GuiTraceRay from theater ray intersection instead of camera position.

rts/Game/Camera.cpp

@@ -13,6 +13,7 @@
 #include "System/float3.h"
 #include "System/Matrix44f.h"
 #include "System/Config/ConfigHandler.h"
+#include "Sim/Units/UnitHandler.h"
 
 #include "System/Misc/TracyDefs.h"
 
@@ -773,6 +774,39 @@ float3 CCamera::GetMoveVectorFromState(bool fromKeyState) const
 	return v;
 }
 
+float3 CCamera::PointToMaxUnitAltitude(const float3& point, const float rayLength, const float maxAltitude) const
+{
+	const float3 dir = (point-pos).Normalize();
+	float dist = CGround::LinePlaneCol(pos, dir, rayLength, maxAltitude);
+	if (dist > 0.0)
+		return pos + dir*dist;
+	return point;
+}
+
+float3 CCamera::NearTheaterIntersection(const float3& dir, const float rayLength) const
+{
+	const float maxAltitude = std::max(unitHandler.MaxUnitAltitude(), readMap->GetCurrMaxHeight());
+	if (pos.y < maxAltitude)
+		return pos;
+	const float3 fv1 = PointToMaxUnitAltitude(GetFrustumVert(CCamera::FRUSTUM_POINT_FBL), rayLength, maxAltitude);
+	const float3 fv2 = PointToMaxUnitAltitude(GetFrustumVert(CCamera::FRUSTUM_POINT_FBR), rayLength, maxAltitude);
+	float3 midFv = (fv1+fv2)/2.0;
+	midFv.y = pos.y;
+
+	// vertical plane from frustum intersection to max height
+	const float3 p = fv1;
+	const float3 norm = midFv-pos;
+	const float d = -(norm.x*p.x+norm.y*p.y+norm.z*p.z);
+	const float4 nearTheaterPlane = float4(norm.x, norm.y, norm.z, d);
+
+	// intersection
+	float3 intersection;
+	const bool res = RayAndPlaneIntersection(pos, pos+dir*rayLength, nearTheaterPlane, false, intersection);
+	if (res)
+		return intersection;
+	return pos;
+}
+
 // http://www.lighthouse3d.com/tutorials/view-frustum-culling/geometric-approach-testing-points-and-spheres/
 bool CCamera::Frustum::IntersectSphere(float3 p, float radius, uint8_t testMask) const
 {

rts/Game/Camera.h

@@ -221,6 +221,9 @@ class CCamera {
 		return (forward.dot(objPos - pos));
 	}
 
+	float3 PointToMaxUnitAltitude(const float3& point, const float rayLength, const float maxAltitude) const;
+	float3 NearTheaterIntersection(const float3& dir, const float rayLength) const;
+
 	/*
 	float ProjectedDistanceShadow(const float3& objPos, const float3& sunDir) const {
 		// FIXME: fix it, cap it for shallow shadows?

rts/Game/UI/GuiHandler.cpp

@@ -1155,8 +1155,9 @@ bool CGuiHandler::TryTarget(const SCommandDescription& cmdDesc) const
 	const CFeature* targetFeature = nullptr;
 
 	const float viewRange = camera->GetFarPlaneDist() * 1.4f;
-	const float dist = TraceRay::GuiTraceRay(camera->GetPos(), mouse->dir, viewRange, NULL, targetUnit, targetFeature, true);
-	const float3 groundPos = camera->GetPos() + mouse->dir * dist;
+	const float3 rayOrigin = camera->NearTheaterIntersection(mouse->dir, viewRange);
+	const float dist = TraceRay::GuiTraceRay(rayOrigin, mouse->dir, viewRange, NULL, targetUnit, targetFeature, true);
+	const float3 groundPos = rayOrigin + mouse->dir * dist;
 
