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diff --git a/game/client/client_virtualreality.cpp b/game/client/client_virtualreality.cpp
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+++ b/game/client/client_virtualreality.cpp
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+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+// $NoKeywords: $
+//===========================================================================//
+#include "cbase.h"
+
+#include "client_virtualreality.h"
+
+#include "materialsystem/itexture.h"
+#include "materialsystem/materialsystem_config.h"
+#include "view_shared.h"
+#include "view_scene.h"
+#include "VGuiMatSurface/IMatSystemSurface.h"
+#include "vgui_controls/Controls.h"
+#include "sourcevr/isourcevirtualreality.h"
+#include "ienginevgui.h"
+#include "cdll_client_int.h"
+#include "vgui/IVGui.h"
+#include "vgui_controls/Controls.h"
+#include "tier0/vprof_telemetry.h"
+#include <time.h>
+#include "steam/steam_api.h"
+
+const char *COM_GetModDirectory(); // return the mod dir (rather than the complete -game param, which can be a path)
+
+CClientVirtualReality g_ClientVirtualReality;
+EXPOSE_SINGLE_INTERFACE_GLOBALVAR( CClientVirtualReality, IClientVirtualReality, 
+	CLIENTVIRTUALREALITY_INTERFACE_VERSION, g_ClientVirtualReality );
+
+
+// --------------------------------------------------------------------
+// A huge pile of VR convars
+// --------------------------------------------------------------------
+ConVar vr_activate_default( "vr_activate_default",		"0", FCVAR_ARCHIVE, "If this is true the game will switch to VR mode once startup is complete." );
+
+
+ConVar vr_moveaim_mode      ( "vr_moveaim_mode",      "3", FCVAR_ARCHIVE, "0=move+shoot from face. 1=move with torso. 2,3,4=shoot with face+mouse cursor. 5+ are probably not that useful." );
+ConVar vr_moveaim_mode_zoom ( "vr_moveaim_mode_zoom", "3", FCVAR_ARCHIVE, "0=move+shoot from face. 1=move with torso. 2,3,4=shoot with face+mouse cursor. 5+ are probably not that useful." );
+
+ConVar vr_moveaim_reticle_yaw_limit        ( "vr_moveaim_reticle_yaw_limit",        "10", FCVAR_ARCHIVE, "Beyond this number of degrees, the mouse drags the torso" );
+ConVar vr_moveaim_reticle_pitch_limit      ( "vr_moveaim_reticle_pitch_limit",      "30", FCVAR_ARCHIVE, "Beyond this number of degrees, the mouse clamps" );
+// Note these are scaled by the zoom factor.
+ConVar vr_moveaim_reticle_yaw_limit_zoom   ( "vr_moveaim_reticle_yaw_limit_zoom",   "0", FCVAR_ARCHIVE, "Beyond this number of degrees, the mouse drags the torso" );
+ConVar vr_moveaim_reticle_pitch_limit_zoom ( "vr_moveaim_reticle_pitch_limit_zoom", "-1", FCVAR_ARCHIVE, "Beyond this number of degrees, the mouse clamps" );
+
+// This are somewhat obsolete.
+ConVar vr_aim_yaw_offset( "vr_aim_yaw_offset", "90", 0, "This value is added to Yaw when returning the vehicle aim angles to Source." );
+
+ConVar vr_stereo_swap_eyes ( "vr_stereo_swap_eyes", "0", 0, "1=swap eyes." );
+
+// Useful for debugging wacky-projection problems, separate from multi-rendering problems.
+ConVar vr_stereo_mono_set_eye ( "vr_stereo_mono_set_eye", "0", 0, "0=off, Set all eyes to 1=left, 2=right, 3=middle eye" );
+
+// Useful for examining anims, etc.
+ConVar vr_debug_remote_cam( "vr_debug_remote_cam", "0" );
+ConVar vr_debug_remote_cam_pos_x( "vr_debug_remote_cam_pos_x", "150.0" );
+ConVar vr_debug_remote_cam_pos_y( "vr_debug_remote_cam_pos_y", "0.0" );
+ConVar vr_debug_remote_cam_pos_z( "vr_debug_remote_cam_pos_z", "0.0" );
+ConVar vr_debug_remote_cam_target_x( "vr_debug_remote_cam_target_x", "0.0" );
+ConVar vr_debug_remote_cam_target_y( "vr_debug_remote_cam_target_y", "0.0" );
+ConVar vr_debug_remote_cam_target_z( "vr_debug_remote_cam_target_z", "-50.0" );
+
+ConVar vr_translation_limit( "vr_translation_limit", "10.0", 0, "How far the in-game head will translate before being clamped." );
+
+// HUD config values
+ConVar vr_render_hud_in_world( "vr_render_hud_in_world", "1" );
+ConVar vr_hud_max_fov( "vr_hud_max_fov", "60", FCVAR_ARCHIVE, "Max FOV of the HUD" );
+ConVar vr_hud_forward( "vr_hud_forward", "500", FCVAR_ARCHIVE, "Apparent distance of the HUD in inches" );
+ConVar vr_hud_display_ratio( "vr_hud_display_ratio", "0.95", FCVAR_ARCHIVE );
+ConVar vr_hud_never_overlay( "vr_hud_never_overlay", "0" );
+
+ConVar vr_hud_axis_lock_to_world( "vr_hud_axis_lock_to_world", "0", FCVAR_ARCHIVE, "Bitfield - locks HUD axes to the world - 0=pitch, 1=yaw, 2=roll" );
+
+// Default distance clips through rocketlauncher, heavy's body, etc.
+ConVar vr_projection_znear_multiplier( "vr_projection_znear_multiplier", "0.3", 0, "Allows moving the ZNear plane to deal with body clipping" );
+
+// Should the viewmodel (weapon) translate with the HMD, or remain fixed to the in-world body (but still rotate with the head)? Purely a graphics effect - no effect on actual bullet aiming.
+// Has no effect in aim modes where aiming is not controlled by the head.
+ConVar vr_viewmodel_translate_with_head ( "vr_viewmodel_translate_with_head", "0", 0, "1=translate the viewmodel with the head motion." );
+
+ConVar vr_zoom_multiplier ( "vr_zoom_multiplier", "2.0", FCVAR_ARCHIVE, "When zoomed, how big is the scope on your HUD?" );
+ConVar vr_zoom_scope_scale ( "vr_zoom_scope_scale", "6.0", 0, "Something to do with the default scope HUD overlay size." );		// Horrible hack - should work out the math properly, but we need to ship.
+
+
+ConVar vr_viewmodel_offset_forward( "vr_viewmodel_offset_forward", "-8", 0 );
+ConVar vr_viewmodel_offset_forward_large( "vr_viewmodel_offset_forward_large", "-15", 0 );
+
+ConVar vr_force_windowed ( "vr_force_windowed", "0", FCVAR_ARCHIVE );
+
+ConVar vr_first_person_uses_world_model ( "vr_first_person_uses_world_model", "1", 0, "Causes the third person model to be drawn instead of the view model" );
+
+// --------------------------------------------------------------------
+// Purpose: Cycle through the aim & move modes.
+// --------------------------------------------------------------------
+void CC_VR_Cycle_Aim_Move_Mode ( const CCommand& args )
+{
+	int hmmCurrentMode = vr_moveaim_mode.GetInt();
+	if ( g_ClientVirtualReality.CurrentlyZoomed() )
+	{
+		hmmCurrentMode = vr_moveaim_mode_zoom.GetInt();
+	}
+
+	hmmCurrentMode++;
+	if ( hmmCurrentMode >= HMM_LAST )
+	{
+		hmmCurrentMode = 0;
+	}
+
+	if ( g_ClientVirtualReality.CurrentlyZoomed() )
+	{
+		vr_moveaim_mode_zoom.SetValue ( hmmCurrentMode );
+		Warning ( "Headtrack mode (zoomed) %d\n", hmmCurrentMode );
+	}
+	else
+	{
+		vr_moveaim_mode.SetValue ( hmmCurrentMode );
+		Warning ( "Headtrack mode %d\n", hmmCurrentMode );
+	}
+}
+static ConCommand vr_cycle_aim_move_mode("vr_cycle_aim_move_mode", CC_VR_Cycle_Aim_Move_Mode, "Cycle through the aim & move modes." );
+
+
+// --------------------------------------------------------------------
+// Purpose:  Switch to/from VR mode.
