| 1 | //
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| 2 | // Cforall Version 1.0.0 Copyright (C) 2021 University of Waterloo
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| 3 | //
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| 4 | // The contents of this file are covered under the licence agreement in the
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| 5 | // file "LICENCE" distributed with Cforall.
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| 6 | //
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| 7 | // io/types.hfa --
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| 8 | //
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| 9 | // Author : Dimitry Kobets
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| 10 | // Created On :
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| 11 | // Last Modified By :
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| 12 | // Last Modified On :
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| 13 | // Update Count :
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| 14 | //
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| 15 |
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| 16 | #pragma once
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| 17 |
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| 18 | #include <math.hfa>
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| 19 |
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| 20 | forall(T)
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| 21 | trait fromint {
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| 22 | void ?{}(T&, int);
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| 23 | };
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| 24 | forall(T)
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| 25 | trait zeroinit {
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| 26 | void ?{}(T&, zero_t);
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| 27 | };
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| 28 | forall(T)
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| 29 | trait zero_assign {
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| 30 | T ?=?(T&, zero_t);
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| 31 | };
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| 32 | forall(T)
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| 33 | trait subtract {
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| 34 | T ?-?(T, T);
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| 35 | };
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| 36 | forall(T)
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| 37 | trait negate {
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| 38 | T -?(T);
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| 39 | };
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| 40 | forall(T)
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| 41 | trait add {
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| 42 | T ?+?(T, T);
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| 43 | };
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| 44 | forall(T)
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| 45 | trait multiply {
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| 46 | T ?*?(T, T);
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| 47 | };
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| 48 | forall(T)
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| 49 | trait divide {
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| 50 | T ?/?(T, T);
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| 51 | };
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| 52 | forall(T)
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| 53 | trait lessthan {
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| 54 | int ?<?(T, T);
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| 55 | };
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| 56 | forall(T)
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| 57 | trait equality {
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| 58 | int ?==?(T, T);
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| 59 | };
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| 60 | forall(T)
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| 61 | trait sqrt {
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| 62 | T sqrt(T);
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| 63 | };
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| 64 |
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| 65 | static inline {
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| 66 | // int
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| 67 | int ?=?(int& n, zero_t) { return n = 0.f; }
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| 68 | // unsigned int
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| 69 | int ?=?(unsigned int& n, zero_t) { return n = 0.f; }
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| 70 | /* float */
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| 71 | void ?{}(float& a, int b) { a = b; }
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| 72 | float ?=?(float& n, zero_t) { return n = 0.f; }
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| 73 | /* double */
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| 74 | void ?{}(double& a, int b) { a = b; }
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| 75 | double ?=?(double& n, zero_t) { return n = 0L; }
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| 76 | // long double
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| 77 | void ?{}(long double& a, int b) { a = b; }
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| 78 | long double ?=?(long double& n, zero_t) { return n = 0L; }
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| 79 | }
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| 80 |
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| 81 | trait dottable(V, T) {
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| 82 | T dot(V, V);
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| 83 | };
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| 84 |
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| 85 | static inline {
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| 86 |
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| 87 | forall(T | sqrt(T), V | dottable(V, T))
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| 88 | T length(V v) {
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| 89 | return sqrt(dot(v, v));
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| 90 | }
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| 91 |
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| 92 | forall(T, V | dottable(V, T))
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| 93 | T length_squared(V v) {
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| 94 | return dot(v, v);
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| 95 | }
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| 96 |
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| 97 | forall(T, V | { T length(V); } | subtract(V))
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| 98 | T distance(V v1, V v2) {
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| 99 | return length(v1 - v2);
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| 100 | }
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| 101 |
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| 102 | forall(T, V | { T length(V); V ?/?(V, T); })
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| 103 | V normalize(V v) {
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| 104 | return v / length(v);
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| 105 | }
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| 106 |
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| 107 | // Project vector u onto vector v
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| 108 | forall(T, V | dottable(V, T) | { V normalize(V); V ?*?(V, T); })
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| 109 | V project(V u, V v) {
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| 110 | V v_norm = normalize(v);
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| 111 | return v_norm * dot(u, v_norm);
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| 112 | }
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| 113 |
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| 114 | // Reflect incident vector v with respect to surface with normal n
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| 115 | forall(T | fromint(T), V | { V project(V, V); V ?*?(T, V); V ?-?(V,V); })
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| 116 | V reflect(V v, V n) {
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| 117 | return v - (T){2} * project(v, n);
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| 118 | }
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| 119 |
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| 120 | // Refract incident vector v with respect to surface with normal n
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| 121 | // eta is the ratio of indices of refraction between starting material and
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| 122 | // entering material (i.e., from air to water, eta = 1/1.33)
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| 123 | // v and n must already be normalized
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| 124 | forall(T | fromint(T) | subtract(T) | multiply(T) | add(T) | lessthan(T) | sqrt(T),
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| 125 | V | dottable(V, T) | { V ?*?(T, V); V ?-?(V,V); void ?{}(V&, zero_t); })
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| 126 | V refract(V v, V n, T eta) {
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| 127 | T dotValue = dot(n, v);
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| 128 | T k = (T){1} - eta * eta * ((T){1} - dotValue * dotValue);
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| 129 | if (k < (T){0}) {
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| 130 | return 0;
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| 131 | }
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| 132 | return eta * v - (eta * dotValue + sqrt(k)) * n;
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| 133 | }
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| 134 |
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| 135 | // Given a perturbed normal and a geometric normal,
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| 136 | // flip the perturbed normal if the geometric normal is pointing away
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| 137 | // from the observer.
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| 138 | // n is the perturbed vector that we want to align
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| 139 | // i is the incident vector
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| 140 | // ng is the geometric normal of the surface
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| 141 | forall(T | lessthan(T) | zeroinit(T), V | dottable(V, T) | negate(V))
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| 142 | V faceforward(V n, V i, V ng) {
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| 143 | return dot(ng, i) < (T){0} ? n : -n;
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| 144 | }
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| 145 |
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| 146 | } // inline
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