From 71b3cd829f80de4c2cd3972d8bfd5ee470a5d180 Mon Sep 17 00:00:00 2001
From: Gone2Daly <71726742+Gone2Daly@users.noreply.github.com>
Date: Sat, 22 Jul 2023 21:05:42 +0200
Subject: init_test

---
 game/addons/zylann.hterrain/hterrain_mesher.gd | 358 +++++++++++++++++++++++++
 1 file changed, 358 insertions(+)
 create mode 100644 game/addons/zylann.hterrain/hterrain_mesher.gd

(limited to 'game/addons/zylann.hterrain/hterrain_mesher.gd')

diff --git a/game/addons/zylann.hterrain/hterrain_mesher.gd b/game/addons/zylann.hterrain/hterrain_mesher.gd
new file mode 100644
index 0000000..0b371e1
--- /dev/null
+++ b/game/addons/zylann.hterrain/hterrain_mesher.gd
@@ -0,0 +1,358 @@
+@tool
+
+#const HT_Logger = preload("./util/logger.gd")
+const HTerrainData = preload("./hterrain_data.gd")
+
+const SEAM_LEFT = 1
+const SEAM_RIGHT = 2
+const SEAM_BOTTOM = 4
+const SEAM_TOP = 8
+const SEAM_CONFIG_COUNT = 16
+
+
+# [seams_mask][lod]
+var _mesh_cache := []
+var _chunk_size_x := 16
+var _chunk_size_y := 16
+
+
+func configure(chunk_size_x: int, chunk_size_y: int, lod_count: int):
+	assert(typeof(chunk_size_x) == TYPE_INT)
+	assert(typeof(chunk_size_y) == TYPE_INT)
+	assert(typeof(lod_count) == TYPE_INT)
+	
+	assert(chunk_size_x >= 2 or chunk_size_y >= 2)
+
+	_mesh_cache.resize(SEAM_CONFIG_COUNT)
+	
+	if chunk_size_x == _chunk_size_x \
+	and chunk_size_y == _chunk_size_y and lod_count == len(_mesh_cache):
+		return
+	
+	_chunk_size_x = chunk_size_x
+	_chunk_size_y = chunk_size_y
+
+	# TODO Will reduce the size of this cache, but need index buffer swap feature
+	for seams in SEAM_CONFIG_COUNT:
+		var slot := []
+		slot.resize(lod_count)
+		_mesh_cache[seams] = slot
+		
+		for lod in lod_count:
+			slot[lod] = make_flat_chunk(_chunk_size_x, _chunk_size_y, 1 << lod, seams)
+
+
+func get_chunk(lod: int, seams: int) -> Mesh:
+	return _mesh_cache[seams][lod] as Mesh
+
+
+static func make_flat_chunk(quad_count_x: int, quad_count_y: int, stride: int, seams: int) -> Mesh:
+	var positions = PackedVector3Array()
+	positions.resize((quad_count_x + 1) * (quad_count_y + 1))
+
+	var i = 0
+	for y in quad_count_y + 1:
+		for x in quad_count_x + 1:
+			positions[i] = Vector3(x * stride, 0, y * stride)
+			i += 1
+		
+	var indices := make_indices(quad_count_x, quad_count_y, seams)
+
+	var arrays := []
+	arrays.resize(Mesh.ARRAY_MAX);
+	arrays[Mesh.ARRAY_VERTEX] = positions
+	arrays[Mesh.ARRAY_INDEX] = indices
+
+	var mesh := ArrayMesh.new()
+	mesh.add_surface_from_arrays(Mesh.PRIMITIVE_TRIANGLES, arrays)
+
+	return mesh
+
+
+# size: chunk size in quads (there are N+1 vertices)
+# seams: Bitfield for which seams are present
+static func make_indices(chunk_size_x: int, chunk_size_y: int, seams: int) -> PackedInt32Array:
+	var output_indices := PackedInt32Array()
+
+	if seams != 0:
+		# LOD seams can't be made properly on uneven chunk sizes
+		assert(chunk_size_x % 2 == 0 and chunk_size_y % 2 == 0)
+
+	var reg_origin_x := 0
+	var reg_origin_y := 0
+	var reg_size_x := chunk_size_x
+	var reg_size_y := chunk_size_y
+	var reg_hstride := 1
+	
+	if seams & SEAM_LEFT:
+		reg_origin_x += 1;
+		reg_size_x -= 1;
+		reg_hstride += 1
+
+	if seams & SEAM_BOTTOM:
+		reg_origin_y += 1
+		reg_size_y -= 1
+
+	if seams & SEAM_RIGHT:
+		reg_size_x -= 1
+		reg_hstride += 1
+
+	if seams & SEAM_TOP:
+		reg_size_y -= 1
+
+	# Regular triangles
+	var ii := reg_origin_x + reg_origin_y * (chunk_size_x + 1)
+
+	for y in reg_size_y:
+		for x in reg_size_x:
+			var i00 := ii
+			var i10 := ii + 1
+			var i01 := ii + chunk_size_x + 1
+			var i11 := i01 + 1
+
+			# 01---11
+			#  |  /|
+			#  | / |
+			#  |/  |
+			# 00---10
+
+			# This flips the pattern to make the geometry orientation-free.
