Random initial color parameter for ParticleMaterial

Works with 2D and 3D GPU Particles

9 files changed, 106 insertions, 2 deletions

diff --git a/doc/classes/CPUParticles2D.xml b/doc/classes/CPUParticles2D.xml
index 0505d8ad36..a4415e89db 100644
--- a/doc/classes/CPUParticles2D.xml
+++ b/doc/classes/CPUParticles2D.xml
@@ -116,6 +116,9 @@
 		<member name="color" type="Color" setter="set_color" getter="get_color" default="Color(1, 1, 1, 1)">
 			Each particle's initial color. If [member texture] is defined, it will be multiplied by this color.
 		</member>
+		<member name="color_initial_ramp" type="Gradient" setter="set_color_initial_ramp" getter="get_color_initial_ramp">
+			Each particle's initial color will vary along this [GradientTexture1D] (multiplied with [member color]).
+		</member>
 		<member name="color_ramp" type="Gradient" setter="set_color_ramp" getter="get_color_ramp">
 			Each particle's color will vary along this [Gradient] (multiplied with [member color]).
 		</member>
diff --git a/doc/classes/CPUParticles3D.xml b/doc/classes/CPUParticles3D.xml
index ad491465f2..83728a807b 100644
--- a/doc/classes/CPUParticles3D.xml
+++ b/doc/classes/CPUParticles3D.xml
@@ -125,6 +125,9 @@
 		<member name="color" type="Color" setter="set_color" getter="get_color" default="Color(1, 1, 1, 1)">
 			Each particle's initial color. To have particle display color in a [BaseMaterial3D] make sure to set [member BaseMaterial3D.vertex_color_use_as_albedo] to [code]true[/code].
 		</member>
+		<member name="color_initial_ramp" type="Gradient" setter="set_color_initial_ramp" getter="get_color_initial_ramp">
+			Each particle's initial color will vary along this [GradientTexture1D] (multiplied with [member color]).
+		</member>
 		<member name="color_ramp" type="Gradient" setter="set_color_ramp" getter="get_color_ramp">
 			Each particle's color will vary along this [GradientTexture1D] over its lifetime (multiplied with [member color]).
 		</member>
diff --git a/doc/classes/ParticlesMaterial.xml b/doc/classes/ParticlesMaterial.xml
index 2cc0d8f2b0..6ff57bd58a 100644
--- a/doc/classes/ParticlesMaterial.xml
+++ b/doc/classes/ParticlesMaterial.xml
@@ -127,6 +127,9 @@
 		<member name="color" type="Color" setter="set_color" getter="get_color" default="Color(1, 1, 1, 1)">
 			Each particle's initial color. If the [GPUParticles2D]'s [code]texture[/code] is defined, it will be multiplied by this color. To have particle display color in a [BaseMaterial3D] make sure to set [member BaseMaterial3D.vertex_color_use_as_albedo] to [code]true[/code].
 		</member>
+		<member name="color_initial_ramp" type="Texture2D" setter="set_color_initial_ramp" getter="get_color_initial_ramp">
+			Each particle's initial color will vary along this [GradientTexture1D] (multiplied with [member color]).
+		</member>
 		<member name="color_ramp" type="Texture2D" setter="set_color_ramp" getter="get_color_ramp">
 			Each particle's color will vary along this [GradientTexture1D] over its lifetime (multiplied with [member color]).
 		</member>
diff --git a/scene/2d/cpu_particles_2d.cpp b/scene/2d/cpu_particles_2d.cpp
index 80c17b6e88..6b1750f9e9 100644
--- a/scene/2d/cpu_particles_2d.cpp
+++ b/scene/2d/cpu_particles_2d.cpp
@@ -398,6 +398,14 @@ Ref<Gradient> CPUParticles2D::get_color_ramp() const {
 	return color_ramp;
 }
 
+void CPUParticles2D::set_color_initial_ramp(const Ref<Gradient> &p_ramp) {
+	color_initial_ramp = p_ramp;
+}
+
+Ref<Gradient> CPUParticles2D::get_color_initial_ramp() const {
+	return color_initial_ramp;
+}
+
 void CPUParticles2D::set_particle_flag(ParticleFlags p_particle_flag, bool p_enable) {
 	ERR_FAIL_INDEX(p_particle_flag, PARTICLE_FLAG_MAX);
 	particle_flags[p_particle_flag] = p_enable;
@@ -727,6 +735,12 @@ void CPUParticles2D::_particles_process(double p_delta) {
 			p.hue_rot_rand = Math::randf();
 			p.anim_offset_rand = Math::randf();
 
