Merge pull request #88312 from Malcolmnixon/face-tracker-provider

Add XR Face Tracking support

5 files changed, 496 insertions, 0 deletions

diff --git a/servers/register_server_types.cpp b/servers/register_server_types.cpp
index 0ee2984a8c..b42e7bf9bb 100644
--- a/servers/register_server_types.cpp
+++ b/servers/register_server_types.cpp
@@ -80,6 +80,7 @@
 #include "text/text_server_dummy.h"
 #include "text/text_server_extension.h"
 #include "text_server.h"
+#include "xr/xr_face_tracker.h"
 #include "xr/xr_interface.h"
 #include "xr/xr_interface_extension.h"
 #include "xr/xr_positional_tracker.h"
@@ -189,6 +190,7 @@ void register_server_types() {
 	GDREGISTER_CLASS(XRInterfaceExtension); // can't register this as virtual because we need a creation function for our extensions.
 	GDREGISTER_CLASS(XRPose);
 	GDREGISTER_CLASS(XRPositionalTracker);
+	GDREGISTER_CLASS(XRFaceTracker);
 
 	GDREGISTER_CLASS(AudioStream);
 	GDREGISTER_CLASS(AudioStreamPlayback);
diff --git a/servers/xr/xr_face_tracker.cpp b/servers/xr/xr_face_tracker.cpp
new file mode 100644
index 0000000000..a38ccfd527
--- /dev/null
+++ b/servers/xr/xr_face_tracker.cpp
@@ -0,0 +1,222 @@
+/**************************************************************************/
+/*  xr_face_tracker.cpp                                                   */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* Permission is hereby granted, free of charge, to any person obtaining  */
+/* a copy of this software and associated documentation files (the        */
+/* "Software"), to deal in the Software without restriction, including    */
+/* without limitation the rights to use, copy, modify, merge, publish,    */
+/* distribute, sublicense, and/or sell copies of the Software, and to     */
+/* permit persons to whom the Software is furnished to do so, subject to  */
+/* the following conditions:                                              */
+/*                                                                        */
+/* The above copyright notice and this permission notice shall be         */
+/* included in all copies or substantial portions of the Software.        */
+/*                                                                        */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
+/**************************************************************************/
+
+#include "xr_face_tracker.h"
+
+void XRFaceTracker::_bind_methods() {
+	// Base Shapes
+	BIND_ENUM_CONSTANT(FT_EYE_LOOK_OUT_RIGHT);
+	BIND_ENUM_CONSTANT(FT_EYE_LOOK_IN_RIGHT);
+	BIND_ENUM_CONSTANT(FT_EYE_LOOK_UP_RIGHT);
+	BIND_ENUM_CONSTANT(FT_EYE_LOOK_DOWN_RIGHT);
+	BIND_ENUM_CONSTANT(FT_EYE_LOOK_OUT_LEFT);
+	BIND_ENUM_CONSTANT(FT_EYE_LOOK_IN_LEFT);
+	BIND_ENUM_CONSTANT(FT_EYE_LOOK_UP_LEFT);
+	BIND_ENUM_CONSTANT(FT_EYE_LOOK_DOWN_LEFT);
+	BIND_ENUM_CONSTANT(FT_EYE_CLOSED_RIGHT);
+	BIND_ENUM_CONSTANT(FT_EYE_CLOSED_LEFT);
+	BIND_ENUM_CONSTANT(FT_EYE_SQUINT_RIGHT);
+	BIND_ENUM_CONSTANT(FT_EYE_SQUINT_LEFT);
+	BIND_ENUM_CONSTANT(FT_EYE_WIDE_RIGHT);
+	BIND_ENUM_CONSTANT(FT_EYE_WIDE_LEFT);
+	BIND_ENUM_CONSTANT(FT_EYE_DILATION_RIGHT);
+	BIND_ENUM_CONSTANT(FT_EYE_DILATION_LEFT);
+	BIND_ENUM_CONSTANT(FT_EYE_CONSTRICT_RIGHT);
+	BIND_ENUM_CONSTANT(FT_EYE_CONSTRICT_LEFT);
+	BIND_ENUM_CONSTANT(FT_BROW_PINCH_RIGHT);
+	BIND_ENUM_CONSTANT(FT_BROW_PINCH_LEFT);
+	BIND_ENUM_CONSTANT(FT_BROW_LOWERER_RIGHT);
+	BIND_ENUM_CONSTANT(FT_BROW_LOWERER_LEFT);
+	BIND_ENUM_CONSTANT(FT_BROW_INNER_UP_RIGHT);
+	BIND_ENUM_CONSTANT(FT_BROW_INNER_UP_LEFT);
+	BIND_ENUM_CONSTANT(FT_BROW_OUTER_UP_RIGHT);
+	BIND_ENUM_CONSTANT(FT_BROW_OUTER_UP_LEFT);
+	BIND_ENUM_CONSTANT(FT_NOSE_SNEER_RIGHT);
