Fix visceroids getting spawned when gas destroys non-crewed vehicles,…

… buildings, and terrain objects

CREDITS.md

@@ -167,6 +167,7 @@ This page lists all the individual contributions to the project by their author.
   - Allow scenarios to have custom score screen bar colors.
   - Add `Inaccuracy` to RocketTypes.
   - Add `TargetZoneScan` to TechnoTypes.
+  - Fix a bug where a visceroid was spawned when poison gas destroyed a non-crewed vehicle, building, or terrain object.
 - **secsome**:
   - Add support for up to 32767 waypoints to be used in scenarios.
 - **Starkku**:

docs/Bugfixes.md

@@ -65,3 +65,4 @@ This page lists all vanilla bugs fixed by Vinifera.
 - `[CombatDamage]->MinDamage` now works as expected and damage is no long always a minimum of `1`.
 - VehicleTypes with Jumpjet locomotion now take damage in flight.
 - Fix the map glitching around when scrolling if the map is not large enough to fill the entire screen.
+- Fix a bug where a visceroid was spawned when poison gas destroyed a non-crewed vehicle, building, or terrain object.

src/extensions/particle/particleext_hooks.cpp

@@ -0,0 +1,104 @@
+/*******************************************************************************
+/*                 O P E N  S O U R C E  --  V I N I F E R A                  **
+/*******************************************************************************
+ *
+ *  @project       Vinifera (Dawn of the Tiberium Age Build)
+ *
+ *  @file          PARTICLEEXT_HOOKS.CPP
+ *
+ *  @author        Rampastring
+ *
+ *  @brief         Contains the hooks for the extended ParticleClass.
+ *
+ *  @license       Vinifera is free software: you can redistribute it and/or
+ *                 modify it under the terms of the GNU General Public License
+ *                 as published by the Free Software Foundation, either version
+ *                 3 of the License, or (at your option) any later version.
+ *
+ *                 Vinifera is distributed in the hope that it will be
+ *                 useful, but WITHOUT ANY WARRANTY; without even the implied
+ *                 warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ *                 PURPOSE. See the GNU General Public License for more details.
+ *
+ *                 You should have received a copy of the GNU General Public
+ *                 License along with this program.
+ *                 If not, see <http://www.gnu.org/licenses/>.
+ *
+ ******************************************************************************/
+#include "building.h"
+#include "house.h"
+#include "housetype.h"
+#include "particlesysext_hooks.h"
+#include "particlesys.h"
+#include "rules.h"
+#include "scenario.h"
+#include "unit.h"
+#include "tibsun_globals.h"
+#include "tibsun_defines.h"
+#include "fatal.h"
+#include "debughandler.h"
+#include "asserthandler.h"
+
+#include "hooker.h"
+#include "hooker_macros.h"
+
+
+UnitClass* Create_Visceroid(ObjectClass* destroyedobject)
+{
+	if (destroyedobject->What_Am_I() == RTTI_INFANTRY ||
+		(destroyedobject->What_Am_I() == RTTI_UNIT && reinterpret_cast<UnitClass*>(destroyedobject)->Class->IsCrew) ||
+		(destroyedobject->What_Am_I() == RTTI_BUILDING && reinterpret_cast<BuildingClass*>(destroyedobject)->Class->IsCrew))
+	{
+		return new UnitClass(Rule->SmallVisceroid, HouseClass::As_Pointer(HouseTypeClass::From_Name("Neutral")));
+	}
+
+	return nullptr;
+}
+
+
+/**
+ *  Fixes a bug where gas clouds are able to turn everything into visceroids, including
+ *  non-crewed vehicles and even terrain objects.
+ */
+DECLARE_PATCH(_ParticleClass_Smoke_And_WeakGas_Behaviour_AI_Tiberium_Death_Patch)
+{
+	GET_REGISTER_STATIC(ObjectClass*, destroyedobject, esi);
+	GET_REGISTER_STATIC(ResultType, result, eax);
+	GET_STACK_STATIC(ObjectClass*, nextobject, esp, 0x40);
+	static UnitClass* visceroid;
+
+	enum {
+		ContinueVisceroidPlacement = 0x005A38FC,
+		SkipToNextObjectOnCell = 0x005A3965
+	};
+
+	_asm { mov esi, dword ptr ds:nextobject }
+
+	if (result != RESULT_DESTROYED) {
+		// Object was not destroyed, do not create visceroid.
+		JMP(SkipToNextObjectOnCell);
+	}
+
+	if (!Scen->IsTiberiumDeathToVisceroid) {
+		// Visceroids spawning from Tiberium death is disabled, do not create visceroid.
+		JMP(SkipToNextObjectOnCell);
+	}
+
+	visceroid = Create_Visceroid(destroyedobject);
+	if (visceroid == nullptr) {
+		// No visceroid was created.
+		JMP(SkipToNextObjectOnCell);
+	}
+
+	_asm { mov edi, dword ptr ds:visceroid }
+	JMP(ContinueVisceroidPlacement);
+}
+
+
+/**
+ *  Main function for patching the hooks.
+ */
+void ParticleClassExtension_Hooks()
+{
+	Patch_Jump(0x005A389C, &_ParticleClass_Smoke_And_WeakGas_Behaviour_AI_Tiberium_Death_Patch);
+}

src/extensions/particle/particleext_hooks.h

@@ -0,0 +1,31 @@
+/*******************************************************************************
+/*                 O P E N  S O U R C E  --  V I N I F E R A                  **
+/*******************************************************************************
+ *
+ *  @project       Vinifera (Dawn of the Tiberium Age Build)
+ *
+ *  @file          PARTICLEEXT_HOOKS.H
+ *
+ *  @author        Rampastring
+ *
+ *  @brief         Contains the hooks for the extended ParticleClass.
+ *
+ *  @license       Vinifera is free software: you can redistribute it and/or
+ *                 modify it under the terms of the GNU General Public License
+ *                 as published by the Free Software Foundation, either version
+ *                 3 of the License, or (at your option) any later version.
+ *
+ *                 Vinifera is distributed in the hope that it will be
+ *                 useful, but WITHOUT ANY WARRANTY; without even the implied
+ *                 warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ *                 PURPOSE. See the GNU General Public License for more details.
+ *
+ *                 You should have received a copy of the GNU General Public
+ *                 License along with this program.
+ *                 If not, see <http://www.gnu.org/licenses/>.
+ *
+ ******************************************************************************/
+#pragma once
+
+
+void ParticleClassExtension_Hooks();