+			# Not sure if it helps in any way though
+			var flip = ((x + reg_origin_x) + (y + reg_origin_y) % 2) % 2 != 0
+
+			if flip:
+				output_indices.push_back( i00 )
+				output_indices.push_back( i10 )
+				output_indices.push_back( i01 )
+
+				output_indices.push_back( i10 )
+				output_indices.push_back( i11 )
+				output_indices.push_back( i01 )
+
+			else:
+				output_indices.push_back( i00 )
+				output_indices.push_back( i11 )
+				output_indices.push_back( i01 )
+
+				output_indices.push_back( i00 )
+				output_indices.push_back( i10 )
+				output_indices.push_back( i11 )
+
+			ii += 1
+		ii += reg_hstride
+
+	# Left seam
+	if seams & SEAM_LEFT:
+
+		#     4 . 5
+		#     |\  .
+		#     | \ .
+		#     |  \.
+		#  (2)|   3
+		#     |  /.
+		#     | / .
+		#     |/  .
+		#     0 . 1
+
+		var i := 0
+		var n := chunk_size_y / 2
+
+		for j in n:
+			var i0 := i
+			var i1 := i + 1
+			var i3 := i + chunk_size_x + 2
+			var i4 := i + 2 * (chunk_size_x + 1)
+			var i5 := i4 + 1
+
+			output_indices.push_back( i0 )
+			output_indices.push_back( i3 )
+			output_indices.push_back( i4 )
+
+			if j != 0 or (seams & SEAM_BOTTOM) == 0:
+				output_indices.push_back( i0 )
+				output_indices.push_back( i1 )
+				output_indices.push_back( i3 )
+
+			if j != n - 1 or (seams & SEAM_TOP) == 0:
+				output_indices.push_back( i3 )
+				output_indices.push_back( i5 )
+				output_indices.push_back( i4 )
+
+			i = i4
+
+	if seams & SEAM_RIGHT:
+
+		#     4 . 5
+		#     .  /|
+		#     . / |
+		#     ./  |
+		#     2   |(3)
+		#     .\  |
+		#     . \ |
+		#     .  \|
+		#     0 . 1
+
+		var i := chunk_size_x - 1
+		var n := chunk_size_y / 2
+
+		for j in n:
+
+			var i0 := i
+			var i1 := i + 1
+			var i2 := i + chunk_size_x + 1
+			var i4 := i + 2 * (chunk_size_x + 1)
+			var i5 := i4 + 1
+
+			output_indices.push_back( i1 )
+			output_indices.push_back( i5 )
+			output_indices.push_back( i2 )
+
+			if j != 0 or (seams & SEAM_BOTTOM) == 0:
+				output_indices.push_back( i0 )
+				output_indices.push_back( i1 )
+				output_indices.push_back( i2 )
+
+			if j != n - 1 or (seams & SEAM_TOP) == 0:
+				output_indices.push_back( i2 )
+				output_indices.push_back( i5 )
+				output_indices.push_back( i4 )
+
+			i = i4;
+
+	if seams & SEAM_BOTTOM:
+
+		#  3 . 4 . 5
+		#  .  / \  .
+		#  . /   \ .
+		#  ./     \.