+// --------------------------------------------------------------------
+CON_COMMAND( vr_activate, "Switch to VR mode" )
+{
+	g_ClientVirtualReality.Activate();
+}
+CON_COMMAND( vr_deactivate, "Switch from VR mode to normal mode" )
+{
+	g_ClientVirtualReality.Deactivate();
+}
+CON_COMMAND( vr_toggle, "Toggles VR mode" )
+{
+	if( g_pSourceVR )
+	{
+		if( g_pSourceVR->ShouldRunInVR() )
+			g_ClientVirtualReality.Deactivate();
+		else
+			g_ClientVirtualReality.Activate();
+	}
+	else
+	{
+		Msg( "VR Mode is not enabled.\n" );
+	}
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Returns true if the matrix is orthonormal
+// --------------------------------------------------------------------
+bool IsOrthonormal ( VMatrix Mat, float fTolerance )
+{
+	float LenFwd = Mat.GetForward().Length();
+	float LenUp = Mat.GetUp().Length();
+	float LenLeft = Mat.GetLeft().Length();
+	float DotFwdUp = Mat.GetForward().Dot ( Mat.GetUp() );
+	float DotUpLeft = Mat.GetUp().Dot ( Mat.GetLeft() );
+	float DotLeftFwd = Mat.GetLeft().Dot ( Mat.GetForward() );
+	if ( fabsf ( LenFwd - 1.0f ) > fTolerance )
+	{
+		return false;
+	}
+	if ( fabsf ( LenUp - 1.0f ) > fTolerance )
+	{
+		return false;
+	}
+	if ( fabsf ( LenLeft - 1.0f ) > fTolerance )
+	{
+		return false;
+	}
+	if ( fabsf ( DotFwdUp ) > fTolerance )
+	{
+		return false;
+	}
+	if ( fabsf ( DotUpLeft ) > fTolerance )
+	{
+		return false;
+	}
+	if ( fabsf ( DotLeftFwd ) > fTolerance )
+	{
+		return false;
+	}
+	return true;
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Computes the FOV from the projection matrix
+// --------------------------------------------------------------------
+void CalcFovFromProjection ( float *pFov, const VMatrix &proj )
+{
+	// The projection matrices should be of the form:
+	// p0  0   z1 p1 
+	// 0   p2  z2 p3
+	// 0   0   z3 1
+	// (p0 = X fov, p1 = X offset, p2 = Y fov, p3 = Y offset )
+	// TODO: cope with more complex projection matrices?
+	float xscale  = proj.m[0][0];
+	Assert ( proj.m[0][1] == 0.0f );
+	float xoffset = proj.m[0][2];
+	Assert ( proj.m[0][3] == 0.0f );
+	Assert ( proj.m[1][0] == 0.0f );
+	float yscale  = proj.m[1][1];
+	float yoffset = proj.m[1][2];
+	Assert ( proj.m[1][3] == 0.0f );
+	// Row 2 determines Z-buffer values - don't care about those for now.
+	Assert ( proj.m[3][0] == 0.0f );
+	Assert ( proj.m[3][1] == 0.0f );
+	Assert ( proj.m[3][2] == -1.0f );
+	Assert ( proj.m[3][3] == 0.0f );
+
+	/*
+	// The math here:
+	// A view-space vector (x,y,z,1) is transformed by the projection matrix
+	// / xscale   0     xoffset  0 \
+	// |    0   yscale  yoffset  0 |
+	// |    ?     ?        ?     ? |
+	// \    0     0       -1     0 /
+	//
+	// Then the result is normalized (i.e. divide by w) and the result clipped to the [-1,+1] unit cube.
+	// (ignore Z for now, and the clipping is slightly different).
+	// So, we want to know what vectors produce a clip value of -1 and +1 in each direction, e.g. in the X direction:
+	//    +-1 = ( xscale*x + xoffset*z ) / (-1*z)
+	//        = xscale*(x/z) + xoffset            (I flipped the signs of both sides)
+	// => (+-1 - xoffset)/xscale = x/z
+	// ...and x/z is tan(theta), and theta is the half-FOV.
+	*/
+
+	float fov_px = 2.0f * RAD2DEG ( atanf ( fabsf ( (  1.0f - xoffset ) / xscale ) ) );
+	float fov_nx = 2.0f * RAD2DEG ( atanf ( fabsf ( ( -1.0f - xoffset ) / xscale ) ) );
+	float fov_py = 2.0f * RAD2DEG ( atanf ( fabsf ( (  1.0f - yoffset ) / yscale ) ) );
+	float fov_ny = 2.0f * RAD2DEG ( atanf ( fabsf ( ( -1.0f - yoffset ) / yscale ) ) );
+
+	*pFov = Max ( Max ( fov_px, fov_nx ), Max ( fov_py, fov_ny ) );
+	// FIXME: hey you know, I could do the Max() series before I call all those expensive atanf()s...
+}
+
+
+// --------------------------------------------------------------------
+// construction/destruction
+// --------------------------------------------------------------------
+CClientVirtualReality::CClientVirtualReality()
+{
+	m_PlayerTorsoOrigin.Init();
+	m_PlayerTorsoAngle.Init();
+	m_WorldFromWeapon.Identity();
+	m_WorldFromMidEye.Identity();
+	
+	m_bOverrideTorsoAngle = false;
+	m_OverrideTorsoOffset.Init();
+
+	// Also reset our model of the player's torso orientation
+	m_PlayerTorsoAngle.Init ( 0.0f, 0.0f, 0.0f );
+
+	m_WorldZoomScale = 1.0f;
+	m_hmmMovementActual = HMM_SHOOTFACE_MOVEFACE;
+	m_iAlignTorsoAndViewToWeaponCountdown = 0;
+
+	m_rtLastMotionSample = 0;
+	m_bMotionUpdated = false;
+
+#if defined( USE_SDL )
+    m_nNonVRSDLDisplayIndex = 0;
+#endif
+}
+
+CClientVirtualReality::~CClientVirtualReality()
+{
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: 
+// --------------------------------------------------------------------
+bool			CClientVirtualReality::Connect( CreateInterfaceFn factory )
+{
+	if ( !factory )
+		return false;
+
+	if ( !BaseClass::Connect( factory ) )
+		return false;
+
+	return true;
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: 
+// --------------------------------------------------------------------
+void			CClientVirtualReality::Disconnect()
+{
+	BaseClass::Disconnect();
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: 
+// --------------------------------------------------------------------
+void *			CClientVirtualReality::QueryInterface( const char *pInterfaceName )
+{
+	CreateInterfaceFn factory = Sys_GetFactoryThis();	// This silly construction is necessary
+	return factory( pInterfaceName, NULL );				// to prevent the LTCG compiler from crashing.
