Add compatibility property and methods

This allows existing projects to use their Lightmap Scale property.
It will be converted into the new Lightmap Texel Scale property automatically.

doc/classes/GeometryInstance3D.xml

@@ -39,8 +39,12 @@
 		<member name="extra_cull_margin" type="float" setter="set_extra_cull_margin" getter="get_extra_cull_margin" default="0.0">
 			The extra distance added to the GeometryInstance3D's bounding box ([AABB]) to increase its cull box.
 		</member>
-		<member name="gi_lightmap_scale" type="float" setter="set_lightmap_scale" getter="get_lightmap_scale" default="1.0">
+		<member name="gi_lightmap_scale" type="int" setter="set_lightmap_scale" getter="get_lightmap_scale" enum="GeometryInstance3D.LightmapScale" default="0" deprecated="Use [member gi_lightmap_texel_scale] instead.">
+			The texel density to use for lightmapping in [LightmapGI].
+		</member>
+		<member name="gi_lightmap_texel_scale" type="float" setter="set_lightmap_texel_scale" getter="get_lightmap_texel_scale" default="1.0">
 			The texel density to use for lightmapping in [LightmapGI]. Greater scale values provide higher resolution in the lightmap, which can result in sharper shadows for lights that have both direct and indirect light baked. However, greater scale values will also increase the space taken by the mesh in the lightmap texture, which increases the memory, storage, and bake time requirements. When using a single mesh at different scales, consider adjusting this value to keep the lightmap texel density consistent across meshes.
+			For example, doubling [member gi_lightmap_texel_scale] doubles the lightmap texture resolution for this object [i]on each axis[/i], so it will [i]quadruple[/i] the texel count.
 		</member>
 		<member name="gi_mode" type="int" setter="set_gi_mode" getter="get_gi_mode" enum="GeometryInstance3D.GIMode" default="1" keywords="global_illumination_mode, light_bake_mode">
 			The global illumination mode to use for the whole geometry. To avoid inconsistent results, use a mode that matches the purpose of the mesh during gameplay (static/dynamic).
@@ -111,6 +115,21 @@
 		<constant name="GI_MODE_DYNAMIC" value="2" enum="GIMode">
 			Dynamic global illumination mode. Use for dynamic objects that contribute to global illumination. This GI mode is only effective when using [VoxelGI], but it has a higher performance impact than [constant GI_MODE_STATIC]. When using other GI methods, this will act the same as [constant GI_MODE_DISABLED]. When using [LightmapGI], the object will receive indirect lighting using lightmap probes instead of using the baked lightmap texture.
 		</constant>
+		<constant name="LIGHTMAP_SCALE_1X" value="0" enum="LightmapScale" deprecated="Use [member gi_lightmap_texel_scale] instead.">
+			The standard texel density for lightmapping with [LightmapGI].
+		</constant>
+		<constant name="LIGHTMAP_SCALE_2X" value="1" enum="LightmapScale" deprecated="Use [member gi_lightmap_texel_scale] instead.">
+			Multiplies texel density by 2× for lightmapping with [LightmapGI]. To ensure consistency in texel density, use this when scaling a mesh by a factor between 1.5 and 3.0.
+		</constant>
+		<constant name="LIGHTMAP_SCALE_4X" value="2" enum="LightmapScale" deprecated="Use [member gi_lightmap_texel_scale] instead.">
+			Multiplies texel density by 4× for lightmapping with [LightmapGI]. To ensure consistency in texel density, use this when scaling a mesh by a factor between 3.0 and 6.0.
+		</constant>
+		<constant name="LIGHTMAP_SCALE_8X" value="3" enum="LightmapScale" deprecated="Use [member gi_lightmap_texel_scale] instead.">
+			Multiplies texel density by 8× for lightmapping with [LightmapGI]. To ensure consistency in texel density, use this when scaling a mesh by a factor greater than 6.0.
+		</constant>
+		<constant name="LIGHTMAP_SCALE_MAX" value="4" enum="LightmapScale" deprecated="Use [member gi_lightmap_texel_scale] instead.">
+			Represents the size of the [enum LightmapScale] enum.
+		</constant>
 		<constant name="VISIBILITY_RANGE_FADE_DISABLED" value="0" enum="VisibilityRangeFadeMode">
 			Will not fade itself nor its visibility dependencies, hysteresis will be used instead. This is the fastest approach to manual LOD, but it can result in noticeable LOD transitions depending on how the LOD meshes are authored. See [member visibility_range_begin] and [member Node3D.visibility_parent] for more information.
 		</constant>

doc/classes/LightmapGI.xml

@@ -70,6 +70,7 @@
 		</member>
 		<member name="texel_scale" type="float" setter="set_texel_scale" getter="get_texel_scale" default="1.0">
 			Scales the lightmap texel density of all meshes for the current bake. This is a multiplier that builds upon the existing lightmap texel size defined in each imported 3D scene, along with the per-mesh density multiplier (which is designed to be used when the same mesh is used at different scales). Lower values will result in faster bake times.
+			For example, doubling [member texel_scale] doubles the lightmap texture resolution for all objects [i]on each axis[/i], so it will [i]quadruple[/i] the texel count.
 		</member>
 		<member name="use_denoiser" type="bool" setter="set_use_denoiser" getter="is_using_denoiser" default="true">
 			If [code]true[/code], uses a GPU-based denoising algorithm on the generated lightmap. This eliminates most noise within the generated lightmap at the cost of longer bake times. File sizes are generally not impacted significantly by the use of a denoiser, although lossless compression may do a better job at compressing a denoised image.

