waving effect that could represent water or cloth.

Notice how in each scenario, the multiply-add node’s utility extends its functionality across different shader types and purposes. By leveraging its ability to conduct two operations in one, you not only streamline your shader code but also potentially improve performance.

As you continue to explore the vast possibilities of visual shaders in Godot 4, remember the impact that nodes like VisualShaderNodeMultiplyAdd can have on the sophistication and efficiency of your visual effects. Push the boundaries and experiment with various inputs and connections to bring your vision to life and truly stand out with your game graphics.

Delving further into the potential of VisualShaderNodeMultiplyAdd, let’s create more intricate effects and leverage this node to refine our shaders. Godot’s shader programming allows us to be as creative as we want, so let’s exploit this feature for more advanced visual treats.

Creating a Fresnel Effect:

Fresnel effects increase the reflectivity of surfaces at glancing angles and are great for a more realistic look, especially on transparent materials. Let’s see how this node could be used in making a Fresnel effect:

var fresnel_node = VisualShaderNodeFresnel.new()
var reflection_intensity = VisualShaderNodeScalarConstant.new()
reflection_intensity.constant = 0.5

shader.add_node(VisualShader.TYPE_FRAGMENT, fresnel_node, Vector2(-400, 0))
shader.add_node(VisualShader.TYPE_FRAGMENT, reflection_intensity, Vector2(-400, 100))

shader.connect_nodes(VisualShader.TYPE_FRAGMENT, fresnel_node.get_output_port_by_name("fresnel"), color_adjust.get_input_port_by_name("a"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, reflection_intensity.get_output_port_by_name("value"), color_adjust.get_input_port_by_name("b"))

In the simple Fresnel effect above, we utilize the VisualShaderNodeMultiplyAdd to control the intensity of the fresnel over the surface of the material, making edges more reflective.

Using Noise for Material Breakup:

Noise is a versatile tool in creating random procedural textures. By combining it with multiply-add, we can enhance the realism of materials:

var noise_tex = VisualShaderNodeNoiseTexture.new()
var noise_strength = VisualShaderNodeScalarConstant.new()
noise_strength.constant = 0.3

shader.add_node(VisualShader.TYPE_FRAGMENT, noise_tex, Vector2(-400, 0))
shader.add_node(VisualShader.TYPE_FRAGMENT, noise_strength, Vector2(-400, 100))

shader.connect_nodes(VisualShader.TYPE_FRAGMENT, noise_tex.get_output_port_by_name("color"), color_adjust.get_input_port_by_name("a"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, noise_strength.get_output_port_by_name("value"), color_adjust.get_input_port_by_name("b"))

In this scenario, the noise texture’s greyscale values are amplified by the noise strength constant before being added to the base color or another texture, creating a more complex and less uniform surface.

Layering with Alpha:

Let’s see how multiply-add can manage layering of two textures with an alpha mask. This is commonly used for decal systems or complex material setups:

var base_tex = VisualShaderNodeTexture.new()
var decal_tex = VisualShaderNodeTexture.new()
var alpha_mask = VisualShaderNodeTexture.new()

shader.add_node(VisualShader.TYPE_FRAGMENT, base_tex, Vector2(-400, 0))
shader.add_node(VisualShader.TYPE_FRAGMENT, decal_tex, Vector2(-400, 100))
shader.add_node(VisualShader.TYPE_FRAGMENT, alpha_mask, Vector2(-400, 200))

shader.connect_nodes(VisualShader.TYPE_FRAGMENT, decal_tex.get_output_port_by_name("color"), color_adjust.get_input_port_by_name("a"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, alpha_mask.get_output_port_by_name("color"), color_adjust.get_input_port_by_name("b"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, base_tex.get_output_port_by_name("color"), color_adjust.get_input_port_by_name("c"))

This code takes the decal texture, multiplies it with the alpha mask to handle transparency, and then adds it on top of the base texture. The result is that the decal only shows where the alpha mask allows it to.

