Horizontal scrolling sticky section

Hello,

Looking to create a horizontal scrolling section inside a sticky div with the following structure:

<div id="sec01" class="the-height-400vh-section"><!-- this has the same height as does the 400vh width, timing should match -->
    <div class="the-sticky-div" id="sticky"  data-scroll data-scroll-sticky data-scroll-target="#sec01"><!-- this is stickying to viewport while we scroll -->
        <div class="the-overflow-hidden-mask">
            <div class="the-width-400vh-scrollable-div" data-scroll data-scroll-direction="horizontal" data-scroll-speed="12" data-scroll-target="#sec01"><!-- we're scrolling this 400vh to the right while we're scrolling the 400vh height of the parent -->
                <div class="the-content">
                    <div class="a-block"></div>
                    <div class="a-block"></div>
                    <div class="a-block"></div>
                    <div class="a-block"></div>  
                </div>
            </div>
        </div>
    </div>
</div>

The following SCSS applies:

.the-sticky-div {
  position: absolute;
  top: 0;
  height: 100vh;
  width: 100%;
  overflow-x: hidden;
  background: #ccc;
  z-index: 1;
}
.the-overflow-hidden-mask {
  position: relative;
  z-index: 200;
  overflow: hidden;
  width: 100%;
  height: 100%;
  background: #000;
}
.the-height-400vh-section {
  position: relative;
  display: flex;
  height: 400vh;
  margin-left: 0px;
  justify-content: center;
  align-items: center;
  border-top: 60px none rgba(36, 36, 36, 0.09);
  background-color: #fff;
}

.the-width-400vh-scrollable-div {
  display: flex;
  width: 400vh;
  position:relative;
  height: 100%;
  flex-wrap: wrap;
  align-items: center;
  will-change: transform;
}
.the-content {
  display: flex;
  width: 100%;
  height: 100%;
  padding-bottom: 10vh;
  justify-content: flex-start;
  align-items: flex-end;
  .a-block {
    overflow: hidden;
    width: 100vw;
    height: 100vh;
    left:0;
    margin-right: 40px;
    margin-left: 40px;
    flex: 0 0 auto;
    border-radius: 6px;
    background-color: hsla(0, 0%, 87.1%, 0.72);
    box-shadow: 0 0 100px 8px rgba(205, 43, 177, 0.25);
  }
}

I have two main issues:

• horizontal scroll initialises too early (when container top enters viewport, not when reached bottom of sticky container)
• horizontal scroll elements start position is not correct (first element scrolls in from right)

The width / height logic seems to make sense although it unfortunately does not work. Any ideas what could be done with the current solution to achieve a similar end result to i.e www.reformcollective.com (elements reach center of viewport > horizontal scroll intialises > horizontal scrolls end with last element and page continues)?

[nuriaheep]

Does anybody found the way to achieve this without GSAP Scrolltrigger?

[jasondibenedetto]

Also interested to know if anyone has achieved this without GSAP Scrolltrigger