quack/addons/cyclops_level_builder/math/math_geometry.gd

# MIT License
#
# Copyright (c) 2023 Mark McKay
# https://github.com/blackears/cyclopsLevelBuilder
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

@tool
#extends RefCounted
class_name MathGeometry
	

static func unit_cylinder(segs:int = 16, radius0:float = 1, radius1:float = 1, top_height:float = 1, bottom_height:float = -1, bottom_cap:bool = false, top_cap:bool = false)->GeometryMesh:
	var mesh:GeometryMesh = GeometryMesh.new()


	var vc0:Vector3 = Vector3(0, 0, -1)
	var vc1:Vector3 = Vector3(0, 0, 1)
	var uvc:Vector2 = Vector2(.5, .5)
	
	for s in range(segs):
		
		var sin0:float = sin(deg_to_rad(360 * s / segs))
		var cos0:float = cos(deg_to_rad(360 * s / segs))
		var sin1:float = sin(deg_to_rad(360 * (s + 1) / segs))
		var cos1:float = cos(deg_to_rad(360 * (s + 1) / segs))
		
		var v00:Vector3 = Vector3(sin0 * radius0, cos0 * radius0, bottom_height)
		var v10:Vector3 = Vector3(sin1 * radius0, cos1 * radius0, bottom_height)
		var v01:Vector3 = Vector3(sin0 * radius1, cos0 * radius1, top_height)
		var v11:Vector3 = Vector3(sin1 * radius1, cos1 * radius1, top_height)
		
		var tan0:Vector3 = Vector3(cos0, sin0, 0)
		var n00:Vector3 = (v01 - v00).cross(tan0)
		n00 = n00.normalized()
		var n01:Vector3 = n00
		var tan1:Vector3 = Vector3(cos1, sin1, 0)
		var n10:Vector3 = (v11 - v10).cross(tan1)
		n10 = n10.normalized()
		var n11 = n10
		
		var uv00:Vector2 = Vector2(s / segs, 0)
		var uv10:Vector2 = Vector2((s + 1) / segs, 0)
		var uv01:Vector2 = Vector2(s / segs, 1)
		var uv11:Vector2 = Vector2((s + 1) / segs, 1)
		
		if radius0 != 0:
			mesh.coords.append(v00)
			mesh.coords.append(v10)
			mesh.coords.append(v11)
			
			mesh.normals.append(n00)
			mesh.normals.append(n10)
			mesh.normals.append(n11)
		
			mesh.uvs.append(uv00)
			mesh.uvs.append(uv10)
			mesh.uvs.append(uv11)

		if radius1 != 0:
			mesh.coords.append(v00)
			mesh.coords.append(v11)
			mesh.coords.append(v01)
			
			mesh.normals.append(n00)
			mesh.normals.append(n11)
			mesh.normals.append(n01)
			
			mesh.uvs.append(uv00)
			mesh.uvs.append(uv11)
			mesh.uvs.append(uv01)
		
		if top_cap and radius1 != 0:
			mesh.coords.append(v01)
			mesh.coords.append(v11)
			mesh.coords.append(vc1)
			
			mesh.normals.append(Vector3(0, 0, 1))
			mesh.normals.append(Vector3(0, 0, 1))
			mesh.normals.append(Vector3(0, 0, 1))
			
			mesh.uvs.append(Vector2(sin0, cos0))
			mesh.uvs.append(Vector2(sin1, cos1))
			mesh.uvs.append(uvc)
		
		if bottom_cap and radius0 != 0:
			mesh.coords.append(v00)
			mesh.coords.append(v10)
			mesh.coords.append(vc0)
			
			mesh.normals.append(-Vector3(0, 0, 1))
			mesh.normals.append(-Vector3(0, 0, 1))
			mesh.normals.append(-Vector3(0, 0, 1))
			
			mesh.uvs.append(Vector2(sin0, cos0))
			mesh.uvs.append(Vector2(sin1, cos1))
			mesh.uvs.append(uvc)
			
		
	return mesh
		
static func unit_sphere(segs_lat:int = 6, segs_long:int = 8)->GeometryMesh:
	var mesh:GeometryMesh = GeometryMesh.new()

	for la in range(segs_lat):
		
		var z0:float = cos(deg_to_rad(180 * la / segs_lat))
		var z1:float = cos(deg_to_rad(180 * (la + 1) / segs_lat))
		var r0:float = sin(deg_to_rad(180 * la / segs_lat))
		var r1:float = sin(deg_to_rad(180 * (la + 1) / segs_lat))
		
		for lo in range(segs_long):
			var cx0:float = sin(deg_to_rad(360 * lo / segs_long))
			var cx1:float = sin(deg_to_rad(360 * (lo + 1) / segs_long))
			var cy0:float = cos(deg_to_rad(360 * lo / segs_long))
			var cy1:float = cos(deg_to_rad(360 * (lo + 1) / segs_long))
			
			var v00:Vector3 = Vector3(cx0 * r0, cy0 * r0, z0)
			var v10:Vector3 = Vector3(cx1 * r0, cy1 * r0, z0)
			var v01:Vector3 = Vector3(cx0 * r1, cy0 * r1, z1)
			var v11:Vector3 = Vector3(cx1 * r1, cy1 * r1, z1)
			
			if la != 0:
				mesh.coords.append(v00)
				mesh.coords.append(v11)
				mesh.coords.append(v10)
			
				mesh.normals.append(v00)
				mesh.normals.append(v10)
				mesh.normals.append(v10)
			
				mesh.uvs.append(Vector2(lo / segs_long, la / segs_lat))
				mesh.uvs.append(Vector2((lo + 1) / segs_long, la / segs_lat))
				mesh.uvs.append(Vector2((lo + 1) / segs_long, (la + 1) / segs_lat))
			
			if la != segs_lat - 1:
				mesh.coords.append(v00)
				mesh.coords.append(v01)
				mesh.coords.append(v11)
			
				mesh.normals.append(v00)
				mesh.normals.append(v01)
				mesh.normals.append(v11)
				
				mesh.uvs.append(Vector2(lo / segs_long, la / segs_lat))
				mesh.uvs.append(Vector2((lo + 1) / segs_long, (la + 1) / segs_lat))
				mesh.uvs.append(Vector2(lo / segs_long, (la + 1) / segs_lat))

	return mesh