extends Node
## Autoload — pre-warms custom shaders on startup by rendering each
## ShaderMaterial once in a hidden 64×64 viewport.
##
## StandardMaterial3D is covered by ubershaders (already enabled).
## This catches the custom .gdshader materials that ubershaders miss.

# Paths to all ShaderMaterial .tres files with custom shaders
const MATERIAL_PATHS: Array[String] = [
	"res://core/daynight/environment_dust_material.tres",
	"res://core/daynight/environment_shadows.tres",
	"res://core/daynight/godrays.tres",
	"res://core/daynight/weather_overlay.tres",
	"res://core/daynight/weather_plain_shader.tres",
	"res://core/biome_generator/wires.tres",
	"res://tgcc/chunk/prop/grass/grass_chunk.tres",
	"res://tgcc/chunk/prop/grass/grass_chunk_weeds.tres",
	"res://tgcc/chunk/prop/grass/grass_chunk_weeds2.tres",
	"res://tgcc/chunk/prop/grass/grass_bank.tres",
	"res://tgcc/chunk/prop/tree/leaves_tree1.tres",
	"res://tgcc/chunk/prop/tree/leaves_tree_small.tres",
	"res://tgcc/chunk/prop/tree/trunk.tres",
	"res://tgcc/chunk/prop/flower/flower.tres",
	"res://tgcc/chunk/prop/flower/bush.tres",
	"res://tgcc/chunk/prop/house/house_emissiv.tres",
	"res://tgcc/chunk/prop/tenda noren/tenda.tres",
	"res://tgcc/chunk/prop/Tori/Tori.tres",
	"res://tgcc/chunk/prop/zen garden/zengardenCircle.tres",
	"res://tgcc/chunk/prop/zen garden/zengarden.tres",
]


func _ready() -> void:
	await get_tree().process_frame
	warmup()


func warmup() -> void:
	var valid: Array[ShaderMaterial] = []
	for path in MATERIAL_PATHS:
		if not ResourceLoader.exists(path):
			continue
		var mat := load(path)
		if mat is ShaderMaterial:
			valid.append(mat)

	if valid.is_empty():
		return

	print("[ShaderWarmup] Pre-warming %d custom ShaderMaterials..." % valid.size())

	# Tiny hidden viewport — 64×64 is cheap to render
	var vp := SubViewport.new()
	vp.size = Vector2i(64, 64)
	vp.render_target_update_mode = SubViewport.UPDATE_ALWAYS
	add_child(vp)

	var cam := Camera3D.new()
	cam.current = true
	cam.environment = null
	vp.add_child(cam)

	var quad := MeshInstance3D.new()
	quad.mesh = QuadMesh.new()
	quad.mesh.size = Vector2(1, 1)
	quad.position = Vector3(0, 0, -2)
	cam.add_child(quad)

	for mat in valid:
		quad.material_override = mat
		await get_tree().process_frame  # one frame renders the quad with this material

	vp.queue_free()
	print("[ShaderWarmup] Done.")