Move GLTF light conversion code into GLTFLight

4 files changed, 159 insertions, 114 deletions

diff --git a/modules/gltf/doc_classes/GLTFLight.xml b/modules/gltf/doc_classes/GLTFLight.xml
index db2dfb487a..7fd59e14bc 100644
--- a/modules/gltf/doc_classes/GLTFLight.xml
+++ b/modules/gltf/doc_classes/GLTFLight.xml
@@ -9,6 +9,34 @@
 	<tutorials>
 		<link title="KHR_lights_punctual GLTF extension spec">https://github.com/KhronosGroup/glTF/blob/main/extensions/2.0/Khronos/KHR_lights_punctual</link>
 	</tutorials>
+	<methods>
+		<method name="from_dictionary" qualifiers="static">
+			<return type="GLTFLight" />
+			<param index="0" name="dictionary" type="Dictionary" />
+			<description>
+				Creates a new GLTFLight instance by parsing the given [Dictionary].
+			</description>
+		</method>
+		<method name="from_node" qualifiers="static">
+			<return type="GLTFLight" />
+			<param index="0" name="light_node" type="Light3D" />
+			<description>
+				Create a new GLTFLight instance from the given Godot [Light3D] node.
+			</description>
+		</method>
+		<method name="to_dictionary" qualifiers="const">
+			<return type="Dictionary" />
+			<description>
+				Serializes this GLTFLight instance into a [Dictionary].
+			</description>
+		</method>
+		<method name="to_node" qualifiers="const">
+			<return type="Light3D" />
+			<description>
+				Converts this GLTFLight instance into a Godot [Light3D] node.
+			</description>
+		</method>
+	</methods>
 	<members>
 		<member name="color" type="Color" setter="set_color" getter="get_color" default="Color(1, 1, 1, 1)">
 			The [Color] of the light. Defaults to white. A black color causes the light to have no effect.
diff --git a/modules/gltf/extensions/gltf_light.cpp b/modules/gltf/extensions/gltf_light.cpp
index af21a4e804..ab5a15c671 100644
--- a/modules/gltf/extensions/gltf_light.cpp
+++ b/modules/gltf/extensions/gltf_light.cpp
@@ -31,6 +31,12 @@
 #include "gltf_light.h"
 
