defaults.ini
===========
include_header = /path/to/defaults.inc


defaults.inc
===========
#include "default_01_00_00.inc"


defaults_01_00_00.inc
===========
// This work is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License.
// To view a copy of this license, visit https://creativecommons.org/licenses/by-sa/3.0/ or send a
// letter to Creative Commons, 444 Castro Street, Suite 900, Mountain View, California, 94041, USA.

// Persistence of Vision Raytracer version 3.8 include file
// File: defaults.inc
// Desc: common identifiers to be referenced by other include files
// Date: 2025-??-??
// Updated: 2025-??-??
// Auth: Richard Callwood III & William H. Walker IV

// avoid version 3.8 errors
#version version
global_settings {assumed_gamma 1.0}

#ifndef (Defaults_Inc_Temp)
	//=============================================
	// VERSION handling
	//=============================================
	#macro Version (_Installed, _Set, _Intended)
		// do versioning stuff here
		// maybe need multiple version handling macros
		// _Set would be what the current #version is set to
	#end

	//=============================================
	#declare Defaults_Inc_Temp = version;
	#version 3.8;
	
	#ifdef (View_POV_Include_Stack)
		#debug "including defaults.inc\n"
	#end


	
	//=============================================
	// default GAMMA
	//=============================================
	#macro Set_Default_Gamma (_Gamma)
		#declare Default_Gamma = _Gamma;
		global_settings {assumed_gamma Default_Gamma}
	#end

	#ifndef (Default_Gamma) 
		Set_Default_Gamma (1.0);
		// https://wiki.povray.org/content/User:Clipka/Gamma
	#end
	//=============================================

	//=============================================
	// default FINISH
	//=============================================

	#macro Set_Default_Ambient (_Ambient)
		#declare Default_Ambient = rgb _Ambient;
	#end

	#macro Set_Default_Diffuse (_Diffuse)
		#declare Default_Diffuse = _Diffuse;
	#end

	#ifndef (Default_Ambient) 
		Set_Default_Ambient (0.0); 
	#end
	
	#ifndef (Default_Diffuse) 
		Set_Default_Diffuse (0.6); 
	#end

	#macro Set_Default_Finish (_Ambient, _Diffuse)
		#default {
			finish { 
				ambient _Ambient
				diffuse _Diffuse
			}
		}
	#end

	Set_Default_Finish (Default_Ambient, Default_Diffuse)

	//=============================================


	// for coincident surfaces:
	#ifndef (Defaults_Epsilon) 
		#declare Defaults_Epsilon = 1e-6; 
		// provide a source-code file and line number reference for this magic number
	#end
	

	//=============================================
	// default FONT
	//=============================================
	#if (file_exists ("Lucida_sans_unicode.ttf"))
		#declare Default_Font = "Lucida_sans_unicode.ttf"
	#else
		// internal 1
		#declare Default_Font = "timrom.ttf"
	#end
	//=============================================

	//=============================================
	// default mathematical CONSTANTS
	//=============================================
	
	// tau
	// https://news.povray.org/5b9b39cb%241%40news.povray.org
	#if (version >= 3.8)
        	// tau is already defined as a keyword
   	#else
		#declare tau = 2*pi;
    	#end

	#declare e = exp (1);
	#declare NAN = val ("NAN");
	#declare INF = val ("INF");
	#declare Phi = (1 + sqrt(5))/2;
	#declare phi = Phi - 1;
	// Golden Angle 
	#declare ga = 180 * (3 - sqrt(5));

	//=============================================	

	//=============================================
	// default physical CONSTANTS
	//=============================================
	
	// Earth gravity
	#declare G = 9.80665; // m/s^2

	//=============================================	

	//=============================================
	// default mathematical FUNCTIONS
	//=============================================

	#declare even = function (x) {select (mod (x, 2), 0, 1, 0)}
	#declare odd  = function (x) {select (mod (x, 2), 1, 0, 1)}
	#declare sgn  = function (x) {select (x, -1, 0, 1)}

	// Pow (_base, _exponent) for handling pow (0, 0)
	https://news.povray.org/povray.advanced-users/thread/%3C5b819469%40news.povray.org%3E/
	#macro Pow (_base, _exp, _mode)
		#if (_base != 0 & _exp != 0)
			pow (_base, _exp)
		#else
			#switch (_mode)
			#case (0)
				0
			#break
			#case (1)
				1
			#break
			#case (2)
				#error "Result for pow (0, 0) is indeterminate."
			#break
			#else
				#error "Invalid Pow () mode."
			#end
		#end
	#end

	#declare fmod = function (Value, Modulo) {select (Value, 1 - mod (abs (Value),
	Modulo), mod (abs (Value), Modulo))}  // this gives a mod function that remains
	consistant across the origin

	// trigonometric functions
	#declare csc = function (N) {1/sin(N)}
	#declare sec = function (N) {1/cos(N)}
	#declare cot = function (N) {1/tan(N)}

	// inverse trigonometric functions
	#declare acsc = function (N) {asin(1 / N)}
	#declare asec = function (N) {acos(1 / N)}
	#declare acot = function (N) {atan(1 / N)}

	// full set of value-tolerant trig functions (macros)

	//=============================================

	//=============================================
	// default SCENE elements
	//=============================================

	#macro Default_Scene ()
		sky_sphere {rgb <1.0, 1.0, 1.0>}
		light_source {<0.0, 10.0, -10.0> rgb 1.0}
	#end

	// Axes
	// Plane

	//=============================================

	#version Defaults_Inc_Temp;
#end