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: 
+// --------------------------------------------------------------------
+InitReturnVal_t	CClientVirtualReality::Init()
+{
+	InitReturnVal_t nRetVal = BaseClass::Init();
+	if ( nRetVal != INIT_OK )
+		return nRetVal;
+
+	return INIT_OK;
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: 
+// --------------------------------------------------------------------
+void			CClientVirtualReality::Shutdown()
+{
+	BaseClass::Shutdown();
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Draws the main menu in Stereo
+// --------------------------------------------------------------------
+void CClientVirtualReality::DrawMainMenu()
+{
+	// have to draw the UI in stereo via the render texture or it won't fuse properly
+
+	// Draw it into the render target first
+	ITexture *pTexture = materials->FindTexture( "_rt_gui", NULL, false );
+	Assert( pTexture );
+	if( !pTexture) 
+		return;
+
+	CMatRenderContextPtr pRenderContext( materials );
+	int viewActualWidth = pTexture->GetActualWidth();
+	int viewActualHeight = pTexture->GetActualHeight();
+
+	int viewWidth, viewHeight;
+	vgui::surface()->GetScreenSize( viewWidth, viewHeight );
+
+	// clear depth in the backbuffer before we push the render target
+	pRenderContext->ClearBuffers( false, true, true );
+
+	// constrain where VGUI can render to the view
+	pRenderContext->PushRenderTargetAndViewport( pTexture, NULL, 0, 0, viewActualWidth, viewActualHeight );
+	pRenderContext->OverrideAlphaWriteEnable( true, true );
+
+	// clear the render target 
+	pRenderContext->ClearColor4ub( 0, 0, 0, 0 );
+	pRenderContext->ClearBuffers( true, false );
+
+	tmZone( TELEMETRY_LEVEL0, TMZF_NONE, "VGui_DrawHud", __FUNCTION__ );
+
+	// Make sure the client .dll root panel is at the proper point before doing the "SolveTraverse" calls
+	vgui::VPANEL root = enginevgui->GetPanel( PANEL_CLIENTDLL );
+	if ( root != 0 )
+	{
+		vgui::ipanel()->SetSize( root, viewWidth, viewHeight );
+	}
+	// Same for client .dll tools
+	root = enginevgui->GetPanel( PANEL_CLIENTDLL_TOOLS );
+	if ( root != 0 )
+	{
+		vgui::ipanel()->SetSize( root, viewWidth, viewHeight );
+	}
+
+	// paint the main menu and cursor
+	render->VGui_Paint( (PaintMode_t) ( PAINT_UIPANELS | PAINT_CURSOR ) );
+
+	pRenderContext->OverrideAlphaWriteEnable( false, true );
+	pRenderContext->PopRenderTargetAndViewport();
+	pRenderContext->Flush();
+
+	int leftX, leftY, leftW, leftH, rightX, rightY, rightW, rightH;
+	g_pSourceVR->GetViewportBounds( ISourceVirtualReality::VREye_Left, &leftX, &leftY, &leftW, &leftH );
+	g_pSourceVR->GetViewportBounds( ISourceVirtualReality::VREye_Right, &rightX, &rightY, &rightW, &rightH );
+
+
+	// render the main view
+	CViewSetup viewEye[STEREO_EYE_MAX];
+	viewEye[ STEREO_EYE_MONO ].zNear = 0.1;
+	viewEye[ STEREO_EYE_MONO ].zFar = 10000.f;
+	viewEye[ STEREO_EYE_MONO ].angles.Init();
+	viewEye[ STEREO_EYE_MONO ].origin.Zero();
+	viewEye[ STEREO_EYE_MONO ].x = viewEye[ STEREO_EYE_MONO ].m_nUnscaledX =  leftX;
+	viewEye[ STEREO_EYE_MONO ].y = viewEye[ STEREO_EYE_MONO ].m_nUnscaledY = leftY;
+	viewEye[ STEREO_EYE_MONO ].width = viewEye[ STEREO_EYE_MONO ].m_nUnscaledWidth = leftW;
+	viewEye[ STEREO_EYE_MONO ].height = viewEye[ STEREO_EYE_MONO ].m_nUnscaledHeight = leftH;
+
+	viewEye[STEREO_EYE_LEFT] = viewEye[STEREO_EYE_RIGHT] = viewEye[ STEREO_EYE_MONO ] ;
+	viewEye[STEREO_EYE_LEFT].m_eStereoEye = STEREO_EYE_LEFT;
+	viewEye[STEREO_EYE_RIGHT].x = rightX;
+	viewEye[STEREO_EYE_RIGHT].y = rightY;
+	viewEye[STEREO_EYE_RIGHT].m_eStereoEye = STEREO_EYE_RIGHT;
+
+	// let sourcevr.dll tell us where to put the cameras
+	ProcessCurrentTrackingState( 0 );
+	Vector vViewModelOrigin;
+	QAngle qViewModelAngles;
+	OverrideView( &viewEye[ STEREO_EYE_MONO ] , &vViewModelOrigin, &qViewModelAngles, HMM_NOOVERRIDE );
+	g_ClientVirtualReality.OverrideStereoView( &viewEye[ STEREO_EYE_MONO ] , &viewEye[STEREO_EYE_LEFT], &viewEye[STEREO_EYE_RIGHT] );
+
+	// render both eyes
+	for( int nView = STEREO_EYE_LEFT; nView <= STEREO_EYE_RIGHT; nView++ )
+	{
+		CMatRenderContextPtr pRenderContextMat( materials );
+		PIXEvent pixEvent( pRenderContextMat, nView == STEREO_EYE_LEFT ? "left eye" : "right eye" );
+
+		ITexture *pColor = g_pSourceVR->GetRenderTarget( (ISourceVirtualReality::VREye)(nView-1), ISourceVirtualReality::RT_Color );
+		ITexture *pDepth = g_pSourceVR->GetRenderTarget( (ISourceVirtualReality::VREye)(nView-1), ISourceVirtualReality::RT_Depth );
+		render->Push3DView( viewEye[nView], VIEW_CLEAR_DEPTH|VIEW_CLEAR_COLOR, pColor, NULL, pDepth );
+		RenderHUDQuad( false,  false );
+		render->PopView( NULL );
+
+		PostProcessFrame( (StereoEye_t)nView );
+
+		OverlayHUDQuadWithUndistort( viewEye[nView], true, true, false );
+	}
+}
+
+
+// --------------------------------------------------------------------
+// Purpose:
+//		Offset the incoming view appropriately.
+//		Set up the "middle eye" from that.
+// --------------------------------------------------------------------
+bool CClientVirtualReality::OverrideView ( CViewSetup *pViewMiddle, Vector *pViewModelOrigin, QAngle *pViewModelAngles, HeadtrackMovementMode_t hmmMovementOverride )
+{
+	if( !UseVR() )
+	{
+		return false;
+	}
+
+	if ( hmmMovementOverride == HMM_NOOVERRIDE )
+	{
+		if ( CurrentlyZoomed() )
+		{
+			m_hmmMovementActual = static_cast<HeadtrackMovementMode_t>( vr_moveaim_mode_zoom.GetInt() );
+		}
+		else
+		{
+			m_hmmMovementActual = static_cast<HeadtrackMovementMode_t>( vr_moveaim_mode.GetInt() );
+		}
+	}
+	else
+	{
+		m_hmmMovementActual = hmmMovementOverride;
+	}
+
+
+	// Incoming data may or may not be useful - it is the origin and aim of the "player", i.e. where bullets come from.
+	// In some modes it is an independent thing, guided by the mouse & keyboard = useful.
+	// In other modes it's just where the HMD was pointed last frame, modified slightly by kbd+mouse.
+	// In those cases, we should use our internal reference (which keeps track thanks to OverridePlayerMotion)
+	QAngle originalMiddleAngles = pViewMiddle->angles;
+	Vector originalMiddleOrigin = pViewMiddle->origin;
+
+	// Figure out the in-game "torso" concept, which corresponds to the player's physical torso.
+	m_PlayerTorsoOrigin = pViewMiddle->origin;
+
+	// Ignore what was passed in - it's just the direction the weapon is pointing, which was determined by last frame's HMD orientation!
+	// Instead use our cached value.
+	QAngle torsoAngles = m_PlayerTorsoAngle;
+
+	VMatrix worldFromTorso;
+	worldFromTorso.SetupMatrixOrgAngles( m_PlayerTorsoOrigin, torsoAngles );
+
+	//// Scale translation e.g. to allow big in-game leans with only a small head movement.
+	//// Clamp HMD movement to a reasonable amount to avoid wallhacks, vis problems, etc.
+	float limit = vr_translation_limit.GetFloat();
+	VMatrix matMideyeZeroFromMideyeCurrent = g_pSourceVR->GetMideyePose();
+	Vector viewTranslation = matMideyeZeroFromMideyeCurrent.GetTranslation();
+	if ( viewTranslation.IsLengthGreaterThan ( limit ) )
+	{
+		viewTranslation.NormalizeInPlace();
+		viewTranslation *= limit;
+		matMideyeZeroFromMideyeCurrent.SetTranslation( viewTranslation );
+	}
+
+	// Now figure out the three principal matrices: m_TorsoFromMideye, m_WorldFromMidEye, m_WorldFromWeapon
+	// m_TorsoFromMideye is done so that OverridePlayerMotion knows what to do with WASD.
+
+	switch ( m_hmmMovementActual )
+	{
+	case HMM_SHOOTFACE_MOVEFACE:
+	case HMM_SHOOTFACE_MOVETORSO:
+		// Aim point is down your nose, i.e. same as the view angles.
+		m_TorsoFromMideye = matMideyeZeroFromMideyeCurrent;
+		m_WorldFromMidEye = worldFromTorso * matMideyeZeroFromMideyeCurrent;
+		m_WorldFromWeapon = m_WorldFromMidEye;
+		break;
+
+	case HMM_SHOOTBOUNDEDMOUSE_LOOKFACE_MOVEFACE:
+	case HMM_SHOOTBOUNDEDMOUSE_LOOKFACE_MOVEMOUSE:
+	case HMM_SHOOTMOUSE_MOVEFACE:
+	case HMM_SHOOTMOVEMOUSE_LOOKFACE:
+		// Aim point is independent of view - leave it as it was, just copy it into m_WorldFromWeapon for our use.
+		m_TorsoFromMideye = matMideyeZeroFromMideyeCurrent;
+		m_WorldFromMidEye = worldFromTorso * matMideyeZeroFromMideyeCurrent;
+		m_WorldFromWeapon.SetupMatrixOrgAngles( originalMiddleOrigin, originalMiddleAngles );
+		break;
+
+	case HMM_SHOOTMOVELOOKMOUSE:
+		// HMD is ignored completely, mouse does everything.
+		m_PlayerTorsoAngle = originalMiddleAngles;
+
+		worldFromTorso.SetupMatrixOrgAngles( m_PlayerTorsoOrigin, originalMiddleAngles );
+
+		m_TorsoFromMideye.Identity();
+		m_WorldFromMidEye = worldFromTorso;
+		m_WorldFromWeapon = worldFromTorso;
+		break;
+
+	case HMM_SHOOTMOVELOOKMOUSEFACE:
+		// mouse does everything, and then we add head tracking on top of that
+		worldFromTorso = worldFromTorso * matMideyeZeroFromMideyeCurrent; 
+
+		m_TorsoFromMideye = matMideyeZeroFromMideyeCurrent;
+		m_WorldFromWeapon = worldFromTorso;
+		m_WorldFromMidEye = worldFromTorso;
+		break;
+
+	default: Assert ( false ); break;
+	}
+
+	// Finally convert back to origin+angles that the game understands.
