5 files changed, 243 insertions, 2 deletions

diff --git a/src/entities/Entity.h b/src/entities/Entity.h
index e975fb13..cdc9a173 100644
--- a/src/entities/Entity.h
+++ b/src/entities/Entity.h
@@ -73,7 +73,7 @@ public:
 	uint32 bRemoveFromWorld : 1;
 	uint32 bHasHitWall : 1;
 	uint32 bImBeingRendered : 1;
-	uint32 m_flagD8 : 1;
+	uint32 m_flagD8 : 1;	// used by cBuoyancy::ProcessBuoyancy
 	uint32 bIsSubway : 1;	// set when subway, but maybe different meaning?
 	uint32 bDrawLast : 1;
 	uint32 m_flagD40 : 1;
diff --git a/src/render/WaterLevel.cpp b/src/render/WaterLevel.cpp
index 30be88e1..4f315cd0 100644
--- a/src/render/WaterLevel.cpp
+++ b/src/render/WaterLevel.cpp
@@ -1240,7 +1240,7 @@ STARTPATCHES
 	InjectHook(0x554FE0, &CWaterLevel::Shutdown, PATCH_JUMP);
 	InjectHook(0x555010, &CWaterLevel::CreateWavyAtomic, PATCH_JUMP);
 	InjectHook(0x5552A0, &CWaterLevel::DestroyWavyAtomic, PATCH_JUMP);
-	InjectHook(0x5552C0, &CWaterLevel::GetWaterLevel, PATCH_JUMP);
+	InjectHook(0x5552C0, (bool (*)(float,float,float,float*,bool))&CWaterLevel::GetWaterLevel, PATCH_JUMP);
 	InjectHook(0x555440, &CWaterLevel::GetWaterLevelNoWaves, PATCH_JUMP);
 	InjectHook(0x5554E0, &CWaterLevel::RenderWater, PATCH_JUMP);
 	InjectHook(0x556C30, &CWaterLevel::RenderOneFlatSmallWaterPoly, PATCH_JUMP);
diff --git a/src/render/WaterLevel.h b/src/render/WaterLevel.h
index b8ec7a4d..afc6eac3 100644
--- a/src/render/WaterLevel.h
+++ b/src/render/WaterLevel.h
@@ -82,6 +82,7 @@ public:
 	static void    CreateWavyAtomic();
 	static void    DestroyWavyAtomic();
 	static bool    GetWaterLevel(float fX, float fY, float fZ, float *pfOutLevel, bool bDontCheckZ);
+	static bool    GetWaterLevel(CVector coors, float *pfOutLevel, bool bDontCheckZ) { return GetWaterLevel(coors.x, coors.y, coors.z, pfOutLevel, bDontCheckZ); }
 	static bool    GetWaterLevelNoWaves(float fX, float fY, float fZ, float *pfOutLevel);
 	static void    RenderWater();
 	static void    RenderOneFlatSmallWaterPoly    (float fX, float fY, float fZ, RwRGBA const &color);
diff --git a/src/vehicles/Floater.cpp b/src/vehicles/Floater.cpp
new file mode 100644
index 00000000..cabe00c3
--- /dev/null
+++ b/src/vehicles/Floater.cpp
@@ -0,0 +1,195 @@
+#include "common.h"
+#include "patcher.h"
+#include "Timer.h"
+#include "WaterLevel.h"
+#include "ModelIndices.h"
+#include "Physical.h"
+#include "Vehicle.h"
+#include "Floater.h"
+
+cBuoyancy &mod_Buoyancy = *(cBuoyancy*)0x8F2674;
+
+//static float fVolMultiplier = 1.0f;
+static float &fVolMultiplier = *(float*)0x601394;
+// amount of boat volume in bounding box
+// 1.0-volume is the empty space in the bbox
+static float fBoatVolumeDistribution[9] = {
+	// rear
+	0.75f, 0.9f, 0.75f,
+	0.95f, 1.0f, 0.95f,
+	0.3f, 0.7f, 0.3f
+	// bow
+};
+
+bool
+cBuoyancy::ProcessBuoyancy(CPhysical *phys, float buoyancy, CVector *impulse, CVector *point)
+{
+	m_numSteps = 2.0f;
+
+	if(!CWaterLevel::GetWaterLevel(phys->GetPosition(), &m_waterlevel, phys->m_flagD8))
+		return false;
+	m_matrix = phys->GetMatrix();
+
+	PreCalcSetup(phys, buoyancy);
