1 files changed, 55 insertions, 7 deletions

diff --git a/modules/webxr/webxr_interface_js.cpp b/modules/webxr/webxr_interface_js.cpp
index 916566fc1b..78a9db9b19 100644
--- a/modules/webxr/webxr_interface_js.cpp
+++ b/modules/webxr/webxr_interface_js.cpp
@@ -58,7 +58,7 @@ void _emwebxr_on_session_supported(char *p_session_mode, int p_supported) {
 	interface->emit_signal(SNAME("session_supported"), session_mode, p_supported ? true : false);
 }
 
-void _emwebxr_on_session_started(char *p_reference_space_type, char *p_enabled_features) {
+void _emwebxr_on_session_started(char *p_reference_space_type, char *p_enabled_features, char *p_environment_blend_mode) {
 	XRServer *xr_server = XRServer::get_singleton();
 	ERR_FAIL_NULL(xr_server);
 
@@ -68,6 +68,7 @@ void _emwebxr_on_session_started(char *p_reference_space_type, char *p_enabled_f
 	String reference_space_type = String(p_reference_space_type);
 	interface->_set_reference_space_type(reference_space_type);
 	interface->_set_enabled_features(p_enabled_features);
+	interface->_set_environment_blend_mode(p_environment_blend_mode);
 	interface->emit_signal(SNAME("session_started"));
 }
 
@@ -230,6 +231,44 @@ Array WebXRInterfaceJS::get_available_display_refresh_rates() const {
 	return ret;
 }
 
+Array WebXRInterfaceJS::get_supported_environment_blend_modes() {
+	Array blend_modes;
+	// The blend mode can't be changed, so return the current blend mode as the only supported one.
+	blend_modes.push_back(environment_blend_mode);
+	return blend_modes;
+}
+
+XRInterface::EnvironmentBlendMode WebXRInterfaceJS::get_environment_blend_mode() const {
+	return environment_blend_mode;
+}
+
+bool WebXRInterfaceJS::set_environment_blend_mode(EnvironmentBlendMode p_new_environment_blend_mode) {
+	if (environment_blend_mode == p_new_environment_blend_mode) {
+		// Environment blend mode can't be changed, but we'll consider it a success to set it
+		// to what it already is.
+		return true;
+	}
+	return false;
+}
+
+void WebXRInterfaceJS::_set_environment_blend_mode(String p_blend_mode_string) {
+	if (p_blend_mode_string == "opaque") {
+		environment_blend_mode = XRInterface::XR_ENV_BLEND_MODE_OPAQUE;
+	} else if (p_blend_mode_string == "additive") {
+		environment_blend_mode = XRInterface::XR_ENV_BLEND_MODE_ADDITIVE;
+	} else if (p_blend_mode_string == "alpha-blend") {
+		environment_blend_mode = XRInterface::XR_ENV_BLEND_MODE_ALPHA_BLEND;
+	} else {
+		// Not all browsers can give us this information, so as a fallback,
+		// we'll make some guesses about the blend mode.
+		if (session_mode == "immersive-ar") {
+			environment_blend_mode = XRInterface::XR_ENV_BLEND_MODE_ALPHA_BLEND;
+		} else {
+			environment_blend_mode = XRInterface::XR_ENV_BLEND_MODE_OPAQUE;
+		}
+	}
+}
+
 StringName WebXRInterfaceJS::get_name() const {
 	return "WebXR";
 };
@@ -336,6 +375,7 @@ void WebXRInterfaceJS::uninitialize() {
 		texture_cache.clear();
 		reference_space_type.clear();
 		enabled_features.clear();
+		environment_blend_mode = XRInterface::XR_ENV_BLEND_MODE_OPAQUE;
 		initialized = false;
 	};
 };
@@ -740,12 +780,20 @@ void WebXRInterfaceJS::_update_input_source(int p_input_source_id) {
 
 			// WebXR doesn't have a palm joint, so we calculate it by finding the middle of the middle finger metacarpal bone.
 			{
-				// 10 is the WebXR middle finger metacarpal joint, and 12 is the offset to the transform origin.
-				const float *start_pos = hand_joints + (10 * 16) + 12;
-				// 11 is the WebXR middle finger phalanx proximal joint, and 12 is the offset to the transform origin.
-				const float *end_pos = hand_joints + (11 * 16) + 12;
-				Transform3D palm_transform;
-				palm_transform.origin = (Vector3(start_pos[0], start_pos[1], start_pos[2]) + Vector3(end_pos[0], end_pos[1], end_pos[2])) / 2.0;
+				// Start by getting the middle finger metacarpal joint.
+				// Note: 10 is the WebXR middle finger metacarpal joint.
+				Transform3D palm_transform = _js_matrix_to_transform(hand_joints + (10 * 16));
+				palm_transform.basis *= bone_adjustment;
+
+				// Get the middle finger phalanx position.
+				// Note: 11 is the WebXR middle finger phalanx proximal joint and 12 is the origin offset.
+				const float *phalanx_pos = hand_joints + (11 * 16) + 12;
+				Vector3 phalanx(phalanx_pos[0], phalanx_pos[1], phalanx_pos[2]);
+
+				// Offset the palm half-way towards the phalanx joint.
+				palm_transform.origin = (palm_transform.origin + phalanx) / 2.0;
+
+				// Set the palm joint and the pose.
 				hand_tracker->set_hand_joint_transform(XRHandTracker::HAND_JOINT_PALM, palm_transform);
 				hand_tracker->set_pose("default", palm_transform, Vector3(), Vector3());
 			}