+	pViewMiddle->origin = m_WorldFromMidEye.GetTranslation();
+	VectorAngles ( m_WorldFromMidEye.GetForward(), m_WorldFromMidEye.GetUp(), pViewMiddle->angles );
+
+	*pViewModelAngles = pViewMiddle->angles;
+	if ( vr_viewmodel_translate_with_head.GetBool() )
+	{
+		*pViewModelOrigin = pViewMiddle->origin;
+	}
+	else
+	{
+		*pViewModelOrigin = originalMiddleOrigin;
+	}
+
+	m_WorldFromMidEyeNoDebugCam = m_WorldFromMidEye;
+	if ( vr_debug_remote_cam.GetBool() )
+	{
+		Vector vOffset ( vr_debug_remote_cam_pos_x.GetFloat(), vr_debug_remote_cam_pos_y.GetFloat(), vr_debug_remote_cam_pos_z.GetFloat() );
+		Vector vLookat ( vr_debug_remote_cam_target_x.GetFloat(), vr_debug_remote_cam_target_y.GetFloat(), vr_debug_remote_cam_target_z.GetFloat() );
+		pViewMiddle->origin += vOffset;
+		Vector vView = vLookat - vOffset;
+		VectorAngles ( vView, m_WorldFromMidEye.GetUp(), pViewMiddle->angles );
+
+		m_WorldFromMidEye.SetupMatrixOrgAngles( pViewMiddle->origin, pViewMiddle->angles );
+
+		m_TorsoFromMideye.Identity();
+	}
+
+	// set the near clip plane so the local player clips less
+	pViewMiddle->zNear *= vr_projection_znear_multiplier.GetFloat();
+
+	return true;
+}
+
+
+// --------------------------------------------------------------------
+// Purpose:
+//		In some aim/move modes, the HUD aim reticle lags because it's
+//		using slightly stale data. This will feed it the newest data. 
+// --------------------------------------------------------------------
+bool CClientVirtualReality::OverrideWeaponHudAimVectors ( Vector *pAimOrigin, Vector *pAimDirection )
+{
+	if( !UseVR() )
+	{
+		return false;
+	}
+
+	Assert ( pAimOrigin != NULL );
+	Assert ( pAimDirection != NULL );
+
+	// So give it some nice high-fps numbers, not the low-fps ones we get from the game.
+	*pAimOrigin = m_WorldFromWeapon.GetTranslation();
+	*pAimDirection = m_WorldFromWeapon.GetForward();
+
+	return true;
+}
+
+
+// --------------------------------------------------------------------
+// Purpose:
+//		Set up the left and right eyes from the middle eye if stereo is on.
+//		Advise calling soonish after OverrideView().
+// --------------------------------------------------------------------
+bool CClientVirtualReality::OverrideStereoView( CViewSetup *pViewMiddle, CViewSetup *pViewLeft, CViewSetup *pViewRight  )
+{
+	// Everything in here is in Source coordinate space.
+	if( !UseVR() )
+	{
+		return false;
+	}
+
+	VMatrix matOffsetLeft = g_pSourceVR->GetMidEyeFromEye( ISourceVirtualReality::VREye_Left );
+	VMatrix matOffsetRight = g_pSourceVR->GetMidEyeFromEye( ISourceVirtualReality::VREye_Right );
+
+	// Move eyes to IPD positions.
+	VMatrix worldFromLeftEye  = m_WorldFromMidEye * matOffsetLeft;
+	VMatrix worldFromRightEye = m_WorldFromMidEye * matOffsetRight;
+
+	Assert ( IsOrthonormal ( worldFromLeftEye, 0.001f ) );
+	Assert ( IsOrthonormal ( worldFromRightEye, 0.001f ) );
+
+	// Finally convert back to origin+angles.
+	MatrixAngles( worldFromLeftEye.As3x4(),  pViewLeft->angles, pViewLeft->origin );
+	MatrixAngles( worldFromRightEye.As3x4(),  pViewRight->angles, pViewRight->origin );
+
+	// Find the projection matrices.
+
+	// TODO: this isn't the fastest thing in the world. Cache them?
+	float headtrackFovScale = m_WorldZoomScale;
+	pViewLeft->m_bViewToProjectionOverride = true;
+	pViewRight->m_bViewToProjectionOverride = true;
+	g_pSourceVR->GetEyeProjectionMatrix (  &pViewLeft->m_ViewToProjection, ISourceVirtualReality::VREye_Left,  pViewMiddle->zNear, pViewMiddle->zFar, 1.0f/headtrackFovScale );
+	g_pSourceVR->GetEyeProjectionMatrix ( &pViewRight->m_ViewToProjection, ISourceVirtualReality::VREye_Right, pViewMiddle->zNear, pViewMiddle->zFar, 1.0f/headtrackFovScale );
+
+	// And bodge together some sort of average for our cyclops friends.
+	pViewMiddle->m_bViewToProjectionOverride = true;
+	for ( int i = 0; i < 4; i++ )
+	{
+		for ( int j = 0; j < 4; j++ )
+		{
+			pViewMiddle->m_ViewToProjection.m[i][j] = (pViewLeft->m_ViewToProjection.m[i][j] + pViewRight->m_ViewToProjection.m[i][j] ) * 0.5f;
+		}
+	}
+
+	switch ( vr_stereo_mono_set_eye.GetInt() )
+	{
+	case 0:
+		// ... nothing.
+		break;
+	case 1:
+		// Override all eyes with left
+		*pViewMiddle = *pViewLeft;
+		*pViewRight = *pViewLeft;
+		pViewRight->m_eStereoEye = STEREO_EYE_RIGHT;
+		break;
+	case 2:
+		// Override all eyes with right
+		*pViewMiddle = *pViewRight;
+		*pViewLeft = *pViewRight;
+		pViewLeft->m_eStereoEye = STEREO_EYE_LEFT;
+		break;
+	case 3:
+		// Override all eyes with middle
+		*pViewRight = *pViewMiddle;
+		*pViewLeft = *pViewMiddle;
+		pViewLeft->m_eStereoEye = STEREO_EYE_LEFT;
+		pViewRight->m_eStereoEye = STEREO_EYE_RIGHT;
+		break;
+	}
+
+	// To make culling work correctly, calculate the widest FOV of each projection matrix.
+	CalcFovFromProjection ( &(pViewLeft  ->fov), pViewLeft  ->m_ViewToProjection );
+	CalcFovFromProjection ( &(pViewRight ->fov), pViewRight ->m_ViewToProjection );
+	CalcFovFromProjection ( &(pViewMiddle->fov), pViewMiddle->m_ViewToProjection );
+
+	// if we don't know the HUD FOV, figure that out now
+	if( m_fHudHorizontalFov == 0.f )
+	{
+		// Figure out the current HUD FOV.
+		m_fHudHorizontalFov = pViewLeft->fov * vr_hud_display_ratio.GetFloat();
+		if( m_fHudHorizontalFov > vr_hud_max_fov.GetFloat() )
+		{
+			m_fHudHorizontalFov = vr_hud_max_fov.GetFloat();
+		}
+	}
+
+	// remember the view angles so we can limit the weapon to something near those
+	m_PlayerViewAngle = pViewMiddle->angles;
+	m_PlayerViewOrigin = pViewMiddle->origin;
+
+
+
+	// Figure out the HUD vectors and frustum.
+
+	// The aspect ratio of the HMD may be something bizarre (e.g. Rift is 640x800), and the pixels may not be square, so don't use that!
+	static const float fAspectRatio = 4.f/3.f;
+	float fHFOV = m_fHudHorizontalFov;
+	float fVFOV = m_fHudHorizontalFov / fAspectRatio;
+
+	const float fHudForward = vr_hud_forward.GetFloat();
+	m_fHudHalfWidth = tan( DEG2RAD( fHFOV * 0.5f ) ) * fHudForward * m_WorldZoomScale;
+	m_fHudHalfHeight = tan( DEG2RAD( fVFOV * 0.5f ) ) * fHudForward * m_WorldZoomScale;
+
+	QAngle HudAngles;
+	switch ( m_hmmMovementActual )
+	{
+	case HMM_SHOOTFACE_MOVETORSO:
+		// Put the HUD in front of the player's torso.
+		// This helps keep you oriented about where "forwards" is, which is otherwise surprisingly tricky!
+		// TODO: try preserving roll and/or pitch from the view?