scene/3d/lightmap_gi.cpp

@@ -333,7 +333,7 @@ void LightmapGI::_find_meshes_and_lights(Node *p_at_node, Vector<MeshesFound> &m
 				mf.node_path = get_path_to(mi);
 				mf.subindex = -1;
 				mf.mesh = mesh;
-				mf.lightmap_scale = mi->get_lightmap_scale();
+				mf.lightmap_scale = mi->get_lightmap_texel_scale();
 
 				Ref<Material> all_override = mi->get_material_override();
 				for (int i = 0; i < mesh->get_surface_count(); i++) {

scene/3d/visual_instance_3d.cpp

@@ -454,14 +454,48 @@ AABB GeometryInstance3D::get_custom_aabb() const {
 	return custom_aabb;
 }
 
-void GeometryInstance3D::set_lightmap_scale(float p_scale) {
-	lightmap_scale = p_scale;
+void GeometryInstance3D::set_lightmap_texel_scale(float p_scale) {
+	lightmap_texel_scale = p_scale;
 }
 
-float GeometryInstance3D::get_lightmap_scale() const {
-	return lightmap_scale;
+float GeometryInstance3D::get_lightmap_texel_scale() const {
+	return lightmap_texel_scale;
 }
 
+#ifndef DISABLE_DEPRECATED
+void GeometryInstance3D::set_lightmap_scale(LightmapScale p_scale) {
+	ERR_FAIL_INDEX(p_scale, LIGHTMAP_SCALE_MAX);
+	switch (p_scale) {
+		case GeometryInstance3D::LIGHTMAP_SCALE_1X:
+			lightmap_texel_scale = 1.0f;
+			break;
+		case GeometryInstance3D::LIGHTMAP_SCALE_2X:
+			lightmap_texel_scale = 2.0f;
+			break;
+		case GeometryInstance3D::LIGHTMAP_SCALE_4X:
+			lightmap_texel_scale = 4.0f;
+			break;
+		case GeometryInstance3D::LIGHTMAP_SCALE_8X:
+			lightmap_texel_scale = 8.0f;
+			break;
+		case GeometryInstance3D::LIGHTMAP_SCALE_MAX:
+			break; // Can't happen, but silences warning.
+	}
+}
+
+GeometryInstance3D::LightmapScale GeometryInstance3D::get_lightmap_scale() const {
+	if (lightmap_texel_scale < 1.5f) {
+		return GeometryInstance3D::LIGHTMAP_SCALE_1X;
+	} else if (lightmap_texel_scale < 3.0f) {
+		return GeometryInstance3D::LIGHTMAP_SCALE_2X;
+	} else if (lightmap_texel_scale < 6.0f) {
+		return GeometryInstance3D::LIGHTMAP_SCALE_4X;
+	}
+
+	return GeometryInstance3D::LIGHTMAP_SCALE_8X;
+}
+#endif // DISABLE_DEPRECATED
+
 void GeometryInstance3D::set_gi_mode(GIMode p_mode) {
 	switch (p_mode) {
 		case GI_MODE_DISABLED: {
@@ -564,8 +598,13 @@ void GeometryInstance3D::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_extra_cull_margin", "margin"), &GeometryInstance3D::set_extra_cull_margin);
 	ClassDB::bind_method(D_METHOD("get_extra_cull_margin"), &GeometryInstance3D::get_extra_cull_margin);
 
+	ClassDB::bind_method(D_METHOD("set_lightmap_texel_scale", "scale"), &GeometryInstance3D::set_lightmap_texel_scale);
+	ClassDB::bind_method(D_METHOD("get_lightmap_texel_scale"), &GeometryInstance3D::get_lightmap_texel_scale);
+
+#ifndef DISABLE_DEPRECATED
 	ClassDB::bind_method(D_METHOD("set_lightmap_scale", "scale"), &GeometryInstance3D::set_lightmap_scale);
 	ClassDB::bind_method(D_METHOD("get_lightmap_scale"), &GeometryInstance3D::get_lightmap_scale);
+#endif // DISABLE_DEPRECATED
 
 	ClassDB::bind_method(D_METHOD("set_gi_mode", "mode"), &GeometryInstance3D::set_gi_mode);
 	ClassDB::bind_method(D_METHOD("get_gi_mode"), &GeometryInstance3D::get_gi_mode);
@@ -590,7 +629,10 @@ void GeometryInstance3D::_bind_methods() {
 
