RID in Godot – Complete Guide

Diving into the world of game development can be thrilling, especially when you begin to unfold the layers of mechanics that shape the experiences we enjoy. One such foundational aspect is the handling of resources, ensuring that the tools and assets within our creations are managed efficiently and effectively. Today, we will explore the realm of RIDs in Godot 4, a recent update to the already powerful and versatile game engine that so many developers have come to love. So, saddle up as we demystify RIDs and their usage within Godot, making something seemingly complex quite approachable and extremely invaluable.

What Is an RID?

An RID, or Resource ID, is essentially a unique identifier for low-level resources in the Godot game engine. These resources range from textures to meshes, and the RID is the way Godot keeps track of them. However, unlike high-level resource handling you might be more familiar with, RIDs represent a more opaque method of interaction, meaning they don’t provide direct access to the resource itself.

What Is It For?

RID is crucial in Godot’s architecture, primarily when working with the server classes like DisplayServer and RenderingServer. This level of interaction is often required when dealing with custom rendering processes or when it’s essential to optimize the game’s performance by directly managing the resources at a low level. It’s the backbone of resource management and ensures that Godot’s performance is both stable and fast.

Why Should I Learn It?

Mastering RIDs in Godot can elevate your game development skills to new heights, providing you with the power to take control of your game’s resources like never before. They may allow for optimizations that are not possible with high-level Resource classes. Whether you’re interested in the fine-tuning of performance or seeking deeper knowledge of how Godot operates under the hood, understanding RIDs will be a valuable asset in your game development toolkit. Let’s embark on this journey to exploit the full potential of Godot 4’s resource management system.

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Creating and Referencing Resources with RIDs

In this section, we will begin by learning how to create an RID and reference a resource using it. Creating an RID in Godot 4 is straightforward. Let’s start by creating a simple texture RID:

var texture_rid = RenderingServer.texture_create()

After we have the RID for the texture, we assign an image to it:

var image = Image.new()
image.load("res://path_to_your_image.png")
RenderingServer.texture_set_data(texture_rid, image)

It’s important to remember that when you want to manipulate the resource, you use the RID you’ve created to reference it:

RenderingServer.texture_set_flags(texture_rid, RenderingServer.TEXTURE_FLAG_REPEAT)

This snippet sets the texture to repeat, which is a common flag used in texture mapping for games.

Using RIDs with Materials and Meshes

Next, let’s look at how we can use RIDs with materials and meshes. Initially, you’ll need to create an RID for a Shader material:

var shader_material_rid = RenderingServer.shader_material_create()

Once we have this RID, we can set a shader to it:

var shader_code = """
shader_type spatial;
void fragment() {
    ALBEDO = vec3(1, 0, 0); // Red color
}
"""
var shader_rid = RenderingServer.shader_create()
RenderingServer.shader_set_code(shader_rid, shader_code)
RenderingServer.material_set_shader(shader_material_rid, shader_rid)

This example shows simple shader code that colors our material red. Now let’s look at how to use this material with a mesh:

var mesh_rid = RenderingServer.mesh_create()

# Assuming we have a mesh instance
var mesh_instance_rid = RenderingServer.instance_create()
RenderingServer.instance_set_base(mesh_instance_rid, mesh_rid)
RenderingServer.instance_set_surface_material(mesh_instance_rid, 0, shader_material_rid)

The `instance_set_surface_material` function associates the shader material we created with the mesh instance. Note that `0` is the material’s surface index.

Advanced Resource Modification with RIDs

Another great strength of using RIDs is the ability to modify resources on-the-fly. Here’s how you can modify texture properties:

# Modify texture properties
var texture_flags = RenderingServer.TEXTURE_FLAG_ANISOTROPIC_FILTER | RenderingServer.TEXTURE_FLAG_MIPMAPS
RenderingServer.texture_set_flags(texture_rid, texture_flags)
RenderingServer.texture_set_path(texture_rid, "res://new_texture_path.png")

In the above code, we are combining different texture flags and setting a new path for the texture associated with our texture RID.

Let’s explore modifying the shader we created before:

var new_shader_code = """
shader_type spatial;
void fragment() {
    ALBEDO = vec3(0, 1, 0); // Green color
}
"""
RenderingServer.shader_set_code(shader_rid, new_shader_code)

By replacing the shader code, we’re effectively changing the material color to green. This operation demonstrates the dynamic nature of using RIDs for resource management without needing to create a new material entirely.