+		HudAngles = m_PlayerTorsoAngle;
+		break;
+	case HMM_SHOOTFACE_MOVEFACE:
+	case HMM_SHOOTMOUSE_MOVEFACE:
+	case HMM_SHOOTMOVEMOUSE_LOOKFACE:
+	case HMM_SHOOTMOVELOOKMOUSE:
+	case HMM_SHOOTMOVELOOKMOUSEFACE:
+	case HMM_SHOOTBOUNDEDMOUSE_LOOKFACE_MOVEFACE:
+	case HMM_SHOOTBOUNDEDMOUSE_LOOKFACE_MOVEMOUSE:
+		// Put the HUD in front of wherever the player is looking.
+		HudAngles = m_PlayerViewAngle;
+		break;
+	default: Assert ( false ); break;
+	}
+
+	// This is a bitfield. A set bit means lock to the world, a clear bit means don't.
+	int iVrHudAxisLockToWorld = vr_hud_axis_lock_to_world.GetInt();
+	if ( ( iVrHudAxisLockToWorld & (1<<ROLL) ) != 0 )
+	{
+		HudAngles[ROLL] = 0.0f;
+	}
+	if ( ( iVrHudAxisLockToWorld & (1<<PITCH) ) != 0 )
+	{
+		HudAngles[PITCH] = 0.0f;
+	}
+	if ( ( iVrHudAxisLockToWorld & (1<<YAW) ) != 0 )
+	{
+		// Locking the yaw to the world is not particularly helpful, so what it actually means is lock it to the weapon.
+		QAngle aimAngles;
+		MatrixAngles( m_WorldFromWeapon.As3x4(), aimAngles );
+		HudAngles[YAW] = aimAngles[YAW];
+	}
+	m_WorldFromHud.SetupMatrixOrgAngles( m_PlayerViewOrigin, HudAngles );
+
+	// Remember in source X forwards, Y left, Z up.
+	// We need to transform to a more conventional X right, Y up, Z backwards before doing the projection.
+	VMatrix WorldFromHudView;
+	WorldFromHudView./*X vector*/SetForward ( -m_WorldFromHud.GetLeft() );
+	WorldFromHudView./*Y vector*/SetLeft    ( m_WorldFromHud.GetUp() );
+	WorldFromHudView./*Z vector*/SetUp      ( -m_WorldFromHud.GetForward() );
+	WorldFromHudView.SetTranslation         ( m_PlayerViewOrigin );
+
+	VMatrix HudProjection;
+	HudProjection.Identity();
+	HudProjection.m[0][0] = fHudForward / m_fHudHalfWidth;
+	HudProjection.m[1][1] = fHudForward / m_fHudHalfHeight;
+	// Z vector is not used/valid, but w is for projection.
+	HudProjection.m[3][2] = -1.0f;
+
+	// This will transform a world point into a homogeneous vector that
+	//  when projected (i.e. divide by w) maps to HUD space [-1,1]
+	m_HudProjectionFromWorld = HudProjection * WorldFromHudView.InverseTR();
+
+	return true;
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Updates player orientation, position and motion according
+//			to HMD status.
+// --------------------------------------------------------------------
+bool CClientVirtualReality::OverridePlayerMotion( float flInputSampleFrametime, const QAngle &oldAngles, const QAngle &curAngles, const Vector &curMotion, QAngle *pNewAngles, Vector *pNewMotion )
+{
+	Assert ( pNewAngles != NULL );
+	Assert ( pNewMotion != NULL );
+	*pNewAngles = curAngles;
+	*pNewMotion = curMotion;
+
+	if ( !UseVR() )
+	{
+		return false;
+	}
+
+
+	m_bMotionUpdated = true;
+
+	// originalAngles tells us what the weapon angles were before whatever mouse, joystick, etc thing changed them - called "old"
+	// curAngles holds the new weapon angles after mouse, joystick, etc. applied.
+	// We need to compute what weapon angles WE want and return them in *pNewAngles - called "new"
+
+
+
+	VMatrix worldFromTorso;
+
+	// Whatever position is already here (set up by OverrideView) needs to be preserved.
+	Vector vWeaponOrigin = m_WorldFromWeapon.GetTranslation();
+
+	switch ( m_hmmMovementActual )
+	{
+	case HMM_SHOOTFACE_MOVEFACE:
+	case HMM_SHOOTFACE_MOVETORSO:
+		{
+			// Figure out what changes were made to the WEAPON by mouse/joystick/etc
+			VMatrix worldFromOldWeapon, worldFromCurWeapon;
+			worldFromOldWeapon.SetupMatrixAngles( oldAngles );
+			worldFromCurWeapon.SetupMatrixAngles( curAngles );
+
+			// We ignore mouse pitch, the mouse can't do rolls, so it's just yaw changes.
+			if( !m_bOverrideTorsoAngle )
+			{
+				m_PlayerTorsoAngle[YAW] += curAngles[YAW] - oldAngles[YAW];
+				m_PlayerTorsoAngle[ROLL] = 0.0f;
+				m_PlayerTorsoAngle[PITCH] = 0.0f;
+			}
+
+			worldFromTorso.SetupMatrixAngles( m_PlayerTorsoAngle );
+
+			// Weapon view = mideye view, so apply that to the torso to find the world view direction.
+			m_WorldFromWeapon = worldFromTorso * m_TorsoFromMideye;
+
+			// ...and we return this new weapon direction as the player's orientation.
+			MatrixAngles( m_WorldFromWeapon.As3x4(), *pNewAngles );
+
+			// Restore the translation.
+			m_WorldFromWeapon.SetTranslation ( vWeaponOrigin );
+		}
+		break;
+	case HMM_SHOOTMOVELOOKMOUSEFACE:
+	case HMM_SHOOTMOVEMOUSE_LOOKFACE:
+	case HMM_SHOOTMOVELOOKMOUSE:
+		{
+			// The mouse just controls the weapon directly.
+			*pNewAngles = curAngles;
+			*pNewMotion = curMotion;
+
+			// Move the torso by the yaw angles - torso should not have roll or pitch or you'll make folks ill.
+			if( !m_bOverrideTorsoAngle && m_hmmMovementActual != HMM_SHOOTMOVELOOKMOUSEFACE )
+			{
+				m_PlayerTorsoAngle[YAW] = curAngles[YAW];
+				m_PlayerTorsoAngle[ROLL] = 0.0f;
+				m_PlayerTorsoAngle[PITCH] = 0.0f;
+			}
+
+			// Let every other system know.
+			m_WorldFromWeapon.SetupMatrixOrgAngles( vWeaponOrigin, *pNewAngles );
+			worldFromTorso.SetupMatrixAngles( m_PlayerTorsoAngle );
+		}
+		break;
+	case HMM_SHOOTBOUNDEDMOUSE_LOOKFACE_MOVEFACE:
+	case HMM_SHOOTBOUNDEDMOUSE_LOOKFACE_MOVEMOUSE:
+		{
+			// The mouse controls the weapon directly.
+			*pNewAngles = curAngles;
+			*pNewMotion = curMotion;
+
+			float fReticleYawLimit = vr_moveaim_reticle_yaw_limit.GetFloat();
+			float fReticlePitchLimit = vr_moveaim_reticle_pitch_limit.GetFloat();
+
+			if ( CurrentlyZoomed() )
+			{
+				fReticleYawLimit = vr_moveaim_reticle_yaw_limit_zoom.GetFloat() * m_WorldZoomScale;
+				fReticlePitchLimit = vr_moveaim_reticle_pitch_limit_zoom.GetFloat() * m_WorldZoomScale;
+				if ( fReticleYawLimit > 180.0f )
+				{
+					fReticleYawLimit = 180.0f;
+				}
+				if ( fReticlePitchLimit > 180.0f )
+				{
+					fReticlePitchLimit = 180.0f;
+				}
+			}
+
+			if ( fReticlePitchLimit >= 0.0f )
+			{
+				// Clamp pitch to within the limits.
+				(*pNewAngles)[PITCH] = Clamp ( curAngles[PITCH], m_PlayerViewAngle[PITCH] - fReticlePitchLimit, m_PlayerViewAngle[PITCH] + fReticlePitchLimit );
+			}
+
+			// For yaw the concept here is the torso stays within a set number of degrees of the weapon in yaw.
+			// However, with drifty tracking systems (e.g. IMUs) the concept of "torso" is hazy.
+			// Really it's just a mechanism to turn the view without moving the head - its absolute
+			// orientation is not that useful.
+			// So... if the mouse is to the right greater than the chosen angle from the view, and then
+			// moves more right, it will drag the torso (and thus the view) right, so it stays on the edge of the view.
+			// But if it moves left towards the view, it does no dragging.
+			// Note that if the mouse does not move, but the view moves, it will NOT drag at all.
+			// This allows people to mouse-aim within their view, but also to flick-turn with the mouse,
+			// and to flick-glance with the head.