 	if (dist <= 0.0f)
 		return false;
@@ -1685,8 +1686,11 @@ int CGuiHandler::GetDefaultCommand(int x, int y, const float3& cameraPos, const
 			unit = minimap->GetSelectUnit(minimap->GetMapPosition(x, y));
 		} else {
 			const float viewRange = camera->GetFarPlaneDist() * 1.4f;
-			const float dist = TraceRay::GuiTraceRay(cameraPos, mouseDir, viewRange, nullptr, unit, feature, true);
-			const float3 hit = cameraPos + mouseDir * dist;
+
+			const float3 rayOrigin = camera->NearTheaterIntersection(mouseDir, viewRange);
+			const float dist = TraceRay::GuiTraceRay(rayOrigin, mouseDir, viewRange, nullptr, unit, feature, true);
+
+			const float3 hit = rayOrigin + mouseDir * dist;
 
 			// make sure the ray hit in the map
 			if (unit == nullptr && feature == nullptr && !hit.IsInBounds())
@@ -2265,7 +2269,9 @@ Command CGuiHandler::GetCommand(int mouseX, int mouseY, int buttonHint, bool pre
 			const CUnit* unit = nullptr;
 			const CFeature* feature = nullptr;
 
-			TraceRay::GuiTraceRay(cameraPos, mouseDir, camera->GetFarPlaneDist() * 1.4f, nullptr, unit, feature, true);
+			const float viewRange = camera->GetFarPlaneDist() * 1.4f;
+			const float3 rayOrigin = camera->NearTheaterIntersection(mouseDir, viewRange);
+			TraceRay::GuiTraceRay(rayOrigin, mouseDir, viewRange, nullptr, unit, feature, true);
 
 			if (unit == nullptr)
 				return defaultRet;
@@ -2282,7 +2288,8 @@ Command CGuiHandler::GetCommand(int mouseX, int mouseY, int buttonHint, bool pre
 			const CFeature* feature = nullptr;
 
 			const float traceDist = camera->GetFarPlaneDist() * 1.4f;
-			const float isectDist = TraceRay::GuiTraceRay(cameraPos, mouseDir, traceDist, nullptr, unit, feature, true);
+			const float3 rayOrigin = camera->NearTheaterIntersection(mouseDir, traceDist);
+			const float isectDist = TraceRay::GuiTraceRay(rayOrigin, mouseDir, traceDist, nullptr, unit, feature, true);
 
 			if (isectDist > (traceDist - 300.0f))
 				return defaultRet;
@@ -2292,7 +2299,7 @@ Command CGuiHandler::GetCommand(int mouseX, int mouseY, int buttonHint, bool pre
 				c.PushParam(unit->id);
 			} else {
 				// clicked in map
-				c.PushPos(cameraPos + (mouseDir * isectDist));
+				c.PushPos(rayOrigin + (mouseDir * isectDist));
 			}
 			return CheckCommand(c);
 		}
@@ -2345,7 +2352,9 @@ Command CGuiHandler::GetCommand(int mouseX, int mouseY, int buttonHint, bool pre
 			if (mouse->buttons[button].movement <= mouse->dragCircleCommandThreshold) {
 				const CUnit* unit = nullptr;
 				const CFeature* feature = nullptr;
-				const float dist2 = TraceRay::GuiTraceRay(cameraPos, mouseDir, camera->GetFarPlaneDist() * 1.4f, NULL, unit, feature, true);
+				const float viewRange = camera->GetFarPlaneDist() * 1.4f;
+				const float3 rayOrigin = camera->NearTheaterIntersection(mouseDir, viewRange);
+				const float dist2 = TraceRay::GuiTraceRay(rayOrigin, mouseDir, viewRange, NULL, unit, feature, true);
 
 				if (dist2 > (camera->GetFarPlaneDist() * 1.4f - 300) && (commands[tempInCommand].type != CMDTYPE_ICON_UNIT_FEATURE_OR_AREA))
 					return defaultRet;
@@ -2362,7 +2371,7 @@ Command CGuiHandler::GetCommand(int mouseX, int mouseY, int buttonHint, bool pre
 					if (explicitCommand < 0 || !ZeroRadiusAllowed(c))
 						return defaultRet;
 