Understand that using RIDs is powerful for optimizing and controlling resources directly. This is just the beginning; as you gain proficiency, you can manipulate and optimize more complex aspects of your game by utilizing the raw power of RIDs.As we delve further into the capabilities of RIDs, you’ll find they open up the opportunity to manipulate different types of resources dynamically during runtime. Let’s look at more examples:

To handle the visibility of an instance, you might toggle it on or off like this:

RenderingServer.instance_set_visible(mesh_instance_rid, false) # Set to 'true' to make visible

Imagine you want to change the texture of multiple objects that share the same material. Instead of setting textures one by one, you can modify the RID directly:

var new_image = Image.new()
new_image.load("res://path_to_new_image.png")
RenderingServer.texture_set_data(texture_rid, new_image)

All instances that use the texture associated with `texture_rid` will automatically display the new texture.

Next, let’s manipulate vertex data in a 3D mesh directly via RID:

var array_mesh = ArrayMesh.new()
var vertices = PoolVector3Array([Vector3(0,0,0), Vector3(0,1,0), Vector3(1,1,0)])
array_mesh.add_surface_from_arrays(Mesh.PRIMITIVE_TRIANGLES, [vertices])
var mesh_rid = RenderingServer.mesh_create_from_surface(array_mesh, 0)

Creating surfaces from arrays is often used for procedural geometry, and here we use a RID to interact with the underlying mesh data.

If you’re developing a 2D game and wish to perform operations on a `CanvasItem`, like a `Sprite`, you would do so like this:

var sprite_rid = RenderingServer.canvas_item_create() 
var transform = Transform2D(0, Vector2(100, 100)) # Move sprite 100 pixels right and down
RenderingServer.canvas_item_set_transform(sprite_rid, transform)

Transforming canvas items is essential for controlling position, rotation, and scale in your 2D environment.

It’s possible you’ll want to adjust the environment settings for a 3D scene dynamically – altering the sky could be quite impactful:

var sky_rid = RenderingServer.sky_create()
var sky_image = Image.new()
sky_image.load("res://path_to_sky_image.hdr")
var texture_rid = RenderingServer.texture_create_from_image(sky_image)
RenderingServer.sky_set_texture(sky_rid, texture_rid)
RenderingServer.environment_set_sky(environment_rid, sky_rid)

By altering the sky texture with RIDs, you immediately affect the lighting and atmosphere of your 3D world.

Lastly, if you need to optimize a game with a high number of similar resources like particles:

var particles_material_rid = RenderingServer.material_create()
RenderingServer.material_set_shader(particles_material_rid, shader_rid)
for i in range(100):
    var particles_instance_rid = RenderingServer.instance_create()
    RenderingServer.instance_set_base(particles_instance_rid, particles_material_rid)

Notice how we use a loop to create a hundred instances of a particle with the same shader material. This method reduces the overhead of individual material assignments.

These examples highlight the versatility of RIDs in handling various game development scenarios. They provide an efficient way to directly manipulate the low-level resources, giving developers the leverage to optimize and enhance gameplay or visuals of their projects in detail. Remember, with great power comes the necessity for responsible management; misuse of RIDs can lead to difficult-to-debug issues. However, with practice, you’ll harness their potential and optimize your Godot games for peak performance and visual fidelity.As we progress, let’s delve into the interaction between script and rendering at runtime using RIDs. This can be particularly useful for tasks like custom rendering processes or when you’re implementing advanced graphical effects.

If you’re working with lights in a 3D scene, managing them with RIDs can be very powerful. You can create a light, set its parameters, and then add it to an instance:

var light_rid = RenderingServer.directional_light_create()
RenderingServer.light_set_color(light_rid, Color(1, 0.9, 0.8)) # A warm light color
RenderingServer.light_set_param(light_rid, RenderingServer.LIGHT_PARAM_ENERGY, 0.8) 
RenderingServer.instance_add_dependency(mesh_instance_rid, light_rid)

In this example, we’re creating a directional light resource, changing its color and energy, and then associating it with a mesh instance to influence how it’s shown.

Let’s consider a scenario where you’d like to update the viewport’s properties dynamically:

var viewport_rid = RenderingServer.viewport_create()
RenderingServer.viewport_set_size(viewport_rid, 1280, 720)
RenderingServer.viewport_set_active(viewport_rid, true)

This snippet configures a new viewport, which can be beneficial if you’re rendering scenes to textures or creating in-game cameras that have different properties from the default viewport.

For instance, if you want to generate reflection probes dynamically in a 3D scene, here’s how it’s done with RIDs:

var reflection_probe_rid = RenderingServer.reflection_probe_create()
RenderingServer.reflection_probe_set_update_mode(reflection_probe_rid, RenderingServer.REFLECTION_PROBE_UPDATE_ALWAYS)
RenderingServer.instance_add_reflection_probe(mesh_instance_rid, reflection_probe_rid)

Reflection probes contribute to realistic environmental reflections. Managing them via RIDs can help you tailor reflectivity dynamically based on gameplay elements.

