From d8235f126628a1f0487b7b66a0812b93b916685d Mon Sep 17 00:00:00 2001
From: Madeline Busig <madeline.busig@outlook.com>
Date: Tue, 6 May 2025 22:24:12 -0700
Subject: [PATCH] Add create_rotation helper function

Rotation matrix construction not implemented in MTL yet
---
 include/fractal.hpp |  4 ++++
 src/fractal.cpp     | 16 +++++++++++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/include/fractal.hpp b/include/fractal.hpp
index 601b5e6..649809a 100644
--- a/include/fractal.hpp
+++ b/include/fractal.hpp
@@ -6,6 +6,10 @@
 #include <mtl/fixed.hpp>
 #include <mtl/vec.hpp>
 #include <mtl/mat.hpp>
+#include <mtl/exception.hpp>
+
+// TODO: Implement in MTL and create version that doesn't need cos of the angle
+mtl::mat<2, 2> create_rotation(mtl::fixed angle_cos);
 
 namespace fractal {
 
diff --git a/src/fractal.cpp b/src/fractal.cpp
index f314216..6f09809 100644
--- a/src/fractal.cpp
+++ b/src/fractal.cpp
@@ -2,9 +2,23 @@
 
 #include <mtl/exception.hpp>
 #include <mtl/log.hpp>
+#include <cmath>
 
 using mtl::endl;
-namespace log = mtl::log;
+namespace mlog = mtl::log;
+
+using mtl::fixed;
+using mtl::vec2;
+using mtl::mat;
+
+mtl::mat<2, 2> create_rotation(mtl::fixed angle_cos) {
+	fixed angle_sin = fixed(1) - angle_cos * angle_cos;
+
+	return mat<2, 2>({
+			{ angle_cos, -angle_sin },
+			{ angle_sin,  angle_cos }
+			});
+}
 
 namespace fractal {