+	BIND_ENUM_CONSTANT(FT_NOSE_SNEER_LEFT);
+	BIND_ENUM_CONSTANT(FT_NASAL_DILATION_RIGHT);
+	BIND_ENUM_CONSTANT(FT_NASAL_DILATION_LEFT);
+	BIND_ENUM_CONSTANT(FT_NASAL_CONSTRICT_RIGHT);
+	BIND_ENUM_CONSTANT(FT_NASAL_CONSTRICT_LEFT);
+	BIND_ENUM_CONSTANT(FT_CHEEK_SQUINT_RIGHT);
+	BIND_ENUM_CONSTANT(FT_CHEEK_SQUINT_LEFT);
+	BIND_ENUM_CONSTANT(FT_CHEEK_PUFF_RIGHT);
+	BIND_ENUM_CONSTANT(FT_CHEEK_PUFF_LEFT);
+	BIND_ENUM_CONSTANT(FT_CHEEK_SUCK_RIGHT);
+	BIND_ENUM_CONSTANT(FT_CHEEK_SUCK_LEFT);
+	BIND_ENUM_CONSTANT(FT_JAW_OPEN);
+	BIND_ENUM_CONSTANT(FT_MOUTH_CLOSED);
+	BIND_ENUM_CONSTANT(FT_JAW_RIGHT);
+	BIND_ENUM_CONSTANT(FT_JAW_LEFT);
+	BIND_ENUM_CONSTANT(FT_JAW_FORWARD);
+	BIND_ENUM_CONSTANT(FT_JAW_BACKWARD);
+	BIND_ENUM_CONSTANT(FT_JAW_CLENCH);
+	BIND_ENUM_CONSTANT(FT_JAW_MANDIBLE_RAISE);
+	BIND_ENUM_CONSTANT(FT_LIP_SUCK_UPPER_RIGHT);
+	BIND_ENUM_CONSTANT(FT_LIP_SUCK_UPPER_LEFT);
+	BIND_ENUM_CONSTANT(FT_LIP_SUCK_LOWER_RIGHT);
+	BIND_ENUM_CONSTANT(FT_LIP_SUCK_LOWER_LEFT);
+	BIND_ENUM_CONSTANT(FT_LIP_SUCK_CORNER_RIGHT);
+	BIND_ENUM_CONSTANT(FT_LIP_SUCK_CORNER_LEFT);
+	BIND_ENUM_CONSTANT(FT_LIP_FUNNEL_UPPER_RIGHT);
+	BIND_ENUM_CONSTANT(FT_LIP_FUNNEL_UPPER_LEFT);
+	BIND_ENUM_CONSTANT(FT_LIP_FUNNEL_LOWER_RIGHT);
+	BIND_ENUM_CONSTANT(FT_LIP_FUNNEL_LOWER_LEFT);
+	BIND_ENUM_CONSTANT(FT_LIP_PUCKER_UPPER_RIGHT);
+	BIND_ENUM_CONSTANT(FT_LIP_PUCKER_UPPER_LEFT);
+	BIND_ENUM_CONSTANT(FT_LIP_PUCKER_LOWER_RIGHT);
+	BIND_ENUM_CONSTANT(FT_LIP_PUCKER_LOWER_LEFT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_UPPER_UP_RIGHT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_UPPER_UP_LEFT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_LOWER_DOWN_RIGHT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_LOWER_DOWN_LEFT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_UPPER_DEEPEN_RIGHT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_UPPER_DEEPEN_LEFT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_UPPER_RIGHT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_UPPER_LEFT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_LOWER_RIGHT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_LOWER_LEFT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_CORNER_PULL_RIGHT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_CORNER_PULL_LEFT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_CORNER_SLANT_RIGHT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_CORNER_SLANT_LEFT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_FROWN_RIGHT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_FROWN_LEFT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_STRETCH_RIGHT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_STRETCH_LEFT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_DIMPLE_RIGHT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_DIMPLE_LEFT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_RAISER_UPPER);
+	BIND_ENUM_CONSTANT(FT_MOUTH_RAISER_LOWER);
+	BIND_ENUM_CONSTANT(FT_MOUTH_PRESS_RIGHT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_PRESS_LEFT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_TIGHTENER_RIGHT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_TIGHTENER_LEFT);
+	BIND_ENUM_CONSTANT(FT_TONGUE_OUT);
+	BIND_ENUM_CONSTANT(FT_TONGUE_UP);
+	BIND_ENUM_CONSTANT(FT_TONGUE_DOWN);
+	BIND_ENUM_CONSTANT(FT_TONGUE_RIGHT);
+	BIND_ENUM_CONSTANT(FT_TONGUE_LEFT);
+	BIND_ENUM_CONSTANT(FT_TONGUE_ROLL);
+	BIND_ENUM_CONSTANT(FT_TONGUE_BLEND_DOWN);
+	BIND_ENUM_CONSTANT(FT_TONGUE_CURL_UP);
+	BIND_ENUM_CONSTANT(FT_TONGUE_SQUISH);
+	BIND_ENUM_CONSTANT(FT_TONGUE_FLAT);
+	BIND_ENUM_CONSTANT(FT_TONGUE_TWIST_RIGHT);
+	BIND_ENUM_CONSTANT(FT_TONGUE_TWIST_LEFT);
