90 lines
3.8 KiB
GDScript
90 lines
3.8 KiB
GDScript
extends Node3D
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# Exported node paths for references in the editor.
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@export var real_particles_path: NodePath # The real GPUParticles3D in the scene.
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@export var real_attractor_path: NodePath # The real attractor node.
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@export var target_collision_box_path: NodePath # a node for the particle target, assumed to be a 1x1x1 cube around its origin.
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@export var debug_label_path: NodePath # A Label node to show "Target Hit: true/false".
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# Variables to hold the real nodes.
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var real_particles: GPUParticles3D
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var real_attractor: Node3D
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var target_collision_box: Node3D
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var debug_label: Label3D
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# Cloned proxy nodes that will live in the offscreen SubViewport.
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var clone_particles: GPUParticles3D
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var clone_attractor: Node3D
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# The SubViewport (and its container) for offscreen rendering.
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var sub_viewport_container: SubViewportContainer
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var sub_viewport: SubViewport
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# Path to your special testing shader resource.
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var test_shader_path := "res://scenes/world_grab_demo/particle_test.gdshader"
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var test_shader: Shader
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var test_shader_material: ShaderMaterial
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func _ready():
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# Get the real nodes from the exported paths.
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real_particles = get_node(real_particles_path) as GPUParticles3D
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real_attractor = get_node(real_attractor_path) as Node3D
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target_collision_box = get_node(target_collision_box_path) as Node3D
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debug_label = get_node(debug_label_path) as Label3D
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# Create a SubViewportContainer and a SubViewport.
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sub_viewport_container = SubViewportContainer.new()
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add_child(sub_viewport_container)
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sub_viewport = SubViewport.new()
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sub_viewport_container.add_child(sub_viewport)
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# Set the SubViewport resolution to a very low value (2x2 pixels).
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sub_viewport.size = Vector2i(2, 2)
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sub_viewport.render_target_update_mode = SubViewport.UPDATE_ALWAYS
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sub_viewport.own_world_3d = true
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#sub_viewport.render_target_v_flip = false
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# Add a Camera3D to the SubViewport
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var camera = Camera3D.new()
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sub_viewport.add_child(camera)
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# Clone the particle system and attractor. Using duplicate() with default flags
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# (which duplicates recursively) so that the clones have similar structure.
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clone_particles = real_particles.duplicate() as GPUParticles3D
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clone_attractor = real_attractor.duplicate() as Node3D
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# Add the clones to the SubViewport so they render in its world.
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sub_viewport.add_child(clone_particles)
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sub_viewport.add_child(clone_attractor)
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# Load the testing shader and assign it to the clone particle system.
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test_shader = load(test_shader_path)
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test_shader_material = ShaderMaterial.new()
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test_shader_material.shader = test_shader
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# Create a copy of the draw_pass_1 mesh
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var mesh_copy = clone_particles.draw_pass_1.duplicate()
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clone_particles.draw_pass_1 = mesh_copy
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# Apply the shader material to the copied mesh
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clone_particles.draw_pass_1.surface_set_material(0, test_shader_material)
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func _process(_delta):
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# Synchronize the global transforms of the clones with the real objects.
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clone_particles.global_transform = real_particles.global_transform
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clone_attractor.global_transform = real_attractor.global_transform
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# update the shader parameter for the target bounds.
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test_shader_material.set_shader_parameter("bbox_min", target_collision_box.global_position)
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test_shader_material.set_shader_parameter("bbox_max", target_collision_box.global_position + Vector3(1, 1, 1))
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# Get the rendered image from the SubViewport.
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var viewport_tex := sub_viewport.get_texture()
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if viewport_tex:
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var img: Image = viewport_tex.get_image()
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if img:
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# Check only the first pixel in the 2x2 render output.
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var col: Color = img.get_pixel(0, 0)
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# Our testing shader outputs red (1,0,0) for particles inside the box.
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var hit := col.r > 0.9 and col.g < 0.1 and col.b < 0.1
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# Update the debug label to show whether the target is hit.
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debug_label.text = "Target Hit: " + ("Yes" if hit else "No")
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