Merge pull request #56888 from FreegleBarr/implement_gpuparticle_subemitters2d

4 files changed, 109 insertions, 0 deletions

diff --git a/doc/classes/GPUParticles2D.xml b/doc/classes/GPUParticles2D.xml
index 72adc49742..f97198658e 100644
--- a/doc/classes/GPUParticles2D.xml
+++ b/doc/classes/GPUParticles2D.xml
@@ -18,6 +18,17 @@
 				Returns a rectangle containing the positions of all existing particles.
 			</description>
 		</method>
+		<method name="emit_particle">
+			<return type="void" />
+			<argument index="0" name="xform" type="Transform2D" />
+			<argument index="1" name="velocity" type="Vector2" />
+			<argument index="2" name="color" type="Color" />
+			<argument index="3" name="custom" type="Color" />
+			<argument index="4" name="flags" type="int" />
+			<description>
+				Emits a single particle. Whether [code]xform[/code], [code]velocity[/code], [code]color[/code] and [code]custom[/code] are applied depends on the value of [code]flags[/code]. See [enum EmitFlags].
+			</description>
+		</method>
 		<method name="restart">
 			<return type="void" />
 			<description>
@@ -67,6 +78,9 @@
 		<member name="speed_scale" type="float" setter="set_speed_scale" getter="get_speed_scale" default="1.0">
 			Particle system's running speed scaling ratio. A value of [code]0[/code] can be used to pause the particles.
 		</member>
+		<member name="sub_emitter" type="NodePath" setter="set_sub_emitter" getter="get_sub_emitter" default="NodePath(&quot;&quot;)">
+			The [NodePath] to the [GPUParticles2D] used for sub-emissions.
+		</member>
 		<member name="texture" type="Texture2D" setter="set_texture" getter="get_texture">
 			Particle texture. If [code]null[/code], particles will be squares.
 		</member>
@@ -92,5 +106,20 @@
 		</constant>
 		<constant name="DRAW_ORDER_REVERSE_LIFETIME" value="2" enum="DrawOrder">
 		</constant>
+		<constant name="EMIT_FLAG_POSITION" value="1" enum="EmitFlags">
+			Particle starts at the specified position.
+		</constant>
+		<constant name="EMIT_FLAG_ROTATION_SCALE" value="2" enum="EmitFlags">
+			Particle starts with specified rotation and scale.
+		</constant>
+		<constant name="EMIT_FLAG_VELOCITY" value="4" enum="EmitFlags">
+			Particle starts with the specified velocity vector, which defines the emission direction and speed.
+		</constant>
+		<constant name="EMIT_FLAG_COLOR" value="8" enum="EmitFlags">
+			Particle starts with specified color.
+		</constant>
+		<constant name="EMIT_FLAG_CUSTOM" value="16" enum="EmitFlags">
+			Particle starts with specificed [code]CUSTOM[/code] data.
+		</constant>
 	</constants>
 </class>
diff --git a/doc/classes/GPUParticles3D.xml b/doc/classes/GPUParticles3D.xml
index 771056cb93..62ac846077 100644
--- a/doc/classes/GPUParticles3D.xml
+++ b/doc/classes/GPUParticles3D.xml
@@ -26,6 +26,7 @@
 			<argument index="3" name="custom" type="Color" />
 			<argument index="4" name="flags" type="int" />
 			<description>
+				Emits a single particle. Whether [code]xform[/code], [code]velocity[/code], [code]color[/code] and [code]custom[/code] are applied depends on the value of [code]flags[/code]. See [enum EmitFlags].
 			</description>
 		</method>
 		<method name="get_draw_pass_mesh" qualifiers="const">
@@ -137,14 +138,19 @@
 			Particles are drawn in order of depth.
 		</constant>
 		<constant name="EMIT_FLAG_POSITION" value="1" enum="EmitFlags">
+			Particle starts at the specified position.
 		</constant>
 		<constant name="EMIT_FLAG_ROTATION_SCALE" value="2" enum="EmitFlags">
+			Particle starts with specified rotation and scale.
 		</constant>
 		<constant name="EMIT_FLAG_VELOCITY" value="4" enum="EmitFlags">
+			Particle starts with the specified velocity vector, which defines the emission direction and speed.
 		</constant>
 		<constant name="EMIT_FLAG_COLOR" value="8" enum="EmitFlags">
+			Particle starts with specified color.
 		</constant>
 		<constant name="EMIT_FLAG_CUSTOM" value="16" enum="EmitFlags">
+			Particle starts with specificed [code]CUSTOM[/code] data.
 		</constant>
 		<constant name="MAX_DRAW_PASSES" value="4">
 			Maximum number of draw passes supported.
diff --git a/scene/2d/gpu_particles_2d.cpp b/scene/2d/gpu_particles_2d.cpp
index b6d1e5c934..11c036ac9c 100644
--- a/scene/2d/gpu_particles_2d.cpp
+++ b/scene/2d/gpu_particles_2d.cpp
@@ -335,6 +335,42 @@ Ref<Texture2D> GPUParticles2D::get_texture() const {
 void GPUParticles2D::_validate_property(PropertyInfo &property) const {
 }
 