+	BIND_ENUM_CONSTANT(FT_SOFT_PALATE_CLOSE);
+	BIND_ENUM_CONSTANT(FT_THROAT_SWALLOW);
+	BIND_ENUM_CONSTANT(FT_NECK_FLEX_RIGHT);
+	BIND_ENUM_CONSTANT(FT_NECK_FLEX_LEFT);
+	// Blended Shapes
+	BIND_ENUM_CONSTANT(FT_EYE_CLOSED);
+	BIND_ENUM_CONSTANT(FT_EYE_WIDE);
+	BIND_ENUM_CONSTANT(FT_EYE_SQUINT);
+	BIND_ENUM_CONSTANT(FT_EYE_DILATION);
+	BIND_ENUM_CONSTANT(FT_EYE_CONSTRICT);
+	BIND_ENUM_CONSTANT(FT_BROW_DOWN_RIGHT);
+	BIND_ENUM_CONSTANT(FT_BROW_DOWN_LEFT);
+	BIND_ENUM_CONSTANT(FT_BROW_DOWN);
+	BIND_ENUM_CONSTANT(FT_BROW_UP_RIGHT);
+	BIND_ENUM_CONSTANT(FT_BROW_UP_LEFT);
+	BIND_ENUM_CONSTANT(FT_BROW_UP);
+	BIND_ENUM_CONSTANT(FT_NOSE_SNEER);
+	BIND_ENUM_CONSTANT(FT_NASAL_DILATION);
+	BIND_ENUM_CONSTANT(FT_NASAL_CONSTRICT);
+	BIND_ENUM_CONSTANT(FT_CHEEK_PUFF);
+	BIND_ENUM_CONSTANT(FT_CHEEK_SUCK);
+	BIND_ENUM_CONSTANT(FT_CHEEK_SQUINT);
+	BIND_ENUM_CONSTANT(FT_LIP_SUCK_UPPER);
+	BIND_ENUM_CONSTANT(FT_LIP_SUCK_LOWER);
+	BIND_ENUM_CONSTANT(FT_LIP_SUCK);
+	BIND_ENUM_CONSTANT(FT_LIP_FUNNEL_UPPER);
+	BIND_ENUM_CONSTANT(FT_LIP_FUNNEL_LOWER);
+	BIND_ENUM_CONSTANT(FT_LIP_FUNNEL);
+	BIND_ENUM_CONSTANT(FT_LIP_PUCKER_UPPER);
+	BIND_ENUM_CONSTANT(FT_LIP_PUCKER_LOWER);
+	BIND_ENUM_CONSTANT(FT_LIP_PUCKER);
+	BIND_ENUM_CONSTANT(FT_MOUTH_UPPER_UP);
+	BIND_ENUM_CONSTANT(FT_MOUTH_LOWER_DOWN);
+	BIND_ENUM_CONSTANT(FT_MOUTH_OPEN);
+	BIND_ENUM_CONSTANT(FT_MOUTH_RIGHT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_LEFT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_SMILE_RIGHT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_SMILE_LEFT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_SMILE);
+	BIND_ENUM_CONSTANT(FT_MOUTH_SAD_RIGHT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_SAD_LEFT);
+	BIND_ENUM_CONSTANT(FT_MOUTH_SAD);
+	BIND_ENUM_CONSTANT(FT_MOUTH_STRETCH);
+	BIND_ENUM_CONSTANT(FT_MOUTH_DIMPLE);
+	BIND_ENUM_CONSTANT(FT_MOUTH_TIGHTENER);
+	BIND_ENUM_CONSTANT(FT_MOUTH_PRESS);
+	BIND_ENUM_CONSTANT(FT_MAX);
+
+	ClassDB::bind_method(D_METHOD("get_blend_shape", "blend_shape"), &XRFaceTracker::get_blend_shape);
+	ClassDB::bind_method(D_METHOD("set_blend_shape", "blend_shape", "weight"), &XRFaceTracker::set_blend_shape);
+
+	ClassDB::bind_method(D_METHOD("get_blend_shapes"), &XRFaceTracker::get_blend_shapes);
+	ClassDB::bind_method(D_METHOD("set_blend_shapes", "weights"), &XRFaceTracker::set_blend_shapes);
+	ADD_PROPERTY(PropertyInfo(Variant::PACKED_FLOAT32_ARRAY, "blend_shapes"), "set_blend_shapes", "get_blend_shapes");
+	ADD_PROPERTY_DEFAULT("blend_shapes", PackedFloat32Array()); // To prevent ludicrously large default values.
+}
+
+float XRFaceTracker::get_blend_shape(BlendShapeEntry p_blend_shape) const {
+	// Fail if the blend shape index is out of range.
+	ERR_FAIL_INDEX_V(p_blend_shape, FT_MAX, 0.0f);
+
+	// Return the blend shape value.
+	return blend_shape_values[p_blend_shape];
+}
+
+void XRFaceTracker::set_blend_shape(BlendShapeEntry p_blend_shape, float p_value) {
+	// Fail if the blend shape index is out of range.
+	ERR_FAIL_INDEX(p_blend_shape, FT_MAX);
+
+	// Save the new blend shape value.
+	blend_shape_values[p_blend_shape] = p_value;
+}
+
+PackedFloat32Array XRFaceTracker::get_blend_shapes() const {
+	// Create a packed float32 array and copy the blend shape values into it.
+	PackedFloat32Array data;
+	data.resize(FT_MAX);
+	memcpy(data.ptrw(), blend_shape_values, sizeof(blend_shape_values));
+
+	// Return the blend shape array.
+	return data;
+}
+
+void XRFaceTracker::set_blend_shapes(const PackedFloat32Array &p_blend_shapes) {
+	// Fail if the blend shape array is not the correct size.
+	ERR_FAIL_COND(p_blend_shapes.size() != FT_MAX);
+
+	// Copy the blend shape values into the blend shape array.
