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Fix ea8c1d85: improve smoothness of smooth-scrolling for 60+Hz screens (#11884)

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Patric Stout 2024-01-28 10:56:21 +01:00 committed by GitHub
parent 0c4e509b60
commit 05b253b33b
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GPG Key ID: B5690EEEBB952194
1 changed files with 15 additions and 23 deletions
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38
src/viewport.cpp
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@ -1884,24 +1884,13 @@ static void ClampSmoothScroll(uint32_t delta_ms, int64_t delta_hi, int64_t delta
{
/** A tile is 64 pixels in width at 1x zoom; viewport coordinates are in 4x zoom. */
constexpr int PIXELS_PER_TILE = TILE_PIXELS * 2 * ZOOM_LVL_BASE;
constexpr int MS_PER_STEP = 30; ///< Time between each step in the smooth scroll.
static uint32_t remainder_time = 0;
assert(delta_hi != 0);
int64_t delta_left = delta_hi;
int max_scroll = 0;
for (uint count = 0; count < (delta_ms + remainder_time) / MS_PER_STEP; count++) {
/* We move 1/4th of the distance per 30ms, to give a smooth movement experience. */
delta_left = delta_left * 3 / 4;
/* But we don't allow more than 16 tiles movement per 30ms; longer distances take longer.
* This means that the full width of a map would take ~1 second, ignoring the slowdown:
* 256 / 16 * 30ms = 480ms. */
max_scroll += Map::ScaleBySize1D(16 * PIXELS_PER_TILE);
}
remainder_time = (delta_ms + remainder_time) % MS_PER_STEP;
/* Move at most 75% of the distance every 30ms, for a smooth experience */
int64_t delta_left = delta_hi * std::pow(0.75, delta_ms / 30.0);
/* Move never more than 16 tiles per 30ms. */
int max_scroll = Map::ScaleBySize1D(16 * PIXELS_PER_TILE * delta_ms / 30);
/* We never go over the max_scroll speed. */
delta_hi_clamped = Clamp(delta_hi - delta_left, -max_scroll, max_scroll);
@ -1912,14 +1901,6 @@ static void ClampSmoothScroll(uint32_t delta_ms, int64_t delta_hi, int64_t delta
if (delta_hi_clamped == 0) {
delta_hi_clamped = delta_hi > 0 ? 1 : -1;
}
/* Also ensure we always move on the lower delta. This is mostly to avoid a
* situation at borders, where you can't move from (x, y) to (x + 1, y),
* but you can move to (x + 1, y + 1). This due to how viewport clamping
* works and rounding issue. */
if (delta_lo_clamped == 0 && delta_lo != 0) {
delta_lo_clamped = delta_lo > 0 ? 1 : -1;
}
}
/**
@ -1944,6 +1925,9 @@ void UpdateViewportPosition(Window *w, uint32_t delta_ms)
int delta_x = w->viewport->dest_scrollpos_x - w->viewport->scrollpos_x;
int delta_y = w->viewport->dest_scrollpos_y - w->viewport->scrollpos_y;
int current_x = w->viewport->scrollpos_x;
int current_y = w->viewport->scrollpos_y;
bool update_overlay = false;
if (delta_x != 0 || delta_y != 0) {
if (_settings_client.gui.smooth_scroll) {
@ -1955,6 +1939,7 @@ void UpdateViewportPosition(Window *w, uint32_t delta_ms)
} else {
ClampSmoothScroll(delta_ms, delta_y, delta_x, delta_y_clamped, delta_x_clamped);
}
w->viewport->scrollpos_x += delta_x_clamped;
w->viewport->scrollpos_y += delta_y_clamped;
} else {
@ -1967,6 +1952,13 @@ void UpdateViewportPosition(Window *w, uint32_t delta_ms)
ClampViewportToMap(vp, &w->viewport->scrollpos_x, &w->viewport->scrollpos_y);
/* When moving small amounts around the border we can get stuck, and
* not actually move. In those cases, teleport to the destination. */
if ((delta_x != 0 || delta_y != 0) && current_x == w->viewport->scrollpos_x && current_y == w->viewport->scrollpos_y) {
w->viewport->scrollpos_x = w->viewport->dest_scrollpos_x;
w->viewport->scrollpos_y = w->viewport->dest_scrollpos_y;
}
SetViewportPosition(w, w->viewport->scrollpos_x, w->viewport->scrollpos_y);
if (update_overlay) RebuildViewportOverlay(w);
}