+			if (color_initial_ramp.is_valid()) {
+				p.start_color_rand = color_initial_ramp->get_color_at_offset(Math::randf());
+			} else {
+				p.start_color_rand = Color(1, 1, 1, 1);
+			}
+
 			real_t angle1_rad = direction.angle() + Math::deg2rad((Math::randf() * 2.0 - 1.0) * spread);
 			Vector2 rot = Vector2(Math::cos(angle1_rad), Math::sin(angle1_rad));
 			p.velocity = rot * Math::lerp(parameters_min[PARAM_INITIAL_LINEAR_VELOCITY], parameters_min[PARAM_INITIAL_LINEAR_VELOCITY], Math::randf());
@@ -946,7 +960,7 @@ void CPUParticles2D::_particles_process(double p_delta) {
 		p.color.g = color_rgb.y;
 		p.color.b = color_rgb.z;
 
-		p.color *= p.base_color;
+		p.color *= p.base_color * p.start_color_rand;
 
 		if (particle_flags[PARTICLE_FLAG_ALIGN_Y_TO_VELOCITY]) {
 			if (p.velocity.length() > 0.0) {
@@ -1173,6 +1187,11 @@ void CPUParticles2D::convert_from_particles(Node *p_particles) {
 		set_color_ramp(gt->get_gradient());
 	}
 
+	Ref<GradientTexture1D> gti = material->get_color_initial_ramp();
+	if (gti.is_valid()) {
+		set_color_initial_ramp(gti->get_gradient());
+	}
+
 	set_particle_flag(PARTICLE_FLAG_ALIGN_Y_TO_VELOCITY, material->get_particle_flag(ParticlesMaterial::PARTICLE_FLAG_ALIGN_Y_TO_VELOCITY));
 
 	set_emission_shape(EmissionShape(material->get_emission_shape()));
@@ -1295,6 +1314,9 @@ void CPUParticles2D::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_color_ramp", "ramp"), &CPUParticles2D::set_color_ramp);
 	ClassDB::bind_method(D_METHOD("get_color_ramp"), &CPUParticles2D::get_color_ramp);
 
+	ClassDB::bind_method(D_METHOD("set_color_initial_ramp", "ramp"), &CPUParticles2D::set_color_initial_ramp);
+	ClassDB::bind_method(D_METHOD("get_color_initial_ramp"), &CPUParticles2D::get_color_initial_ramp);
+
 	ClassDB::bind_method(D_METHOD("set_particle_flag", "particle_flag", "enable"), &CPUParticles2D::set_particle_flag);
 	ClassDB::bind_method(D_METHOD("get_particle_flag", "particle_flag"), &CPUParticles2D::get_particle_flag);
 
@@ -1386,6 +1408,7 @@ void CPUParticles2D::_bind_methods() {
 	ADD_GROUP("Color", "");
 	ADD_PROPERTY(PropertyInfo(Variant::COLOR, "color"), "set_color", "get_color");
 	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "color_ramp", PROPERTY_HINT_RESOURCE_TYPE, "Gradient"), "set_color_ramp", "get_color_ramp");
+	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "color_initial_ramp", PROPERTY_HINT_RESOURCE_TYPE, "Gradient"), "set_color_initial_ramp", "get_color_initial_ramp");
 
 	ADD_GROUP("Hue Variation", "hue_");
 	ADD_PROPERTYI(PropertyInfo(Variant::FLOAT, "hue_variation_min", PROPERTY_HINT_RANGE, "-1,1,0.01"), "set_param_min", "get_param_min", PARAM_HUE_VARIATION);
diff --git a/scene/2d/cpu_particles_2d.h b/scene/2d/cpu_particles_2d.h
index 391f51224e..3cb3d64855 100644
--- a/scene/2d/cpu_particles_2d.h
+++ b/scene/2d/cpu_particles_2d.h
@@ -89,6 +89,7 @@ private:
 		real_t scale_rand = 0.0;
 		real_t hue_rot_rand = 0.0;
 		real_t anim_offset_rand = 0.0;
+		Color start_color_rand;
 		double time = 0.0;
 		double lifetime = 0.0;
 		Color base_color;
@@ -156,6 +157,7 @@ private:
 	Ref<Curve> curve_parameters[PARAM_MAX];
 	Color color;
 	Ref<Gradient> color_ramp;
+	Ref<Gradient> color_initial_ramp;
 
 	bool particle_flags[PARTICLE_FLAG_MAX];
 
@@ -250,6 +252,9 @@ public:
 	void set_color_ramp(const Ref<Gradient> &p_ramp);
 	Ref<Gradient> get_color_ramp() const;
 
