Tweak Decal distance fade defaults and add property hints

The new default values are more usable in real world scenarios
when smooth fading of distant decals is desired for performance reasons.

The Decal distance fade property hints were adjusted based on the
GeometryInstance3D visibility range fade property hints. `or_greater`
was also added to allow specifying larger values if needed.

5 files changed, 21 insertions, 15 deletions

diff --git a/doc/classes/Decal.xml b/doc/classes/Decal.xml
index 861b4b480c..b86104a5e3 100644
--- a/doc/classes/Decal.xml
+++ b/doc/classes/Decal.xml
@@ -63,14 +63,14 @@
 		<member name="cull_mask" type="int" setter="set_cull_mask" getter="get_cull_mask" default="1048575">
 			Specifies which [member VisualInstance3D.layers] this decal will project on. By default, Decals affect all layers. This is used so you can specify which types of objects receive the Decal and which do not. This is especially useful so you can ensure that dynamic objects don't accidentally receive a Decal intended for the terrain under them.
 		</member>
-		<member name="distance_fade_begin" type="float" setter="set_distance_fade_begin" getter="get_distance_fade_begin" default="10.0">
-			Distance from the camera at which the Decal begins to fade away.
+		<member name="distance_fade_begin" type="float" setter="set_distance_fade_begin" getter="get_distance_fade_begin" default="40.0">
+			The distance from the camera at which the Decal begins to fade away (in 3D units).
 		</member>
 		<member name="distance_fade_enabled" type="bool" setter="set_enable_distance_fade" getter="is_distance_fade_enabled" default="false">
-			If [code]true[/code], decals will smoothly fade away when far from the active [Camera3D] starting at [member distance_fade_begin]. The Decal will fade out over [member distance_fade_length], after which it will be culled and not sent to the shader at all. Use this to reduce the number of active Decals in a scene and thus improve performance.
+			If [code]true[/code], decals will smoothly fade away when far from the active [Camera3D] starting at [member distance_fade_begin]. The Decal will fade out over [member distance_fade_begin] + [member distance_fade_length], after which it will be culled and not sent to the shader at all. Use this to reduce the number of active Decals in a scene and thus improve performance.
 		</member>
-		<member name="distance_fade_length" type="float" setter="set_distance_fade_length" getter="get_distance_fade_length" default="1.0">
-			Distance over which the Decal fades. The Decal becomes slowly more transparent over this distance and is completely invisible at the end.
+		<member name="distance_fade_length" type="float" setter="set_distance_fade_length" getter="get_distance_fade_length" default="10.0">
+			The distance over which the Decal fades (in 3D units). The Decal becomes slowly more transparent over this distance and is completely invisible at the end.
 		</member>
 		<member name="emission_energy" type="float" setter="set_emission_energy" getter="get_emission_energy" default="1.0">
 			Energy multiplier for the emission texture. This will make the decal emit light at a higher intensity.
diff --git a/scene/3d/decal.cpp b/scene/3d/decal.cpp
index 01cab493ec..0112f24e0c 100644
--- a/scene/3d/decal.cpp
+++ b/scene/3d/decal.cpp
@@ -215,11 +215,13 @@ void Decal::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_cull_mask"), &Decal::get_cull_mask);
 
 	ADD_PROPERTY(PropertyInfo(Variant::VECTOR3, "extents", PROPERTY_HINT_RANGE, "0,1024,0.001,or_greater,suffix:m"), "set_extents", "get_extents");
+
 	ADD_GROUP("Textures", "texture_");
 	ADD_PROPERTYI(PropertyInfo(Variant::OBJECT, "texture_albedo", PROPERTY_HINT_RESOURCE_TYPE, "Texture"), "set_texture", "get_texture", TEXTURE_ALBEDO);
 	ADD_PROPERTYI(PropertyInfo(Variant::OBJECT, "texture_normal", PROPERTY_HINT_RESOURCE_TYPE, "Texture"), "set_texture", "get_texture", TEXTURE_NORMAL);
 	ADD_PROPERTYI(PropertyInfo(Variant::OBJECT, "texture_orm", PROPERTY_HINT_RESOURCE_TYPE, "Texture"), "set_texture", "get_texture", TEXTURE_ORM);
 	ADD_PROPERTYI(PropertyInfo(Variant::OBJECT, "texture_emission", PROPERTY_HINT_RESOURCE_TYPE, "Texture"), "set_texture", "get_texture", TEXTURE_EMISSION);
+
 	ADD_GROUP("Parameters", "");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "emission_energy", PROPERTY_HINT_RANGE, "0,128,0.01"), "set_emission_energy", "get_emission_energy");
 	ADD_PROPERTY(PropertyInfo(Variant::COLOR, "modulate"), "set_modulate", "get_modulate");
@@ -227,13 +229,16 @@ void Decal::_bind_methods() {
 	// A Normal Fade of 1.0 causes the decal to be invisible even if fully perpendicular to a surface.
 	// Due to this, limit Normal Fade to 0.999.
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "normal_fade", PROPERTY_HINT_RANGE, "0,0.999,0.001"), "set_normal_fade", "get_normal_fade");
+
 	ADD_GROUP("Vertical Fade", "");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "upper_fade", PROPERTY_HINT_EXP_EASING, "attenuation"), "set_upper_fade", "get_upper_fade");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "lower_fade", PROPERTY_HINT_EXP_EASING, "attenuation"), "set_lower_fade", "get_lower_fade");
+
 	ADD_GROUP("Distance Fade", "distance_fade_");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "distance_fade_enabled"), "set_enable_distance_fade", "is_distance_fade_enabled");
-	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "distance_fade_begin", PROPERTY_HINT_NONE, "suffix:m"), "set_distance_fade_begin", "get_distance_fade_begin");
-	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "distance_fade_length", PROPERTY_HINT_NONE, "suffix:m"), "set_distance_fade_length", "get_distance_fade_length");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "distance_fade_begin", PROPERTY_HINT_RANGE, "0.0,4096.0,0.01,or_greater,suffix:m"), "set_distance_fade_begin", "get_distance_fade_begin");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "distance_fade_length", PROPERTY_HINT_RANGE, "0.0,4096.0,0.01,or_greater,suffix:m"), "set_distance_fade_length", "get_distance_fade_length");
+
 	ADD_GROUP("Cull Mask", "");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "cull_mask", PROPERTY_HINT_LAYERS_3D_RENDER), "set_cull_mask", "get_cull_mask");
 
