VisualShaderNodeFloatParameter in Godot – Complete Guide

VisualShaderNodeFloatParameter is a versatile yet simple node in Godot 4’s shading language that can significantly impact how we create visual effects in games. This class acts as a bridge, allowing us to set up adjustable parameters within Godot’s VisualShader editor, leading to highly dynamic and interactive shaders. Whether you’re making the next hit indie game or just dabbling in Godot’s rich environment, understanding VisualShaderNodeFloatParameter can bring a new level of polish to your designs.

What is VisualShaderNodeFloatParameter?

The VisualShaderNodeFloatParameter class is a specialized node within Godot’s visual shader graph system. It corresponds to a scalar (single-value) float parameter that we can use and reuse to control various aspects of a shader’s appearance. In shader language, this translates to a uniform float, a type of variable that can be set externally from the shader code and remains constant for every pixel the shader processes.

What is it for?

VisualShaderNodeFloatParameter is mainly used for creating configurable shaders. This means that without writing any additional code, developers and artists alike can tweak visual properties such as transparency, glossiness, or the intensity of effects directly from the editor. By encapsulating these properties into parameters, we facilitate iterative design and make our shaders easily adjustable for different scenarios or assets.

Why Should I Learn It?

Learning to use VisualShaderNodeFloatParameter opens up a realm of creative possibilities. It allows for dynamic visual changes in a game, which can react to in-game events or user interaction. For instance, changing the intensity of a glow effect when a player picks up an item or adjusting the color of a character’s outfit on the fly. Mastering this node is a step forward in crafting custom visual styles and making your game stand out. Plus, the ability to adjust shader parameters on the fly can drastically speed up the development process, giving you more time to focus on other aspects of your project.

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Setting Up a Basic VisualShaderNodeFloatParameter

To start working with VisualShaderNodeFloatParameter, we’ll introduce a simple example where we create a parameter that modifies the transparency of a sprite.

// First, we need to create a new VisualShader
var shader = VisualShader.new()

// Then we create a VisualShaderNodeFloatParameter
var float_param = VisualShaderNodeFloatParameter.new()

// Set a default value for the parameter
float_param.default_value = 0.5

// Give it a name so we can identify it later
float_param.parameter_name = "transparency"

// Now we must add this node to our shader
shader.add_node(VisualShader.TYPE_FRAGMENT, float_param, Vector2(0, 0))

// To make the transparency effective, we connect the parameter's output to the shader's alpha
var output_node = shader.get_graph_node(VisualShader.TYPE_FRAGMENT)
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, float_param.get_output_port_index("value"), output_node.get_instance_id(), output_node.get_input_port_index("alpha"))

This code sets up a shader with a controllable transparency level. By setting the `default_value` to `0.5`, we establish a base level of half-transparency, but this can be adjusted in the editor later on.

Connecting Parameters to a Color Ramp

A common use of float parameters is to control the transition points in a color ramp. Let’s assume you have a ColorRamp node and you want to use a float parameter to dynamically change one of the ramp’s transition points.

// Create the ColorRamp node
var color_ramp = VisualShaderNodeColorRamp.new()

// And our float param
var color_ramp_param = VisualShaderNodeFloatParameter.new()
color_ramp_param.parameter_name = "ramp_position"

// Adding them to the shader
shader.add_node(VisualShader.TYPE_FRAGMENT, color_ramp, Vector2(100, 0))
shader.add_node(VisualShader.TYPE_FRAGMENT, color_ramp_param, Vector2(100, 100))

// Connect the float param to the ramp position
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, color_ramp_param.get_output_port_index("value"), color_ramp.get_instance_id(), color_ramp.get_input_port_index("offset"))

In this example, the value of `ramp_position` will control where in the gradient a particular color is located. Syncing this parameter with gameplay events, for instance, could create a visual effect where a character powers up, turning from blue to red.

Creating Time-Based Effects

Animations and variations over time can be added to shaders using VisualShaderNodeFloatParameter in conjunction with a VisualShaderNodeTime node. We can create dynamic effects such as pulsating glow or fading in and out by making use of time.

// First, we need a Time node
var time_node = VisualShaderNodeTime.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, time_node, Vector2(200, 0))

// We combine it with a sine function to get a cyclic value
var sine_node = VisualShaderNodeSine.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, sine_node, Vector2(300, 0))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, time_node.get_output_port_index("time"), sine_node.get_instance_id(), sine_node.get_input_port_index("in"))

// Then, we connect our cyclic sine value to a parameter that scales this effect
var time_effect_param = VisualShaderNodeFloatParameter.new()
time_effect_param.parameter_name = "time_effect_scale"
shader.add_node(VisualShader.TYPE_FRAGMENT, time_effect_param, Vector2(300, 100))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, sine_node.get_output_port_index("value"), time_effect_param.get_instance_id(), time_effect_param.get_input_port_index("value"))

The sine function will generate a value between -1 and 1 in a continuous wave, and this can be scaled up or down using the `time_effect_scale` parameter. Plug this into your shader’s intensity, color, or other properties to achieve effects that smoothly transition over time.