+void GPUParticles2D::emit_particle(const Transform2D &p_transform2d, const Vector2 &p_velocity2d, const Color &p_color, const Color &p_custom, uint32_t p_emit_flags) {
+	Transform3D transform;
+	transform.basis.set_axis(0, Vector3(p_transform2d.get_axis(0).x, p_transform2d.get_axis(0).y, 0));
+	transform.basis.set_axis(1, Vector3(p_transform2d.get_axis(1).x, p_transform2d.get_axis(1).y, 0));
+	transform.set_origin(Vector3(p_transform2d.get_origin().x, p_transform2d.get_origin().y, 0));
+	Vector3 velocity = Vector3(p_velocity2d.x, p_velocity2d.y, 0);
+
+	RS::get_singleton()->particles_emit(particles, transform, velocity, p_color, p_custom, p_emit_flags);
+}
+
+void GPUParticles2D::_attach_sub_emitter() {
+	Node *n = get_node_or_null(sub_emitter);
+	if (n) {
+		GPUParticles2D *sen = Object::cast_to<GPUParticles2D>(n);
+		if (sen && sen != this) {
+			RS::get_singleton()->particles_set_subemitter(particles, sen->particles);
+		}
+	}
+}
+
+void GPUParticles2D::set_sub_emitter(const NodePath &p_path) {
+	if (is_inside_tree()) {
+		RS::get_singleton()->particles_set_subemitter(particles, RID());
+	}
+
+	sub_emitter = p_path;
+
+	if (is_inside_tree() && sub_emitter != NodePath()) {
+		_attach_sub_emitter();
+	}
+}
+
+NodePath GPUParticles2D::get_sub_emitter() const {
+	return sub_emitter;
+}
+
 void GPUParticles2D::restart() {
 	RS::get_singleton()->particles_restart(particles);
 	RS::get_singleton()->particles_set_emitting(particles, true);
@@ -462,6 +498,16 @@ void GPUParticles2D::_notification(int p_what) {
 #endif
 	}
 
+	if (p_what == NOTIFICATION_ENTER_TREE) {
+		if (sub_emitter != NodePath()) {
+			_attach_sub_emitter();
+		}
+	}
+
+	if (p_what == NOTIFICATION_EXIT_TREE) {
+		RS::get_singleton()->particles_set_subemitter(particles, RID());
+	}
+
 	if (p_what == NOTIFICATION_PAUSED || p_what == NOTIFICATION_UNPAUSED) {
 		if (can_process()) {
 			RS::get_singleton()->particles_set_speed_scale(particles, speed_scale);
@@ -523,6 +569,11 @@ void GPUParticles2D::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("restart"), &GPUParticles2D::restart);
 