diff --git a/scene/3d/decal.h b/scene/3d/decal.h
index d5990272c6..38da4c14e3 100644
--- a/scene/3d/decal.h
+++ b/scene/3d/decal.h
@@ -57,8 +57,8 @@ private:
 	real_t upper_fade = 0.3;
 	real_t lower_fade = 0.3;
 	bool distance_fade_enabled = false;
-	real_t distance_fade_begin = 10.0;
-	real_t distance_fade_length = 1.0;
+	real_t distance_fade_begin = 40.0;
+	real_t distance_fade_length = 10.0;
 
 protected:
 	static void _bind_methods();
diff --git a/scene/3d/visual_instance_3d.cpp b/scene/3d/visual_instance_3d.cpp
index 69917f6992..e76e85cfef 100644
--- a/scene/3d/visual_instance_3d.cpp
+++ b/scene/3d/visual_instance_3d.cpp
@@ -461,15 +461,16 @@ void GeometryInstance3D::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "extra_cull_margin", PROPERTY_HINT_RANGE, "0,16384,0.01,suffix:m"), "set_extra_cull_margin", "get_extra_cull_margin");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "lod_bias", PROPERTY_HINT_RANGE, "0.001,128,0.001"), "set_lod_bias", "get_lod_bias");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "ignore_occlusion_culling"), "set_ignore_occlusion_culling", "is_ignoring_occlusion_culling");
+
 	ADD_GROUP("Global Illumination", "gi_");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "gi_mode", PROPERTY_HINT_ENUM, "Disabled,Static (VoxelGI/SDFGI/LightmapGI),Dynamic (VoxelGI only)"), "set_gi_mode", "get_gi_mode");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "gi_lightmap_scale", PROPERTY_HINT_ENUM, String::utf8("1×,2×,4×,8×")), "set_lightmap_scale", "get_lightmap_scale");
 
 	ADD_GROUP("Visibility Range", "visibility_range_");
-	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "visibility_range_begin", PROPERTY_HINT_RANGE, "0.0,4096.0,0.01,suffix:m"), "set_visibility_range_begin", "get_visibility_range_begin");
-	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "visibility_range_begin_margin", PROPERTY_HINT_RANGE, "0.0,4096.0,0.01,suffix:m"), "set_visibility_range_begin_margin", "get_visibility_range_begin_margin");
-	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "visibility_range_end", PROPERTY_HINT_RANGE, "0.0,4096.0,0.01,suffix:m"), "set_visibility_range_end", "get_visibility_range_end");
-	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "visibility_range_end_margin", PROPERTY_HINT_RANGE, "0.0,4096.0,0.01,suffix:m"), "set_visibility_range_end_margin", "get_visibility_range_end_margin");
+	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");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "visibility_range_begin_margin", PROPERTY_HINT_RANGE, "0.0,4096.0,0.01,or_greater,suffix:m"), "set_visibility_range_begin_margin", "get_visibility_range_begin_margin");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "visibility_range_end", PROPERTY_HINT_RANGE, "0.0,4096.0,0.01,or_greater,suffix:m"), "set_visibility_range_end", "get_visibility_range_end");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "visibility_range_end_margin", PROPERTY_HINT_RANGE, "0.0,4096.0,0.01,or_greater,suffix:m"), "set_visibility_range_end_margin", "get_visibility_range_end_margin");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "visibility_range_fade_mode", PROPERTY_HINT_ENUM, "Disabled,Self,Dependencies"), "set_visibility_range_fade_mode", "get_visibility_range_fade_mode");
 
 	BIND_ENUM_CONSTANT(SHADOW_CASTING_SETTING_OFF);
diff --git a/servers/rendering/renderer_rd/storage_rd/texture_storage.h b/servers/rendering/renderer_rd/storage_rd/texture_storage.h
index 1a5a3dd023..1eb4a283ca 100644
--- a/servers/rendering/renderer_rd/storage_rd/texture_storage.h
+++ b/servers/rendering/renderer_rd/storage_rd/texture_storage.h
@@ -191,8 +191,8 @@ struct Decal {
 	float upper_fade = 0.3;
 	float lower_fade = 0.3;
 	bool distance_fade = false;
-	float distance_fade_begin = 10;
-	float distance_fade_length = 1;
+	float distance_fade_begin = 40.0;
+	float distance_fade_length = 10.0;
 	float normal_fade = 0.0;
 
 	Dependency dependency;