+	void set_color_initial_ramp(const Ref<Gradient> &p_ramp);
+	Ref<Gradient> get_color_initial_ramp() const;
+
 	void set_particle_flag(ParticleFlags p_particle_flag, bool p_enable);
 	bool get_particle_flag(ParticleFlags p_particle_flag) const;
 
diff --git a/scene/3d/cpu_particles_3d.cpp b/scene/3d/cpu_particles_3d.cpp
index d347d24c2c..cfe538398d 100644
--- a/scene/3d/cpu_particles_3d.cpp
+++ b/scene/3d/cpu_particles_3d.cpp
@@ -368,6 +368,14 @@ Ref<Gradient> CPUParticles3D::get_color_ramp() const {
 	return color_ramp;
 }
 
+void CPUParticles3D::set_color_initial_ramp(const Ref<Gradient> &p_ramp) {
+	color_initial_ramp = p_ramp;
+}
+
+Ref<Gradient> CPUParticles3D::get_color_initial_ramp() const {
+	return color_initial_ramp;
+}
+
 void CPUParticles3D::set_particle_flag(ParticleFlags p_particle_flag, bool p_enable) {
 	ERR_FAIL_INDEX(p_particle_flag, PARTICLE_FLAG_MAX);
 	particle_flags[p_particle_flag] = p_enable;
@@ -748,6 +756,12 @@ void CPUParticles3D::_particles_process(double p_delta) {
 			p.hue_rot_rand = Math::randf();
 			p.anim_offset_rand = Math::randf();
 
+			if (color_initial_ramp.is_valid()) {
+				p.start_color_rand = color_initial_ramp->get_color_at_offset(Math::randf());
+			} else {
+				p.start_color_rand = Color(1, 1, 1, 1);
+			}
+
 			if (particle_flags[PARTICLE_FLAG_DISABLE_Z]) {
 				real_t angle1_rad = Math::atan2(direction.y, direction.x) + Math::deg2rad((Math::randf() * 2.0 - 1.0) * spread);
 				Vector3 rot = Vector3(Math::cos(angle1_rad), Math::sin(angle1_rad), 0.0);
@@ -1046,7 +1060,7 @@ void CPUParticles3D::_particles_process(double p_delta) {
 		p.color.g = color_rgb.y;
 		p.color.b = color_rgb.z;
 
-		p.color *= p.base_color;
+		p.color *= p.base_color * p.start_color_rand;
 
 		if (particle_flags[PARTICLE_FLAG_DISABLE_Z]) {
 			if (particle_flags[PARTICLE_FLAG_ALIGN_Y_TO_VELOCITY]) {
@@ -1333,6 +1347,11 @@ void CPUParticles3D::convert_from_particles(Node *p_particles) {
 		set_color_ramp(gt->get_gradient());
 	}
 
+	Ref<GradientTexture1D> gti = material->get_color_initial_ramp();
+	if (gti.is_valid()) {
+		set_color_initial_ramp(gti->get_gradient());
+	}
+
 	set_particle_flag(PARTICLE_FLAG_ALIGN_Y_TO_VELOCITY, material->get_particle_flag(ParticlesMaterial::PARTICLE_FLAG_ALIGN_Y_TO_VELOCITY));
 	set_particle_flag(PARTICLE_FLAG_ROTATE_Y, material->get_particle_flag(ParticlesMaterial::PARTICLE_FLAG_ROTATE_Y));
 	set_particle_flag(PARTICLE_FLAG_DISABLE_Z, material->get_particle_flag(ParticlesMaterial::PARTICLE_FLAG_DISABLE_Z));
@@ -1459,6 +1478,9 @@ void CPUParticles3D::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_color_ramp", "ramp"), &CPUParticles3D::set_color_ramp);
 	ClassDB::bind_method(D_METHOD("get_color_ramp"), &CPUParticles3D::get_color_ramp);
 
+	ClassDB::bind_method(D_METHOD("set_color_initial_ramp", "ramp"), &CPUParticles3D::set_color_initial_ramp);
+	ClassDB::bind_method(D_METHOD("get_color_initial_ramp"), &CPUParticles3D::get_color_initial_ramp);
+
 	ClassDB::bind_method(D_METHOD("set_particle_flag", "particle_flag", "enable"), &CPUParticles3D::set_particle_flag);
 	ClassDB::bind_method(D_METHOD("get_particle_flag", "particle_flag"), &CPUParticles3D::get_particle_flag);
 