Modifying Texture UVs

Textures are a vital part of any game’s visuals. With VisualShaderNodeFloatParameter, you can dynamically alter the UVs of a texture to create interesting outcomes like scrolling backgrounds or wavy distortion effects.

// Assume we have a texture we want to scroll
var texture_node = VisualShaderNodeTexture.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, texture_node, Vector2(400, 0))

// Here's our UV-scrolling parameter
var uv_scroll_param = VisualShaderNodeFloatParameter.new()
uv_scroll_param.parameter_name = "uv_scroll_speed"
shader.add_node(VisualShader.TYPE_FRAGMENT, uv_scroll_param, Vector2(400, 100))

// We also need a UV map node to modify the UV coordinates
var uv_node = VisualShaderNodeUV.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, uv_node, Vector2(500, 0))

// Now we can wish to add our scroll speed to the x-coordinate of our UV map
var vec_add_node = VisualShaderNodeVectorOp.new()
vec_add_node.operation = VisualShaderNodeVectorOp.OPERATION_ADD
shader.add_node(VisualShader.TYPE_FRAGMENT, vec_add_node, Vector2(500, 100))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, uv_node.get_output_port_index("uv"), vec_add_node.get_instance_id(), vec_add_node.get_input_port_index("a"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, uv_scroll_param.get_output_port_index("value"), vec_add_node.get_instance_id(), vec_add_node.get_input_port_index("b:x"))

// Finally, let's map the altered UVs back to the texture
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, vec_add_node.get_output_port_index("vec3"), texture_node.get_instance_id(), texture_node.get_input_port_index("uv"))

Now you have a basic scrolling texture effect. The `uv_scroll_speed` can be modified to change the speed of the scroll. You can expand upon this by adding more parameters to control the direction or add multiple layers scrolling at different rates for a parallax effect.Animating Shader Properties
Animating properties within your shader can add an extra layer of interactivity to your game’s atmosphere. Let’s look at an example of how to animate a property using VisualShaderNodeFloatParameter to change the emission strength of a material over time.

// First, we need a VisualShaderNodeTime node to get the shader time
var time_node = VisualShaderNodeTime.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, time_node, Vector2(600, 0))

// We also create a sine function node to generate a pulsating effect
var sine_node = VisualShaderNodeSine.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, sine_node, Vector2(700, 0))

// Connect the time node to the sine function node
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, time_node.get_output_port_index("time"), sine_node.get_instance_id(), sine_node.get_input_port_index("in"))

// Now, we'll multiply the sine wave with a float parameter to control the emission strength
var emission_strength = VisualShaderNodeFloatParameter.new()
emission_strength.parameter_name = "emission_strength"
shader.add_node(VisualShader.TYPE_FRAGMENT, emission_strength, Vector2(700, 100))

// We'll need a multiply node to combine the sine wave with our emission strength parameter
var multiply_node = VisualShaderNodeScalarOp.new()
multiply_node.operation = VisualShaderNodeScalarOp.OPERATION_MULTIPLY
shader.add_node(VisualShader.TYPE_FRAGMENT, multiply_node, Vector2(800, 0))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, sine_node.get_output_port_index("value"), multiply_node.get_instance_id(), multiply_node.get_input_port_index("a"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, emission_strength.get_output_port_index("value"), multiply_node.get_instance_id(), multiply_node.get_input_port_index("b"))

The shader now has an emission property that pulses over time, and this can be tuned to create effects such as a flickering light or a heartbeat.

Blend Modes for Textures
Combining textures with different blend modes can achieve effects such as damage, weathering, or transitions. The VisualShaderNodeFloatParameter can be used to control the intensity of such blending.

// Let's create two texture nodes for the textures we want to blend
var base_texture = VisualShaderNodeTexture.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, base_texture, Vector2(900, 0))

var blend_texture = VisualShaderNodeTexture.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, blend_texture, Vector2(900, 100))

// Now, we create a blend mode node, for this example, a mix function
var mix_node = VisualShaderNodeMix.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, mix_node, Vector2(1000, 0))

// We connect both textures to our mix node
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, base_texture.get_output_port_index("color"), mix_node.get_instance_id(), mix_node.get_input_port_index("color1"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, blend_texture.get_output_port_index("color"), mix_node.get_instance_id(), mix_node.get_input_port_index("color2"))

// Lastly, we create a float parameter to control the blend amount
var blend_amount = VisualShaderNodeFloatParameter.new()
blend_amount.parameter_name = "blend_amount"
shader.add_node(VisualShader.TYPE_FRAGMENT, blend_amount, Vector2(1000, 100))

// Connect the float parameter to control the mix ratio
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, blend_amount.get_output_port_index("value"), mix_node.get_instance_id(), mix_node.get_input_port_index("ratio"))

You can now control how much each texture contributes to the final output via the `blend_amount` parameter, allowing for dynamic texture blending in your game.