+			if ( fReticleYawLimit >= 0.0f )
+			{
+				float fViewToWeaponYaw = AngleDiff ( curAngles[YAW], m_PlayerViewAngle[YAW] );
+				float fWeaponYawMovement = AngleDiff ( curAngles[YAW], oldAngles[YAW] );
+				if ( fViewToWeaponYaw > fReticleYawLimit )
+				{
+					if ( fWeaponYawMovement > 0.0f )
+					{
+						m_PlayerTorsoAngle[YAW] += fWeaponYawMovement;
+					}
+				}
+				else if ( fViewToWeaponYaw < -fReticleYawLimit )
+				{
+					if ( fWeaponYawMovement < 0.0f )
+					{
+						m_PlayerTorsoAngle[YAW] += fWeaponYawMovement;
+					}
+				}
+			}
+
+			// Let every other system know.
+			m_WorldFromWeapon.SetupMatrixOrgAngles( vWeaponOrigin, *pNewAngles );
+			worldFromTorso.SetupMatrixAngles( m_PlayerTorsoAngle );
+		}
+		break;
+	case HMM_SHOOTMOUSE_MOVEFACE:
+		{
+			(*pNewAngles)[PITCH] = clamp( (*pNewAngles)[PITCH], m_PlayerViewAngle[PITCH]-15.f, m_PlayerViewAngle[PITCH]+15.f );
+
+			float fDiff = AngleDiff( (*pNewAngles)[YAW], m_PlayerViewAngle[YAW] );
+
+			if( fDiff > 15.f )
+			{
+				(*pNewAngles)[YAW] = AngleNormalize( m_PlayerViewAngle[YAW] + 15.f );
+				if( !m_bOverrideTorsoAngle )
+					m_PlayerTorsoAngle[ YAW ] += fDiff - 15.f;
+			}
+			else if( fDiff < -15.f )
+			{
+				(*pNewAngles)[YAW] = AngleNormalize( m_PlayerViewAngle[YAW] - 15.f );
+				if( !m_bOverrideTorsoAngle )
+					m_PlayerTorsoAngle[ YAW ] += fDiff + 15.f;
+			}
+			else
+			{
+				m_PlayerTorsoAngle[ YAW ] += AngleDiff( curAngles[YAW], oldAngles[YAW] ) /2.f;
+			}
+
+			m_WorldFromWeapon.SetupMatrixOrgAngles( vWeaponOrigin, *pNewAngles );
+			worldFromTorso.SetupMatrixAngles( m_PlayerTorsoAngle );
+		}
+		break;
+	default: Assert ( false ); break;
+	}
+
+	// Figure out player motion.
+	switch ( m_hmmMovementActual )
+	{
+	case HMM_SHOOTBOUNDEDMOUSE_LOOKFACE_MOVEFACE:
+		{
+			// The motion passed in is meant to be relative to the face, so jimmy it to be relative to the new weapon aim.
+			VMatrix mideyeFromWorld = m_WorldFromMidEye.InverseTR();
+			VMatrix newMidEyeFromWeapon = mideyeFromWorld * m_WorldFromWeapon;
+			newMidEyeFromWeapon.SetTranslation ( Vector ( 0.0f, 0.0f, 0.0f ) );
+			*pNewMotion = newMidEyeFromWeapon * curMotion;
+		}
+		break;
+	case HMM_SHOOTFACE_MOVETORSO:
+		{
+			// The motion passed in is meant to be relative to the torso, so jimmy it to be relative to the new weapon aim.
+			VMatrix torsoFromWorld = worldFromTorso.InverseTR();
+			VMatrix newTorsoFromWeapon = torsoFromWorld * m_WorldFromWeapon;
+			newTorsoFromWeapon.SetTranslation ( Vector ( 0.0f, 0.0f, 0.0f ) );
+			*pNewMotion = newTorsoFromWeapon * curMotion;
+		}
+		break;
+	case HMM_SHOOTBOUNDEDMOUSE_LOOKFACE_MOVEMOUSE:
+	case HMM_SHOOTMOVELOOKMOUSEFACE:
+	case HMM_SHOOTFACE_MOVEFACE:
+	case HMM_SHOOTMOUSE_MOVEFACE:
+	case HMM_SHOOTMOVEMOUSE_LOOKFACE:
+	case HMM_SHOOTMOVELOOKMOUSE:
+		// Motion is meant to be relative to the weapon, so we're fine.
+		*pNewMotion = curMotion;
+		break;
+	default: Assert ( false ); break;
+	}
+
+	// If the game told us to, recenter the torso yaw to match the weapon
+	if ( m_iAlignTorsoAndViewToWeaponCountdown > 0 )
+	{
+		m_iAlignTorsoAndViewToWeaponCountdown--;
+
+		// figure out the angles from the torso to the head
+		QAngle torsoFromHeadAngles;
+		MatrixAngles( m_TorsoFromMideye.As3x4(), torsoFromHeadAngles );
+
+		QAngle weaponAngles;
+		MatrixAngles( m_WorldFromWeapon.As3x4(), weaponAngles );
+		m_PlayerTorsoAngle[ YAW ] = weaponAngles[ YAW ] - torsoFromHeadAngles[ YAW ] ;
+		NormalizeAngles( m_PlayerTorsoAngle );
+	}
+
+	// remember the motion for stat tracking
+	m_PlayerLastMovement = *pNewMotion;
+
+
+
+	return true;
+}
+
+// --------------------------------------------------------------------
+// Purpose: Returns true if the world is zoomed
+// --------------------------------------------------------------------
+bool CClientVirtualReality::CurrentlyZoomed()
+{
+	return ( m_WorldZoomScale != 1.0f );
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Tells the headtracker to keep the torso angle of the player
+//			fixed at this point until the game tells us something 
+//			different.
+// --------------------------------------------------------------------
+void CClientVirtualReality::OverrideTorsoTransform( const Vector & position, const QAngle & angles )
+{
+	if( m_iAlignTorsoAndViewToWeaponCountdown > 0 )
+	{
+		m_iAlignTorsoAndViewToWeaponCountdown--;
+
+		// figure out the angles from the torso to the head
+		QAngle torsoFromHeadAngles;
+		MatrixAngles( m_TorsoFromMideye.As3x4(), torsoFromHeadAngles );
+
+		// this is how far off the torso we actually set will need to be to keep the current "forward"
+		// vector while the torso angle is being overridden.
+		m_OverrideTorsoOffset[ YAW ] = -torsoFromHeadAngles[ YAW ];
+	}
+
+	m_bOverrideTorsoAngle = true;
+	m_OverrideTorsoAngle = angles + m_OverrideTorsoOffset;
+
+	// overriding pitch and roll isn't allowed to avoid making people sick
+	m_OverrideTorsoAngle[ PITCH ] = 0;
+	m_OverrideTorsoAngle[ ROLL ] = 0;
+
+	NormalizeAngles( m_OverrideTorsoAngle );
+	
+	m_PlayerTorsoAngle = m_OverrideTorsoAngle;
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Tells the headtracker to resume using its own notion of 
+//			where the torso is pointed.
+// --------------------------------------------------------------------
+void CClientVirtualReality::CancelTorsoTransformOverride()
+{
+	m_bOverrideTorsoAngle = false;
+}
+
+
+bool CClientVirtualReality::CanOverlayHudQuad()
+{
+	bool bCanOverlay = true;
+
+	bCanOverlay = bCanOverlay && vr_render_hud_in_world.GetBool();
+	bCanOverlay = bCanOverlay && ( ! vr_hud_never_overlay.GetBool() );
+	bCanOverlay = bCanOverlay && ( vr_hud_axis_lock_to_world.GetInt() == 0 );
+	bCanOverlay = bCanOverlay && ( m_hmmMovementActual != HMM_SHOOTFACE_MOVETORSO );
+
+	return bCanOverlay;
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Returns the bounds in world space where the game should 
+//			position the HUD.
+// --------------------------------------------------------------------
+void CClientVirtualReality::GetHUDBounds( Vector *pViewer, Vector *pUL, Vector *pUR, Vector *pLL, Vector *pLR )
+{
+	Vector vHalfWidth = m_WorldFromHud.GetLeft() * -m_fHudHalfWidth;
+	Vector vHalfHeight = m_WorldFromHud.GetUp() * m_fHudHalfHeight;
+	Vector vHUDOrigin = m_PlayerViewOrigin + m_WorldFromHud.GetForward() * vr_hud_forward.GetFloat();
+
+	*pViewer = m_PlayerViewOrigin;
+	*pUL = vHUDOrigin - vHalfWidth + vHalfHeight;
+	*pUR = vHUDOrigin + vHalfWidth + vHalfHeight;
+	*pLL = vHUDOrigin - vHalfWidth - vHalfHeight;
+	*pLR = vHUDOrigin + vHalfWidth - vHalfHeight;
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Renders the HUD in the world.
