Lecture Notes: Creating 3D Planets in Godot

Overview

• Topic: Level design in Super Mario Galaxy and a tutorial for creating similar 3D planets in Godot.
• Key Mechanics: Walking around planets, gravitational attraction between planets, and character movement.

Mechanics Breakdown

1. Gravitational Attraction
2. Character Movement

Setting Up Planets

• Use Godot's powerful physics options.
• Essential nodes:
  • StaticBody: Walkable surface
  • Area: Handles gravitational attraction

Steps to Create a Planet

1. StaticBody Node
   • Add a spherical MeshInstance
   • Add a matching sphere CollisionShape
2. Area Node
   • Add a sphere CollisionShape larger than the planet for gravity
   • Enable gravity point
   • Set gravity_vec to (0, 0, 0)
   • Change space override to replace
   • Adjust gravity strength

Scene Setup

• Add two planets with overlapping gravity areas for inter-planet jumps.
• Position a camera to capture both planets.

Character Setup

• Use a RigidBody for the character to leverage Godot's physics.
• Add capsule CollisionShape and mesh for the character's body.
• Enable character mode to keep the character upright.
• Enable contact monitor and set contacts_reported to at least 1.

Player Controls and Orientation

1. Controls Relative to Character
2. Orientation to the Planet

• All movement handled in _integrate_forces()
• Calculate player’s input direction
• Use xform function to align character’s move direction
• Move character using add_force
• Align model with movement using Basis
• Calculate third vector with vector cross product
• Use spherical lerp for smooth turning

Implementing Jumping Mechanic

• Use contact monitoring to check if character is on the floor
• Loop through contact points and normals every frame
• Use dot product to compare angle of vectors
• If dot product > 0.5, assume character is on the floor
• Apply impulse in the opposite direction of gravity when jumping

Additional Information

• Promotion for Learn to Code from Zero, with Godot on Kickstarter.
• Free, open-source app in development to learn Godot’s GDScript in browser.
• Campaign details and deadline: until October 31.

Action Items

• Check out the Kickstarter campaign for early access and support the development of the learning platform.