인프런 커뮤니티 질문&답변

두번째 스크롤비디오 처리 강의에서 잡아주시네요

감사합니다!

stickt-elme 오타는 sticky-elem로 수정 했습니다

(() => {
    let yOffset = 0; // window.pageYOffset 대신 사용할 변수
    let prevScrollHeight = 0; // 현재 스크롤 위치(yOffset)보다 이전에 위치한 스크롤 섹션들의 스크롤 높이값의 합
    let currentScene = 0; // 현재 활성화된(뷰포트) 씬(scroll-section)
    let enterNewScene = false; // 새로운 씬이 시작되는 순간 true

    const sceneInfo = [{
            // 0
            type: 'sticky',
            heightNum: 5, // 브라우저 높이의 5배로 scrollHeight 세팅
            scrollHeight: 0,
            objs: {
                container: document.querySelector('#scroll-section-0'),
                messageA: document.querySelector('#scroll-section-0 .main-message.a'),
                messageB: document.querySelector('#scroll-section-0 .main-message.b'),
                messageC: document.querySelector('#scroll-section-0 .main-message.c'),
                messageD: document.querySelector('#scroll-section-0 .main-message.d')
            },
            values: {
                messageA_opacity_in: [0, 1, { start: 0.1, end: 0.2 }],
                messageB_opacity_in: [0, 1, { start: 0.3, end: 0.4 }],
                messageC_opacity_in: [0, 1, { start: 0.5, end: 0.6 }],
                messageD_opacity_in: [0, 1, { start: 0.7, end: 0.8 }],
                messageA_translateY_in: [20, 0, { start: 0.1, end: 0.2 }],
                messageB_translateY_in: [20, 0, { start: 0.3, end: 0.4 }],
                messageC_translateY_in: [20, 0, { start: 0.5, end: 0.6 }],
                messageD_translateY_in: [20, 0, { start: 0.7, end: 0.8 }],
                messageA_opacity_out: [1, 0, { start: 0.25, end: 0.3 }],
                messageB_opacity_out: [1, 0, { start: 0.45, end: 0.5 }],
                messageC_opacity_out: [1, 0, { start: 0.65, end: 0.7 }],
                messageD_opacity_out: [1, 0, { start: 0.85, end: 0.9 }],
                messageA_translateY_out: [0, -20, { start: 0.25, end: 0.3 }],
                messageB_translateY_out: [0, -20, { start: 0.45, end: 0.5 }],
                messageC_translateY_out: [0, -20, { start: 0.65, end: 0.7 }],
                messageD_translateY_out: [0, -20, { start: 0.85, end: 0.9 }]
            }
        },
        {
            // 1
            type: 'normal',
            // heightNum: 5, // type normal에서는 필요 없음
            scrollHeight: 0,
            objs: {
                container: document.querySelector('#scroll-section-1')
            }
        },
        {
            // 2
            type: 'sticky',
            heightNum: 5,
            scrollHeight: 0,
            objs: {
                container: document.querySelector('#scroll-section-2'),
                messageA: document.querySelector('#scroll-section-2 .a'),
                messageB: document.querySelector('#scroll-section-2 .b'),
                messageC: document.querySelector('#scroll-section-2 .c'),
                pinB: document.querySelector('#scroll-section-2 .b .pin'),
                pinC: document.querySelector('#scroll-section-2 .c .pin')
            },
            values: {
                messageA_translateY_in: [20, 0, { start: 0.15, end: 0.2 }],
                messageB_translateY_in: [30, 0, { start: 0.6, end: 0.65 }],
                messageC_translateY_in: [30, 0, { start: 0.87, end: 0.92 }],
                messageA_opacity_in: [0, 1, { start: 0.25, end: 0.3 }],
                messageB_opacity_in: [0, 1, { start: 0.6, end: 0.65 }],
                messageC_opacity_in: [0, 1, { start: 0.87, end: 0.92 }],
                messageA_translateY_out: [0, -20, { start: 0.4, end: 0.45 }],
                messageB_translateY_out: [0, -20, { start: 0.68, end: 0.73 }],
                messageC_translateY_out: [0, -20, { start: 0.95, end: 1 }],
                messageA_opacity_out: [1, 0, { start: 0.4, end: 0.45 }],
                messageB_opacity_out: [1, 0, { start: 0.68, end: 0.73 }],
                messageC_opacity_out: [1, 0, { start: 0.95, end: 1 }],
                pinB_scaleY: [0.5, 1, { start: 0.6, end: 0.65 }],
                pinC_scaleY: [0.5, 1, { start: 0.87, end: 0.92 }]
            }
        },
        {
            // 3
            type: 'sticky',
            heightNum: 5,
            scrollHeight: 0,
            objs: {
                container: document.querySelector('#scroll-section-3'),
                canvasCaption: document.querySelector('.canvas-caption')
            },
            values: {