+	memcpy(blend_shape_values, p_blend_shapes.ptr(), sizeof(blend_shape_values));
+}
diff --git a/servers/xr/xr_face_tracker.h b/servers/xr/xr_face_tracker.h
new file mode 100644
index 0000000000..b9f553cba6
--- /dev/null
+++ b/servers/xr/xr_face_tracker.h
@@ -0,0 +1,213 @@
+/**************************************************************************/
+/*  xr_face_tracker.h                                                     */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* Permission is hereby granted, free of charge, to any person obtaining  */
+/* a copy of this software and associated documentation files (the        */
+/* "Software"), to deal in the Software without restriction, including    */
+/* without limitation the rights to use, copy, modify, merge, publish,    */
+/* distribute, sublicense, and/or sell copies of the Software, and to     */
+/* permit persons to whom the Software is furnished to do so, subject to  */
+/* the following conditions:                                              */
+/*                                                                        */
+/* The above copyright notice and this permission notice shall be         */
+/* included in all copies or substantial portions of the Software.        */
+/*                                                                        */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
+/**************************************************************************/
+
+#ifndef XR_FACE_TRACKER_H
+#define XR_FACE_TRACKER_H
+
+#include "core/object/ref_counted.h"
+
+/**
+	The XRFaceTracker class provides face blend shape weights.
+
+	The supported blend shapes are based on the Unified Expressions
+	standard, and as such have a well defined mapping to ARKit, SRanipal,
+	and Meta Movement standards.
+ */
+
+class XRFaceTracker : public RefCounted {
+	GDCLASS(XRFaceTracker, RefCounted);
+	_THREAD_SAFE_CLASS_
+
+public:
+	enum BlendShapeEntry {
+		// Base Shapes
+		FT_EYE_LOOK_OUT_RIGHT, // Right eye looks outwards.
+		FT_EYE_LOOK_IN_RIGHT, // Right eye looks inwards.
+		FT_EYE_LOOK_UP_RIGHT, // Right eye looks upwards.
+		FT_EYE_LOOK_DOWN_RIGHT, // Right eye looks downwards.
+		FT_EYE_LOOK_OUT_LEFT, // Left eye looks outwards.
+		FT_EYE_LOOK_IN_LEFT, // Left eye looks inwards.
+		FT_EYE_LOOK_UP_LEFT, // Left eye looks upwards.
+		FT_EYE_LOOK_DOWN_LEFT, // Left eye looks downwards.
+		FT_EYE_CLOSED_RIGHT, // Closes the right eyelid.
+		FT_EYE_CLOSED_LEFT, // Closes the left eyelid.
+		FT_EYE_SQUINT_RIGHT, // Squeezes the right eye socket muscles.
+		FT_EYE_SQUINT_LEFT, // Squeezes the left eye socket muscles.
+		FT_EYE_WIDE_RIGHT, // Right eyelid widens beyond relaxed.
+		FT_EYE_WIDE_LEFT, // Left eyelid widens beyond relaxed.
+		FT_EYE_DILATION_RIGHT, // Dilates the right eye pupil.
+		FT_EYE_DILATION_LEFT, // Dilates the left eye pupil.
+		FT_EYE_CONSTRICT_RIGHT, // Constricts the right eye pupil.
+		FT_EYE_CONSTRICT_LEFT, // Constricts the left eye pupil.
+		FT_BROW_PINCH_RIGHT, // Right eyebrow pinches in.
+		FT_BROW_PINCH_LEFT, // Left eyebrow pinches in.
+		FT_BROW_LOWERER_RIGHT, // Outer right eyebrow pulls down.
+		FT_BROW_LOWERER_LEFT, // Outer left eyebrow pulls down.
+		FT_BROW_INNER_UP_RIGHT, // Inner right eyebrow pulls up.
+		FT_BROW_INNER_UP_LEFT, // Inner left eyebrow pulls up.
+		FT_BROW_OUTER_UP_RIGHT, // Outer right eyebrow pulls up.
+		FT_BROW_OUTER_UP_LEFT, // Outer left eyebrow pulls up.
+		FT_NOSE_SNEER_RIGHT, // Right side face sneers.
+		FT_NOSE_SNEER_LEFT, // Left side face sneers.
+		FT_NASAL_DILATION_RIGHT, // Right side nose canal dilates.