+	SimpleCalcBuoyancy();
+	float f = CalcBuoyancyForce(phys, impulse, point);
+	if(m_isBoat)
+		return true;
+	return f != 0.0f;
+}
+
+void
+cBuoyancy::PreCalcSetup(CPhysical *phys, float buoyancy)
+{
+	CColModel *colModel;
+
+	m_isBoat = phys->IsVehicle() && ((CVehicle*)phys)->IsBoat();
+	colModel = phys->GetColModel();
+	m_dimMin = colModel->boundingBox.min;
+	m_dimMax = colModel->boundingBox.max;
+
+	if(m_isBoat){
+		if(phys->GetModelIndex() == MI_PREDATOR){
+			m_dimMax.y *= 0.9f;
+			m_dimMin.y *= 0.9f;
+		}else if(phys->GetModelIndex() == MI_SPEEDER){
+			m_dimMax.y *= 1.1f;
+			m_dimMin.y *= 0.9f;
+		}else if(phys->GetModelIndex() == MI_REEFER){
+			m_dimMin.y *= 0.9f;
+		}else{
+			m_dimMax.y *= 0.9f;
+			m_dimMin.y *= 0.9f;
+		}
+	}
+
+	m_step = (m_dimMax - m_dimMin)/m_numSteps;
+
+	if(m_step.z > m_step.x && m_step.z > m_step.y){
+		m_stepRatio.x = m_step.x/m_step.z;
+		m_stepRatio.y = m_step.y/m_step.z;
+		m_stepRatio.z = 1.0f;
+	}else if(m_step.y > m_step.x && m_step.y > m_step.z){
+		m_stepRatio.x = m_step.x/m_step.y;
+		m_stepRatio.y = 1.0f;
+		m_stepRatio.z = m_step.z/m_step.y;
+	}else{
+		m_stepRatio.x = 1.0f;
+		m_stepRatio.y = m_step.y/m_step.x;
+		m_stepRatio.z = m_step.z/m_step.x;
+	}
+
+	m_haveVolume = false;
+	m_numPartialVolumes = 1.0f;
+	m_volumeUnderWater = 0.0f;
+	m_impulse = CVector(0.0f, 0.0f, 0.0f);
+	m_position = phys->GetPosition();
+	m_positionZ = CVector(0.0f, 0.0f, m_position.z);
+	m_buoyancy = buoyancy;
+	m_waterlevel += m_waterLevelInc;
+}
+
+void
+cBuoyancy::SimpleCalcBuoyancy(void)
+{
+	float x, y;
+	int ix, i;
+	tWaterLevel waterPosition;
+
+	// Floater is divided into 3x3 parts. Process and sum each of them
+	ix = 0;
+	for(x = m_dimMin.x; x <= m_dimMax.x; x += m_step.x){
+		i = ix;
+		for(y = m_dimMin.y; y <= m_dimMax.y; y += m_step.y){
+			CVector waterLevel(x, y, 0.0f);
+			FindWaterLevel(m_positionZ, &waterLevel, &waterPosition);
+			fVolMultiplier = m_isBoat ? fBoatVolumeDistribution[i] : 1.0f;
+			if(waterPosition != FLOATER_ABOVE_WATER)
+				SimpleSumBuoyancyData(waterLevel, waterPosition);
+			i += 3;
+		}
+		ix++;
+	}
+
+	m_volumeUnderWater /= (m_dimMax.z - m_dimMin.z)*sq(m_numSteps+1.0f);
+}
+
+float
+cBuoyancy::SimpleSumBuoyancyData(CVector &waterLevel, tWaterLevel waterPosition)
+{
+	static float fThisVolume;
+	static CVector AverageOfWaterLevel;
+	static float fFraction;
+	static float fRemainingSlice;
+
+	float submerged = Abs(waterLevel.z - m_dimMin.z);
+	// subtract empty space from submerged volume
+	fThisVolume = submerged - (1.0f - fVolMultiplier);
+	if(fThisVolume < 0.0f)
+		return 0.0f;
+
+	if(m_isBoat){
+		fThisVolume *= fVolMultiplier;
+		if(fThisVolume < 0.5f)
+			fThisVolume = 2.0f*sq(fThisVolume);
+		if(fThisVolume < 1.0f)
+			fThisVolume = sq(fThisVolume);
+		fThisVolume = sq(fThisVolume);
+	}
+
+	m_volumeUnderWater += fThisVolume;
+
+	AverageOfWaterLevel.x = waterLevel.x * m_stepRatio.x;
+	AverageOfWaterLevel.y = waterLevel.y * m_stepRatio.y;
+	AverageOfWaterLevel.z = (waterLevel.z+m_dimMin.z)/2.0f * m_stepRatio.z;
