Function createFractalTree

geometry.js:364–475

(i, count)

}

function createFractalTree(i, count) {
    // Fractal Tree parameters
    const trunkLength = 35;        // Initial trunk length
    const branchRatio = 0.67;      // Each branch is this ratio of parent length
    const maxDepth = 6;            // Maximum branching depth
    const branchAngle = Math.PI / 5; // Angle between branches (36 degrees)
    
    // Pre-calculate the total particles needed per depth level
    // Distribute particles more towards deeper levels
    const particlesPerLevel = [];
    let totalWeight = 0;
    
    for (let depth = 0; depth <= maxDepth; depth++) {
        // More branches at deeper levels, distribute particles accordingly
        // Each level has 2^depth branches
        const branches = Math.pow(2, depth);
        const weight = branches * Math.pow(branchRatio, depth);
        totalWeight += weight;
        particlesPerLevel.push(weight);
    }
    
    // Normalize to get actual count per level
    let cumulativeCount = 0;
    const particleCount = [];
    
    for (let depth = 0; depth <= maxDepth; depth++) {
        const levelCount = Math.floor((particlesPerLevel[depth] / totalWeight) * count);
        particleCount.push(levelCount);
        cumulativeCount += levelCount;
    }
    
    // Adjust the last level to ensure we use exactly count particles
    particleCount[maxDepth] += (count - cumulativeCount);
    
    // Determine which depth level this particle belongs to
    let depth = 0;
    let levelStartIndex = 0;
    
    while (depth < maxDepth && i >= levelStartIndex + particleCount[depth]) {
        levelStartIndex += particleCount[depth];
        depth++;
    }
    
    // Calculate the relative index within this depth level
    const indexInLevel = i - levelStartIndex;
    const levelCount = particleCount[depth];
    
    // Calculate position parameters
    const t = indexInLevel / (levelCount || 1); // Normalized position in level
    
    // For the trunk (depth 0)
    if (depth === 0) {
        // Simple line for the trunk
        return new THREE.Vector3(
            (Math.random() * 2 - 1) * 0.5, // Small random spread for thickness
            -trunkLength / 2 + t * trunkLength,
            (Math.random() * 2 - 1) * 0.5  // Small random spread for thickness
        );