+		FT_NASAL_DILATION_LEFT, // Left side nose canal dilates.
+		FT_NASAL_CONSTRICT_RIGHT, // Right side nose canal constricts.
+		FT_NASAL_CONSTRICT_LEFT, // Left side nose canal constricts.
+		FT_CHEEK_SQUINT_RIGHT, // Raises the right side cheek.
+		FT_CHEEK_SQUINT_LEFT, // Raises the left side cheek.
+		FT_CHEEK_PUFF_RIGHT, // Puffs the right side cheek.
+		FT_CHEEK_PUFF_LEFT, // Puffs the left side cheek.
+		FT_CHEEK_SUCK_RIGHT, // Sucks in the right side cheek.
+		FT_CHEEK_SUCK_LEFT, // Sucks in the left side cheek.
+		FT_JAW_OPEN, // Opens jawbone.
+		FT_MOUTH_CLOSED, // Closes the mouth.
+		FT_JAW_RIGHT, // Pushes jawbone right.
+		FT_JAW_LEFT, // Pushes jawbone left.
+		FT_JAW_FORWARD, // Pushes jawbone forward.
+		FT_JAW_BACKWARD, // Pushes jawbone backward.
+		FT_JAW_CLENCH, // Flexes jaw muscles.
+		FT_JAW_MANDIBLE_RAISE, // Raises the jawbone.
+		FT_LIP_SUCK_UPPER_RIGHT, // Upper right lip part tucks in the mouth.
+		FT_LIP_SUCK_UPPER_LEFT, // Upper left lip part tucks in the mouth.
+		FT_LIP_SUCK_LOWER_RIGHT, // Lower right lip part tucks in the mouth.
+		FT_LIP_SUCK_LOWER_LEFT, // Lower left lip part tucks in the mouth.
+		FT_LIP_SUCK_CORNER_RIGHT, // Right lip corner folds into the mouth.
+		FT_LIP_SUCK_CORNER_LEFT, // Left lip corner folds into the mouth.
+		FT_LIP_FUNNEL_UPPER_RIGHT, // Upper right lip part pushes into a funnel.
+		FT_LIP_FUNNEL_UPPER_LEFT, // Upper left lip part pushes into a funnel.
+		FT_LIP_FUNNEL_LOWER_RIGHT, // Lower right lip part pushes into a funnel.
+		FT_LIP_FUNNEL_LOWER_LEFT, // Lower left lip part pushes into a funnel.
+		FT_LIP_PUCKER_UPPER_RIGHT, // Upper right lip part pushes outwards.
+		FT_LIP_PUCKER_UPPER_LEFT, // Upper left lip part pushes outwards.
+		FT_LIP_PUCKER_LOWER_RIGHT, // Lower right lip part pushes outwards.
+		FT_LIP_PUCKER_LOWER_LEFT, // Lower left lip part pushes outwards.
+		FT_MOUTH_UPPER_UP_RIGHT, // Upper right part of the lip pulls up.
+		FT_MOUTH_UPPER_UP_LEFT, // Upper left part of the lip pulls up.
+		FT_MOUTH_LOWER_DOWN_RIGHT, // Lower right part of the lip pulls up.
+		FT_MOUTH_LOWER_DOWN_LEFT, // Lower left part of the lip pulls up.
+		FT_MOUTH_UPPER_DEEPEN_RIGHT, // Upper right lip part pushes in the cheek.
+		FT_MOUTH_UPPER_DEEPEN_LEFT, // Upper left lip part pushes in the cheek.
+		FT_MOUTH_UPPER_RIGHT, // Moves upper lip right.
+		FT_MOUTH_UPPER_LEFT, // Moves upper lip left.
+		FT_MOUTH_LOWER_RIGHT, // Moves lower lip right.
+		FT_MOUTH_LOWER_LEFT, // Moves lower lip left.
+		FT_MOUTH_CORNER_PULL_RIGHT, // Right lip corner pulls diagonally up and out.
+		FT_MOUTH_CORNER_PULL_LEFT, // Left lip corner pulls diagonally up and out.
+		FT_MOUTH_CORNER_SLANT_RIGHT, // Right corner lip slants up.
+		FT_MOUTH_CORNER_SLANT_LEFT, // Left corner lip slants up.
+		FT_MOUTH_FROWN_RIGHT, // Right corner lip pulls down.
+		FT_MOUTH_FROWN_LEFT, // Left corner lip pulls down.
+		FT_MOUTH_STRETCH_RIGHT, // Mouth corner lip pulls out and down.
+		FT_MOUTH_STRETCH_LEFT, // Mouth corner lip pulls out and down.
+		FT_MOUTH_DIMPLE_RIGHT, // Right lip corner is pushed backwards.
+		FT_MOUTH_DIMPLE_LEFT, // Left lip corner is pushed backwards.
+		FT_MOUTH_RAISER_UPPER, // Raises and slightly pushes out the upper mouth.
+		FT_MOUTH_RAISER_LOWER, // Raises and slightly pushes out the lower mouth.
+		FT_MOUTH_PRESS_RIGHT, // Right side lips press and flatten together vertically.
+		FT_MOUTH_PRESS_LEFT, // Left side lips press and flatten together vertically.
+		FT_MOUTH_TIGHTENER_RIGHT, // Right side lips squeeze together horizontally.
+		FT_MOUTH_TIGHTENER_LEFT, // Left side lips squeeze together horizontally.