 void GLTFLight::_bind_methods() {
+	ClassDB::bind_static_method("GLTFLight", D_METHOD("from_node", "light_node"), &GLTFLight::from_node);
+	ClassDB::bind_method(D_METHOD("to_node"), &GLTFLight::to_node);
+
+	ClassDB::bind_static_method("GLTFLight", D_METHOD("from_dictionary", "dictionary"), &GLTFLight::from_dictionary);
+	ClassDB::bind_method(D_METHOD("to_dictionary"), &GLTFLight::to_dictionary);
+
 	ClassDB::bind_method(D_METHOD("get_color"), &GLTFLight::get_color);
 	ClassDB::bind_method(D_METHOD("set_color", "color"), &GLTFLight::set_color);
 	ClassDB::bind_method(D_METHOD("get_intensity"), &GLTFLight::get_intensity);
@@ -99,3 +105,116 @@ float GLTFLight::get_outer_cone_angle() {
 void GLTFLight::set_outer_cone_angle(float p_outer_cone_angle) {
 	outer_cone_angle = p_outer_cone_angle;
 }
+
+Ref<GLTFLight> GLTFLight::from_node(const Light3D *p_light) {
+	Ref<GLTFLight> l;
+	l.instantiate();
+	l->color = p_light->get_color();
+	if (cast_to<DirectionalLight3D>(p_light)) {
+		l->light_type = "directional";
+		const DirectionalLight3D *light = cast_to<const DirectionalLight3D>(p_light);
+		l->intensity = light->get_param(DirectionalLight3D::PARAM_ENERGY);
+		l->range = FLT_MAX; // Range for directional lights is infinite in Godot.
+	} else if (cast_to<const OmniLight3D>(p_light)) {
+		l->light_type = "point";
+		const OmniLight3D *light = cast_to<const OmniLight3D>(p_light);
+		l->range = light->get_param(OmniLight3D::PARAM_RANGE);
+		l->intensity = light->get_param(OmniLight3D::PARAM_ENERGY);
+	} else if (cast_to<const SpotLight3D>(p_light)) {
+		l->light_type = "spot";
+		const SpotLight3D *light = cast_to<const SpotLight3D>(p_light);
+		l->range = light->get_param(SpotLight3D::PARAM_RANGE);
+		l->intensity = light->get_param(SpotLight3D::PARAM_ENERGY);
+		l->outer_cone_angle = Math::deg_to_rad(light->get_param(SpotLight3D::PARAM_SPOT_ANGLE));
+		// This equation is the inverse of the import equation (which has a desmos link).
+		float angle_ratio = 1 - (0.2 / (0.1 + light->get_param(SpotLight3D::PARAM_SPOT_ATTENUATION)));
+		angle_ratio = MAX(0, angle_ratio);
+		l->inner_cone_angle = l->outer_cone_angle * angle_ratio;
+	}
+	return l;
+}
+
+Light3D *GLTFLight::to_node() const {
+	if (light_type == "directional") {
+		DirectionalLight3D *light = memnew(DirectionalLight3D);
+		light->set_param(Light3D::PARAM_ENERGY, intensity);
+		light->set_color(color);
+		return light;
+	}
+	const float range = CLAMP(this->range, 0, 4096);
+	if (light_type == "point") {
+		OmniLight3D *light = memnew(OmniLight3D);
+		light->set_param(OmniLight3D::PARAM_ENERGY, intensity);
+		light->set_param(OmniLight3D::PARAM_RANGE, range);
+		light->set_color(color);
+		return light;
+	}
+	if (light_type == "spot") {
+		SpotLight3D *light = memnew(SpotLight3D);
+		light->set_param(SpotLight3D::PARAM_ENERGY, intensity);
+		light->set_param(SpotLight3D::PARAM_RANGE, range);
+		light->set_param(SpotLight3D::PARAM_SPOT_ANGLE, Math::rad_to_deg(outer_cone_angle));
+		light->set_color(color);
+		// Line of best fit derived from guessing, see https://www.desmos.com/calculator/biiflubp8b
+		// The points in desmos are not exact, except for (1, infinity).
+		float angle_ratio = inner_cone_angle / outer_cone_angle;
+		float angle_attenuation = 0.2 / (1 - angle_ratio) - 0.1;
+		light->set_param(SpotLight3D::PARAM_SPOT_ATTENUATION, angle_attenuation);
+		return light;
+	}
+	return memnew(Light3D);
+}
+
+Ref<GLTFLight> GLTFLight::from_dictionary(const Dictionary p_dictionary) {
+	ERR_FAIL_COND_V_MSG(!p_dictionary.has("type"), Ref<GLTFLight>(), "Failed to parse GLTF light, missing required field 'type'.");
+	Ref<GLTFLight> light;
+	light.instantiate();
+	const String &type = p_dictionary["type"];
+	light->light_type = type;
+
+	if (p_dictionary.has("color")) {
+		const Array &arr = p_dictionary["color"];
+		if (arr.size() == 3) {
+			light->color = Color(arr[0], arr[1], arr[2]).linear_to_srgb();
+		} else {
+			ERR_PRINT("Error parsing GLTF light: The color must have exactly 3 numbers.");
+		}
+	}
+	if (p_dictionary.has("intensity")) {
+		light->intensity = p_dictionary["intensity"];
+	}
+	if (p_dictionary.has("range")) {
+		light->range = p_dictionary["range"];
+	}
+	if (type == "spot") {
+		const Dictionary &spot = p_dictionary["spot"];
+		light->inner_cone_angle = spot["innerConeAngle"];
+		light->outer_cone_angle = spot["outerConeAngle"];
+		if (light->inner_cone_angle >= light->outer_cone_angle) {
+			ERR_PRINT("Error parsing GLTF light: The inner angle must be smaller than the outer angle.");
+		}
+	} else if (type != "point" && type != "directional") {
+		ERR_PRINT("Error parsing GLTF light: Light type '" + type + "' is unknown.");
+	}
+	return light;
+}
+
+Dictionary GLTFLight::to_dictionary() const {
+	Dictionary d;
+	Array color_array;
+	color_array.resize(3);
+	color_array[0] = color.r;
+	color_array[1] = color.g;
+	color_array[2] = color.b;
+	d["color"] = color_array;
+	d["type"] = light_type;
+	if (light_type == "spot") {
+		Dictionary spot_dict;
+		spot_dict["innerConeAngle"] = inner_cone_angle;
+		spot_dict["outerConeAngle"] = outer_cone_angle;
+		d["spot"] = spot_dict;
+	}
+	d["intensity"] = intensity;
+	d["range"] = range;
+	return d;
+}
diff --git a/modules/gltf/extensions/gltf_light.h b/modules/gltf/extensions/gltf_light.h
index f0765a1bbc..04980e144c 100644
--- a/modules/gltf/extensions/gltf_light.h
+++ b/modules/gltf/extensions/gltf_light.h
@@ -70,6 +70,12 @@ public:
 
