Allow viewport stretch without shrink

doc/classes/SubViewport.xml

@@ -26,7 +26,7 @@
 		</member>
 		<member name="size" type="Vector2i" setter="set_size" getter="get_size" default="Vector2i(512, 512)">
 			The width and height of the sub-viewport. Must be set to a value greater than or equal to 2 pixels on both dimensions. Otherwise, nothing will be displayed.
-			[b]Note:[/b] If the parent node is a [SubViewportContainer] and its [member SubViewportContainer.stretch] is [code]true[/code], the viewport size cannot be changed manually.
+			[b]Note:[/b] If the parent node is a [SubViewportContainer] and its [member SubViewportContainer.stretch] is [code]true[/code] and its [member SubViewportContainer.stretch_shrink] is not [code]0[/code], the viewport size cannot be changed manually.
 		</member>
 		<member name="size_2d_override" type="Vector2i" setter="set_size_2d_override" getter="get_size_2d_override" default="Vector2i(0, 0)">
 			The 2D size override of the sub-viewport. If either the width or height is [code]0[/code], the override is disabled.

doc/classes/SubViewportContainer.xml

@@ -12,13 +12,14 @@
 	</tutorials>
 	<members>
 		<member name="stretch" type="bool" setter="set_stretch" getter="is_stretch_enabled" default="false">
-			If [code]true[/code], the sub-viewport will be automatically resized to the control's size.
-			[b]Note:[/b] If [code]true[/code], this will prohibit changing [member SubViewport.size] of its children manually.
+			If [code]true[/code] and [member stretch_shrink] is not [code]0[/code], the sub-viewport will be automatically resized to the control's size.
+			[b]Note:[/b] If [code]true[/code] and [member stretch_shrink] is not [code]0[/code], this will prohibit changing [member SubViewport.size] of its children manually.
 		</member>
 		<member name="stretch_shrink" type="int" setter="set_stretch_shrink" getter="get_stretch_shrink" default="1">
-			Divides the sub-viewport's effective resolution by this value while preserving its scale. This can be used to speed up rendering.
+			If not [code]0[/code], divides the sub-viewport's effective resolution by this value while preserving its scale. This can be used to speed up rendering.
 			For example, a 1280×720 sub-viewport with [member stretch_shrink] set to [code]2[/code] will be rendered at 640×360 while occupying the same size in the container.
 			[b]Note:[/b] [member stretch] must be [code]true[/code] for this property to work.
+			[b]Note:[/b] If [code]0[/code], sub-viewport texture is stretched across the container regardless of its size or aspect ratio.
 		</member>
 	</members>
 </class>

scene/gui/subviewport_container.cpp

@@ -69,7 +69,7 @@ bool SubViewportContainer::is_stretch_enabled() const {
 }
 
 void SubViewportContainer::set_stretch_shrink(int p_shrink) {
-	ERR_FAIL_COND(p_shrink < 1);
+	ERR_FAIL_COND(p_shrink < 0);
 	if (shrink == p_shrink) {
 		return;
 	}
@@ -81,7 +81,7 @@ void SubViewportContainer::set_stretch_shrink(int p_shrink) {
 }
 
 void SubViewportContainer::recalc_force_viewport_sizes() {
-	if (!stretch) {
+	if (!stretch || shrink == 0) {
 		return;
 	}
 
@@ -192,13 +192,7 @@ void SubViewportContainer::gui_input(const Ref<InputEvent> &p_event) {
 		return;
 	}
 
-	if (stretch && shrink > 1) {
-		Transform2D xform;
-		xform.scale(Vector2(1, 1) / shrink);
-		_send_event_to_viewports(p_event->xformed_by(xform));
-	} else {
-		_send_event_to_viewports(p_event);
-	}
+	_send_event_to_viewports(p_event);
 }
 
 void SubViewportContainer::_send_event_to_viewports(const Ref<InputEvent> &p_event) {
@@ -208,7 +202,13 @@ void SubViewportContainer::_send_event_to_viewports(const Ref<InputEvent> &p_eve
 			continue;
 		}
 
-		c->push_input(p_event);
+		if (stretch && shrink != 1) {
+			Transform2D xform;
+			xform.scale(Vector2(c->get_size()) / get_size());
+			c->push_input(p_event->xformed_by(xform));
+		} else {
+			c->push_input(p_event);
+		}
 	}
 }
 

scene/main/viewport.cpp

@@ -4320,7 +4320,7 @@ void SubViewport::set_size_force(const Size2i &p_size) {
 
 void SubViewport::_internal_set_size(const Size2i &p_size, bool p_force) {
 	SubViewportContainer *c = Object::cast_to<SubViewportContainer>(get_parent());
-	if (!p_force && c && c->is_stretch_enabled()) {
+	if (!p_force && c && c->is_stretch_enabled() && c->get_stretch_shrink() != 0) {
 #ifdef DEBUG_ENABLED
 		WARN_PRINT("Can't change the size of a `SubViewport` with a `SubViewportContainer` parent that has `stretch` enabled. Set `SubViewportContainer.stretch` to `false` to allow changing the size manually.");
 #endif // DEBUG_ENABLED
@@ -4385,8 +4385,8 @@ Transform2D SubViewport::get_screen_transform_internal(bool p_absolute_position)
 	Transform2D container_transform;
 	SubViewportContainer *c = Object::cast_to<SubViewportContainer>(get_parent());
 	if (c) {
-		if (c->is_stretch_enabled()) {
-			container_transform.scale(Vector2(c->get_stretch_shrink(), c->get_stretch_shrink()));
+		if (c->is_stretch_enabled() && c->get_stretch_shrink() != 1) {
+			container_transform.scale(c->get_size() / Vector2(get_size()));
 		}
 		container_transform = c->get_viewport()->get_screen_transform_internal(p_absolute_position) * c->get_global_transform_with_canvas() * container_transform;
 	} else {
@@ -4404,8 +4404,8 @@ Transform2D SubViewport::get_popup_base_transform() const {
 		return get_final_transform();
 	}
 	Transform2D container_transform;
-	if (c->is_stretch_enabled()) {
-		container_transform.scale(Vector2(c->get_stretch_shrink(), c->get_stretch_shrink()));
+	if (c->is_stretch_enabled() && c->get_stretch_shrink() != 1) {
+		container_transform.scale(c->get_size() / Vector2(get_size()));
 	}
 	return c->get_screen_transform() * container_transform * get_final_transform();
 }
@@ -4464,7 +4464,7 @@ void SubViewport::_bind_methods() {
 void SubViewport::_validate_property(PropertyInfo &p_property) const {
 	if (p_property.name == "size") {
 		SubViewportContainer *parent_svc = Object::cast_to<SubViewportContainer>(get_parent());
-		if (parent_svc && parent_svc->is_stretch_enabled()) {
+		if (parent_svc && parent_svc->is_stretch_enabled() && parent_svc->get_stretch_shrink() != 0) {
 			p_property.usage = PROPERTY_USAGE_DEFAULT | PROPERTY_USAGE_READ_ONLY;
 		} else {
 			p_property.usage = PROPERTY_USAGE_DEFAULT;