Using Mixamo Animations with JSON Configuration in Three.js

Based on your image and requirements, I can provide guidance on setting up Mixamo animations through a JSON configuration in Three.js.

Basic Implementation Approach

To implement a system where animations are defined in JSON and then loaded into your Three.js scene, you'll need to:

1. Create a JSON structure to define your animations
2. Load the model and animation files
3. Set up an animation system using Three.js animation classes
4. Parse your JSON configuration to apply the animations

Key Components

From the Three.js animation system, you'll need to use:

• AnimationLoader - to load animation files
• AnimationClip - to store animation data
• AnimationMixer - to play animations on your model
• AnimationAction - to control individual animations

Example Implementation

Here's how you might structure your code:

JAVASCRIPTCopied
// 1. Define your JSON configuration (similar to what's shown in your image)
const animationsConfig = {
  "idle": {
    "url": "animations/idle.fbx",
    "options": {
      "loop": true,
      "timeScale": 1.0
    }
  },
  "walk": {
    "url": "animations/walk.fbx",
    "options": {
      "loop": true,
      "timeScale": 1.2
    }
  },
  "run": {
    "url": "animations/run.fbx",
    "options": {
      "loop": true,
      "timeScale": 1.5
    }
  }
};

// 2. Create a class to manage animations
class AnimationController {
  constructor(model) {
    this.model = model;
    this.mixer = new THREE.AnimationMixer(model);
    this.animations = {};
    this.currentAction = null;
  }

  // Load animations based on JSON config
  loadAnimations(config) {
    const loader = new THREE.AnimationLoader();
    
    Object.entries(config).forEach(([name, details]) => {
      loader.load(
        details.url,
        (animationData) => {
          // For FBX files, you might need to use FBXLoader instead
          // and extract the animations from the loaded model
          const clip = animationData[0]; // Assuming animationData is an array of AnimationClips
          
          // Create an action from the clip
          const action = this.mixer.clipAction(clip);
          
          // Apply options from config
          if (details.options) {
            if (details.options.loop !== undefined) {
              action.loop = details.options.loop ? THREE.LoopRepeat : THREE.LoopOnce;
            }
            if (details.options.timeScale !== undefined) {
              action.timeScale = details.options.timeScale;
            }
          }
          
          this.animations[name] = action;
        },
        (xhr) => {
          console.log(`${name} animation: ${(xhr.loaded / xhr.total * 100)}% loaded`);
        },
        (error) => {
          console.error(`Error loading animation ${name}:`, error);
        }
      );
    });
  }

  // Play a specific animation
  play(name, crossFadeDuration = 0.5) {
    if (!this.animations[name]) {
      console.warn(`Animation "${name}" not found`);
      return;
    }

    const action = this.animations[name];
    
    if (this.currentAction && this.currentAction !== action) {
      this.currentAction.crossFadeTo(action, crossFadeDuration, true);
    }
    
    action.play();
    this.currentAction = action;
  }

  // Update the mixer in your animation loop
  update(deltaTime) {
    if (this.mixer) {
      this.mixer.update(deltaTime);
    }
  }
}

// 3. Usage in your Three.js application
let model, animationController;

// Load your character model first
const fbxLoader = new THREE.FBXLoader();
fbxLoader.load('models/character.fbx', (loadedModel) => {
  model = loadedModel;
  scene.add(model);
  
  // Initialize animation controller with the loaded model
  animationController = new AnimationController(model);
  
  // Load animations from your JSON config
  animationController.loadAnimations(animationsConfig);
  
  // After a short delay to ensure animations are loaded
  setTimeout(() => {
    // Play the idle animation by default
    animationController.play('idle');
  }, 1000);
});

// In your animation loop
function animate() {
  requestAnimationFrame(animate);
  
  const deltaTime = clock.getDelta();
  
  if (animationController) {
    animationController.update(deltaTime);
  }
  
  renderer.render(scene, camera);
}

Notes for Mixamo Animations

1. Mixamo animations typically come as FBX files, so you'll need to use FBXLoader rather than AnimationLoader
2. You may need to adjust the scale and rotation of your model
3. For better organization, consider storing your animations in a separate folder structure

This implementation provides a foundation that you can expand upon based on your specific requirements. The JSON configuration allows you to easily add, remove, or modify animations without changing your core code.