Add intersects_ray() method to OpenXRCompositionLayer

modules/openxr/doc_classes/OpenXRCompositionLayer.xml

@@ -10,6 +10,15 @@
 	<tutorials>
 	</tutorials>
 	<methods>
+		<method name="intersects_ray" qualifiers="const">
+			<return type="Vector2" />
+			<param index="0" name="origin" type="Vector3" />
+			<param index="1" name="direction" type="Vector3" />
+			<description>
+				Returns UV coordinates where the given ray intersects with the composition layer. [param origin] and [param direction] must be in global space.
+				Returns [code]Vector2(-1.0, -1.0)[/code] if the ray doesn't intersect.
+			</description>
+		</method>
 		<method name="is_natively_supported" qualifiers="const">
 			<return type="bool" />
 			<description>

modules/openxr/scene/openxr_composition_layer.cpp

@@ -88,6 +88,8 @@ void OpenXRCompositionLayer::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("is_natively_supported"), &OpenXRCompositionLayer::is_natively_supported);
 
+	ClassDB::bind_method(D_METHOD("intersects_ray", "origin", "direction"), &OpenXRCompositionLayer::intersects_ray);
+
 	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "layer_viewport", PROPERTY_HINT_NODE_TYPE, "SubViewport"), "set_layer_viewport", "get_layer_viewport");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "sort_order", PROPERTY_HINT_NONE, ""), "set_sort_order", "get_sort_order");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "alpha_blend", PROPERTY_HINT_NONE, ""), "set_alpha_blend", "get_alpha_blend");
@@ -199,6 +201,10 @@ bool OpenXRCompositionLayer::is_natively_supported() const {
 	return false;
 }
 
+Vector2 OpenXRCompositionLayer::intersects_ray(const Vector3 &p_origin, const Vector3 &p_direction) const {
+	return Vector2(-1.0, -1.0);
+}
+
 void OpenXRCompositionLayer::_reset_fallback_material() {
 	ERR_FAIL_NULL(fallback);
 

modules/openxr/scene/openxr_composition_layer.h

@@ -84,6 +84,8 @@ class OpenXRCompositionLayer : public Node3D {
 
 	virtual PackedStringArray get_configuration_warnings() const override;
 
+	virtual Vector2 intersects_ray(const Vector3 &p_origin, const Vector3 &p_direction) const;
+
 	OpenXRCompositionLayer();
 	~OpenXRCompositionLayer();
 };

modules/openxr/scene/openxr_composition_layer_cylinder.cpp

@@ -188,3 +188,48 @@ void OpenXRCompositionLayerCylinder::set_fallback_segments(uint32_t p_fallback_s
 uint32_t OpenXRCompositionLayerCylinder::get_fallback_segments() const {
 	return fallback_segments;
 }
+
+Vector2 OpenXRCompositionLayerCylinder::intersects_ray(const Vector3 &p_origin, const Vector3 &p_direction) const {
+	Transform3D cylinder_transform = get_global_transform();
+	Vector3 cylinder_axis = cylinder_transform.basis.get_column(1);
+
+	Vector3 offset = p_origin - cylinder_transform.origin;
+	float a = p_direction.dot(p_direction - cylinder_axis * p_direction.dot(cylinder_axis));
+	float b = 2.0 * (p_direction.dot(offset - cylinder_axis * offset.dot(cylinder_axis)));
+	float c = offset.dot(offset - cylinder_axis * offset.dot(cylinder_axis)) - (radius * radius);
+
+	float discriminant = b * b - 4.0 * a * c;
+	if (discriminant < 0.0) {
+		return Vector2(-1.0, -1.0);
+	}
+
+	float t0 = (-b - Math::sqrt(discriminant)) / (2.0 * a);
+	float t1 = (-b + Math::sqrt(discriminant)) / (2.0 * a);
+	float t = MAX(t0, t1);
+
+	if (t < 0.0) {
+		return Vector2(-1.0, -1.0);
+	}
+	Vector3 intersection = p_origin + p_direction * t;
+
+	Basis correction = cylinder_transform.basis.inverse();
+	correction.rotate(Vector3(0.0, 1.0, 0.0), -Math_PI / 2.0);
+	Vector3 relative_point = correction.xform(intersection - cylinder_transform.origin);
+
+	Vector2 projected_point = Vector2(relative_point.x, relative_point.z);
+	float intersection_angle = Math::atan2(projected_point.y, projected_point.x);
+	if (Math::abs(intersection_angle) > central_angle / 2.0) {
+		return Vector2(-1.0, -1.0);
+	}
+
+	float arc_length = radius * central_angle;
+	float height = aspect_ratio * arc_length;
+	if (Math::abs(relative_point.y) > height / 2.0) {
+		return Vector2(-1.0, -1.0);
+	}
+
+	float u = 0.5 + (intersection_angle / central_angle);
+	float v = 1.0 - (0.5 + (relative_point.y / height));
+
+	return Vector2(u, v);
+}

modules/openxr/scene/openxr_composition_layer_cylinder.h

@@ -66,6 +66,8 @@ class OpenXRCompositionLayerCylinder : public OpenXRCompositionLayer {
 	void set_fallback_segments(uint32_t p_fallback_segments);
 	uint32_t get_fallback_segments() const;
 