@@ -1572,6 +1594,7 @@ void CPUParticles3D::_bind_methods() {
 	ADD_GROUP("Color", "");
 	ADD_PROPERTY(PropertyInfo(Variant::COLOR, "color"), "set_color", "get_color");
 	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "color_ramp", PROPERTY_HINT_RESOURCE_TYPE, "Gradient"), "set_color_ramp", "get_color_ramp");
+	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "color_initial_ramp", PROPERTY_HINT_RESOURCE_TYPE, "Gradient"), "set_color_initial_ramp", "get_color_initial_ramp");
 
 	ADD_GROUP("Hue Variation", "hue_");
 	ADD_PROPERTYI(PropertyInfo(Variant::FLOAT, "hue_variation_min", PROPERTY_HINT_RANGE, "-1,1,0.01"), "set_param_min", "get_param_min", PARAM_HUE_VARIATION);
diff --git a/scene/3d/cpu_particles_3d.h b/scene/3d/cpu_particles_3d.h
index aca7328a27..6addeab1a6 100644
--- a/scene/3d/cpu_particles_3d.h
+++ b/scene/3d/cpu_particles_3d.h
@@ -91,6 +91,7 @@ private:
 		real_t scale_rand = 0.0;
 		real_t hue_rot_rand = 0.0;
 		real_t anim_offset_rand = 0.0;
+		Color start_color_rand;
 		double time = 0.0;
 		double lifetime = 0.0;
 		Color base_color;
@@ -160,6 +161,7 @@ private:
 	Ref<Curve> curve_parameters[PARAM_MAX];
 	Color color = Color(1, 1, 1, 1);
 	Ref<Gradient> color_ramp;
+	Ref<Gradient> color_initial_ramp;
 
 	bool particle_flags[PARTICLE_FLAG_MAX] = {};
 
@@ -261,6 +263,9 @@ public:
 	void set_color_ramp(const Ref<Gradient> &p_ramp);
 	Ref<Gradient> get_color_ramp() const;
 
+	void set_color_initial_ramp(const Ref<Gradient> &p_ramp);
+	Ref<Gradient> get_color_initial_ramp() const;
+
 	void set_particle_flag(ParticleFlags p_particle_flag, bool p_enable);
 	bool get_particle_flag(ParticleFlags p_particle_flag) const;
 
diff --git a/scene/resources/particles_material.cpp b/scene/resources/particles_material.cpp
index e77f5a0be7..6b7eef3712 100644
--- a/scene/resources/particles_material.cpp
+++ b/scene/resources/particles_material.cpp
@@ -85,6 +85,7 @@ void ParticlesMaterial::init_shaders() {
 
 	shader_names->color = "color_value";
 	shader_names->color_ramp = "color_ramp";
+	shader_names->color_initial_ramp = "color_initial_ramp";
 
 	shader_names->emission_sphere_radius = "emission_sphere_radius";
 	shader_names->emission_box_extents = "emission_box_extents";
@@ -232,6 +233,10 @@ void ParticlesMaterial::_update_shader() {
 		code += "uniform sampler2D color_ramp;\n";
 	}
 
+	if (color_initial_ramp.is_valid()) {
+		code += "uniform sampler2D color_initial_ramp;\n";
+	}
+
 	if (tex_parameters[PARAM_INITIAL_LINEAR_VELOCITY].is_valid()) {
 		code += "uniform sampler2D linear_velocity_texture;\n";
 	}
@@ -311,6 +316,9 @@ void ParticlesMaterial::_update_shader() {
 	code += "	float scale_rand = rand_from_seed(alt_seed);\n";
 	code += "	float hue_rot_rand = rand_from_seed(alt_seed);\n";
 	code += "	float anim_offset_rand = rand_from_seed(alt_seed);\n";
+	if (color_initial_ramp.is_valid()) {
+		code += "	float color_initial_rand = rand_from_seed(alt_seed);\n";
+	}
 	code += "	float pi = 3.14159;\n";
 	code += "	float degree_to_rad = pi / 180.0;\n";
 	code += "\n";
@@ -462,6 +470,10 @@ void ParticlesMaterial::_update_shader() {
 	code += "	float scale_rand = rand_from_seed(alt_seed);\n";
 	code += "	float hue_rot_rand = rand_from_seed(alt_seed);\n";
 	code += "	float anim_offset_rand = rand_from_seed(alt_seed);\n";
+	if (color_initial_ramp.is_valid()) {
+		code += "	float color_initial_rand = rand_from_seed(alt_seed);\n";
+	}
+
 	code += "	float pi = 3.14159;\n";
 	code += "	float degree_to_rad = pi / 180.0;\n";
 	code += "\n";
@@ -620,6 +632,12 @@ void ParticlesMaterial::_update_shader() {
 	} else {
 		code += "	COLOR = hue_rot_mat * color_value;\n";
 	}
+
+	if (color_initial_ramp.is_valid()) {
+		code += "	vec4 start_color = textureLod(color_initial_ramp, vec2(color_initial_rand, 0.0), 0.0);\n";
+		code += "	COLOR *= start_color;\n";
+	}
+
 	if (emission_color_texture.is_valid() && (emission_shape == EMISSION_SHAPE_POINTS || emission_shape == EMISSION_SHAPE_DIRECTED_POINTS)) {
 		code += "	COLOR *= texelFetch(emission_texture_color, emission_tex_ofs, 0);\n";
 	}
@@ -988,6 +1006,18 @@ Ref<Texture2D> ParticlesMaterial::get_color_ramp() const {
 	return color_ramp;
 }
 
