diff --git a/source/games/blood/src/aigilbst.cpp b/source/games/blood/src/aigilbst.cpp
index fdff03e82..e74490ac9 100644
--- a/source/games/blood/src/aigilbst.cpp
+++ b/source/games/blood/src/aigilbst.cpp
@@ -116,9 +116,9 @@ static void gillThinkChase(DBloodActor* actor)
 	DUDEINFO* pDudeInfo = getDudeInfo(actor->spr.type);
 	if (!actor->ValidateTarget(__FUNCTION__)) return;
 	auto target = actor->GetTarget();
-	int dx = target->int_pos().X - actor->int_pos().X;
-	int dy = target->int_pos().Y - actor->int_pos().Y;
-	aiChooseDirection(actor, VecToAngle(dx, dy));
+	auto dv = target->spr.pos.XY() - actor->spr.pos.XY();
+	DAngle nAngle = VecToAngle(dv);
+	aiChooseDirection(actor, nAngle);
 	if (actor->xspr.health == 0)
 	{
 		if (pXSector && pXSector->Underwater)
@@ -135,20 +135,20 @@ static void gillThinkChase(DBloodActor* actor)
 			aiNewState(actor, &gillBeastSearch);
 		return;
 	}
-	int nDist = approxDist(dx, dy);
-	if (nDist <= pDudeInfo->seeDist)
+	double nDist = dv.Length();
+	if (nDist <= pDudeInfo->SeeDist())
 	{
-		int nDeltaAngle = getincangle(actor->int_ang(), getangle(dx, dy));
+		DAngle nDeltaAngle = absangle(actor->spr.angle, nAngle);
 		double height = (pDudeInfo->eyeHeight * actor->spr.yrepeat) * REPEAT_SCALE;
 		if (cansee(target->spr.pos, target->sector(), actor->spr.pos.plusZ(-height), actor->sector()))
 		{
-			if (nDist < pDudeInfo->seeDist && abs(nDeltaAngle) <= pDudeInfo->periphery)
+			if (nDist < pDudeInfo->SeeDist() && nDeltaAngle <= pDudeInfo->Periphery())
 			{
 				aiSetTarget(actor, actor->GetTarget());
-				actor->dudeSlope = nDist == 0 ? 0 : DivScale(target->int_pos().Z - actor->int_pos().Z, nDist, 10);
-				if (nDist < 921 && abs(nDeltaAngle) < 28)
+				actor->dudeSlope = nDist == 0 ? 0 : (target->spr.pos.Z - actor->spr.pos.Z) / nDist * 16384;
+				if (nDist < 57.5625 && abs(nDeltaAngle) < DAngle1 * 5)
 				{
-					int hit = HitScan_(actor, actor->spr.pos.Z, dx, dy, 0, CLIPMASK1, 0);
+					int hit = HitScan(actor, actor->spr.pos.Z, DVector3(dv, 0), CLIPMASK1, 0);
 					switch (hit)
 					{
 					case -1: