Add support for custom filter entities

Starting with filter_activator_context

extension.cpp

@@ -37,6 +37,8 @@
 #include <IEngineTrace.h>
 #include <server_class.h>
 #include <ispatialpartition.h>
+#include <utlvector.h>
+#include <string_t.h>
 
 #define SetBit(A,I)		((A)[(I) >> 5] |= (1 << ((I) & 31)))
 #define ClearBit(A,I)	((A)[(I) >> 5] &= ~(1 << ((I) & 31)))
@@ -173,6 +175,13 @@ struct variant_hax
 	const char *pszValue;
 };
 
+struct ResponseContext_t
+{
+	string_t m_iszName;
+	string_t m_iszValue;
+	float m_fExpirationTime;
+};
+
 struct inputdata_t
 {
 	// The entity that initially caused this chain of output events.
@@ -202,6 +211,8 @@ IGameConfig *g_pGameConf = NULL;
 
 CDetour *g_pDetour_InputTestActivator = NULL;
 CDetour *g_pDetour_PostConstructor = NULL;
+CDetour *g_pDetour_CreateEntityByName = NULL;
+CDetour *g_pDetour_PassesFilterImpl = NULL;
 CDetour *g_pDetour_FindUseEntity = NULL;
 CDetour *g_pDetour_CTraceFilterSimple = NULL;
 CDetour *g_pDetour_KeyValue = NULL;
@@ -243,6 +254,64 @@ DETOUR_DECL_MEMBER1(DETOUR_PostConstructor, void, const char *, szClassname)
 	DETOUR_MEMBER_CALL(DETOUR_PostConstructor)(szClassname);
 }
 
+// Implementation for custom filter entities
+DETOUR_DECL_MEMBER2(DETOUR_PassesFilterImpl, bool, CBaseEntity*, pCaller, CBaseEntity*, pEntity)
+{
+	CBaseEntity* pThisEnt = (CBaseEntity*)this;
+
+	// filter_activator_context: filters activators based on whether they have a given context with a nonzero value
+	// https://developer.valvesoftware.com/wiki/Filter_activator_context
+	// Implemented here because CUtlVectors are not supported in sourcepawn
+	if (!strcasecmp(gamehelpers->GetEntityClassname(pThisEnt), "filter_activator_context"))
+	{
+		static int m_ResponseContexts_offset = 0, m_iszResponseContext_offset = 0;
+
+		if (!m_ResponseContexts_offset && !m_iszResponseContext_offset)
+		{
+			datamap_t *pDataMap = gamehelpers->GetDataMap(pEntity);
+			sm_datatable_info_t info;
+			
+			// Both are CBaseEntity members, so the offsets will always be the same across different entity classes
+			gamehelpers->FindDataMapInfo(pDataMap, "m_ResponseContexts", &info);
+			m_ResponseContexts_offset = info.actual_offset;
+
+			gamehelpers->FindDataMapInfo(pDataMap, "m_iszResponseContext", &info);
+			m_iszResponseContext_offset = info.actual_offset;
+		}
+
+		CUtlVector<ResponseContext_t> vecResponseContexts;
+		vecResponseContexts = *(CUtlVector<ResponseContext_t>*)((uint8_t*)pEntity + m_ResponseContexts_offset);
+
+		const char *szFilterContext = (*(string_t*)((uint8_t*)pThisEnt + m_iszResponseContext_offset)).ToCStr();
+		const char *szContext;
+		int iContextValue;
+
+		for (int i = 0; i < vecResponseContexts.Count(); i++)
+		{
+			szContext = vecResponseContexts[i].m_iszName.ToCStr();
+			iContextValue = atoi(vecResponseContexts[i].m_iszValue.ToCStr());
+
+			if (!strcasecmp(szFilterContext, szContext) && iContextValue > 0)
+				return true;
+		}
+
+		return false;
+	}
+	
+	// CBaseFilter::PassesFilterImpl just returns true so no need to call it
+	return true;
+}
+
+// Switch new entity classnames to ones that can be instantiated while keeping the classname keyvalue intact so it can be used later
+DETOUR_DECL_STATIC2(DETOUR_CreateEntityByName, CBaseEntity*, const char*, className, int, iForceEdictIndex)
+{
+	// Nice of valve to expose CBaseFilter as filter_base :)
+	if (strcasecmp(className, "filter_activator_context") == 0)
+		className = "filter_base";
+
+	return DETOUR_STATIC_CALL(DETOUR_CreateEntityByName)(className, iForceEdictIndex);
+}
+
 DETOUR_DECL_MEMBER2(DETOUR_KeyValue, bool, const char *, szKeyName, const char *, szValue)
 {
 	// Fix crash bug in engine
@@ -455,6 +524,22 @@ bool CSSFixes::SDK_OnLoad(char *error, size_t maxlength, bool late)
 		return false;
 	}
 
