Add 64 bit map distance square function, use clamping for uint version

JGRennison · Oct 20, 2024 · 713014c · 713014c
1 parent fd05cdd
commit 713014c
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Showing 4 changed files with 7 additions and 8 deletions.
diff --git a/src/linkgraph/linkgraph_gui.cpp b/src/linkgraph/linkgraph_gui.cpp
@@ -648,10 +648,8 @@ bool LinkGraphOverlay::ShowTooltip(Point pt, TooltipCloseCondition close_cond)
 				builder += "\n\n";
 				TileIndex t0 = Station::Get(i->from_id)->xy;
 				TileIndex t1 = Station::Get(i->to_id)->xy;
-				uint dx = Delta(TileX(t0), TileX(t1));
-				uint dy = Delta(TileY(t0), TileY(t1));
 				SetDParam(0, DistanceManhattan(t0, t1));
-				SetDParam(1, IntSqrt64(((uint64_t)dx * (uint64_t)dx) + ((uint64_t)dy * (uint64_t)dy))); // Avoid overflow in DistanceSquare
+				SetDParam(1, IntSqrt64(DistanceSquare64(t0, t1))); // Avoid overflow in DistanceSquare
 				GetString(builder, STR_LINKGRAPH_STATS_TOOLTIP_DISTANCE);
 			}
 

diff --git a/src/map.cpp b/src/map.cpp
@@ -250,10 +250,10 @@ uint DistanceManhattan(TileIndex t0, TileIndex t1)
  * @param t1 the end tile
  * @return the distance
  */
-uint DistanceSquare(TileIndex t0, TileIndex t1)
+uint64_t DistanceSquare64(TileIndex t0, TileIndex t1)
 {
-	const int dx = TileX(t0) - TileX(t1);
-	const int dy = TileY(t0) - TileY(t1);
+	const int64_t dx = (int)TileX(t0) - (int)TileX(t1);
+	const int64_t dy = (int)TileY(t0) - (int)TileY(t1);
 	return dx * dx + dy * dy;
 }
 

diff --git a/src/map_func.h b/src/map_func.h
@@ -350,7 +350,8 @@ inline TileIndexDiffC TileIndexToTileIndexDiffC(TileIndex tile_a, TileIndex tile
 
 /* Functions to calculate distances */
 uint DistanceManhattan(TileIndex, TileIndex); ///< also known as L1-Norm. Is the shortest distance one could go over diagonal tracks (or roads)
-uint DistanceSquare(TileIndex, TileIndex); ///< euclidian- or L2-Norm squared
+uint64_t DistanceSquare64(TileIndex, TileIndex); ///< euclidian- or L2-Norm squared
+inline uint DistanceSquare(TileIndex t0, TileIndex t1) { return ClampTo<uint>(DistanceSquare64(t0, t1)); }
 uint DistanceMax(TileIndex, TileIndex); ///< also known as L-Infinity-Norm
 uint DistanceMaxPlusManhattan(TileIndex, TileIndex); ///< Max + Manhattan
 uint DistanceFromEdge(TileIndex); ///< shortest distance from any edge of the map

diff --git a/src/viewport.cpp b/src/viewport.cpp
@@ -6477,7 +6477,7 @@ calc_heightdiff_single_direction:;
 			if (dx != 1 || dy != 1) {
 				heightdiff = CalcHeightdiff(style, 0, t0, t1);
 				SetDParam(0, DistanceManhattan(t0, t1));
-				SetDParam(1, IntSqrt64(((uint64_t)dx * (uint64_t)dx) + ((uint64_t)dy * (uint64_t)dy))); // Avoid overflow in DistanceSquare
+				SetDParam(1, IntSqrt64(DistanceSquare64(t0, t1))); // Avoid overflow in DistanceSquare
 			} else {
 				SetDParam(0, 0);
 				SetDParam(1, 0);