From 333f7b4fb4e09b1831efa01cf493207e8495a60a Mon Sep 17 00:00:00 2001
From: vladislavbelov <vladislavbelov@wildfiregames.com>
Date: Wed, 3 Feb 2021 17:03:44 +0000
Subject: [PATCH] Fixes building snapping for non-square foundations. Fixes
 #5976

Tested By: Freagarach, Langbart, Stan
Differential Revision: https://code.wildfiregames.com/D3510
This was SVN commit r24827.
---
 .../simulation/helpers/ObstructionSnap.js     | 25 +++++++++++++------
 .../scripting/JSInterface_Simulation.cpp      |  6 ++---
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/binaries/data/mods/public/simulation/helpers/ObstructionSnap.js b/binaries/data/mods/public/simulation/helpers/ObstructionSnap.js
index 0e4a2ea40a..ace8f31218 100644
--- a/binaries/data/mods/public/simulation/helpers/ObstructionSnap.js
+++ b/binaries/data/mods/public/simulation/helpers/ObstructionSnap.js
@@ -68,13 +68,25 @@ class ObstructionSnap
 		return scoreA - scoreB;
 	}
 
+	getNearestSizeAlongNormal(width, depth, angle, normal)
+	{
+		// Front face direction.
+		let direction = new Vector2D(0.0, 1.0);
+		direction.rotate(angle);
+		let dot = direction.dot(normal);
+		const threshold = Math.cos(Math.PI / 4.0);
+		if (Math.abs(dot) > threshold)
+			return [depth, width];
+		return [width, depth];
+	}
+
 	getPosition(data, template)
 	{
 		if (!data.snapToEdges || !template.Obstruction || !template.Obstruction.Static)
 			return undefined;
 
-		let width = template.Obstruction.Static["@depth"] / 2;
-		let depth = template.Obstruction.Static["@width"] / 2;
+		const width = template.Obstruction.Static["@width"] / 2;
+		const depth = template.Obstruction.Static["@depth"] / 2;
 		const maxSide = Math.max(width, depth);
 		let templatePos = Vector2D.from3D(data);
 		let templateAngle = data.angle || 0;
@@ -97,16 +109,15 @@ class ObstructionSnap
 			difference = Math.min(difference, Math.PI * 2 - difference);
 			if (difference < Math.PI / 4 + this.EPS)
 			{
-				// We need to swap sides for orthogonal cases.
-				if (dir % 2 == 0)
-					[width, depth] = [depth, width];
 				templateAngle = angleCandidate;
 				break;
 			}
 		}
+		let [sizeToBaseEdge, sizeToPairedEdge] =
+			this.getNearestSizeAlongNormal(width, depth, templateAngle, baseEdge.normal);
 
 		let distance = Vector2D.dot(baseEdge.normal, templatePos) - Vector2D.dot(baseEdge.normal, baseEdge.begin);
-		templatePos.sub(Vector2D.mult(baseEdge.normal, distance - width - this.getPadding(baseEdge)));
+		templatePos.sub(Vector2D.mult(baseEdge.normal, distance - sizeToBaseEdge - this.getPadding(baseEdge)));
 		edges = this.getValidEdges(data.snapToEdges, templatePos, maxSide);
 		if (edges.length > 1)
 		{
@@ -136,7 +147,7 @@ class ObstructionSnap
 					if (this.compareEdges(edge, secondEdge) < 0)
 						secondEdge = edge;
 				let distance = Vector2D.dot(secondEdge.normal, templatePos) - Vector2D.dot(secondEdge.normal, secondEdge.begin);
-				templatePos.sub(Vector2D.mult(secondEdge.normal, distance - depth - this.getPadding(secondEdge)));
+				templatePos.sub(Vector2D.mult(secondEdge.normal, distance - sizeToPairedEdge - this.getPadding(secondEdge)));
 			}
 		}
 		return {
diff --git a/source/simulation2/scripting/JSInterface_Simulation.cpp b/source/simulation2/scripting/JSInterface_Simulation.cpp
index 6dba9bd66d..b8452e16f6 100644
--- a/source/simulation2/scripting/JSInterface_Simulation.cpp
+++ b/source/simulation2/scripting/JSInterface_Simulation.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2020 Wildfire Games.
+/* Copyright (C) 2021 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -156,7 +156,7 @@ JS::Value JSI_Simulation::GetEdgesOfStaticObstructionsOnScreenNearTo(ScriptInter
 			halfSize,
 			CFixedVector2D(halfSize.X, -halfSize.Y)
 		};
-		fixed angle = cmpPosition->GetRotation().Y;
+		const fixed angle = cmpPosition->GetRotation().Y;
 		for (CFixedVector2D& corner : corners)
 			corner = corner.Rotate(angle) + cmpPosition->GetPosition2D();
 
@@ -166,7 +166,7 @@ JS::Value JSI_Simulation::GetEdgesOfStaticObstructionsOnScreenNearTo(ScriptInter
 			const CFixedVector2D& corner = corners[i];
 			const CFixedVector2D& nextCorner = corners[(i + 1) % corners.size()];
 
-			fixed distanceToEdge =
+			const fixed distanceToEdge =
 				Geometry::DistanceToSegment(entityPos, corner, nextCorner);
 			if (distanceToEdge.ToFloat() > distanceThreshold)
 				continue;