 	float get_outer_cone_angle();
 	void set_outer_cone_angle(float p_outer_cone_angle);
+
+	static Ref<GLTFLight> from_node(const Light3D *p_light);
+	Light3D *to_node() const;
+
+	static Ref<GLTFLight> from_dictionary(const Dictionary p_dictionary);
+	Dictionary to_dictionary() const;
 };
 
 #endif // GLTF_LIGHT_H
diff --git a/modules/gltf/gltf_document.cpp b/modules/gltf/gltf_document.cpp
index 87ba1d9869..4f9eaca2a9 100644
--- a/modules/gltf/gltf_document.cpp
+++ b/modules/gltf/gltf_document.cpp
@@ -4534,28 +4534,7 @@ Error GLTFDocument::_serialize_lights(Ref<GLTFState> state) {
 	}
 	Array lights;
 	for (GLTFLightIndex i = 0; i < state->lights.size(); i++) {
-		Dictionary d;
-		Ref<GLTFLight> light = state->lights[i];
-		Array color;
-		color.resize(3);
-		color[0] = light->color.r;
-		color[1] = light->color.g;
-		color[2] = light->color.b;
-		d["color"] = color;
-		d["type"] = light->light_type;
-		if (light->light_type == "spot") {
-			Dictionary s;
-			float inner_cone_angle = light->inner_cone_angle;
-			s["innerConeAngle"] = inner_cone_angle;
-			float outer_cone_angle = light->outer_cone_angle;
-			s["outerConeAngle"] = outer_cone_angle;
-			d["spot"] = s;
-		}
-		float intensity = light->intensity;
-		d["intensity"] = intensity;
-		float range = light->range;
-		d["range"] = range;
-		lights.push_back(d);
+		lights.push_back(state->lights[i]->to_dictionary());
 	}
 
 	Dictionary extensions;
@@ -4627,35 +4606,10 @@ Error GLTFDocument::_parse_lights(Ref<GLTFState> state) {
 	const Array &lights = lights_punctual["lights"];
 
 	for (GLTFLightIndex light_i = 0; light_i < lights.size(); light_i++) {
-		const Dictionary &d = lights[light_i];
-
-		Ref<GLTFLight> light;
-		light.instantiate();
-		ERR_FAIL_COND_V(!d.has("type"), ERR_PARSE_ERROR);
-		const String &type = d["type"];
-		light->light_type = type;
-
-		if (d.has("color")) {
-			const Array &arr = d["color"];
-			ERR_FAIL_COND_V(arr.size() != 3, ERR_PARSE_ERROR);
-			const Color c = Color(arr[0], arr[1], arr[2]).linear_to_srgb();
-			light->color = c;
-		}
-		if (d.has("intensity")) {
-			light->intensity = d["intensity"];
-		}
-		if (d.has("range")) {
-			light->range = d["range"];
-		}
-		if (type == "spot") {
-			const Dictionary &spot = d["spot"];
-			light->inner_cone_angle = spot["innerConeAngle"];
-			light->outer_cone_angle = spot["outerConeAngle"];
-			ERR_CONTINUE_MSG(light->inner_cone_angle >= light->outer_cone_angle, "The inner angle must be smaller than the outer angle.");
-		} else if (type != "point" && type != "directional") {
-			ERR_CONTINUE_MSG(true, "Light type is unknown.");
+		Ref<GLTFLight> light = GLTFLight::from_dictionary(lights[light_i]);
+		if (light.is_null()) {
+			return Error::ERR_PARSE_ERROR;
 		}
-
 		state->lights.push_back(light);
 	}
 
@@ -5148,45 +5102,7 @@ Node3D *GLTFDocument::_generate_light(Ref<GLTFState> state, const GLTFNodeIndex
 	print_verbose("glTF: Creating light for: " + gltf_node->get_name());
 
