Changeset - r28587:b120416d7705
[Not reviewed]
master
0 1 0
Patric Stout - 10 months ago 2024-01-28 09:56:21
truebrain@openttd.org
Fix ea8c1d85: improve smoothness of smooth-scrolling for 60+Hz screens (#11884)
1 file changed with 15 insertions and 23 deletions:
0 comments (0 inline, 0 general)
src/viewport.cpp
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@@ -1884,24 +1884,13 @@ static void ClampSmoothScroll(uint32_t d
 
{
 
	/** 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 d
 
	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, u
 
		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, u
 
				} 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, u
 

	
 
		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);
 
	}
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