Glow Boarder Effect

The Glow Boarder Effect Renderer contains shader setup with a glowing boarder effect for selected objects. The user can turn the glow border effect on and off and select glow color for individual objects.

How does it work?

The GlowBorderEffectRender scene is included in the scene tree and objects that should recevie the glow border effect must include the GDScript glow_border_effect_object.gd on Spatial node that is a parent to any VisualInstances the object may consists of. In the demo project the GlowingObject is a Spatial node with a MeshInstance as the child.

Updating camera

In the GlowBorderEffectDemo a GDScript is used on the scene Camera to ensure that the internal cameras of the GlowBorderEffectRender is updated when the camera position is update.

# Called when the node enters the scene tree for the first time.
func _ready():
	# Update the internal cameras in the glow border effect renderer
	_glow_border_effect_renderer.set_camera_parameters(self)
	
	# Turn on notification for camera transform changes
	set_notify_transform(true)


func _notification(what):
	# Update the camera transform each time the camera transform change
	if what == NOTIFICATION_TRANSFORM_CHANGED:
		_glow_border_effect_renderer.camera_transform_changed(self)

Resizeing

If the parent viewport change size the internal viewports of the GlowBorderEffectRenderer need to be updated as well. In the example below the resize function

# Called when the node enters the scene tree for the first time.
func _ready():
	get_viewport().connect("size_changed", self, "resized")


# Callback for handling change in window size
func resized():
	$GlowBorderEffectRenderer.resize()

Behind the scene

Inside the GlowBorderEffectRender a number of ViewportContainers and Viewports are used with shaders that first in the prepass render a shadow instance of each of the objects with glow border effect enabled. The prepass is so filtered with a blure filter to produce the glowing effect. Finaly the scene is rendered and a shader that do:

scene_color + (blure - prepass)

The different steps are illustrated in the screendump below from the glow_border_efffect_explained scene.

Screenshots