 	Ref<GLTFLight> l = state->lights[gltf_node->light];
-
-	float intensity = l->intensity;
-	if (intensity > 10) {
-		// GLTF spec has the default around 1, but Blender defaults lights to 100.
-		// The only sane way to handle this is to check where it came from and
-		// handle it accordingly. If it's over 10, it probably came from Blender.
-		intensity /= 100;
-	}
-
-	if (l->light_type == "directional") {
-		DirectionalLight3D *light = memnew(DirectionalLight3D);
-		light->set_param(Light3D::PARAM_ENERGY, intensity);
-		light->set_color(l->color);
-		return light;
-	}
-
-	const float range = CLAMP(l->range, 0, 4096);
-	if (l->light_type == "point") {
-		OmniLight3D *light = memnew(OmniLight3D);
-		light->set_param(OmniLight3D::PARAM_ENERGY, intensity);
-		light->set_param(OmniLight3D::PARAM_RANGE, range);
-		light->set_color(l->color);
-		return light;
-	}
-	if (l->light_type == "spot") {
-		SpotLight3D *light = memnew(SpotLight3D);
-		light->set_param(SpotLight3D::PARAM_ENERGY, intensity);
-		light->set_param(SpotLight3D::PARAM_RANGE, range);
-		light->set_param(SpotLight3D::PARAM_SPOT_ANGLE, Math::rad_to_deg(l->outer_cone_angle));
-		light->set_color(l->color);
-
-		// Line of best fit derived from guessing, see https://www.desmos.com/calculator/biiflubp8b
-		// The points in desmos are not exact, except for (1, infinity).
-		float angle_ratio = l->inner_cone_angle / l->outer_cone_angle;
-		float angle_attenuation = 0.2 / (1 - angle_ratio) - 0.1;
-		light->set_param(SpotLight3D::PARAM_SPOT_ATTENUATION, angle_attenuation);
-		return light;
-	}
-	return memnew(Node3D);
+	return l->to_node();
 }
 
 Camera3D *GLTFDocument::_generate_camera(Ref<GLTFState> state, const GLTFNodeIndex node_index) {
@@ -5228,31 +5144,7 @@ GLTFCameraIndex GLTFDocument::_convert_camera(Ref<GLTFState> state, Camera3D *p_
 GLTFLightIndex GLTFDocument::_convert_light(Ref<GLTFState> state, Light3D *p_light) {
 	print_verbose("glTF: Converting light: " + p_light->get_name());
 
-	Ref<GLTFLight> l;
-	l.instantiate();
-	l->color = p_light->get_color();
-	if (cast_to<DirectionalLight3D>(p_light)) {
-		l->light_type = "directional";
-		DirectionalLight3D *light = cast_to<DirectionalLight3D>(p_light);
-		l->intensity = light->get_param(DirectionalLight3D::PARAM_ENERGY);
-		l->range = FLT_MAX; // Range for directional lights is infinite in Godot.
-	} else if (cast_to<OmniLight3D>(p_light)) {
-		l->light_type = "point";
-		OmniLight3D *light = cast_to<OmniLight3D>(p_light);
-		l->range = light->get_param(OmniLight3D::PARAM_RANGE);
-		l->intensity = light->get_param(OmniLight3D::PARAM_ENERGY);
-	} else if (cast_to<SpotLight3D>(p_light)) {
-		l->light_type = "spot";
-		SpotLight3D *light = cast_to<SpotLight3D>(p_light);
-		l->range = light->get_param(SpotLight3D::PARAM_RANGE);
-		l->intensity = light->get_param(SpotLight3D::PARAM_ENERGY);
-		l->outer_cone_angle = Math::deg_to_rad(light->get_param(SpotLight3D::PARAM_SPOT_ANGLE));
-
-		// This equation is the inverse of the import equation (which has a desmos link).
-		float angle_ratio = 1 - (0.2 / (0.1 + light->get_param(SpotLight3D::PARAM_SPOT_ATTENUATION)));
-		angle_ratio = MAX(0, angle_ratio);
-		l->inner_cone_angle = l->outer_cone_angle * angle_ratio;
-	}
+	Ref<GLTFLight> l = GLTFLight::from_node(p_light);
 
 	GLTFLightIndex light_index = state->lights.size();
 	state->lights.push_back(l);