            }
        }
    ];


    function setLayout() {
        // 각 스크롤 섹션의 높이 세팅
        for (let i = 0; i < sceneInfo.length; i++) {
            if (sceneInfo[i].type === 'sticky') {
                sceneInfo[i].scrollHeight = sceneInfo[i].heightNum * window.innerHeight;
            } else if (sceneInfo[i].type === 'normal') {
                sceneInfo[i].scrollHeight = sceneInfo[i].objs.container.offsetHeight;
            }
            sceneInfo[i].objs.container.style.height = `${sceneInfo[i].scrollHeight}px`;
        }

        // 새로고침 이슈 방지
        yOffset = window.pageYOffset;
        let totalScrollHeight = 0;
        for (let i = 0; i < sceneInfo.length; i++) {
            totalScrollHeight += sceneInfo[i].scrollHeight;
            if (totalScrollHeight >= yOffset) {
                currentScene = i;
                break;
            }
        }
        document.body.setAttribute("id", `show-scene-${currentScene}`);
    }

    function calcValues(values, currentYOffset) {
        let rv;
        // 현재 씬(스크롤섹션)에서 스크롤된 범위를 비율로 구하기
        const scrollHeight = sceneInfo[currentScene].scrollHeight;
        const scrollRatio = currentYOffset / scrollHeight;

        if (values.length === 3) {
            // start ~ end 사이에 애니메이션 실행
            const partScrollStart = values[2].start * scrollHeight;
            const partScrollEnd = values[2].end * scrollHeight;
            const partScrollHeight = partScrollEnd - partScrollStart;

            if (currentYOffset >= partScrollStart && currentYOffset <= partScrollEnd) {
                rv = (currentYOffset - partScrollStart) / partScrollHeight * (values[1] - values[0]) + values[0];
            } else if (currentYOffset < partScrollStart) {
                rv = values[0];
            } else if (currentYOffset > partScrollEnd) {
                rv = values[1];
            }
        } else {
            rv = scrollRatio * (values[1] - values[0]) + values[0];
        }

        return rv;
    }

    function playAnimation() {
        const objs = sceneInfo[currentScene].objs;
        const values = sceneInfo[currentScene].values;
        const currentYOffset = yOffset - prevScrollHeight;
        const scrollHeight = sceneInfo[currentScene].scrollHeight;
        const scrollRatio = currentYOffset / scrollHeight;

        switch (currentScene) {
            case 0:
                // console.log('0 play');
                if (scrollRatio <= 0.22) {
                    // in
                    objs.messageA.style.opacity = calcValues(values.messageA_opacity_in, currentYOffset);
                    objs.messageA.style.transform = `translate3d(0, ${calcValues(values.messageA_translateY_in, currentYOffset)}%, 0)`;
                } else {
                    // out
                    objs.messageA.style.opacity = calcValues(values.messageA_opacity_out, currentYOffset);
                    objs.messageA.style.transform = `translate3d(0, ${calcValues(values.messageA_translateY_out, currentYOffset)}%, 0)`;
                }

                if (scrollRatio <= 0.42) {
                    // in
                    objs.messageB.style.opacity = calcValues(values.messageB_opacity_in, currentYOffset);
                    objs.messageB.style.transform = `translate3d(0, ${calcValues(values.messageB_translateY_in, currentYOffset)}%, 0)`;
                } else {
                    // out
                    objs.messageB.style.opacity = calcValues(values.messageB_opacity_out, currentYOffset);
                    objs.messageB.style.transform = `translate3d(0, ${calcValues(values.messageB_translateY_out, currentYOffset)}%, 0)`;
                }

