Creating an Engaging 3D Minimap in Godot with C#
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Chapter 1: Introduction to the 3D Minimap
In this tutorial, we will explore how to capture our scene from two different perspectives simultaneously, providing players with both a top-down and an abstract view of the level.
Navigating through a foreign digital environment can sometimes confuse players. To combat this, many games incorporate a minimap that offers a bird’s-eye view, aiding players in comprehending the layout of their surroundings. In this guide, we will learn how to create such a minimap within Godot.
By the conclusion of this tutorial, you will be equipped with the knowledge to utilize a secondary Camera3D node within a 3D scene to capture the level from a unique angle. We will also leverage Godot's viewport capabilities to display this camera's view on the screen in a designated area.
This tutorial builds on the dungeon-like level created in a previous episode, where we discussed attaching a 3D camera to our protagonist in an RPG-style setup without encountering wall clipping or collisions.
Ensure you are using a version of Godot that has .NET capabilities enabled. Download a suitable version to get started with C#! Additionally, all demo scenes and assets for this example can be found on my GitHub, alongside other Godot tutorials. The spaceship and icon assets are sourced from Kenney’s library.
For those interested in 2D tools for future Godot 4/C# projects, I recommend checking out my new concise ebook: "L'Almanach: Mini-2D Platformer!" This guide teaches essential concepts for creating 2D games in Godot, including tilemaps, 2D physics, animations, character controllers, and more. You will even construct your own 2D platformer step-by-step.
With that said, let’s dive into setting up a basic third-person camera using Godot and C#!
Section 1.1: Utilizing Multiple Cameras
To start, we need to understand how to employ multiple cameras in a Godot scene. By stacking multiple camera renders on the same screen, we can maintain a player-focused view while also displaying a top view for our minimap.
However, simply adding a second Camera3D node and directing it downwards in orthographic mode will not suffice, as the minimap won't display when the game is run. This is because we cannot automatically render multiple cameras on the screen by just adding them to the hierarchy. Instead, we must utilize Godot's viewports.
A viewport essentially serves as a screen for rendering. By default, a Godot scene contains a root viewport for the active camera. Typically, our player-focused camera is the active one, rendering to the root viewport, which occupies the entire screen.
To enable dual rendering, we can create a SubViewport node in our hierarchy for our minimap camera. This allows us to render the minimap camera simultaneously with the main camera.
Note: Remember, only one active camera can exist per viewport, and it will always render to the closest viewport in the hierarchy.
Next, we need to wrap our SubViewport in a SubViewportContainer UI node to display its content on the screen. We can position this container in the bottom-right corner and enable the Stretch option for automatic resizing. After adjusting the dimensions, we will see our top-down minimap camera rendering in real-time as the game progresses.
The first video titled "Setting up a 3D minimap [Godot 4/C# Tutorial]" walks you through the process of implementing a 3D minimap in Godot, enhancing your game's navigation features.
Section 1.2: Keeping the Minimap Centered on the Player
Given that our demo focuses on an RPG-style character, it would be advantageous for the minimap to consistently track the player. However, since our minimap camera is in a different viewport, we cannot simply parent it to the player node.
Instead, we will create a C# script for the minimap camera named MinimapCamera.cs and export a reference to a Node3D as the target:
using Godot;
public partial class MinimapCamera : Camera3D {
[Export] private Node3D _target = null;
}
After rebuilding the project, we can assign our player node to this reference slot. In the _Ready function of our script, we will calculate the current offset between the minimap camera and its target. This will allow us to maintain this offset as we track the player:
using Godot;
public partial class MinimapCamera : Camera3D {
[Export] private Node3D _target = null;
private Vector3 _offset;
public override void _Ready() {
if (_target == null) {
GD.PrintErr("No target assigned for the minimap camera");
return;
}
_offset = GlobalPosition - _target.GlobalPosition;
}
}
Next, we will update the camera's position in the _Process method to follow the player:
public override void _Process(double delta) {
GlobalPosition = _target.GlobalPosition + _offset;
}
With this setup, the minimap will now consistently follow the player avatar.
Chapter 2: Enhancing the Minimap's Visual Appeal
To make the minimap more visually appealing, we can place everything within a MarginContainer that stretches across the screen, allowing us to add some padding in the bottom-right corner.
Next, we can employ a PanelContainer to customize the minimap further. By adjusting the Container Sizing options, we can resize it to fit the corner. In the Theme Overrides section, we can create a flat style, increase content margins for a border, change the background color, and adjust shadow options for better contrast.
Now that we have improved its appearance, you might be curious about simplifying the minimap's representation.
Section 2.1: Utilizing Visibility Layers and Culling
To allow our main camera and minimap camera to render different asset versions, we can utilize visibility layers and culling masks. This method enables us to instruct Godot's camera to render specific objects based on matching culling masks and visibility layers.
For instance, we can create a Sprite3D in the player hierarchy with a simple circle texture and assign it to the second visibility layer. Then, we’ll ensure our main camera’s culling mask excludes this layer, while the minimap camera renders only the second layer.
When we run the game, the minimap will now display just our player as a small dot. By applying similar techniques to other assets, we can achieve a minimalist visual representation on the minimap.
Note: To ensure certain visuals appear in front of others, position them higher on the vertical Y-axis, as higher elements will be rendered closer to the minimap camera.
The second video titled "How I built an advanced 3D Mini Map system in UE" provides insights into advanced techniques for creating effective minimaps in game development.
Conclusion
Congratulations! You now know how to establish a basic minimap system for a 3D scene using Godot's viewport tools, implement player-following functionality, and customize the minimap's visuals through visibility layers and culling.
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