generated from krampus/template-godot4
105 lines
3.4 KiB
GDScript
105 lines
3.4 KiB
GDScript
class_name GunkBody extends StaticBody3D
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## StaticBody3D with an associated "gunkable" mesh.
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const CONTINUITY_LIMIT := 64
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const BUFFER_LIMIT := 3
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const FACE_EPSILON := 0.4
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const MASK_COLOR := Color.RED
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@export var mask_dim := 1024
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var meshtool := MeshDataTool.new()
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var _polyline_buffer: Array[Vector2] = []
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var _continuous := false
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var _painted_this_frame := false
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@onready var mesh_instance: MeshInstance3D = $MeshInstance3D
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@onready var mesh: ArrayMesh = mesh_instance.mesh
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@onready var gunk_mat: ShaderMaterial = mesh_instance.get_surface_override_material(0).next_pass
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@onready var mask_viewport: SubViewport = %MaskViewport
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@onready var mask_control: DrawController = %MaskControl
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func _ready() -> void:
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mask_viewport.size = Vector2(mask_dim, mask_dim)
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gunk_mat.set_shader_parameter("gunk_mask", mask_viewport.get_texture())
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meshtool.create_from_surface(mesh, 0)
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## Transform cartesian coordinates to barycentric wrt the given triangle
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func _barycentric(p: Vector3, a: Vector3, b: Vector3, c: Vector3) -> Vector3:
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var v0 := b - a
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var v1 := c - a
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var v2 := p - a
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var d00 := v0.dot(v0)
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var d01 := v0.dot(v1)
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var d11 := v1.dot(v1)
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var d20 := v2.dot(v0)
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var d21 := v2.dot(v1)
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var denom := d00 * d11 - d01 * d01
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var v := (d11 * d20 - d01 * d21) / denom
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var w := (d00 * d21 - d01 * d20) / denom
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var u := 1.0 - v - w
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return Vector3(u, v, w)
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func _is_in_triangle(point: Vector3, v1: Vector3, v2: Vector3, v3: Vector3) -> bool:
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var bc := _barycentric(point, v1, v2, v3)
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return (bc.x > 0 and bc.x < 1) and (bc.y > 0 and bc.y < 1) and (bc.z > 0 and bc.z < 1)
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func _get_face(point: Vector3, normal: Vector3) -> int:
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for i in range(meshtool.get_face_count()):
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if meshtool.get_face_normal(i).distance_squared_to(normal) > FACE_EPSILON:
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continue
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# Normals match, so check if the point is on this face
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var v1 := meshtool.get_vertex(meshtool.get_face_vertex(i, 0))
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var v2 := meshtool.get_vertex(meshtool.get_face_vertex(i, 1))
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var v3 := meshtool.get_vertex(meshtool.get_face_vertex(i, 2))
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if _is_in_triangle(point, v1, v2, v3):
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return i
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return -1
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func _get_uv(point: Vector3, normal: Vector3) -> Vector2:
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var face := _get_face(point, normal)
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if face < 0:
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return Vector2.INF
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var fv0 := meshtool.get_face_vertex(face, 0)
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var fv1 := meshtool.get_face_vertex(face, 1)
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var fv2 := meshtool.get_face_vertex(face, 2)
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var v1 := meshtool.get_vertex(fv0)
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var v2 := meshtool.get_vertex(fv1)
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var v3 := meshtool.get_vertex(fv2)
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var bc := _barycentric(point, v1, v2, v3) # TODO memoize
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var uv1 := meshtool.get_vertex_uv(fv0)
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var uv2 := meshtool.get_vertex_uv(fv1)
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var uv3 := meshtool.get_vertex_uv(fv2)
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return (uv1 * bc.x) + (uv2 * bc.y) + (uv3 * bc.z)
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func paint_continuous(point: Vector3, normal: Vector3, width: float) -> void:
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var px := _get_uv(point * global_transform, normal * global_basis) * mask_control.size
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if _polyline_buffer and px.distance_to(_polyline_buffer[0]) <= CONTINUITY_LIMIT:
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_polyline_buffer.push_front(px)
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if len(_polyline_buffer) > BUFFER_LIMIT:
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_polyline_buffer.pop_back()
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var polyline := PackedVector2Array(_polyline_buffer)
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mask_control.queue_draw(
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func() -> void: mask_control.draw_polyline(polyline, MASK_COLOR, width * 2, true)
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)
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else:
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_polyline_buffer = [px]
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mask_control.queue_draw(
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func() -> void: mask_control.draw_circle(px, width, MASK_COLOR, true, -1, true)
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)
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_painted_this_frame = true
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func _process(_delta: float) -> void:
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if not _painted_this_frame:
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_polyline_buffer = []
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_painted_this_frame = false
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