Let’s see some environmental effects next:

Simulating Water Caustics:

Water caustics are patterns created by light being refracted through water waves. We can simulate this effect in Godot:

var water_normal = VisualShaderNodeTexture.new()
water_normal.texture_type = VisualShaderNodeTexture.TYPE_NORMALMAP
var light_vector = VisualShaderNodeVec3Constant.new()
light_vector.constant = Vector3(0.0, 1.0, 0.0) # Assuming a light coming from above

shader.add_node(VisualShader.TYPE_FRAGMENT, water_normal, Vector2(-400, 0))
shader.add_node(VisualShader.TYPE_FRAGMENT, light_vector, Vector2(-400, 100))

shader.connect_nodes(VisualShader.TYPE_FRAGMENT, water_normal.get_output_port_by_name("normal"), color_adjust.get_input_port_by_name("a"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, light_vector.get_output_port_by_name("vec3"), color_adjust.get_input_port_by_name("b"))

This code uses the water normal map to affect the light vector, simulating the wavy patterns that you might see on the seabed due to water refraction.

Creating a Glow Effect on Edges:

Edge glow can make objects stand out in a scene, especially to emphasize special items or hazards:

var edge_detect = VisualShaderNodeEdgeDetect.new()
var glow_color = VisualShaderNodeColorConstant.new()
glow_color.constant = Color(1.0, 0.5, 0.0) # A fiery glow

shader.add_node(VisualShader.TYPE_FRAGMENT, edge_detect, Vector2(-400, 0))
shader.add_node(VisualShader.TYPE_FRAGMENT, glow_color, Vector2(-400, 100))

shader.connect_nodes(VisualShader.TYPE_FRAGMENT, edge_detect.get_output_port_by_name("edge"), color_adjust.get_input_port_by_name("a"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, glow_color.get_output_port_by_name("color"), color_adjust.get_input_port_by_name("b"))

The VisualShaderNodeMultiplyAdd can modulate the edge detection with a glow color, making the edges softly blend with the color set in glow_color, creating a halo effect around the object.

The examples shown here illustrate how VisualShaderNodeMultiplyAdd is not just a technical node but a gateway to creative explorations in the visual aspect of your games. We at Zenva encourage you to take these concepts, tweak them, and creatively adapt them in ways that best suit the ambiance and aesthetics of your game. It’s through such experiments you’ll truly harness the power of Godot shaders to materialize your imaginative visions.

Continue Your Game Development Journey

You’ve taken a significant step in mastering visual shaders with Godot 4, but the learning doesn’t stop here. To continue honing your skills and expanding your game development knowledge, we at Zenva encourage you to explore our Godot Game Development Mini-Degree. This collection of courses is designed to take you further into Godot 4, helping you to create engaging games with both 2D and 3D elements.

Our Godot 4 Game Development Mini-Degree is perfect for beginners and more experienced developers alike. You’ll build games from scratch, understand gameplay control flow, and dive into advanced topics such as player mechanics and combat systems. With the ability to access courses 24/7, you can learn at your own pace and choose the modules that interest you the most. The hands-on approach ensures you’ll be creating your own games in no time!

For an even wider array of Godot-powered learning resources, check out our comprehensive range of Godot courses. Each course is geared towards empowering you with the skills needed to turn your creative visions into reality. Remember, with Zenva, you can go from beginner to pro and earn certificates along the way. So what are you waiting for? Embark on your next learning adventure with us and become a proficient game developer in the Godot engine.

Conclusion

In your journey through the intricacies of the VisualShaderNodeMultiplyAdd in Godot 4, you’ve unlocked a new level of creative control over the visual details in your games. Whether it’s enhancing realism with subtle effects or adding a bold, otherworldly flair, these shader techniques are indispensable tools in a game developer’s palette. But remember, this is just the beginning. Each project you create offers a new opportunity to innovate and refine your craft.

Stay curious and continue pushing the boundaries of what’s possible in game development. Dive deeper into Godot 4 with our comprehensive Godot Game Development Mini-Degree. With each lesson, challenge, and project, you’re building not just games, but a robust set of skills that will serve you in all your future endeavors. So, bring your game ideas to life with Zenva – where we transform learners into creators.

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