+void ParticlesMaterial::set_color_initial_ramp(const Ref<Texture2D> &p_texture) {
+	color_initial_ramp = p_texture;
+	RID tex_rid = p_texture.is_valid() ? p_texture->get_rid() : RID();
+	RenderingServer::get_singleton()->material_set_param(_get_material(), shader_names->color_initial_ramp, tex_rid);
+	_queue_shader_change();
+	notify_property_list_changed();
+}
+
+Ref<Texture2D> ParticlesMaterial::get_color_initial_ramp() const {
+	return color_initial_ramp;
+}
+
 void ParticlesMaterial::set_particle_flag(ParticleFlags p_particle_flag, bool p_enable) {
 	ERR_FAIL_INDEX(p_particle_flag, PARTICLE_FLAG_MAX);
 	particle_flags[p_particle_flag] = p_enable;
@@ -1282,6 +1312,9 @@ void ParticlesMaterial::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_color_ramp", "ramp"), &ParticlesMaterial::set_color_ramp);
 	ClassDB::bind_method(D_METHOD("get_color_ramp"), &ParticlesMaterial::get_color_ramp);
 
+	ClassDB::bind_method(D_METHOD("set_color_initial_ramp", "ramp"), &ParticlesMaterial::set_color_initial_ramp);
+	ClassDB::bind_method(D_METHOD("get_color_initial_ramp"), &ParticlesMaterial::get_color_initial_ramp);
+
 	ClassDB::bind_method(D_METHOD("set_particle_flag", "particle_flag", "enable"), &ParticlesMaterial::set_particle_flag);
 	ClassDB::bind_method(D_METHOD("get_particle_flag", "particle_flag"), &ParticlesMaterial::get_particle_flag);
 
@@ -1414,6 +1447,7 @@ void ParticlesMaterial::_bind_methods() {
 	ADD_GROUP("Color", "");
 	ADD_PROPERTY(PropertyInfo(Variant::COLOR, "color"), "set_color", "get_color");
 	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "color_ramp", PROPERTY_HINT_RESOURCE_TYPE, "GradientTexture1D"), "set_color_ramp", "get_color_ramp");
+	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "color_initial_ramp", PROPERTY_HINT_RESOURCE_TYPE, "GradientTexture1D"), "set_color_initial_ramp", "get_color_initial_ramp");
 
 	ADD_GROUP("Hue Variation", "hue_");
 	ADD_PROPERTYI(PropertyInfo(Variant::FLOAT, "hue_variation_min", PROPERTY_HINT_RANGE, "-1,1,0.01"), "set_param_min", "get_param_min", PARAM_HUE_VARIATION);
diff --git a/scene/resources/particles_material.h b/scene/resources/particles_material.h
index 36bc456978..9c0bbe3b5d 100644
--- a/scene/resources/particles_material.h
+++ b/scene/resources/particles_material.h
@@ -194,6 +194,7 @@ private:
 
 		StringName color;
 		StringName color_ramp;
+		StringName color_initial_ramp;
 
 		StringName emission_sphere_radius;
 		StringName emission_box_extents;
@@ -237,6 +238,7 @@ private:
 	Ref<Texture2D> tex_parameters[PARAM_MAX];
 	Color color;
 	Ref<Texture2D> color_ramp;
+	Ref<Texture2D> color_initial_ramp;
 
 	bool particle_flags[PARTICLE_FLAG_MAX];
 
@@ -299,6 +301,9 @@ public:
 	void set_color_ramp(const Ref<Texture2D> &p_texture);
 	Ref<Texture2D> get_color_ramp() const;
 
+	void set_color_initial_ramp(const Ref<Texture2D> &p_texture);
+	Ref<Texture2D> get_color_initial_ramp() const;
+
 	void set_particle_flag(ParticleFlags p_particle_flag, bool p_enable);
 	bool get_particle_flag(ParticleFlags p_particle_flag) const;