-					c.PushPos(cameraPos + (mouseDir * dist2));
+					c.PushPos(rayOrigin + (mouseDir * dist2));
 					c.PushParam(0); // zero radius
 
 					if (c.GetID() == CMD_UNLOAD_UNITS)
@@ -2408,7 +2417,8 @@ Command CGuiHandler::GetCommand(int mouseX, int mouseY, int buttonHint, bool pre
 				const CFeature* feature = nullptr;
 
 				const float traceDist = camera->GetFarPlaneDist() * 1.4f;
-				const float outerDist = TraceRay::GuiTraceRay(cameraPos, mouseDir, traceDist, nullptr, unit, feature, true);
+				const float3 rayOrigin = camera->NearTheaterIntersection(mouseDir, traceDist);
+				const float outerDist = TraceRay::GuiTraceRay(rayOrigin, mouseDir, traceDist, nullptr, unit, feature, true);
 
 				if (outerDist > (traceDist - 300.0f))
 					return defaultRet;
@@ -2421,7 +2431,7 @@ Command CGuiHandler::GetCommand(int mouseX, int mouseY, int buttonHint, bool pre
 					if (explicitCommand < 0)
 						return defaultRet;
 
-					c.PushPos(cameraPos + (mouseDir * outerDist));
+					c.PushPos(rayOrigin + (mouseDir * outerDist));
 				}
 			} else {
 				// create rectangular area-command
@@ -2503,7 +2513,9 @@ size_t CGuiHandler::GetBuildPositions(const BuildInfo& startInfo, const BuildInf
 		const CUnit* unit = nullptr;
 		const CFeature* feature = nullptr;
 
-		TraceRay::GuiTraceRay(cameraPos, mouseDir, camera->GetFarPlaneDist() * 1.4f, nullptr, unit, feature, startInfo.def->floatOnWater);
+		const float viewRange = camera->GetFarPlaneDist() * 1.4f;
+		const float3 rayOrigin = camera->NearTheaterIntersection(mouseDir, viewRange);
+		TraceRay::GuiTraceRay(rayOrigin, mouseDir, viewRange, nullptr, unit, feature, startInfo.def->floatOnWater);
 
 		if (unit != nullptr) {
 			other.def = unit->unitDef;
@@ -3710,7 +3722,8 @@ void CGuiHandler::DrawMapStuff(bool onMiniMap)
 			unit = minimap->GetSelectUnit(tracePos);
 		} else {
 			// ignore the returned distance, we don't care about it here
-			TraceRay::GuiTraceRay(tracePos, traceDir, maxTraceDist, nullptr, unit, feature, false);
+			const float3 rayOrigin = camera->NearTheaterIntersection(traceDir, maxTraceDist);
+			TraceRay::GuiTraceRay(rayOrigin, traceDir, maxTraceDist, nullptr, unit, feature, false);
 		}
 
 		if (unit != nullptr && (gu->spectatingFullView || unit->IsInLosForAllyTeam(gu->myAllyTeam))) {

rts/Game/UI/MouseHandler.cpp

@@ -569,7 +569,9 @@ void CMouseHandler::MouseRelease(int x, int y, int button)
 			const CUnit* unit = nullptr;
 			const CFeature* feature = nullptr;
 
-			TraceRay::GuiTraceRay(camera->GetPos(), dir, camera->GetFarPlaneDist() * 1.4f, nullptr, unit, feature, false);
+			const float viewRange = camera->GetFarPlaneDist() * 1.4f;
+			const float3 rayOrigin = camera->NearTheaterIntersection(dir, viewRange);
+			TraceRay::GuiTraceRay(rayOrigin, dir, viewRange, nullptr, unit, feature, false);
 			lastClicked = unit;
 
 			const bool selectType = (bp.lastRelease >= (gu->gameTime - doubleClickTime) && unit == _lastClicked);
@@ -701,8 +703,9 @@ std::string CMouseHandler::GetCurrentTooltip() const
 	const CUnit* unit = nullptr;
 	const CFeature* feature = nullptr;
 