Considering skeletal animation, here’s how you can create skeletons and use them with mesh instances:

var skeleton_rid = RenderingServer.skeleton_create()
RenderingServer.skeleton_allocate(skeleton_rid, 20) # For 20 bones
RenderingServer.instance_attach_skeleton(mesh_instance_rid, skeleton_rid)

Allocating and attaching a skeleton to mesh instances allows for animation control at a granular level, ideal for dynamic character animations.

For advanced texture manipulation, such as creating a procedural texture at runtime, consider the following:

var procedural_texture_rid = RenderingServer.texture_create()
var procedural_image = Image.new()
procedural_image.create(512, 512, false, Image.FORMAT_RGBA8)
procedural_image.fill(Color(1, 0, 0, 1)) # Fill with red
RenderingServer.texture_set_data(procedural_texture_rid, procedural_image)

By creating textures in this way, you can introduce a range of visual effects, from dynamic damage marks to evolving environmental details, all based on in-game conditions.

For developers interested in custom shaders, here’s how you can get information out of your shaders using RIDs:

var my_shader_rid = RenderingServer.shader_create()
var uniform_name = "time"
var time_val = RenderingServer.shader_get_param(my_shader_rid, uniform_name)
print("Shader time uniform value: ", time_val)

This script fetches the value of the “time” uniform from a shader. This might not seem useful at first glance, but reading shader parameters allows you to create interactive debugging tools or interfaces that react to real-time changes in your shaders.

Lastly, RIDs are particularly useful when dealing with multiple canvas layers in 2D:

var new_canvas_layer_rid = RenderingServer.canvas_layer_create()
RenderingServer.canvas_item_set_parent(sprite_rid, new_canvas_layer_rid)
RenderingServer.canvas_layer_set_transform(new_canvas_layer_rid, Transform2D(1.0, Vector2(50, 50)))

If you are layering UI elements or need to control the rendering order of various elements, RIDs can give you precise control over each canvas layer’s transformation and properties.

Through these examples, we’ve covered a wide breadth of possibilities when using RIDs in Godot 4. From dynamically managing lights to creating reflective surfaces, the control over game resources that RIDs facilitate is enormous. These are powerful tools in the hands of a skilled developer, allowing fine-tuned optimizations and dynamic content creation that can make your game stand out.
At Zenva, we strive to provide you with comprehensive learning experiences. If you’ve found this journey through RIDs in Godot insightful, explore more with our courses and tutorials tailored to help you master the complexities and nuances of game development. We are passionate about empowering you to transform your creative visions into reality.

Where to Go Next with Your Godot Learning Journey

Navigating the world of game development can be exhilarating and with the foundations of RIDs in Godot 4 under your belt, your journey into game creation is just heating up. We at Zenva understand the thrill of expanding your skills, which is why we encourage you to continue forging your path in game development with our Godot Game Development Mini-Degree. This comprehensive program dives into creating both 2D and 3D games using the innovative and community-loved Godot 4 engine, covering essential topics such as GDScript, gameplay control flow, and various game mechanics to sharpen your development prowess.
Whether you are at the beginning of your game development journey or looking to level up your existing skills, the range of courses we offer can accommodate your learning curve. With a curriculum tailored to incorporate practical projects, our aim is to equip you with in-demand, marketable skills that will help you succeed in the game development industry. For a broader exploration, you can also check out our extensive collection of Godot courses that cater to a wide array of topics and proficiency levels. Embrace the flexibility of our courses and embark on your quest to become a professional game developer with Zenva.
Remember, the best way to solidify your understanding is by applying what you’ve learned in real projects and scenarios. The practical, project-based approach of our Mini-Degree ensures you build a portfolio as you learn, paving the way for a rewarding future in game development. So why wait? Continue your education with us, and turn your game development dreams into reality.

Conclusion

Your journey through the intricacies of RIDs in Godot reveals the vast potential that lies in mastering game engine mechanics. Now, with these insights and a curiosity to delve deeper, your path as a game developer is poised for remarkable growth. Embrace the challenge, let creativity be your guide, and watch as your virtual worlds come to life with the power of Godot 4 at your fingertips.
At Zenva, we’re here to support every step of your learning adventure. Expand your skills and continue to push the boundaries of what you can create by joining our Godot Game Development Mini-Degree. With a plethora of courses and projects waiting for you, the next chapter of your game development story is just a click away. Let us be the wind in your sails as you navigate the thrilling seas of game creation!
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