@tool
extends MeshInstance2D

@export var pixels_per_subdivision: float = 10.0  # 每个细分包含的像素数
@export_tool_button("重置 mesh") var reset_mesh = create_rope_mesh


func create_rope_mesh():
	var texture_size = texture.get_size()
	var texture_width = texture_size.x
	var texture_height = texture_size.y
	var aspect_ratio = texture_width / texture_height
	# 整体缩放系数
	var scale_factor := float(texture_height)

	# 根据纹理宽度和期望的细分密度计算水平细分数
	var horizontal_subdivisions = max(int(texture_width / pixels_per_subdivision), 1000)
	# 垂直细分较少，因为麻绳主要是水平变形
	var vertical_subdivisions = max(int(texture_height / pixels_per_subdivision), 10)

	# 计算实际显示尺寸（保持纹理比例）
	var display_width = aspect_ratio * scale_factor
	var display_height = 1.0 * scale_factor

	var array_mesh = ArrayMesh.new()
	var arrays = []
	arrays.resize(Mesh.ARRAY_MAX)

	var vertices = PackedVector2Array()
	var uvs = PackedVector2Array()
	var indices = PackedInt32Array()

	# 创建网格顶点
	for y in range(vertical_subdivisions + 1):
		for x in range(horizontal_subdivisions + 1):
			var u = float(x) / float(horizontal_subdivisions)
			var v = float(y) / float(vertical_subdivisions)

			# 顶点位置（居中）
			var vertex_x = (u - 0.5) * display_width
			var vertex_y = (v - 0.5) * display_height

			vertices.append(Vector2(vertex_x, vertex_y))
			uvs.append(Vector2(u, v))

	# 创建三角形索引
	for y in range(vertical_subdivisions):
		for x in range(horizontal_subdivisions):
			var top_left = y * (horizontal_subdivisions + 1) + x
			var top_right = top_left + 1
			var bottom_left = (y + 1) * (horizontal_subdivisions + 1) + x
			var bottom_right = bottom_left + 1

			# 第一个三角形
			indices.append(top_left)
			indices.append(bottom_left)
			indices.append(top_right)

			# 第二个三角形
			indices.append(top_right)
			indices.append(bottom_left)
			indices.append(bottom_right)

	arrays[Mesh.ARRAY_VERTEX] = vertices
	arrays[Mesh.ARRAY_TEX_UV] = uvs
	arrays[Mesh.ARRAY_INDEX] = indices

	array_mesh.add_surface_from_arrays(Mesh.PRIMITIVE_TRIANGLES, arrays)
	mesh = array_mesh

	print(
		(
			"创建网格: %dx%d 细分, 纹理尺寸: %dx%d, 显示尺寸: %.2fx%.2f"
			% [
				horizontal_subdivisions,
				vertical_subdivisions,
				texture_width,
				texture_height,
				display_width,
				display_height
			]
		)
	)


# 运行时调整隆起参数的便捷方法
func set_bulge(pos: float):
	if material and material is ShaderMaterial:
		material.set_shader_parameter("bulge_position", pos)
		# material.set_shader_parameter("bulge_height", height)
		# material.set_shader_parameter("bulge_width", width)