                if (scrollRatio <= 0.62) {
                    // in
                    objs.messageC.style.opacity = calcValues(values.messageC_opacity_in, currentYOffset);
                    objs.messageC.style.transform = `translate3d(0, ${calcValues(values.messageC_translateY_in, currentYOffset)}%, 0)`;
                } else {
                    // out
                    objs.messageC.style.opacity = calcValues(values.messageC_opacity_out, currentYOffset);
                    objs.messageC.style.transform = `translate3d(0, ${calcValues(values.messageC_translateY_out, currentYOffset)}%, 0)`;
                }

                if (scrollRatio <= 0.82) {
                    // in
                    objs.messageD.style.opacity = calcValues(values.messageD_opacity_in, currentYOffset);
                    objs.messageD.style.transform = `translate3d(0, ${calcValues(values.messageD_translateY_in, currentYOffset)}%, 0)`;
                } else {
                    // out
                    objs.messageD.style.opacity = calcValues(values.messageD_opacity_out, currentYOffset);
                    objs.messageD.style.transform = `translate3d(0, ${calcValues(values.messageD_translateY_out, currentYOffset)}%, 0)`;
                }

                break;

            case 2:
                // console.log('2 play');
                if (scrollRatio <= 0.32) {
                    // in
                    objs.messageA.style.opacity = calcValues(values.messageA_opacity_in, currentYOffset);
                    objs.messageA.style.transform = `translate3d(0, ${calcValues(values.messageA_translateY_in, currentYOffset)}%, 0)`;
                } else {
                    // out
                    objs.messageA.style.opacity = calcValues(values.messageA_opacity_out, currentYOffset);
                    objs.messageA.style.transform = `translate3d(0, ${calcValues(values.messageA_translateY_out, currentYOffset)}%, 0)`;
                }

                if (scrollRatio <= 0.67) {
                    // in
                    objs.messageB.style.transform = `translate3d(0, ${calcValues(values.messageB_translateY_in, currentYOffset)}%, 0)`;
                    objs.messageB.style.opacity = calcValues(values.messageB_opacity_in, currentYOffset);
                    objs.pinB.style.transform = `scaleY(${calcValues(values.pinB_scaleY, currentYOffset)})`;
                } else {
                    // out
                    objs.messageB.style.transform = `translate3d(0, ${calcValues(values.messageB_translateY_out, currentYOffset)}%, 0)`;
                    objs.messageB.style.opacity = calcValues(values.messageB_opacity_out, currentYOffset);
                    objs.pinB.style.transform = `scaleY(${calcValues(values.pinB_scaleY, currentYOffset)})`;
                }

                if (scrollRatio <= 0.93) {
                    // in
                    objs.messageC.style.transform = `translate3d(0, ${calcValues(values.messageC_translateY_in, currentYOffset)}%, 0)`;
                    objs.messageC.style.opacity = calcValues(values.messageC_opacity_in, currentYOffset);
                    objs.pinC.style.transform = `scaleY(${calcValues(values.pinC_scaleY, currentYOffset)})`;
                } else {
                    // out
                    objs.messageC.style.transform = `translate3d(0, ${calcValues(values.messageC_translateY_out, currentYOffset)}%, 0)`;
                    objs.messageC.style.opacity = calcValues(values.messageC_opacity_out, currentYOffset);
                    objs.pinC.style.transform = `scaleY(${calcValues(values.pinC_scaleY, currentYOffset)})`;
                }

                break;

            case 3:
                // console.log('3 play');
                break;
        }
    }


    function scrollLoop() {
        enterNewScene = false;
        prevScrollHeight = 0;
        for (let i = 0; i < currentScene; i++) {
            prevScrollHeight += sceneInfo[i].scrollHeight;
        }
        if (yOffset > prevScrollHeight + sceneInfo[currentScene].scrollHeight) {
            enterNewScene = true;
            currentScene++;
            document.body.setAttribute("id", `show-scene-${currentScene}`);
        }
        if (yOffset < prevScrollHeight) {
            if (currentScene === 0) return; // 브라우저 바운스 효과로 인해 마이너스가 되는 것을 방지(모바일)
            enterNewScene = true;
            currentScene--;
            document.body.setAttribute("id", `show-scene-${currentScene}`);
        }
        if (enterNewScene) return;
        playAnimation();
    }

    window.addEventListener("scroll", () => {
        yOffset = window.pageYOffset;
        scrollLoop();
    });
    // window.addEventListener("DOMContentLoadded", setLayout);
    window.addEventListener("load", setLayout);
    window.addEventListener("resize", setLayout);
})();

