properly consider frame index for multi-section vxl shadow

src/Ext/TechnoType/Hooks.cpp

@@ -355,14 +355,15 @@ DEFINE_HOOK(0x4DB157, FootClass_DrawVoxelShadow_TurretShadow, 0x8)
 
 	if (pTypeExt->TurretShadow.Get(RulesExt::Global()->DrawTurretShadow) && tur->VXL && tur->HVA)
 	{
-		auto mtx = pThis->Locomotor->Shadow_Matrix(0);
+		auto mtx = Matrix3D::GetIdentity();
 		pTypeExt->ApplyTurretOffset(&mtx, *reinterpret_cast<double*>(0xB1D008));
-		mtx.TranslateZ(-tur->HVA->Matrixes[0].GetZVal());
 		mtx.RotateZ(static_cast<float>(pThis->SecondaryFacing.Current().GetRadian<32>() - pThis->PrimaryFacing.Current().GetRadian<32>()));
-		Matrix3D::MatrixMultiply(&mtx, &Matrix3D::VoxelDefaultMatrix, &mtx);
+		mtx = *pMatrix * mtx;
 
 		pThis->DrawVoxelShadow(tur, 0, angle, 0, a4, &a3, &mtx, a9, pSurface, pos);
-		auto bar = &pType->BarrelVoxel;
+
+		auto bar = (pType->TurretCount == 0 || pType->IsGattling) ?
+			&pType->BarrelVoxel : &pType->ChargerBarrels[pThis->CurrentTurretNumber];
 
 		if (bar->VXL && bar->HVA)
 			pThis->DrawVoxelShadow(bar, 0, angle, 0, a4, &a3, &mtx, a9, pSurface, pos);
@@ -376,13 +377,48 @@ DEFINE_HOOK(0x4DB157, FootClass_DrawVoxelShadow_TurretShadow, 0x8)
 	{
 		for (auto index : pTypeExt->ShadowIndices)
 		{
-			auto hva = pVXL->HVA;
-			Matrix3D idxmtx = *pMatrix;
-			idxmtx.TranslateZ(-hva->Matrixes[index].GetZVal());
-			Matrix3D::MatrixMultiply(&idxmtx, &Matrix3D::VoxelDefaultMatrix, &idxmtx);
 			pThis->DrawVoxelShadow(pVXL, index, angle, a5, a4, &a3, pMatrix, a9, pSurface, pos);
 		}
 	}
 
 	return 0x4DB195;
 }
+
+DEFINE_HOOK(0x7072A1, sub707280_TryFixingTheMatrix, 0x7)
+{
+	GET(FootClass*, pThis, EBX);
+	GET(VoxelStruct*, pVXL, EBP);
+	GET_STACK(Matrix3D*, pMat, STACK_OFFSET(0xE8, 0xC));
+	GET_STACK(int, shadow_index, STACK_OFFSET(0xE8, 0x18));
+
+	REF_STACK(Matrix3D, matRet, STACK_OFFSET(0xE8, -0x60));
+
+	auto hva = pVXL->HVA;
+	// cursed
+	int index = shadow_index + hva->LayerCount * (pThis->WalkedFramesSoFar % hva->FrameCount);
+	Matrix3D hvamat = hva->Matrixes[index];
+	// TODO : what is this Z offset supposed to be exactly? In order to properly shift the sections to the same level
+	hvamat.TranslateZ(
+		-hvamat.GetZVal()
+		- pVXL->VXL->TailerData->MinBounds.Z
+	);
+
+	matRet = *pMat * hvamat;
+
+	// Recover vanilla instructions
+	auto pType = pThis->GetTechnoType();
+	if (pType->UseBuffer)
+		*reinterpret_cast<DWORD*>(0xB43180) = 1;
+
+	REF_STACK(Matrix3D, b, STACK_OFFSET(0xE8, -0x90));
+	b.MakeIdentity();
+
+	// TODO: properly scale this
+	if (pType->ConsideredAircraft)
+		b.Scale(
+		//	1.f - 0.5f * std::clamp(pThis->GetHeight(), 0, 728) / 728.f
+			0.5f
+		);
+
+	return 0x707331;
+}