+		#  0-------2
+		#     (1)
+
+		var i := 0;
+		var n := chunk_size_x / 2;
+		
+		for j in n:
+
+			var i0 := i
+			var i2 := i + 2
+			var i3 := i + chunk_size_x + 1
+			var i4 := i3 + 1
+			var i5 := i4 + 1
+
+			output_indices.push_back( i0 )
+			output_indices.push_back( i2 )
+			output_indices.push_back( i4 )
+
+			if j != 0 or (seams & SEAM_LEFT) == 0:
+				output_indices.push_back( i0 )
+				output_indices.push_back( i4 )
+				output_indices.push_back( i3 )
+
+			if j != n - 1 or (seams & SEAM_RIGHT) == 0:
+				output_indices.push_back( i2 )
+				output_indices.push_back( i5 )
+				output_indices.push_back( i4 )
+
+			i = i2
+
+	if seams & SEAM_TOP:
+
+		#     (4)
+		#  3-------5
+		#  .\     /.
+		#  . \   / .
+		#  .  \ /  .
+		#  0 . 1 . 2
+
+		var i := (chunk_size_y - 1) * (chunk_size_x + 1)
+		var n := chunk_size_x / 2
+
+		for j in n:
+
+			var i0 := i
+			var i1 := i + 1
+			var i2 := i + 2
+			var i3 := i + chunk_size_x + 1
+			var i5 := i3 + 2
+
+			output_indices.push_back( i3 )
+			output_indices.push_back( i1 )
+			output_indices.push_back( i5 )
+
+			if j != 0 or (seams & SEAM_LEFT) == 0:
+				output_indices.push_back( i0 )
+				output_indices.push_back( i1 )
+				output_indices.push_back( i3 )
+
+			if j != n - 1 or (seams & SEAM_RIGHT) == 0:
+				output_indices.push_back( i1 )
+				output_indices.push_back( i2 )
+				output_indices.push_back( i5 )
+
+			i = i2
+
+	return output_indices
+
+
+static func get_mesh_size(width: int, height: int) -> Dictionary:
+	return {
+		"vertices": width * height,
+		"triangles": (width - 1) * (height - 1) * 2
+	}
+
+
+# Makes a full mesh from a heightmap, without any LOD considerations.
+# Using this mesh for rendering is very expensive on large terrains.
+# Initially used as a workaround for Godot to use for navmesh generation.
+static func make_heightmap_mesh(heightmap: Image, stride: int, scale: Vector3, 
+	logger = null) -> Mesh:
+	
+	var size_x := heightmap.get_width() / stride
+	var size_z := heightmap.get_height() / stride
+
+	assert(size_x >= 2)
+	assert(size_z >= 2)
+	
+	var positions := PackedVector3Array()
+	positions.resize(size_x * size_z)
+	
+	var i := 0
+	
+	if heightmap.get_format() == Image.FORMAT_RH or heightmap.get_format() == Image.FORMAT_RF:
+		for mz in size_z:
+			for mx in size_x:
+				var x := mx * stride
+				var z := mz * stride
+				var y := heightmap.get_pixel(x, z).r
+				positions[i] = Vector3(x, y, z) * scale
+				i += 1
+
+	elif heightmap.get_format() == Image.FORMAT_RGB8:
+		for mz in size_z:
+			for mx in size_x:
+				var x := mx * stride
+				var z := mz * stride
+				var c := heightmap.get_pixel(x, z)
+				var y := HTerrainData.decode_height_from_rgb8_unorm(c)
+				positions[i] = Vector3(x, y, z) * scale
+				i += 1
+				
+	else:
+		logger.error("Unknown heightmap format!")
+		return null
+	
+	var indices := make_indices(size_x - 1, size_z - 1, 0)
+
+	var arrays := []
+	arrays.resize(Mesh.ARRAY_MAX);
+	arrays[Mesh.ARRAY_VERTEX] = positions
+	arrays[Mesh.ARRAY_INDEX] = indices
+	
+	if logger != null:
+		logger.debug(str("Generated mesh has ", len(positions),
+			" vertices and ", len(indices) / 3, " triangles"))
+
+	var mesh := ArrayMesh.new()
+	mesh.add_surface_from_arrays(Mesh.PRIMITIVE_TRIANGLES, arrays)
+	
+	return mesh
-- 
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