@charset 'utf-8';
html {
    font-family: 'Noto Sans KR', sans-serif;
    font-size: 14px;
}

body {
    overflow-x: hidden;
    color: rgb(29, 29, 31);
    letter-spacing: 0.05em;
    background: #fff;
}


/* navigation */

a {
    color: rgb(29, 29, 31);
    text-decoration: none;
}

p {
    line-height: 1.6;
}

.global-nav {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 44px;
    padding: 0 1rem;
}

.local-nav {
    position: absolute;
    top: 45px;
    left: 0;
    width: 100%;
    height: 52px;
    border-bottom: 1px solid #ddd;
    padding: 0 1rem;
}

.global-nav-links,
.local-nav-links {
    display: flex;
    align-items: center;
    max-width: 1000px;
    height: 100%;
    margin: 0 auto;
}

.global-nav-links {
    justify-content: space-between;
}

.product-name {
    margin-right: auto;
    font-size: 1.2rem;
    font-weight: bold;
}

.local-nav-links a:not(.product-name) {
    margin-left: 2em;
    font-size: 0.8rem;
}


/* content */

.scroll-section {
    border: 3px solid red;
    padding-top: 50vh;
}

#scroll-section-0 h1 {
    font-size: 4rem;
    text-align: center;
}

.main-message {
    display: flex;
    align-items: center;
    justify-content: center;
    top: 35vh;
    margin: 5px 0;
    height: 3em;
    font-size: 2.5rem;
    opacity: 0;
}

.main-message p {
    font-weight: bold;
    text-align: center;
    line-height: 1.2;
}

.main-message small {
    display: block;
    margin-bottom: 0.5em;
    font-size: 1.2rem;
}

#scroll-section-2 .main-message {
    font-size: 3.5rem;
}

.description {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 1rem;
    font-size: 1.2rem;
    color: #888;
}

.description strong {
    float: left;
    margin-left: 0.2em;
    font-size: 3rem;
    color: rgb(29, 29, 31);
}

.desc-message {
    width: 50%;
    font-weight: bold;
}

#scroll-section-2 .b {
    top: 10%;
    left: 40%;
}

#scroll-section-2 .c {
    top: 15%;
    left: 45%;
}

.pin {
    width: 1px;
    height: 100px;
    background: rgb(29, 29, 31);
}

.mid-message {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 1rem;
    font-size: 2rem;
    color: #888;
}

.mid-message strong {
    color: rgb(29, 29, 31);
}

.canvas-caption {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 1rem;
    font-size: 1.2rem;
    color: #888;
    /* text-align: center; */
}

.footer {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 7rem;
    color: #fff;
    background: darkorange;
}

.stickt-elme {
    display: none;
    position: fixed;
    left: 0;
    width: 100%;
}

#show-scene-0 #scroll-section-0 .stickt-elme,
#show-scene-1 #scroll-section-1 .stickt-elme,
#show-scene-2 #scroll-section-2 .stickt-elme,
#show-scene-3 #scroll-section-3 .stickt-elme {
    display: block;
}

@media (min-width: 1024px) {
    #scroll-section-0 h1 {
        font-size: 9vw;
    }
    .main-message {
        font-size: 4vw;
    }
    .description {
        font-size: 2rem;
    }
    .description strong {
        font-size: 6rem;
    }
    #scroll-section-2 .main-message {
        font-size: 6vw;
    }
    .main-message small {
        font-size: 1.5vw
    }
    .desc-message {
        width: 20%;
    }
    #scroll-section-2 .b {
        top: 20%;
        left: 53%;
    }
    #scroll-section-2 .c {
        left: 55%;
    }
    .mid-message {
        font-size: 4vw;
    }
    .canvas-caption {
        font-size: 2rem;
    }
}

작업하고 계신 CSS와 JS 파일을 보아야 문제를 알 수 있을 것 같습니다.
여기 댓글로 소스를 붙여넣어주시면 봐드릴게요!