+	virtual Vector2 intersects_ray(const Vector3 &p_origin, const Vector3 &p_direction) const override;
+
 	OpenXRCompositionLayerCylinder();
 	~OpenXRCompositionLayerCylinder();
 };

modules/openxr/scene/openxr_composition_layer_equirect.cpp

@@ -207,3 +207,54 @@ void OpenXRCompositionLayerEquirect::set_fallback_segments(uint32_t p_fallback_s
 uint32_t OpenXRCompositionLayerEquirect::get_fallback_segments() const {
 	return fallback_segments;
 }
+
+Vector2 OpenXRCompositionLayerEquirect::intersects_ray(const Vector3 &p_origin, const Vector3 &p_direction) const {
+	Transform3D equirect_transform = get_global_transform();
+
+	Vector3 offset = p_origin - equirect_transform.origin;
+	float a = p_direction.dot(p_direction);
+	float b = 2.0 * offset.dot(p_direction);
+	float c = offset.dot(offset) - (radius * radius);
+
+	float discriminant = b * b - 4.0 * a * c;
+	if (discriminant < 0.0) {
+		return Vector2(-1.0, -1.0);
+	}
+
+	float t0 = (-b - Math::sqrt(discriminant)) / (2.0 * a);
+	float t1 = (-b + Math::sqrt(discriminant)) / (2.0 * a);
+	float t = MAX(t0, t1);
+
+	if (t < 0.0) {
+		return Vector2(-1.0, -1.0);
+	}
+	Vector3 intersection = p_origin + p_direction * t;
+
+	Basis correction = equirect_transform.basis.inverse();
+	correction.rotate(Vector3(0.0, 1.0, 0.0), -Math_PI / 2.0);
+	Vector3 relative_point = correction.xform(intersection - equirect_transform.origin);
+
+	float horizontal_intersection_angle = Math::atan2(relative_point.z, relative_point.x);
+	if (Math::abs(horizontal_intersection_angle) > central_horizontal_angle / 2.0) {
+		return Vector2(-1.0, -1.0);
+	}
+
+	float vertical_intersection_angle = Math::acos(relative_point.y / radius) - (Math_PI / 2.0);
+	if (vertical_intersection_angle < 0) {
+		if (Math::abs(vertical_intersection_angle) > upper_vertical_angle) {
+			return Vector2(-1.0, -1.0);
+		}
+	} else if (vertical_intersection_angle > lower_vertical_angle) {
+		return Vector2(-1.0, -1.0);
+	}
+
+	// Re-center the intersection angle if the vertical angle is uneven between upper and lower.
+	if (upper_vertical_angle != lower_vertical_angle) {
+		vertical_intersection_angle -= (-upper_vertical_angle + lower_vertical_angle) / 2.0;
+	}
+
+	float u = 0.5 + (horizontal_intersection_angle / central_horizontal_angle);
+	float v = 0.5 + (vertical_intersection_angle / (upper_vertical_angle + lower_vertical_angle));
+
+	return Vector2(u, v);
+}

modules/openxr/scene/openxr_composition_layer_equirect.h

@@ -70,6 +70,8 @@ class OpenXRCompositionLayerEquirect : public OpenXRCompositionLayer {
 	void set_fallback_segments(uint32_t p_fallback_segments);
 	uint32_t get_fallback_segments() const;
 
+	virtual Vector2 intersects_ray(const Vector3 &p_origin, const Vector3 &p_direction) const override;
+
 	OpenXRCompositionLayerEquirect();
 	~OpenXRCompositionLayerEquirect();
 };

modules/openxr/scene/openxr_composition_layer_quad.cpp

@@ -96,3 +96,36 @@ void OpenXRCompositionLayerQuad::set_quad_size(const Size2 &p_size) {
 Size2 OpenXRCompositionLayerQuad::get_quad_size() const {
 	return quad_size;
 }
+
+Vector2 OpenXRCompositionLayerQuad::intersects_ray(const Vector3 &p_origin, const Vector3 &p_direction) const {
+	Transform3D quad_transform = get_global_transform();
+	Vector3 quad_normal = quad_transform.basis.get_column(2);
+
+	float denom = quad_normal.dot(p_direction);
+	if (Math::abs(denom) > 0.0001) {
+		Vector3 vector = quad_transform.origin - p_origin;
+		float t = vector.dot(quad_normal) / denom;
+		if (t < 0.0) {
+			return Vector2(-1.0, -1.0);
+		}
+		Vector3 intersection = p_origin + p_direction * t;
+
+		Vector3 relative_point = intersection - quad_transform.origin;
+		Vector2 projected_point = Vector2(
+				relative_point.dot(quad_transform.basis.get_column(0)),
+				relative_point.dot(quad_transform.basis.get_column(1)));
+		if (Math::abs(projected_point.x) > quad_size.x / 2.0) {
+			return Vector2(-1.0, -1.0);
+		}
+		if (Math::abs(projected_point.y) > quad_size.y / 2.0) {
+			return Vector2(-1.0, -1.0);
+		}
+
+		float u = 0.5 + (projected_point.x / quad_size.x);
+		float v = 1.0 - (0.5 + (projected_point.y / quad_size.y));
+
+		return Vector2(u, v);
+	}
+
+	return Vector2(-1.0, -1.0);
+}

modules/openxr/scene/openxr_composition_layer_quad.h

@@ -54,6 +54,8 @@ class OpenXRCompositionLayerQuad : public OpenXRCompositionLayer {
 	void set_quad_size(const Size2 &p_size);
 	Size2 get_quad_size() const;
 
+	virtual Vector2 intersects_ray(const Vector3 &p_origin, const Vector3 &p_direction) const override;
+
 	OpenXRCompositionLayerQuad();
 	~OpenXRCompositionLayerQuad();
 };