 	ADD_GROUP("Global Illumination", "gi_");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "gi_mode", PROPERTY_HINT_ENUM, "Disabled,Static,Dynamic"), "set_gi_mode", "get_gi_mode");
-	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "gi_lightmap_scale", PROPERTY_HINT_RANGE, "0.01,10,0.0001,or_greater"), "set_lightmap_scale", "get_lightmap_scale");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "gi_lightmap_texel_scale", PROPERTY_HINT_RANGE, "0.01,10,0.0001,or_greater"), "set_lightmap_texel_scale", "get_lightmap_texel_scale");
+#ifndef DISABLE_DEPRECATED
+	ADD_PROPERTY(PropertyInfo(Variant::INT, "gi_lightmap_scale", PROPERTY_HINT_ENUM, String::utf8("1×,2×,4×,8×"), PROPERTY_USAGE_NONE), "set_lightmap_scale", "get_lightmap_scale");
+#endif // DISABLE_DEPRECATED
 
 	ADD_GROUP("Visibility Range", "visibility_range_");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "visibility_range_begin", PROPERTY_HINT_RANGE, "0.0,4096.0,0.01,or_greater,suffix:m"), "set_visibility_range_begin", "get_visibility_range_begin");
@@ -608,6 +650,12 @@ void GeometryInstance3D::_bind_methods() {
 	BIND_ENUM_CONSTANT(GI_MODE_STATIC);
 	BIND_ENUM_CONSTANT(GI_MODE_DYNAMIC);
 
+	BIND_ENUM_CONSTANT(LIGHTMAP_SCALE_1X);
+	BIND_ENUM_CONSTANT(LIGHTMAP_SCALE_2X);
+	BIND_ENUM_CONSTANT(LIGHTMAP_SCALE_4X);
+	BIND_ENUM_CONSTANT(LIGHTMAP_SCALE_8X);
+	BIND_ENUM_CONSTANT(LIGHTMAP_SCALE_MAX);
+
 	BIND_ENUM_CONSTANT(VISIBILITY_RANGE_FADE_DISABLED);
 	BIND_ENUM_CONSTANT(VISIBILITY_RANGE_FADE_SELF);
 	BIND_ENUM_CONSTANT(VISIBILITY_RANGE_FADE_DEPENDENCIES);

scene/3d/visual_instance_3d.h

@@ -100,6 +100,14 @@ class GeometryInstance3D : public VisualInstance3D {
 		GI_MODE_DYNAMIC
 	};
 
+	enum LightmapScale {
+		LIGHTMAP_SCALE_1X,
+		LIGHTMAP_SCALE_2X,
+		LIGHTMAP_SCALE_4X,
+		LIGHTMAP_SCALE_8X,
+		LIGHTMAP_SCALE_MAX,
+	};
+
 	enum VisibilityRangeFadeMode {
 		VISIBILITY_RANGE_FADE_DISABLED = RS::VISIBILITY_RANGE_FADE_DISABLED,
 		VISIBILITY_RANGE_FADE_SELF = RS::VISIBILITY_RANGE_FADE_SELF,
@@ -126,7 +134,7 @@ class GeometryInstance3D : public VisualInstance3D {
 
 	float extra_cull_margin = 0.0;
 	AABB custom_aabb;
-	float lightmap_scale = 1.0;
+	float lightmap_texel_scale = 1.0f;
 	GIMode gi_mode = GI_MODE_STATIC;
 	bool ignore_occlusion_culling = false;
 
@@ -177,8 +185,13 @@ class GeometryInstance3D : public VisualInstance3D {
 	void set_gi_mode(GIMode p_mode);
 	GIMode get_gi_mode() const;
 
-	void set_lightmap_scale(float p_scale);
-	float get_lightmap_scale() const;
+	void set_lightmap_texel_scale(float p_scale);
+	float get_lightmap_texel_scale() const;
+
+#ifndef DISABLE_DEPRECATED
+	void set_lightmap_scale(GeometryInstance3D::LightmapScale p_scale);
+	LightmapScale get_lightmap_scale() const;
+#endif // DISABLE_DEPRECATED
 
 	void set_instance_shader_parameter(const StringName &p_name, const Variant &p_value);
 	Variant get_instance_shader_parameter(const StringName &p_name) const;
@@ -196,6 +209,7 @@ class GeometryInstance3D : public VisualInstance3D {
 
 VARIANT_ENUM_CAST(GeometryInstance3D::ShadowCastingSetting);
 VARIANT_ENUM_CAST(GeometryInstance3D::GIMode);
+VARIANT_ENUM_CAST(GeometryInstance3D::LightmapScale);
 VARIANT_ENUM_CAST(GeometryInstance3D::VisibilityRangeFadeMode);
 
 #endif // VISUAL_INSTANCE_3D_H