+	const float3 rayOrigin = camera->NearTheaterIntersection(dir, range);
 	{
-		dist = TraceRay::GuiTraceRay(camera->GetPos(), dir, range, nullptr, unit, feature, true, false, true);
+		dist = TraceRay::GuiTraceRay(rayOrigin, dir, range, nullptr, unit, feature, true, false, true);
 
 		if (unit    != nullptr) return CTooltipConsole::MakeUnitString(unit);
 		if (feature != nullptr) return CTooltipConsole::MakeFeatureString(feature);
@@ -714,7 +717,7 @@ std::string CMouseHandler::GetCurrentTooltip() const
 		return selTip;
 
 	if (dist <= range)
-		return CTooltipConsole::MakeGroundString(camera->GetPos() + (dir * dist));
+		return CTooltipConsole::MakeGroundString(rayOrigin + (dir * dist));
 
 	return "";
 }

rts/Lua/LuaSyncedCtrl.cpp

@@ -3261,6 +3261,7 @@ int LuaSyncedCtrl::SetUnitMidAndAimPos(lua_State* L)
 
 	if (updateQuads) {
 		quadField.MovedUnit(unit);
+		unitHandler.MovedUnit(unit);
 	}
 
 	lua_pushboolean(L, true);
@@ -3296,6 +3297,7 @@ int LuaSyncedCtrl::SetUnitRadiusAndHeight(lua_State* L)
 
 	if (updateQuads) {
 		quadField.MovedUnit(unit);
+		unitHandler.MovedUnit(unit);
 	}
 
 	lua_pushboolean(L, true);

rts/Lua/LuaUnsyncedRead.cpp

@@ -2952,10 +2952,15 @@ int LuaUnsyncedRead::TraceScreenRay(lua_State* L)
 	const float3 pxlDir = camera->CalcPixelDir(wx, wy);
 
 	// trace for player's allyteam
-	const float traceDist = TraceRay::GuiTraceRay(camPos, pxlDir, rawRange, nullptr, unit, feature, true, onlyCoords, ignoreWater);
+	float3 rayOrigin;
+	if (onlyCoords)
+		rayOrigin = camPos;
+	else
+		rayOrigin = camera->NearTheaterIntersection(pxlDir, rawRange);
+	const float traceDist = TraceRay::GuiTraceRay(rayOrigin, pxlDir, rawRange, nullptr, unit, feature, true, onlyCoords, ignoreWater);
 	const float planeDist = CGround::LinePlaneCol(camPos, pxlDir, rawRange, luaL_optnumber(L, newArgIdx, 0.0f));
 
-	const float3 tracePos = camPos + (pxlDir * traceDist);
+	const float3 tracePos = rayOrigin + (pxlDir * traceDist);
 	const float3 planePos = camPos + (pxlDir * planeDist); // backup (for includeSky and onlyCoords)
 
 	if ((traceDist < 0.0f || traceDist > badRange) && unit == nullptr && feature == nullptr) {
@@ -4890,4 +4895,4 @@ int LuaUnsyncedRead::SolveNURBSCurve(lua_State* L)
 		lua_rawseti(L, -2, ++i);
 	}
 	return 1;
-}
+}

rts/Rendering/UniformConstants.cpp

@@ -275,9 +275,10 @@ void UniformConstants::UpdateParamsImpl(UniformParamsBuffer* updateBuffer)
 		const float3 pxlDir = camPlayer->CalcPixelDir(wx, wy);
 
 		// trace for player's allyteam
-		const float traceDist = TraceRay::GuiTraceRay(camPos, pxlDir, rawRange, nullptr, unit, feature, true, false, true);
+		const float3 rayOrigin = camPlayer->NearTheaterIntersection(pxlDir, rawRange);
+		const float traceDist = TraceRay::GuiTraceRay(rayOrigin, pxlDir, rawRange, nullptr, unit, feature, true, false, true);
 