+		FT_TONGUE_OUT, // Tongue visibly sticks out of the mouth.
+		FT_TONGUE_UP, // Tongue points upwards.
+		FT_TONGUE_DOWN, // Tongue points downwards.
+		FT_TONGUE_RIGHT, // Tongue points right.
+		FT_TONGUE_LEFT, // Tongue points left.
+		FT_TONGUE_ROLL, // Sides of the tongue funnel, creating a roll.
+		FT_TONGUE_BLEND_DOWN, // Tongue arches up then down inside the mouth.
+		FT_TONGUE_CURL_UP, // Tongue arches down then up inside the mouth.
+		FT_TONGUE_SQUISH, // Tongue squishes together and thickens.
+		FT_TONGUE_FLAT, // Tongue flattens and thins out.
+		FT_TONGUE_TWIST_RIGHT, // Tongue tip rotates clockwise, with the rest following gradually.
+		FT_TONGUE_TWIST_LEFT, // Tongue tip rotates counter-clockwise, with the rest following gradually.
+		FT_SOFT_PALATE_CLOSE, // Inner mouth throat closes.
+		FT_THROAT_SWALLOW, // The Adam's apple visibly swallows.
+		FT_NECK_FLEX_RIGHT, // Right side neck visibly flexes.
+		FT_NECK_FLEX_LEFT, // Left side neck visibly flexes.
+		// Blended Shapes
+		FT_EYE_CLOSED, // Closes both eye lids.
+		FT_EYE_WIDE, // Widens both eye lids.
+		FT_EYE_SQUINT, // Squints both eye lids.
+		FT_EYE_DILATION, // Dilates both pupils.
+		FT_EYE_CONSTRICT, // Constricts both pupils.
+		FT_BROW_DOWN_RIGHT, // Pulls the right eyebrow down and in.
+		FT_BROW_DOWN_LEFT, // Pulls the left eyebrow down and in.
+		FT_BROW_DOWN, // Pulls both eyebrows down and in.
+		FT_BROW_UP_RIGHT, // Right brow appears worried.
+		FT_BROW_UP_LEFT, // Left brow appears worried.
+		FT_BROW_UP, // Both brows appear worried.
+		FT_NOSE_SNEER, // Entire face sneers.
+		FT_NASAL_DILATION, // Both nose canals dilate.
+		FT_NASAL_CONSTRICT, // Both nose canals constrict.
+		FT_CHEEK_PUFF, // Puffs both cheeks.
+		FT_CHEEK_SUCK, // Sucks in both cheeks.
+		FT_CHEEK_SQUINT, // Raises both cheeks.
+		FT_LIP_SUCK_UPPER, // Tucks in the upper lips.
+		FT_LIP_SUCK_LOWER, // Tucks in the lower lips.
+		FT_LIP_SUCK, // Tucks in both lips.
+		FT_LIP_FUNNEL_UPPER, // Funnels in the upper lips.
+		FT_LIP_FUNNEL_LOWER, // Funnels in the lower lips.
+		FT_LIP_FUNNEL, // Funnels in both lips.
+		FT_LIP_PUCKER_UPPER, // Upper lip part pushes outwards.
+		FT_LIP_PUCKER_LOWER, // Lower lip part pushes outwards.
+		FT_LIP_PUCKER, // Lips push outwards.
+		FT_MOUTH_UPPER_UP, // Raises the upper lips.
+		FT_MOUTH_LOWER_DOWN, // Lowers the lower lips.
+		FT_MOUTH_OPEN, // Mouth opens, revealing teeth.
+		FT_MOUTH_RIGHT, // Moves mouth right.
+		FT_MOUTH_LEFT, // Moves mouth left.
+		FT_MOUTH_SMILE_RIGHT, // Right side of the mouth smiles.
+		FT_MOUTH_SMILE_LEFT, // Left side of the mouth smiles.
+		FT_MOUTH_SMILE, // Mouth expresses a smile.
+		FT_MOUTH_SAD_RIGHT, // Right side of the mouth expresses sadness.
+		FT_MOUTH_SAD_LEFT, // Left side of the mouth expresses sadness.
+		FT_MOUTH_SAD, // Mouth expresses sadness.
+		FT_MOUTH_STRETCH, // Mouth stretches.
+		FT_MOUTH_DIMPLE, // Lip corners dimple.
+		FT_MOUTH_TIGHTENER, // Mouth tightens.
+		FT_MOUTH_PRESS, // Mouth presses together.
+		FT_MAX // Maximum blend shape.
+	};
+
+	float get_blend_shape(BlendShapeEntry p_blend_shape) const;
+	void set_blend_shape(BlendShapeEntry p_blend_shape, float p_value);
+
+	PackedFloat32Array get_blend_shapes() const;
+	void set_blend_shapes(const PackedFloat32Array &p_blend_shapes);
+
+protected:
+	static void _bind_methods();
+
+private:
+	float blend_shape_values[FT_MAX] = {};
+};
+
+VARIANT_ENUM_CAST(XRFaceTracker::BlendShapeEntry);
+
+#endif // XR_FACE_TRACKER_H
diff --git a/servers/xr_server.cpp b/servers/xr_server.cpp
index e7f644d53f..b3bb0a3702 100644
--- a/servers/xr_server.cpp
+++ b/servers/xr_server.cpp
@@ -30,6 +30,7 @@
 
