Revert 7cda0f8 and project the shadow

I know it's ugly, just stay in consistency with others for the moment

Author: chaserli

docs/Whats-New.md

@@ -522,7 +522,6 @@ Vanilla fixes:
 - Fixed disguised units not using the correct palette if target has custom palette (by NetsuNegi)
 - Building upgrades now consistently use building's `PowerUpN` animation settings corresponding to the upgrade's `PowersUpToLevel` where possible (by Starkku)
 - Subterranean units are no longer allowed to perform deploy functions like firing weapons or `IsSimpleDeployer` while burrowed or burrowing, they will instead emerge first like they do for transport unloading (by Starkku)
-- Subterranean units no longer draw an incorrectly positioned shadow when burrowing etc. (by Starkku)
 - Fixed `Temporal=true` Warheads potentially crashing game if used to attack `Slaved=true` infantry (by Starkku)
 
 Phobos fixes:

src/Ext/Techno/Hooks.cpp

@@ -596,11 +596,6 @@ DEFINE_HOOK(0x6F9FA9, TechnoClass_AI_PromoteAnim, 0x6)
 	return aresProcess();
 }
 
-// TunnelLocomotionClass_IsToHaveShadow, skip shadow on all but idle.
-// TODO: Investigate if it is possible to fix the shadows not tilting on the burrowing etc. states.
-DEFINE_JUMP(LJMP, 0x72A070, 0x72A07F);
-
-
 DEFINE_HOOK(0x51B20E, InfantryClass_AssignTarget_FireOnce, 0x6)
 {
 	enum { SkipGameCode = 0x51B255 };

src/Ext/TechnoType/Hooks.cpp

@@ -21,6 +21,7 @@
 #include <JumpjetLocomotionClass.h>
 #include <FlyLocomotionClass.h>
 #include <RocketLocomotionClass.h>
+#include <TunnelLocomotionClass.h>
 
 DEFINE_HOOK(0x6F64A9, TechnoClass_DrawHealthBar_Hide, 0x5)
 {
@@ -312,6 +313,49 @@ struct DummyExtHere // TODO: move it
 	VoxelStruct NoSpawnAltVXL;
 };
 
+Matrix3D* __stdcall TunnelLocomotionClass_ShadowMatrix(ILocomotion* iloco, Matrix3D* ret,VoxelIndexKey* key)
+{
+	__assume(iloco != nullptr);
+	auto tLoco = static_cast<TunnelLocomotionClass*>(iloco);
+	*ret = tLoco->LocomotionClass::Shadow_Matrix(key);
+	if (tLoco->State != TunnelLocomotionClass::State::Idle)
+	{
+		double theta = 0.;
+		switch (tLoco->State)
+		{
+		case TunnelLocomotionClass::State::DiggingIn:
+			if (key)key->Invalidate();
+			theta = Math::HalfPi;
+			if (auto total = tLoco->DigTimer.Rate)
+				theta *= 1.0 - double(tLoco->DigTimer.GetTimeLeft()) / double(total);
+			break;
+		case TunnelLocomotionClass::State::DugIn:
+			theta = Math::HalfPi;
+			break;
+		case TunnelLocomotionClass::State::PreDigOut:
+			theta = -Math::HalfPi;
+			break;
+		case TunnelLocomotionClass::State::DiggingOut:
+			if (key)key->Invalidate();
+			theta = -Math::HalfPi;
+			if (auto total = tLoco->DigTimer.Rate)
+				theta *= double(tLoco->DigTimer.GetTimeLeft()) / double(total);
+			break;
+		case TunnelLocomotionClass::State::DugOut:
+			if (key)key->Invalidate();
+			theta = Math::HalfPi;
+			if (auto total = tLoco->DigTimer.Rate)
+				theta *= double(tLoco->DigTimer.GetTimeLeft()) / double(total);
+			break;
+		default:break;
+		}
+		ret->ScaleX((float)Math::cos(theta));// I know it's ugly
+	}
+	return ret;
+}
+
+DEFINE_JUMP(VTABLE, 0x7F5A4C, GET_OFFSET(TunnelLocomotionClass_ShadowMatrix));
+
 DEFINE_HOOK(0x73C47A, UnitClass_DrawAsVXL_Shadow, 0x5)
 {
 	GET(UnitClass*, pThis, EBP);