-		const float3 tracePos = camPos + (pxlDir * traceDist);
+		const float3 tracePos = rayOrigin + (pxlDir * traceDist);
 
 		if (unit)
 			updateBuffer->mouseWorldPos = float4{ unit->drawPos, 1.0f };

rts/Sim/Units/Unit.cpp

@@ -531,6 +531,7 @@ void CUnit::ForcedMove(const float3& newPos)
 
 	eventHandler.UnitMoved(this);
 	quadField.MovedUnit(this);
+	unitHandler.MovedUnit(this);
 }
 
 
@@ -741,6 +742,7 @@ void CUnit::UpdateTransportees()
 		// see ::AttachUnit
 		if (transportee->IsStunned()) {
 			quadField.MovedUnit(transportee);
+			unitHandler.MovedUnit(transportee);
 		}
 	}
 }

rts/Sim/Units/UnitHandler.cpp

@@ -55,6 +55,7 @@ CR_REG_METADATA(CUnitHandler, (
 
 	CR_MEMBER(maxUnits),
 	CR_MEMBER(maxUnitRadius),
+	CR_MEMBER_UN(maxUnitAltitude),
 
 	CR_MEMBER(inUpdateCall)
 ))
@@ -115,6 +116,7 @@ void CUnitHandler::Init() {
 		// other team in the respective allyteam
 		maxUnits = CalcMaxUnits();
 		maxUnitRadius = 0.0f;
+		maxUnitAltitude = 0.0f;
 	}
 	{
 		activeSlowUpdateUnit = 0;
@@ -170,6 +172,7 @@ void CUnitHandler::Kill()
 	{
 		maxUnits = 0;
 		maxUnitRadius = 0.0f;
+		maxUnitAltitude = 0.0f;
 	}
 }
 
@@ -236,6 +239,7 @@ bool CUnitHandler::AddUnit(CUnit* unit)
 	spring::VectorInsertUnique(GetUnitsByTeamAndDef(unit->team, unit->unitDef->id), unit, false);
 
 	maxUnitRadius = std::max(unit->radius, maxUnitRadius);
+	MovedUnit(unit);
 	return true;
 }
 
@@ -408,13 +412,15 @@ void CUnitHandler::UpdateUnits()
 {
 	SCOPED_TIMER("Sim::Unit::Update");
 
+	maxUnitAltitude = 0.0f;
 	size_t activeUnitCount = activeUnits.size();
 	for (size_t i = 0; i < activeUnitCount; ++i) {
 		CUnit* unit = activeUnits[i];
 
 		unit->SanityCheck();
 		unit->Update();
 		unit->moveType->UpdateCollisionMap();
+		MovedUnit(unit);
 		// unsynced; done on-demand when drawing unit
 		// unit->UpdateLocalModel();
 		unit->SanityCheck();
@@ -514,3 +520,7 @@ unsigned int CUnitHandler::CalcMaxUnits() const
 	return n;
 }
 
+void CUnitHandler::MovedUnit(CUnit* unit)
+{
+	maxUnitAltitude = std::max(unit->pos.y + unit->radius, maxUnitAltitude);
+}

rts/Sim/Units/UnitHandler.h

@@ -28,6 +28,7 @@ class CUnitHandler
 
 	void Update();
 	bool AddUnit(CUnit* unit);
+	void MovedUnit(CUnit* unit);
 
 	bool CanAddUnit(int id) const {
 		// do we want to be assigned a random ID and are any left in pool?
@@ -46,6 +47,7 @@ class CUnitHandler
 	unsigned int CalcMaxUnits() const;
 
 	float MaxUnitRadius() const { return maxUnitRadius; }
+	float MaxUnitAltitude() const { return maxUnitAltitude; }
 
 	/// Returns true if a unit of type unitID can be built, false otherwise
 	bool CanBuildUnit(const UnitDef* unitdef, int team) const;
@@ -115,6 +117,10 @@ class CUnitHandler
 	///< spatial query filters in GameHelper use this)
 	float maxUnitRadius = 0.0f;
 
+	///< highest altitude of any unit added so far
+	///< (ray tracing uses this in some cases)
+	float maxUnitAltitude = 0.0f;
+
 	bool inUpdateCall = false;
 };