 #include "xr_server.h"
 #include "core/config/project_settings.h"
+#include "xr/xr_face_tracker.h"
 #include "xr/xr_interface.h"
 #include "xr/xr_positional_tracker.h"
 
@@ -74,6 +75,11 @@ void XRServer::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_trackers", "tracker_types"), &XRServer::get_trackers);
 	ClassDB::bind_method(D_METHOD("get_tracker", "tracker_name"), &XRServer::get_tracker);
 
+	ClassDB::bind_method(D_METHOD("add_face_tracker", "tracker_name", "face_tracker"), &XRServer::add_face_tracker);
+	ClassDB::bind_method(D_METHOD("remove_face_tracker", "tracker_name"), &XRServer::remove_face_tracker);
+	ClassDB::bind_method(D_METHOD("get_face_trackers"), &XRServer::get_face_trackers);
+	ClassDB::bind_method(D_METHOD("get_face_tracker", "tracker_name"), &XRServer::get_face_tracker);
+
 	ClassDB::bind_method(D_METHOD("get_primary_interface"), &XRServer::get_primary_interface);
 	ClassDB::bind_method(D_METHOD("set_primary_interface", "interface"), &XRServer::set_primary_interface);
 
@@ -97,6 +103,10 @@ void XRServer::_bind_methods() {
 	ADD_SIGNAL(MethodInfo("tracker_added", PropertyInfo(Variant::STRING_NAME, "tracker_name"), PropertyInfo(Variant::INT, "type")));
 	ADD_SIGNAL(MethodInfo("tracker_updated", PropertyInfo(Variant::STRING_NAME, "tracker_name"), PropertyInfo(Variant::INT, "type")));
 	ADD_SIGNAL(MethodInfo("tracker_removed", PropertyInfo(Variant::STRING_NAME, "tracker_name"), PropertyInfo(Variant::INT, "type")));
+
+	ADD_SIGNAL(MethodInfo("face_tracker_added", PropertyInfo(Variant::STRING_NAME, "tracker_name"), PropertyInfo(Variant::OBJECT, "face_tracker", PROPERTY_HINT_RESOURCE_TYPE, "XRFaceTracker")));
+	ADD_SIGNAL(MethodInfo("face_tracker_updated", PropertyInfo(Variant::STRING_NAME, "tracker_name"), PropertyInfo(Variant::OBJECT, "face_tracker", PROPERTY_HINT_RESOURCE_TYPE, "XRFaceTracker")));
+	ADD_SIGNAL(MethodInfo("face_tracker_removed", PropertyInfo(Variant::STRING_NAME, "tracker_name")));
 };
 
