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db3dbe1 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 | /**
* Global scroll progress, kept OUTSIDE React state so the R3F render loop can
* read it every frame (via getScroll()) without triggering re-renders. Lenis
* writes to it; the 3D scene and any rAF consumer read from it.
*/
export interface ScrollState {
/** 0–1 progress across the entire page. */
progress: number
/** Raw scroll offset in px. */
scrollY: number
/** Total scrollable height in px. */
limit: number
/** Viewport height in px. */
viewport: number
}
const state: ScrollState = {
progress: 0,
scrollY: 0,
limit: 1,
viewport: typeof window !== 'undefined' ? window.innerHeight : 1,
}
export function setScroll(scrollY: number, limit: number) {
state.scrollY = scrollY
state.limit = Math.max(1, limit)
state.progress = Math.min(1, Math.max(0, scrollY / state.limit))
state.viewport = window.innerHeight
}
export function getScroll(): ScrollState {
return state
}
/**
* Progress (0–1) of a single section, given its index and the total number of
* full-viewport sections. Lets the 3D scene know "how far through the hero / the
* descent are we" independent of total page height.
*/
export function sectionProgress(
sectionIndex: number,
totalSections: number,
): number {
const per = 1 / totalSections
const start = sectionIndex * per
const local = (state.progress - start) / per
return Math.min(1, Math.max(0, local))
}
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