+// --------------------------------------------------------------------
+void CClientVirtualReality::RenderHUDQuad( bool bBlackout, bool bTranslucent )
+{
+	// If we can overlay the HUD directly onto the target later, we'll do that instead (higher image quality).
+	if ( CanOverlayHudQuad() )
+		return;
+
+	Vector vHead, vUL, vUR, vLL, vLR;
+	GetHUDBounds ( &vHead, &vUL, &vUR, &vLL, &vLR );
+
+	CMatRenderContextPtr pRenderContext( materials );
+
+	{
+		IMaterial *mymat = NULL;
+		if ( bTranslucent )
+		{
+			mymat = materials->FindMaterial( "vgui/inworldui", TEXTURE_GROUP_VGUI );
+		}
+		else
+		{
+			mymat = materials->FindMaterial( "vgui/inworldui_opaque", TEXTURE_GROUP_VGUI );
+		}
+		Assert( !mymat->IsErrorMaterial() );
+
+		IMesh *pMesh = pRenderContext->GetDynamicMesh( true, NULL, NULL, mymat );
+
+		CMeshBuilder meshBuilder;
+		meshBuilder.Begin( pMesh, MATERIAL_TRIANGLE_STRIP, 2 );
+
+		meshBuilder.Position3fv (vLR.Base() );
+		meshBuilder.TexCoord2f( 0, 1, 1 );
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 1>();
+
+		meshBuilder.Position3fv (vLL.Base());
+		meshBuilder.TexCoord2f( 0, 0, 1 );
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 1>();
+
+		meshBuilder.Position3fv (vUR.Base());
+		meshBuilder.TexCoord2f( 0, 1, 0 );
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 1>();
+
+		meshBuilder.Position3fv (vUL.Base());
+		meshBuilder.TexCoord2f( 0, 0, 0 );
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 1>();
+
+		meshBuilder.End();
+		pMesh->Draw();
+	}
+
+	if( bBlackout )
+	{
+		Vector vbUL, vbUR, vbLL, vbLR;
+		// "Reflect" the HUD bounds through the viewer to find the ones behind the head.
+		vbUL = 2 * vHead - vLR;
+		vbUR = 2 * vHead - vLL;
+		vbLL = 2 * vHead - vUR;
+		vbLR = 2 * vHead - vUL;
+
+		IMaterial *mymat = materials->FindMaterial( "vgui/black", TEXTURE_GROUP_VGUI );
+		IMesh *pMesh = pRenderContext->GetDynamicMesh( true, NULL, NULL, mymat );
+
+		// Tube around the outside.
+		CMeshBuilder meshBuilder;
+		meshBuilder.Begin( pMesh, MATERIAL_TRIANGLE_STRIP, 8 );
+
+		meshBuilder.Position3fv (vLR.Base());
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 0>();
+
+		meshBuilder.Position3fv (vbLR.Base() );
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 0>();
+
+		meshBuilder.Position3fv (vLL.Base());
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 0>();
+
+		meshBuilder.Position3fv (vbLL.Base());
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 0>();
+
+		meshBuilder.Position3fv (vUL.Base());
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 0>();
+
+		meshBuilder.Position3fv (vbUL.Base());
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 0>();
+
+		meshBuilder.Position3fv (vUR.Base());
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 0>();
+
+		meshBuilder.Position3fv (vbUR.Base());
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 0>();
+
+		meshBuilder.Position3fv (vLR.Base());
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 0>();
+
+		meshBuilder.Position3fv (vbLR.Base());
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 0>();
+
+		meshBuilder.End();
+		pMesh->Draw();
+
+		// Cap behind the viewer.
+		meshBuilder.Begin( pMesh, MATERIAL_TRIANGLE_STRIP, 2 );
+
+		meshBuilder.Position3fv (vbUR.Base() );
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 0>();
+
+		meshBuilder.Position3fv (vbUL.Base());
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 0>();
+
+		meshBuilder.Position3fv (vbLR.Base());
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 0>();
+
+		meshBuilder.Position3fv (vbLL.Base());
+		meshBuilder.AdvanceVertexF<VTX_HAVEPOS, 0>();
+
+		meshBuilder.End();
+		pMesh->Draw();
+	}
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Gets the amount of zoom to apply
+// --------------------------------------------------------------------
+float CClientVirtualReality::GetZoomedModeMagnification()
+{
+	return m_WorldZoomScale * vr_zoom_scope_scale.GetFloat();
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Does some client-side tracking work and then tells headtrack
+//			to do its own work.
+// --------------------------------------------------------------------
+bool CClientVirtualReality::ProcessCurrentTrackingState( float fGameFOV )
+{
+	m_WorldZoomScale = 1.0f;
+	if ( fGameFOV != 0.0f )
+	{
+		// To compensate for the lack of pixels on most HUDs, let's grow this a bit.
+		// Remember that MORE zoom equals LESS fov!
+		fGameFOV *= ( 1.0f / vr_zoom_multiplier.GetFloat() );
+		fGameFOV = Min ( fGameFOV, 170.0f );
+
+		// The game has overridden the FOV, e.g. because of a sniper scope. So we need to match this view with whatever actual FOV the HUD has.
+		float wantedGameTanfov = tanf ( DEG2RAD ( fGameFOV * 0.5f ) );
+		// OK, so now in stereo mode, we're going to also draw an overlay, but that overlay usually covers more of the screen (because in a good HMD usually our actual FOV is much wider)
+		float overlayActualPhysicalTanfov = tanf ( DEG2RAD ( m_fHudHorizontalFov * 0.5f ) );
+		// Therefore... (remembering that a zoom > 1.0 means you zoom *out*)
+		m_WorldZoomScale = wantedGameTanfov / overlayActualPhysicalTanfov;
+	}
+
+	return g_pSourceVR->SampleTrackingState( fGameFOV, 0.f /* seconds to predict */ );
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Returns the projection matrix to use for the HUD
+// --------------------------------------------------------------------
+const VMatrix &CClientVirtualReality::GetHudProjectionFromWorld()
+{
+	// This matrix will transform a world-space position into a homogenous HUD-space vector.
+	// So if you divide x+y by w, you will get the position on the HUD in [-1,1] space.
+	return m_HudProjectionFromWorld;
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Returns the aim vector relative to the torso
+// --------------------------------------------------------------------
+void CClientVirtualReality::GetTorsoRelativeAim( Vector *pPosition, QAngle *pAngles )
+{
+	MatrixAngles( m_TorsoFromMideye.As3x4(), *pAngles, *pPosition );
+	pAngles->y += vr_aim_yaw_offset.GetFloat();
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Returns distance of the HUD in front of the eyes.
+// --------------------------------------------------------------------
+float CClientVirtualReality::GetHUDDistance()
+{
+	return vr_hud_forward.GetFloat();
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Returns true if the HUD should be rendered into a render 
+//			target and then into the world on a quad.
+// --------------------------------------------------------------------
+bool CClientVirtualReality::ShouldRenderHUDInWorld()
+{
+	return UseVR() && vr_render_hud_in_world.GetBool();
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Lets headtrack tweak the view model origin and angles to match 
+//			aim angles and handle strange viewmode FOV stuff
+// --------------------------------------------------------------------
+void CClientVirtualReality::OverrideViewModelTransform( Vector & vmorigin, QAngle & vmangles, bool bUseLargeOverride ) 
+{
+	Vector vForward, vRight, vUp;
+	AngleVectors( vmangles, &vForward, &vRight, &vUp );
+
+	float fForward = bUseLargeOverride ? vr_viewmodel_offset_forward_large.GetFloat() : vr_viewmodel_offset_forward.GetFloat();
+
+	vmorigin += vForward * fForward;
+	MatrixAngles( m_WorldFromWeapon.As3x4(), vmangles );
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Tells the head tracker to reset the torso position in case
+//			we're on a drifty tracker.
+// --------------------------------------------------------------------
+void CClientVirtualReality::AlignTorsoAndViewToWeapon()
+{
+	if( !UseVR() )
+		return;
+
+	if( g_pSourceVR->WillDriftInYaw() )
+	{
+		m_iAlignTorsoAndViewToWeaponCountdown = 2;
+	}
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Lets VR do stuff at the very end of the rendering process
+// --------------------------------------------------------------------
+void CClientVirtualReality::PostProcessFrame( StereoEye_t eEye )
+{
+	if( !UseVR() )
+		return;
+
+	g_pSourceVR->DoDistortionProcessing( eEye == STEREO_EYE_LEFT ? ISourceVirtualReality::VREye_Left : ISourceVirtualReality::VREye_Right );
+}
+
+
+// --------------------------------------------------------------------
+// Pastes the HUD directly onto the backbuffer / render target.