+	g_pDetour_CreateEntityByName = DETOUR_CREATE_STATIC(DETOUR_CreateEntityByName, "CreateEntityByName");
+	if (g_pDetour_CreateEntityByName == NULL)
+	{
+		snprintf(error, maxlength, "Could not create detour for CreateEntityByName");
+		SDK_OnUnload();
+		return false;
+	}
+
+	g_pDetour_PassesFilterImpl = DETOUR_CREATE_MEMBER(DETOUR_PassesFilterImpl, "CBaseFilter_PassesFilterImpl");
+	if (g_pDetour_PassesFilterImpl == NULL)
+	{
+		snprintf(error, maxlength, "Could not create detour for CBaseFilter_PassesFilterImpl");
+		SDK_OnUnload();
+		return false;
+	}
+
 	g_pDetour_FindUseEntity = DETOUR_CREATE_MEMBER(DETOUR_FindUseEntity, "CBasePlayer_FindUseEntity");
 	if(g_pDetour_FindUseEntity == NULL)
 	{
@@ -497,6 +582,8 @@ bool CSSFixes::SDK_OnLoad(char *error, size_t maxlength, bool late)
 
 	g_pDetour_InputTestActivator->EnableDetour();
 	g_pDetour_PostConstructor->EnableDetour();
+	g_pDetour_CreateEntityByName->EnableDetour();
+	g_pDetour_PassesFilterImpl->EnableDetour();
 	g_pDetour_FindUseEntity->EnableDetour();
 	g_pDetour_CTraceFilterSimple->EnableDetour();
 	g_pDetour_KeyValue->EnableDetour();
@@ -625,6 +712,18 @@ void CSSFixes::SDK_OnUnload()
 		g_pDetour_PostConstructor = NULL;
 	}
 
+	if (g_pDetour_CreateEntityByName != NULL)
+	{
+		g_pDetour_CreateEntityByName->Destroy();
+		g_pDetour_CreateEntityByName = NULL;
+	}
+
+	if (g_pDetour_PassesFilterImpl != NULL)
+	{
+		g_pDetour_PassesFilterImpl->Destroy();
+		g_pDetour_PassesFilterImpl = NULL;
+	}
+
 	if(g_pDetour_FindUseEntity != NULL)
 	{
 		g_pDetour_FindUseEntity->Destroy();

gamedata/CSSFixes.txt

@@ -16,6 +16,18 @@
 				"linux"		"@_ZN11CBaseEntity15PostConstructorEPKc"
 			}
 			
+			"CBaseFilter_PassesFilterImpl"
+			{
+				"library"	"server"
+				"linux"		"@_ZN11CBaseFilter16PassesFilterImplEP11CBaseEntityS1_"
+			}
+
+			"CreateEntityByName"
+			{
+				"library"	"server"
+				"linux"		"@_Z18CreateEntityByNamePKci"
+			}
+
 			"CBasePlayer_FindUseEntity"
 			{
 				"library"	"server"