val-blog/themes/dreamscape/assets/js/dreamscape.js

/* ═══════════════════════════════════════════════════════════════
   VAL'S DREAMSCAPE — 星空粒子 + 滚动动画
   ═══════════════════════════════════════════════════════════════ */

(function() {
    'use strict';

    // ═══ 星空粒子系统 ═══
    const canvas = document.getElementById('starfield');
    if (!canvas) return;
    const ctx = canvas.getContext('2d');
    let width, height, stars, nebulas;
    let animationId;

    function init() {
        resize();
        createStars();
        createNebulas();
        animate();
    }

    function resize() {
        width = canvas.width = window.innerWidth;
        height = canvas.height = window.innerHeight;
    }

    function createStars() {
        const count = Math.floor((width * height) / 8000);
        stars = [];
        for (let i = 0; i < count; i++) {
            stars.push({
                x: Math.random() * width,
                y: Math.random() * height,
                size: Math.random() * 1.5 + 0.5,
                speed: Math.random() * 0.3 + 0.1,
                opacity: Math.random() * 0.8 + 0.2,
                twinkle: Math.random() * Math.PI * 2,
                color: Math.random() > 0.7 ? 
                    `hsl(${220 + Math.random() * 60}, 70%, 80%)` : 
                    '#ffffff'
            });
        }
    }

    function createNebulas() {
        nebulas = [
            { x: width * 0.2, y: height * 0.3, r: 200, color: 'rgba(123,104,238,0.03)' },
            { x: width * 0.8, y: height * 0.7, r: 250, color: 'rgba(34,211,238,0.02)' },
            { x: width * 0.5, y: height * 0.5, r: 300, color: 'rgba(74,144,217,0.02)' }
        ];
    }

    function animate() {
        ctx.fillStyle = 'rgba(3,3,8,0.1)';
        ctx.fillRect(0, 0, width, height);

        // 绘制星云
        nebulas.forEach(n => {
            const gradient = ctx.createRadialGradient(n.x, n.y, 0, n.x, n.y, n.r);
            gradient.addColorStop(0, n.color);
            gradient.addColorStop(1, 'transparent');
            ctx.fillStyle = gradient;
            ctx.beginPath();
            ctx.arc(n.x, n.y, n.r, 0, Math.PI * 2);
            ctx.fill();
        });

        // 绘制星星
        stars.forEach(star => {
            star.twinkle += 0.02;
            const twinkleFactor = 0.5 + Math.sin(star.twinkle) * 0.5;
            const currentOpacity = star.opacity * twinkleFactor;

            ctx.beginPath();
            ctx.arc(star.x, star.y, star.size, 0, Math.PI * 2);
            ctx.fillStyle = star.color;
            ctx.globalAlpha = currentOpacity;
            ctx.fill();
            ctx.globalAlpha = 1;

            // 缓慢漂移
            star.y += star.speed;
            if (star.y > height + 10) {
                star.y = -10;
                star.x = Math.random() * width;
            }
        });

        animationId = requestAnimationFrame(animate);
    }

    // ═══ 滚动显示动画 ═══
    function setupReveal() {
        const reveals = document.querySelectorAll('.reveal');
        
        const observer = new IntersectionObserver((entries) => {
            entries.forEach(entry => {
                if (entry.isIntersecting) {
                    entry.target.classList.add('visible');
                }
            });
        }, {
            threshold: 0.1,
            rootMargin: '0px 0px -50px 0px'
        });

        reveals.forEach(el => observer.observe(el));
    }

    // ═══ 视差效果 ═══
    function setupParallax() {
        const hero = document.querySelector('.hero');
        if (!hero) return;

        window.addEventListener('scroll', () => {
            const scrollY = window.scrollY;
            const opacity = Math.max(0, 1 - scrollY / 600);
            hero.style.opacity = opacity;
            hero.style.transform = `translateY(${scrollY * 0.3}px)`;
        }, { passive: true });
    }

    // ═══ 鼠标光效 ═══
    function setupGlow() {
        const cards = document.querySelectorAll('.dream-card');
        cards.forEach(card => {
            card.addEventListener('mousemove', (e) => {
                const rect = card.getBoundingClientRect();
                const x = e.clientX - rect.left;
                const y = e.clientY - rect.top;
                card.style.setProperty('--mouse-x', `${x}px`);
                card.style.setProperty('--mouse-y', `${y}px`);
            });
        });
    }

    // ═══ 场景滚动进度 + 旅程节点高亮 ═══
    function setupStoryJourney() {
        const body = document.getElementById('storyBody');
        const progress = document.getElementById('storyProgress');
        if (!body || !progress) return;

        const scenes = Array.from(body.querySelectorAll(':scope > p'));
        if (!scenes.length) return;

        const onScroll = () => {
            const rect = body.getBoundingClientRect();
            const total = Math.max(body.scrollHeight - window.innerHeight, 1);
            const scrolled = Math.min(Math.max(-rect.top, 0), total);
            const ratio = scrolled / total;
            progress.style.width = `${(ratio * 100).toFixed(2)}%`;

            let activeIndex = 0;
            let minDistance = Infinity;
            scenes.forEach((p, idx) => {
                const r = p.getBoundingClientRect();
                const d = Math.abs(r.top - window.innerHeight * 0.35);
                if (d < minDistance) {
                    minDistance = d;
                    activeIndex = idx;
                }
            });
            scenes.forEach((p, idx) => p.classList.toggle('active-scene', idx === activeIndex));
        };

        window.addEventListener('scroll', onScroll, { passive: true });
        onScroll();
    }

    // ═══ 漂浮光团轻微视差 ═══
    function setupOrbsParallax() {
        const orbs = document.querySelectorAll('.story-orb');
        if (!orbs.length) return;

        window.addEventListener('scroll', () => {
            const y = window.scrollY;
            orbs.forEach((orb, i) => {
                const factor = (i + 1) * 0.04;
                const xShift = Math.sin(y * 0.002 + i) * 10;
                const yShift = y * factor;
                orb.style.transform = `translate(${xShift}px, ${yShift}px)`;
            });
        }, { passive: true });
    }

    // ═══ 初始化 ═══
    window.addEventListener('resize', () => {
        resize();
        createStars();
        createNebulas();
    });

    document.addEventListener('DOMContentLoaded', () => {
        document.body.classList.add('js-ready');
        init();
        setupReveal();
        setupParallax();
        setupGlow();
        setupStoryJourney();
        setupOrbsParallax();
    });

})();