Controlling Vector Properties
Sometimes we want to animate not just a single value but a vector property, like a color or direction. We can use VisualShaderNodeFloatParameter for each component of the vector.

// Assume we want to create an animated color property
var color_r = VisualShaderNodeFloatParameter.new()
color_r.parameter_name = "color_r"
shader.add_node(VisualShader.TYPE_FRAGMENT, color_r, Vector2(1100, 0))

var color_g = VisualShaderNodeFloatParameter.new()
color_g.parameter_name = "color_g"
shader.add_node(VisualShader.TYPE_FRAGMENT, color_g, Vector2(1100, 100))

var color_b = VisualShaderNodeFloatParameter.new()
color_b.parameter_name = "color_b"
shader.add_node(VisualShader.TYPE_FRAGMENT, color_b, Vector2(1100, 200))

// We need a node to construct the vector from its components
var vec_construct = VisualShaderNodeVectorCompose.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, vec_construct, Vector2(1200, 100))

// Connect each color component parameter to the corresponding input of the vector compose node
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, color_r.get_output_port_index("value"), vec_construct.get_instance_id(), vec_construct.get_input_port_index("x"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, color_g.get_output_port_index("value"), vec_construct.get_instance_id(), vec_construct.get_input_port_index("y"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, color_b.get_output_port_index("value"), vec_construct.get_instance_id(), vec_construct.get_input_port_index("z"))

We’ve just set up a system where we can animate each channel of a color independently, allowing for color shifts and pulsating effects.

Procedural Texture Manipulation
VisualShaderNodeFloatParameter can be instrumental in creating procedural textures that change over gameplay or time. An example could be water waves where we alter the normal map intensity.

// Assuming we have a normal map texture node
var normal_map = VisualShaderNodeTexture.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, normal_map, Vector2(1300, 0))

// Creating the float parameter to control the normal map intensity
var normal_intensity = VisualShaderNodeFloatParameter.new()
normal_intensity.parameter_name = "normal_intensity"
shader.add_node(VisualShader.TYPE_FRAGMENT, normal_intensity, Vector2(1300, 100))

// We scale the normal map with our intensity parameter
var scale_node = VisualShaderNodeVec3Scaling.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, scale_node, Vector2(1400, 0))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, normal_map.get_output_port_index("color"), scale_node.get_instance_id(), scale_node.get_input_port_index("vec3"))
shader.connect_nodes(VisualShader.TYPE_FRAGMENT, normal_intensity.get_output_port_index("value"), scale_node.get_instance_id(), scale_scale_node.get_input_port_index("scaler"))

By setting the intensity parameter, you control how strong the normal map affects the surface lighting, simulating calm or stormy water.

These examples only scratch the surface of what VisualShaderNodeFloatParameter can achieve in Godot 4. Whether you’re adjusting emission strength, blending textures, animating colors, or controlling procedural effects, this versatile node is an essential tool for creating engaging and responsive visual elements in your games.Creating a Dynamic Fog Effect
Fog can create an atmosphere of mystery or dread in a game scene. With VisualShaderNodeFloatParameter, we can control the distance at which the fog begins and its density.

// Create parameters for fog start distance and fog density
var fog_start = VisualShaderNodeFloatParameter.new()
fog_start.parameter_name = "fog_start"
shader.add_node(VisualShader.TYPE_FRAGMENT, fog_start, Vector2(1500, 0))

var fog_density = VisualShaderNodeFloatParameter.new()
fog_density.parameter_name = "fog_density"
shader.add_node(VisualShader.TYPE_FRAGMENT, fog_density, Vector2(1500, 100))

// To calculate the fog effect, we also need the camera's depth information
var depth_node = VisualShaderNodeDepth.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, depth_node, Vector2(1600, 0))

// Now let's calculate the fog factor based on the camera's depth and our fog parameters
var fog_calculation = VisualShaderNodeExpression.new()
fog_calculation.expression = "float fogFactor = clamp((depth-${fog_start}) * ${fog_density}, 0.0, 1.0);"
shader.add_node(VisualShader.TYPE_FRAGMENT, fog_calculation, Vector2(1700, 0))

The expression constructs the logic for a non-linear fog where the fog factor is clamped between 0 and 1, creating a smooth transition as objects move further away into the fog.

Light Direction Influence on Surface
The direction of light can have varying effects on a surface, like creating highlights or shading. We can simulate such behavior by manipulating properties with respect to the light direction.