+
+	if(m_flipAverage)
+		AverageOfWaterLevel = -AverageOfWaterLevel;
+
+	fFraction = 1.0f/m_numPartialVolumes;
+	fRemainingSlice = 1.0f - fFraction;
+	m_impulse = m_impulse*fRemainingSlice + AverageOfWaterLevel*fThisVolume*fFraction;
+	m_numPartialVolumes += 1.0f;
+	m_haveVolume = true;
+	return fThisVolume;
+}
+
+void
+cBuoyancy::FindWaterLevel(const CVector &zpos, CVector *waterLevel, tWaterLevel *waterPosition)
+{
+	*waterPosition = FLOATER_IN_WATER;
+	// waterLevel is a local x,y point
+	// m_position is the global position of our floater
+	// zpos is the global z coordinate of our floater
+	CVector xWaterLevel = Multiply3x3(m_matrix, *waterLevel);
+	CWaterLevel::GetWaterLevel(xWaterLevel.x + m_position.x, xWaterLevel.y + m_position.y, m_position.z,
+		&waterLevel->z, true);
+	waterLevel->z -= xWaterLevel.z + zpos.z;	// make local
+	if(waterLevel->z > m_dimMax.z){
+		waterLevel->z = m_dimMax.z;
+		*waterPosition = FLOATER_UNDER_WATER;
+	}else if(waterLevel->z < m_dimMin.z){
+		waterLevel->z = m_dimMin.z;
+		*waterPosition = FLOATER_ABOVE_WATER;
+	}
+}
+
+bool
+cBuoyancy::CalcBuoyancyForce(CPhysical *phys, CVector *impulse, CVector *point)
+{
+	if(!m_haveVolume)
+		return false;
+
+	*impulse = Multiply3x3(m_matrix, m_impulse);
+	*point = CVector(0.0f, 0.0f, m_volumeUnderWater*m_buoyancy*CTimer::GetTimeStep());
+	return true;
+}
+
+STARTPATCHES
+	InjectHook(0x546270, &cBuoyancy::ProcessBuoyancy, PATCH_JUMP);
+	InjectHook(0x546360, &cBuoyancy::PreCalcSetup, PATCH_JUMP);
+	InjectHook(0x5466F0, &cBuoyancy::SimpleCalcBuoyancy, PATCH_JUMP);
+	InjectHook(0x546820, &cBuoyancy::SimpleSumBuoyancyData, PATCH_JUMP);
+	InjectHook(0x546620, &cBuoyancy::FindWaterLevel, PATCH_JUMP);
+	InjectHook(0x5465A0, &cBuoyancy::CalcBuoyancyForce, PATCH_JUMP);
+ENDPATCHES
diff --git a/src/vehicles/Floater.h b/src/vehicles/Floater.h
new file mode 100644
index 00000000..ede2b9d0
--- /dev/null
+++ b/src/vehicles/Floater.h
@@ -0,0 +1,45 @@
+#pragma once
+
+class Physical;
+
+enum tWaterLevel
+{
+	FLOATER_ABOVE_WATER,
+	FLOATER_IN_WATER,
+	FLOATER_UNDER_WATER,
+};
+
+class cBuoyancy
+{
+public:
+	CVector m_position;
+	CMatrix m_matrix;
+	int m_field_54;
+	CVector m_positionZ;
+	float m_waterlevel;
+	float m_waterLevelInc;
+	float m_buoyancy;
+	CVector m_dimMax;
+	CVector m_dimMin;
+	float m_numPartialVolumes;
+	int m_field_8C;
+	int m_field_90;
+	int m_field_94;
+	bool m_haveVolume;
+	CVector m_step;
+	CVector m_stepRatio;
+	float m_numSteps;
+	bool m_flipAverage;
+	char m_field_B9;
+	bool m_isBoat;
+	float m_volumeUnderWater;
+	CVector m_impulse;
+
+	bool ProcessBuoyancy(CPhysical *phys, float buoyancy, CVector *impulse, CVector *point);
+	void PreCalcSetup(CPhysical *phys, float buoyancy);
+	void SimpleCalcBuoyancy(void);
+	float SimpleSumBuoyancyData(CVector &waterLevel, tWaterLevel waterPosition);
+	void FindWaterLevel(const CVector &zpos, CVector *waterLevel, tWaterLevel *waterPosition);
+	bool CalcBuoyancyForce(CPhysical *phys, CVector *impulse, CVector *point);
+};
+extern cBuoyancy &mod_Buoyancy;