+	ClassDB::bind_method(D_METHOD("set_sub_emitter", "path"), &GPUParticles2D::set_sub_emitter);
+	ClassDB::bind_method(D_METHOD("get_sub_emitter"), &GPUParticles2D::get_sub_emitter);
+
+	ClassDB::bind_method(D_METHOD("emit_particle", "xform", "velocity", "color", "custom", "flags"), &GPUParticles2D::emit_particle);
+
 	ClassDB::bind_method(D_METHOD("set_trail_enabled", "enabled"), &GPUParticles2D::set_trail_enabled);
 	ClassDB::bind_method(D_METHOD("set_trail_length", "secs"), &GPUParticles2D::set_trail_length);
 
@@ -538,6 +589,7 @@ void GPUParticles2D::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "emitting"), "set_emitting", "is_emitting");
 	ADD_PROPERTY_DEFAULT("emitting", true); // Workaround for doctool in headless mode, as dummy rasterizer always returns false.
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "amount", PROPERTY_HINT_RANGE, "1,1000000,1,exp"), "set_amount", "get_amount");
+	ADD_PROPERTY(PropertyInfo(Variant::NODE_PATH, "sub_emitter", PROPERTY_HINT_NODE_PATH_VALID_TYPES, "GPUParticles2D"), "set_sub_emitter", "get_sub_emitter");
 	ADD_GROUP("Time", "");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "lifetime", PROPERTY_HINT_RANGE, "0.01,600.0,0.01,or_greater"), "set_lifetime", "get_lifetime");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "one_shot"), "set_one_shot", "get_one_shot");
@@ -566,6 +618,12 @@ void GPUParticles2D::_bind_methods() {
 	BIND_ENUM_CONSTANT(DRAW_ORDER_INDEX);
 	BIND_ENUM_CONSTANT(DRAW_ORDER_LIFETIME);
 	BIND_ENUM_CONSTANT(DRAW_ORDER_REVERSE_LIFETIME);
+
+	BIND_ENUM_CONSTANT(EMIT_FLAG_POSITION);
+	BIND_ENUM_CONSTANT(EMIT_FLAG_ROTATION_SCALE);
+	BIND_ENUM_CONSTANT(EMIT_FLAG_VELOCITY);
+	BIND_ENUM_CONSTANT(EMIT_FLAG_COLOR);
+	BIND_ENUM_CONSTANT(EMIT_FLAG_CUSTOM);
 }
 
 GPUParticles2D::GPUParticles2D() {
diff --git a/scene/2d/gpu_particles_2d.h b/scene/2d/gpu_particles_2d.h
index aa9a8da129..fc95ae27b2 100644
--- a/scene/2d/gpu_particles_2d.h
+++ b/scene/2d/gpu_particles_2d.h
@@ -79,6 +79,8 @@ private:
 
 	RID mesh;
 
+	void _attach_sub_emitter();
+
 protected:
 	static void _bind_methods();
 	virtual void _validate_property(PropertyInfo &property) const override;
@@ -139,6 +141,19 @@ public:
 
 	TypedArray<String> get_configuration_warnings() const override;
 
+	void set_sub_emitter(const NodePath &p_path);
+	NodePath get_sub_emitter() const;
+
+	enum EmitFlags {
+		EMIT_FLAG_POSITION = RS::PARTICLES_EMIT_FLAG_POSITION,
+		EMIT_FLAG_ROTATION_SCALE = RS::PARTICLES_EMIT_FLAG_ROTATION_SCALE,
+		EMIT_FLAG_VELOCITY = RS::PARTICLES_EMIT_FLAG_VELOCITY,
+		EMIT_FLAG_COLOR = RS::PARTICLES_EMIT_FLAG_COLOR,
+		EMIT_FLAG_CUSTOM = RS::PARTICLES_EMIT_FLAG_CUSTOM
+	};
+
+	void emit_particle(const Transform2D &p_transform, const Vector2 &p_velocity, const Color &p_color, const Color &p_custom, uint32_t p_emit_flags);
+
 	void restart();
 	Rect2 capture_rect() const;
 	GPUParticles2D();
@@ -146,5 +161,6 @@ public:
 };
 
 VARIANT_ENUM_CAST(GPUParticles2D::DrawOrder)
+VARIANT_ENUM_CAST(GPUParticles2D::EmitFlags)
 
 #endif // PARTICLES_2D_H