Allow MSDF rendering for system fonts, fix crash on loading damaged / unsupported font files.

doc/classes/SystemFont.xml

@@ -34,6 +34,9 @@
 		<member name="hinting" type="int" setter="set_hinting" getter="get_hinting" enum="TextServer.Hinting" default="1">
 			Font hinting mode.
 		</member>
+		<member name="multichannel_signed_distance_field" type="bool" setter="set_multichannel_signed_distance_field" getter="is_multichannel_signed_distance_field" default="false">
+			If set to [code]true[/code], glyphs of all sizes are rendered using single multichannel signed distance field generated from the dynamic font vector data.
+		</member>
 		<member name="oversampling" type="float" setter="set_oversampling" getter="get_oversampling" default="0.0">
 			Font oversampling factor, if set to [code]0.0[/code] global oversampling factor is used instead.
 		</member>

modules/text_server_adv/text_server_adv.cpp

@@ -1313,12 +1313,14 @@ _FORCE_INLINE_ bool TextServerAdvanced::_ensure_cache_for_size(FontAdvanced *p_f
 		fargs.stream = &fd->stream;
 
 		int max_index = 0;
-		FT_Face tmp_face;
+		FT_Face tmp_face = nullptr;
 		error = FT_Open_Face(ft_library, &fargs, -1, &tmp_face);
-		if (error == 0) {
+		if (tmp_face && error == 0) {
 			max_index = tmp_face->num_faces - 1;
 		}
-		FT_Done_Face(tmp_face);
+		if (tmp_face) {
+			FT_Done_Face(tmp_face);
+		}
 
 		error = FT_Open_Face(ft_library, &fargs, CLAMP(p_font_data->face_index, 0, max_index), &fd->face);
 		if (error) {

modules/text_server_fb/text_server_fb.cpp

@@ -733,12 +733,14 @@ _FORCE_INLINE_ bool TextServerFallback::_ensure_cache_for_size(FontFallback *p_f
 		fargs.stream = &fd->stream;
 
 		int max_index = 0;
-		FT_Face tmp_face;
+		FT_Face tmp_face = nullptr;
 		error = FT_Open_Face(ft_library, &fargs, -1, &tmp_face);
-		if (error == 0) {
+		if (tmp_face && error == 0) {
 			max_index = tmp_face->num_faces - 1;
 		}
-		FT_Done_Face(tmp_face);
+		if (tmp_face) {
+			FT_Done_Face(tmp_face);
+		}
 
 		error = FT_Open_Face(ft_library, &fargs, CLAMP(p_font_data->face_index, 0, max_index), &fd->face);
 		if (error) {

scene/resources/font.cpp

@@ -2714,6 +2714,9 @@ void SystemFont::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_subpixel_positioning", "subpixel_positioning"), &SystemFont::set_subpixel_positioning);
 	ClassDB::bind_method(D_METHOD("get_subpixel_positioning"), &SystemFont::get_subpixel_positioning);
 
+	ClassDB::bind_method(D_METHOD("set_multichannel_signed_distance_field", "msdf"), &SystemFont::set_multichannel_signed_distance_field);
+	ClassDB::bind_method(D_METHOD("is_multichannel_signed_distance_field"), &SystemFont::is_multichannel_signed_distance_field);
+
 	ClassDB::bind_method(D_METHOD("set_oversampling", "oversampling"), &SystemFont::set_oversampling);
 	ClassDB::bind_method(D_METHOD("get_oversampling"), &SystemFont::get_oversampling);
 
@@ -2729,6 +2732,7 @@ void SystemFont::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "force_autohinter"), "set_force_autohinter", "is_force_autohinter");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "hinting", PROPERTY_HINT_ENUM, "None,Light,Normal"), "set_hinting", "get_hinting");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "subpixel_positioning", PROPERTY_HINT_ENUM, "Disabled,Auto,One half of a pixel,One quarter of a pixel"), "set_subpixel_positioning", "get_subpixel_positioning");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "multichannel_signed_distance_field"), "set_multichannel_signed_distance_field", "is_multichannel_signed_distance_field");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "oversampling", PROPERTY_HINT_RANGE, "0,10,0.1"), "set_oversampling", "get_oversampling");
 	ADD_PROPERTY(PropertyInfo(Variant::ARRAY, "fallbacks", PROPERTY_HINT_ARRAY_TYPE, vformat("%s/%s:%s", Variant::OBJECT, PROPERTY_HINT_RESOURCE_TYPE, "Font")), "set_fallbacks", "get_fallbacks");
 }
@@ -2805,6 +2809,7 @@ void SystemFont::_update_base_font() {
 		file->set_force_autohinter(force_autohinter);
 		file->set_hinting(hinting);
 		file->set_subpixel_positioning(subpixel_positioning);
+		file->set_multichannel_signed_distance_field(msdf);
 		file->set_oversampling(oversampling);
 
 		base_font = file;
@@ -2840,6 +2845,7 @@ void SystemFont::reset_state() {
 	hinting = TextServer::HINTING_LIGHT;
 	subpixel_positioning = TextServer::SUBPIXEL_POSITIONING_DISABLED;
 	oversampling = 0.f;
+	msdf = false;
 
 	Font::reset_state();
 }
@@ -2969,6 +2975,20 @@ TextServer::SubpixelPositioning SystemFont::get_subpixel_positioning() const {
 	return subpixel_positioning;
 }
 
+void SystemFont::set_multichannel_signed_distance_field(bool p_msdf) {
+	if (msdf != p_msdf) {
+		msdf = p_msdf;
+		if (base_font.is_valid()) {
+			base_font->set_multichannel_signed_distance_field(msdf);
+		}
+		emit_changed();
+	}
+}
+
+bool SystemFont::is_multichannel_signed_distance_field() const {
+	return msdf;
+}
+
 void SystemFont::set_oversampling(real_t p_oversampling) {
 	if (oversampling != p_oversampling) {
 		oversampling = p_oversampling;

scene/resources/font.h

@@ -404,6 +404,7 @@ class SystemFont : public Font {
 	TextServer::Hinting hinting = TextServer::HINTING_LIGHT;
 	TextServer::SubpixelPositioning subpixel_positioning = TextServer::SUBPIXEL_POSITIONING_AUTO;
 	real_t oversampling = 0.f;
+	bool msdf = false;
 
 protected:
 	static void _bind_methods();
@@ -434,6 +435,9 @@ public:
 	virtual void set_oversampling(real_t p_oversampling);
 	virtual real_t get_oversampling() const;
 
+	virtual void set_multichannel_signed_distance_field(bool p_msdf);
+	virtual bool is_multichannel_signed_distance_field() const;
+
 	virtual void set_font_names(const PackedStringArray &p_names);
 	virtual PackedStringArray get_font_names() const;