From 1a3e2ff18e42b2c07a3b84b157f5689c0598eb55 Mon Sep 17 00:00:00 2001
From: Nyx Linden <nyx@lindenlab.com>
Date: Wed, 3 Apr 2013 18:59:50 -0400
Subject: [PATCH] SH-4050 FIX camera goes below ground when avatar offset set
 to 0

Added a constraint to ensure that the avatar's height (with offset)
does not go below 0.1 meters. Camera was getting confused since the avatar's
effective height was negative.

Note the avatar is mostly underground/contorted even at 0.1 meters, but
most users setting values this low will be making ultra-tinies and would
be hiding the avatar mesh. Camera stays above ground when height is at 0.1.

Conflicts:

	indra/llappearance/llavatarappearance.cpp
---
 indra/llappearance/llavatarappearance.cpp     | 21 ++++++++++++++++++-
 .../llappearance/llavatarappearancedefines.h  |  2 ++
 indra/newview/llvoavatar.cpp                  |  2 +-
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/indra/llappearance/llavatarappearance.cpp b/indra/llappearance/llavatarappearance.cpp
index 385546798..413e28951 100644
--- a/indra/llappearance/llavatarappearance.cpp
+++ b/indra/llappearance/llavatarappearance.cpp
@@ -465,7 +465,7 @@ void LLAvatarAppearance::computeBodySize()
 
 	LLVector3 old_offset = mAvatarOffset;
 
-	mAvatarOffset.mV[VZ] = getVisualParamWeight(11001);
+	mAvatarOffset.mV[VZ] = getVisualParamWeight(AVATAR_HOVER);
 
 	mPelvisToFoot = hip.mV[VZ] * pelvis_scale.mV[VZ] -
 				 	knee.mV[VZ] * hip_scale.mV[VZ] -
@@ -489,6 +489,25 @@ void LLAvatarAppearance::computeBodySize()
 	mAvatarOffset.mV[VX] = 0.0f;
 	mAvatarOffset.mV[VY] = 0.0f;
 
+	// Certain configurations of avatars can force the overall height (with offset) to go negative.
+	// Enforce a constraint to make sure we don't go below 0.1 meters.
+	// Camera positioning and other things start to break down when your avatar is "walking" while being fully underground
+	if (new_body_size.mV[VZ] + mAvatarOffset.mV[VZ] < 0.1f) 
+	{
+		mAvatarOffset.mV[VZ] = -(new_body_size.mV[VZ] - 0.11f); // avoid floating point rounding making the above check continue to fail.
+
+		llassert(new_body_size.mV[VZ] + mAvatarOffset.mV[VZ] >= 0.1f);
+
+		if (mWearableData) 
+		{
+			LLWearable* shape = mWearableData->getWearable(LLWearableType::WT_SHAPE, 0);
+			if (shape) 
+			{
+				shape->setVisualParamWeight(AVATAR_HOVER, mAvatarOffset.mV[VZ], false);
+			}
+		}
+	}
+
 	if (new_body_size != mBodySize || old_offset != mAvatarOffset)
 	{
 		mBodySize = new_body_size;
diff --git a/indra/llappearance/llavatarappearancedefines.h b/indra/llappearance/llavatarappearancedefines.h
index 496f85c10..8a1d2c470 100644
--- a/indra/llappearance/llavatarappearancedefines.h
+++ b/indra/llappearance/llavatarappearancedefines.h
@@ -41,6 +41,8 @@ extern const S32 SCRATCH_TEX_WIDTH;
 extern const S32 SCRATCH_TEX_HEIGHT;
 extern const S32 IMPOSTOR_PERIOD;
 
+static const U32 AVATAR_HOVER = 11001;
+
 //--------------------------------------------------------------------
 // Enums
 //--------------------------------------------------------------------
diff --git a/indra/newview/llvoavatar.cpp b/indra/newview/llvoavatar.cpp
index 7df112448..72e94c72c 100644
--- a/indra/newview/llvoavatar.cpp
+++ b/indra/newview/llvoavatar.cpp
@@ -3758,7 +3758,7 @@ BOOL LLVOAvatar::updateCharacter(LLAgent &agent)
 		}
 
 		root_pos = gAgent.getPosGlobalFromAgent(getRenderPosition());
-		root_pos.mdV[VZ] += getVisualParamWeight(11001);
+		root_pos.mdV[VZ] += getVisualParamWeight(AVATAR_HOVER);
 
 
 		resolveHeightGlobal(root_pos, ground_under_pelvis, normal);