+// (higher quality than the RenderHUDQuad() path but can't always be used)
+// --------------------------------------------------------------------
+void CClientVirtualReality::OverlayHUDQuadWithUndistort( const CViewSetup &eyeView, bool bDoUndistort, bool bBlackout, bool bTranslucent )
+{
+	if ( ! UseVR() )
+		return;
+
+	// If we can't overlay the HUD, it will be handled on another path (rendered into the scene with RenderHUDQuad()).
+	if ( ! CanOverlayHudQuad() )
+		return;
+
+	// Get the position of the HUD quad in world space as used by RenderHUDQuad().  Then convert to a rectangle in normalized
+	// device coordinates.
+
+	Vector vHead, vUL, vUR, vLL, vLR;
+	GetHUDBounds ( &vHead, &vUL, &vUR, &vLL, &vLR );
+
+	VMatrix worldToView, viewToProjection, worldToProjection, worldToPixels;
+	render->GetMatricesForView( eyeView, &worldToView, &viewToProjection, &worldToProjection, &worldToPixels );
+
+	Vector pUL, pUR, pLL, pLR;
+
+	worldToProjection.V3Mul( vUL, pUL );
+	worldToProjection.V3Mul( vUR, pUR );
+	worldToProjection.V3Mul( vLL, pLL );
+	worldToProjection.V3Mul( vLR, pLR );
+
+	float ndcHudBounds[4];
+	ndcHudBounds[0] = Min ( Min( pUL.x, pUR.x ), Min( pLL.x, pLR.x ) );
+	ndcHudBounds[1] = Min ( Min( pUL.y, pUR.y ), Min( pLL.y, pLR.y ) );
+	ndcHudBounds[2] = Max ( Max( pUL.x, pUR.x ), Max( pLL.x, pLR.x ) );
+	ndcHudBounds[3] = Max ( Max( pUL.y, pUR.y ), Max( pLL.y, pLR.y ) );
+
+	ISourceVirtualReality::VREye sourceVrEye = ( eyeView.m_eStereoEye == STEREO_EYE_LEFT ) ? ISourceVirtualReality::VREye_Left : ISourceVirtualReality::VREye_Right;
+
+	g_pSourceVR->CompositeHud ( sourceVrEye, ndcHudBounds, bDoUndistort, bBlackout, bTranslucent );
+}
+
+
+// --------------------------------------------------------------------
+// Purpose: Switches to VR mode
+// --------------------------------------------------------------------
+void CClientVirtualReality::Activate()
+{
+	// we can only do this if a headtrack DLL is loaded
+	if( !g_pSourceVR )
+		return;
+
+	// These checks don't apply if we're in VR mode because Steam said so.
+	if ( !ShouldForceVRActive() )
+	{
+		// see if VR mode is even enabled
+		if ( materials->GetCurrentConfigForVideoCard().m_nVRModeAdapter == -1 )
+		{
+			Warning( "Enable VR mode in the video options before trying to use it.\n" );
+			return;
+		}
+
+		// See if we have an actual adapter
+		int32 nVRModeAdapter = g_pSourceVR->GetVRModeAdapter();
+		if ( nVRModeAdapter == -1 )
+		{
+			Warning( "Unable to get VRMode adapter from OpenVR. VR mode cannot be enabled. Try restarting and then enabling VR again.\n" );
+			return;
+		}
+
+		// we can only activate if we've got a VR device
+		if ( materials->GetCurrentConfigForVideoCard().m_nVRModeAdapter != nVRModeAdapter )
+		{
+			Warning( "VR Mode expects adapter %d which is different from %d which we are currently using. Try restarting and enabling VR mode again.\n",
+				nVRModeAdapter, materials->GetCurrentConfigForVideoCard().m_nVRModeAdapter );
+			engine->ExecuteClientCmd( "mat_enable_vrmode 0\n" );
+			return;
+		}
+	}
+
+
+	// can't activate twice
+	if( UseVR() )
+		return;
+
+	// remember where we were
+	m_bNonVRWindowed = g_pMaterialSystem->GetCurrentConfigForVideoCard().Windowed();
+	vgui::surface()->GetScreenSize( m_nNonVRWidth, m_nNonVRHeight );
+#if defined( USE_SDL )
+    static ConVarRef sdl_displayindex( "sdl_displayindex" );
+    m_nNonVRSDLDisplayIndex = sdl_displayindex.GetInt();
+#endif
+
+	if( !g_pSourceVR->Activate() )
+	{
+		// we couldn't activate, so just punt on this whole thing
+		return;
+	}
+
+	// general all-game stuff
+	engine->ExecuteClientCmd( "mat_reset_rendertargets\n" );
+
+	// game specific VR config
+	CUtlString sCmd;
+	sCmd.Format( "exec sourcevr_%s.cfg\n", COM_GetModDirectory() );
+	engine->ExecuteClientCmd( sCmd.Get() );
+
+    vgui::surface()->SetSoftwareCursor( true );
+
+#if defined(POSIX)
+	ConVarRef m_rawinput( "m_rawinput" );
+    m_bNonVRRawInput = m_rawinput.GetBool();
+    m_rawinput.SetValue( 1 );
+
+	ConVarRef mat_vsync( "mat_vsync" );
+	mat_vsync.SetValue( 0 );
+#endif
+
+	g_pMatSystemSurface->ForceScreenSizeOverride(true, 640, 480 );
+	int nViewportWidth, nViewportHeight;
+
+	g_pSourceVR->GetViewportBounds( ISourceVirtualReality::VREye_Left, NULL, NULL, &nViewportWidth, &nViewportHeight );
+	g_pMatSystemSurface->SetFullscreenViewportAndRenderTarget( 0, 0, nViewportWidth, nViewportHeight, g_pSourceVR->GetRenderTarget( ISourceVirtualReality::VREye_Left, ISourceVirtualReality::RT_Color ) );
+
+	vgui::ivgui()->SetVRMode( true );
+
+	// we can skip this extra mode change if we've always been in VR mode
+	if ( !ShouldForceVRActive() )
+	{
+		VRRect_t rect;
+		if ( g_pSourceVR->GetDisplayBounds( &rect ) )
+		{
+
+			// set mode
+			char szCmd[256];
+			Q_snprintf( szCmd, sizeof(szCmd), "mat_setvideomode %i %i %i\n", rect.nWidth, rect.nHeight, vr_force_windowed.GetBool() ? 1 : 0 );
+			engine->ClientCmd_Unrestricted( szCmd );
+		}
+	}
+}
+
+
+void CClientVirtualReality::Deactivate()
+{
+	// can't deactivate when we aren't active
+	if( !UseVR() )
+		return;
+
+	g_pSourceVR->Deactivate();
+
+	g_pMatSystemSurface->ForceScreenSizeOverride(false, 0, 0 );
+	g_pMaterialSystem->GetRenderContext()->Viewport( 0, 0, m_nNonVRWidth, m_nNonVRHeight );
+	g_pMatSystemSurface->SetFullscreenViewportAndRenderTarget( 0, 0, m_nNonVRWidth, m_nNonVRHeight, NULL );
+
+    static ConVarRef cl_software_cursor( "cl_software_cursor" );
+    vgui::surface()->SetSoftwareCursor( cl_software_cursor.GetBool() );
+
+#if defined( USE_SDL )
+    static ConVarRef sdl_displayindex( "sdl_displayindex" );
+    sdl_displayindex.SetValue( m_nNonVRSDLDisplayIndex );
+#endif
+
+#if defined(POSIX)
+    ConVarRef m_rawinput( "m_rawinput" );
+    m_rawinput.SetValue( m_bNonVRRawInput );
+#endif
+
+    // Make sure the client .dll root panel is at the proper point before doing the "SolveTraverse" calls
+	vgui::VPANEL root = enginevgui->GetPanel( PANEL_CLIENTDLL );
+	if ( root != 0 )
+	{
+		vgui::ipanel()->SetSize( root, m_nNonVRWidth, m_nNonVRHeight );
+	}
+	// Same for client .dll tools
+	root = enginevgui->GetPanel( PANEL_CLIENTDLL_TOOLS );
+	if ( root != 0 )
+	{
+		vgui::ipanel()->SetSize( root, m_nNonVRWidth, m_nNonVRHeight );
+	}
+
+	int viewWidth, viewHeight;
+	vgui::surface()->GetScreenSize( viewWidth, viewHeight );
+
+	engine->ExecuteClientCmd( "mat_reset_rendertargets\n" );
+
+	// set mode
+	char szCmd[ 256 ];
+	Q_snprintf( szCmd, sizeof( szCmd ), "mat_setvideomode %i %i %i\n", m_nNonVRWidth, m_nNonVRHeight, m_bNonVRWindowed ? 1 : 0 );
+	engine->ClientCmd_Unrestricted( szCmd );
+
+}
+
+
+// Called when startup is complete
+void CClientVirtualReality::StartupComplete()
+{
+	if ( vr_activate_default.GetBool() || ShouldForceVRActive() )
+		Activate();
+}
+