From 3ec8a91f30d881f66630dff9ac2d29a6f727c145 Mon Sep 17 00:00:00 2001
From: Stan <stan@wildfiregames.com>
Date: Thu, 31 Dec 2020 16:17:58 +0000
Subject: [PATCH] Fix incorrect prop height for floating objects.

Differential Revision: https://code.wildfiregames.com/D3033
This was SVN commit r24491.
---
 source/graphics/Model.cpp       | 46 +++++++++++++++++++--------------
 source/graphics/Model.h         |  4 +--
 source/graphics/ObjectEntry.cpp |  9 +++++--
 3 files changed, 35 insertions(+), 24 deletions(-)

diff --git a/source/graphics/Model.cpp b/source/graphics/Model.cpp
index f9e8a6fd3b..1a1f483bf1 100644
--- a/source/graphics/Model.cpp
+++ b/source/graphics/Model.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2019 Wildfire Games.
+/* Copyright (C) 2020 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -40,6 +40,7 @@
 #include "renderer/RenderingOptions.h"
 #include "simulation2/Simulation2.h"
 #include "simulation2/components/ICmpTerrain.h"
+#include "simulation2/components/ICmpWaterManager.h"
 
 
 /////////////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -381,13 +382,27 @@ void CModel::ValidatePosition()
 	// that doing so will cause a revalidation of this model (see recursion above).
 	m_PositionValid = true;
 
-	// re-position and validate all props
-	for (size_t j = 0; j < m_Props.size(); ++j)
+	CMatrix3D translate;
+	CVector3D objTranslation = m_Transform.GetTranslation();
+	float objectHeight = 0.0f;
+
+	CmpPtr<ICmpTerrain> cmpTerrain(m_Simulation, SYSTEM_ENTITY);
+	if (cmpTerrain)
+		objectHeight = cmpTerrain->GetExactGroundLevel(objTranslation.X, objTranslation.Z);
+
+	// Object height is incorrect for floating objects. We use water height instead.
+	CmpPtr<ICmpWaterManager> cmpWaterManager(m_Simulation, SYSTEM_ENTITY);
+	if (cmpWaterManager)
 	{
-		const Prop& prop=m_Props[j];
+		float waterHeight = cmpWaterManager->GetExactWaterLevel(objTranslation.X, objTranslation.Z);
+		if (waterHeight >= objectHeight && m_Flags & MODELFLAG_FLOATONWATER)
+			objectHeight = waterHeight;
+	}
 
+	// re-position and validate all props
+	for (const Prop& prop : m_Props)
+	{
 		CMatrix3D proptransform = prop.m_Point->m_Transform;
-
 		if (prop.m_Point->m_BoneIndex != 0xff)
 		{
 			CMatrix3D boneMatrix = m_BoneMatrices[prop.m_Point->m_BoneIndex];
@@ -402,22 +417,13 @@ void CModel::ValidatePosition()
 		}
 
 		// Adjust prop height to terrain level when needed
-		if (prop.m_MaxHeight != 0.f || prop.m_MinHeight != 0.f)
+		if (cmpTerrain && (prop.m_MaxHeight != 0.f || prop.m_MinHeight != 0.f))
 		{
-			CVector3D propTranslation = proptransform.GetTranslation();
-			CVector3D objTranslation = m_Transform.GetTranslation();
-
-			CmpPtr<ICmpTerrain> cmpTerrain(m_Simulation, SYSTEM_ENTITY);
-			if (cmpTerrain)
-			{
-				float objTerrain = cmpTerrain->GetExactGroundLevel(objTranslation.X, objTranslation.Z);
-				float propTerrain = cmpTerrain->GetExactGroundLevel(propTranslation.X, propTranslation.Z);
-				float translateHeight = std::min(prop.m_MaxHeight,
-				                                 std::max(prop.m_MinHeight, propTerrain - objTerrain));
-				CMatrix3D translate = CMatrix3D();
-				translate.SetTranslation(0.f, translateHeight, 0.f);
-				proptransform.Concatenate(translate);
-			}
+			const CVector3D& propTranslation = proptransform.GetTranslation();
+			const float propTerrain = cmpTerrain->GetExactGroundLevel(propTranslation.X, propTranslation.Z);
+			const float translateHeight = std::min(prop.m_MaxHeight, std::max(prop.m_MinHeight, propTerrain - objectHeight));
+			translate.SetTranslation(0.f, translateHeight, 0.f);
+			proptransform.Concatenate(translate);
 		}
 
 		prop.m_Model->SetTransform(proptransform);
diff --git a/source/graphics/Model.h b/source/graphics/Model.h
index 8bf254fb87..cc21fdff05 100644
--- a/source/graphics/Model.h
+++ b/source/graphics/Model.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2016 Wildfire Games.
+/* Copyright (C) 2020 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -41,7 +41,7 @@ class CSimulation2;
 #define MODELFLAG_SILHOUETTE_DISPLAY	(1<<2)
 #define MODELFLAG_SILHOUETTE_OCCLUDER	(1<<3)
 #define MODELFLAG_IGNORE_LOS		(1<<4)
-
+#define MODELFLAG_FLOATONWATER		(1<<5)
 ///////////////////////////////////////////////////////////////////////////////
 // CModel: basically, a mesh object - holds the texturing and skinning
 // information for a model in game
diff --git a/source/graphics/ObjectEntry.cpp b/source/graphics/ObjectEntry.cpp
index 254163da91..c48053a21d 100644
--- a/source/graphics/ObjectEntry.cpp
+++ b/source/graphics/ObjectEntry.cpp
@@ -246,10 +246,15 @@ bool CObjectEntry::BuildVariation(const std::vector<std::set<CStr> >& selections
 			LOGERROR("Failed to find matching prop point called \"%s\" in model \"%s\" for actor \"%s\"", ppn, m_ModelName.string8(), utf8_from_wstring(m_Base->m_ShortName));
 	}
 
-	// setup flags
+	// Setup flags.
 	if (m_Base->m_Properties.m_CastShadows)
 	{
-		model->SetFlags(model->GetFlags()|MODELFLAG_CASTSHADOWS);
+		model->SetFlags(model->GetFlags() | MODELFLAG_CASTSHADOWS);
+	}
+
+	if (m_Base->m_Properties.m_FloatOnWater)
+	{
+		model->SetFlags(model->GetFlags() | MODELFLAG_FLOATONWATER);
 	}
 
 	return true;