// First, we need a parameter to adjust the impact of our light direction
var light_impact = VisualShaderNodeFloatParameter.new()
light_impact.parameter_name = "light_impact"
shader.add_node(VisualShader.TYPE_FRAGMENT, light_impact, Vector2(1800, 0))

// We'll also need the global light direction
var light_dir_node = VisualShaderNodeGlobalExpression.new()
light_dir_node.global_expression = "uniform vec3 light_direction;"
shader.add_node(VisualShader.TYPE_FRAGMENT, light_dir_node, Vector2(1900, 0))

// Using the light direction, we can adjust the color output to simulate lighting influence
var light_influence_calc = VisualShaderNodeExpression.new()
light_influence_calc.expression = "vec3 lightInfluence = max(dot(NORMAL, -light_direction), 0.0) * light_impact;"
shader.add_node(VisualShader.TYPE_FRAGMENT, light_influence_calc, Vector2(2000, 0))

This setup creates a basic representation of how the angle between the surface normal and the light direction affects the surface appearance, with the intensity of that effect controlled by `light_impact`.

Height-Based Color Gradients
Creating a terrain shader that changes color based on height is a useful technique for simulating different materials or ecosystem levels.

// Create two float parameters to determine the heights at which colors transition
var height_low = VisualShaderNodeFloatParameter.new()
height_low.parameter_name = "height_low"
shader.add_node(VisualShader.TYPE_FRAGMENT, height_low, Vector2(2100, 0))

var height_high = VisualShaderNodeFloatParameter.new()
height_high.parameter_name = "height_high"
shader.add_node(VisualShader.TYPE_FRAGMENT, height_high, Vector2(2100, 100))

// We'll use a UV2 node to get the second UV layer where our height map is stored
var uv2_node = VisualShaderNodeUV2.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, uv2_node, Vector2(2200, 0))

// Now, let's interpolate between two colors based on these heights using a step function
var height_color_interpolate = VisualShaderNodeExpression.new()
height_color_interpolate.expression = "vec3 colorLow = vec3(0.0, 1.0, 0.0);\\nvec3 colorHigh = vec3(1.0, 0.0, 0.0);\\nfloat heightFactor = step(height_low, UV2.y) * step(UV2.y, height_high);\\nvec3 final_color = mix(colorLow, colorHigh, heightFactor);"
shader.add_node(VisualShader.TYPE_FRAGMENT, height_color_interpolate, Vector2(2300, 0))

This code will determine two height levels marked by `height_low` and `height_high`, and the result will be a transition from a low-height green to a high-height red.

Dynamic Distortion Maps
Distortion effects, such as heat haze or water refraction, can be created by manipulating UVs with a distortion map. By controlling the intensity of this distortion dynamically, we can simulate the ebb and flow of heat or wavy water.

// Define a float parameter for distortion intensity
var distortion_intensity = VisualShaderNodeFloatParameter.new()
distortion_intensity.parameter_name = "distortion_intensity"
shader.add_node(VisualShader.TYPE_FRAGMENT, distortion_intensity, Vector2(2400, 0))

// Create a texture node for the distortion map
var distortion_map = VisualShaderNodeTexture.new()
shader.add_node(VisualShader.TYPE_FRAGMENT, distortion_map, Vector2(2500, 100))

// We'll adjust the UVs by adding the intensity-scaled distortion map to them
var distort_uv = VisualShaderNodeExpression.new()
distort_uv.expression = "vec2 distortion = texture(distortion_map, UV).rg * 2.0 - 1.0;\\ndistortion *= distortion_intensity;\\nvec2 distortedUV = UV + distortion;"
shader.add_node(VisualShader.TYPE_FRAGMENT, distort_uv, Vector2(2600, 0))

Here we add the vector obtained from the distortion map, which is then multiplied by the `distortion_intensity`, to the UV coordinates. The result is a UV map that animates and fluctuates based on this intensity, giving the final texture a moving and changing appearance.

These shader snippets not only demonstrate the versatility of VisualShaderNodeFloatParameter in Godot 4 but also illustrate how it can be an essential tool in a developer’s arsenal for crafting immersive and responsive game environments. By understanding and leveraging these examples, you can take your shaders to the next level, making your game aesthetically intriguing and technologically advanced.

Where to Go Next?

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Conclusion

In the dynamic world of game development, the VisualShaderNodeFloatParameter is a beacon of creativity, offering a path to dynamic and responsive visual effects in Godot 4. It is an essential skillset for both the novice and the veteran game developer. By wielding this versatile tool, you can unleash the full potential of your games, crafting visually stunning experiences that captivate your players. Join us at Zenva and unlock the door to mastering this and many other game development techniques, setting the stage for your success in the ever-evolving gaming landscape.

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