From 4ca856e7117cf6e4bf87301fbb59156ddec5b56e Mon Sep 17 00:00:00 2001
From: Nicolas Mellado <nmellado0@gmail.com>
Date: Fri, 26 Mar 2021 10:41:36 +0100
Subject: [PATCH] add constexpr sqrt implementation
---
src/libRender/RadiumNBR/SphereSampler.hpp | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/src/libRender/RadiumNBR/SphereSampler.hpp b/src/libRender/RadiumNBR/SphereSampler.hpp
index aa07fa6..253caff 100644
--- a/src/libRender/RadiumNBR/SphereSampler.hpp
+++ b/src/libRender/RadiumNBR/SphereSampler.hpp
@@ -9,12 +9,24 @@
#include <random>
namespace RadiumNBR {
+
+Scalar constexpr sqrtNewtonRaphsonhelper(Scalar x, Scalar curr, Scalar prev)
+{
+ return curr == prev
+ ? curr
+ : sqrtNewtonRaphsonhelper(x, 0.5_ra * (curr + x / curr), curr);
+}
+Scalar constexpr ct_sqrt(Scalar x){
+ return sqrtNewtonRaphsonhelper( x, x, 0_ra );
+}
+
/// Implements the 2D fibonacci sequence
/// (i, N) => [i / phi, i / N]
/// where phi = (1 + sqrt(5)) / 2
class NodeBasedRenderer_LIBRARY_API FibonacciSequence
{
- static constexpr Scalar phi = ( 1_ra + std::sqrt( 5_ra ) ) / 2_ra;
+
+ static constexpr Scalar phi = ( 1_ra + ct_sqrt( 5_ra ) ) / 2_ra;
int n;
public:
--
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