 double XRServer::get_world_scale() const {
@@ -352,6 +362,44 @@ PackedStringArray XRServer::get_suggested_pose_names(const StringName &p_tracker
 	return arr;
 }
 
+void XRServer::add_face_tracker(const StringName &p_tracker_name, Ref<XRFaceTracker> p_face_tracker) {
+	ERR_FAIL_COND(p_face_tracker.is_null());
+
+	if (!face_trackers.has(p_tracker_name)) {
+		// We don't have a tracker with this name, we're going to add it.
+		face_trackers[p_tracker_name] = p_face_tracker;
+		emit_signal(SNAME("face_tracker_added"), p_tracker_name, p_face_tracker);
+	} else if (face_trackers[p_tracker_name] != p_face_tracker) {
+		// We already have a tracker with this name, we're going to replace it.
+		face_trackers[p_tracker_name] = p_face_tracker;
+		emit_signal(SNAME("face_tracker_updated"), p_tracker_name, p_face_tracker);
+	}
+}
+
+void XRServer::remove_face_tracker(const StringName &p_tracker_name) {
+	// Skip if no face tracker is found.
+	if (!face_trackers.has(p_tracker_name)) {
+		return;
+	}
+
+	// Send the removed signal, then remove the face tracker.
+	emit_signal(SNAME("face_tracker_removed"), p_tracker_name);
+	face_trackers.erase(p_tracker_name);
+}
+
+Dictionary XRServer::get_face_trackers() const {
+	return face_trackers;
+}
+
+Ref<XRFaceTracker> XRServer::get_face_tracker(const StringName &p_tracker_name) const {
+	// Skip if no tracker is found.
+	if (!face_trackers.has(p_tracker_name)) {
+		return Ref<XRFaceTracker>();
+	}
+
+	return face_trackers[p_tracker_name];
+}
+
 void XRServer::_process() {
 	// called from our main game loop before we handle physics and game logic
 	// note that we can have multiple interfaces active if we have interfaces that purely handle tracking
diff --git a/servers/xr_server.h b/servers/xr_server.h
index fe59fc22cb..0a4e020a1f 100644
--- a/servers/xr_server.h
+++ b/servers/xr_server.h
@@ -39,6 +39,7 @@
 
 class XRInterface;
 class XRPositionalTracker;
+class XRFaceTracker;
 
 /**
 	The XR server is a singleton object that gives access to the various
@@ -86,6 +87,8 @@ private:
 	Vector<Ref<XRInterface>> interfaces;
 	Dictionary trackers;
 
+	Dictionary face_trackers;
+
 	Ref<XRInterface> primary_interface; /* we'll identify one interface as primary, this will be used by our viewports */
 
 	double world_scale; /* scale by which we multiply our tracker positions */
@@ -183,6 +186,14 @@ public:
 	PackedStringArray get_suggested_pose_names(const StringName &p_tracker_name) const;
 	// Q: Should we add get_suggested_input_names and get_suggested_haptic_names even though we don't use them for the IDE?
 
+	/*
+		Face trackers are objects that expose the tracked blend shapes of a face.
+	 */
+	void add_face_tracker(const StringName &p_tracker_name, Ref<XRFaceTracker> p_face_tracker);
+	void remove_face_tracker(const StringName &p_tracker_name);
+	Dictionary get_face_trackers() const;
+	Ref<XRFaceTracker> get_face_tracker(const StringName &p_tracker_name) const;
+
 	// Process is called before we handle our physics process and game process. This is where our interfaces will update controller data and such.
 	void _process();