From 909a7c8ae17e2a816bc92fdaec227c2672bddab3 Mon Sep 17 00:00:00 2001
From: cinnaboot <cinnaboot@protonmail.com>
Date: Mon, 13 Mar 2023 11:26:40 -0400
Subject: [PATCH] fix the source of all the 'nan' position errors

We were getting slight floating point errors from glm::dot() before
sending the result to acos(). Anything out of the range of -1 >= x <= 1
is undefined
---
 src/game.cpp   |  4 +++-
 src/main.cpp   |  7 ++++---
 src/orbits.cpp | 11 +++++++++--
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/src/game.cpp b/src/game.cpp
index 5c469b0..c82be5d 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -247,9 +247,11 @@ applyManeuver(GameOrbit* orbit, ManeuverNode* maneuver)
 
 	// FIXME: debugging code
 
+#if 0
 	GameOrbit old_orbit = *orbit;
 	if (!old_orbit.in_use) exit(1); // don't optimize out
-	
+#endif
+
 	// FIXME: debugging code
 
 	dvec3 pos = orbitGetPositionVector(r, theta);
diff --git a/src/main.cpp b/src/main.cpp
index 2dab369..ea3117a 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -267,11 +267,12 @@ loadRandomOrbits(GameState* gs,
 		double semi_major_axis = fmod(fabs((double) rand()), semi_major_axis_range) + min_semi_major_axis;
 		double eccentricity = max_eccentricity * rand() / RAND_MAX;
 		double nu = max_nu * rand() / RAND_MAX;
-		//double omega = 2 * M_PI * rand() / RAND_MAX;
-		double omega = 0;
+		double omega = 2 * M_PI * rand() / RAND_MAX;
+		double iota = 2 * M_PI * rand() / RAND_MAX;
+		double ohm = 2 * M_PI * rand() / RAND_MAX;
 
 		GameOrbit* gorb = loadOrbit(gs, rs, body,
-				orbitInit(semi_major_axis, eccentricity, 0, 0, omega, nu),
+				orbitInit(semi_major_axis, eccentricity, iota, ohm, omega, nu),
 				rg, "???");
 
 		addManeuver(gs, gorb, ImpulseType::CIRCULARIZE_LOWERING);
diff --git a/src/orbits.cpp b/src/orbits.cpp
index ad5a6f2..2b1e981 100644
--- a/src/orbits.cpp
+++ b/src/orbits.cpp
@@ -111,12 +111,19 @@ orbitGetElementsFromStateVectors(glm::dvec3 r, glm::dvec3 v, double mu)
 		if (ecc_v.z < 0) el.omega = 2 * M_PI - el.omega; // quadrant check
 	}
 
-	// FIXME: I think this is the smoking gun for the source of all the nan
-	// 	position and velocity components
 	if (el.e == 0) {
 		el.nu = 0;
 	} else {
 		double cos_theta = glm::dot(r, ecc_v) / (el.e * r_mag);
+
+		// NOTE: clamp to vaild range for acos function
+		// 	we were getting slight floating point errors out of the glm::dot()
+		// 	function above
+		if (cos_theta > 1.0)
+			cos_theta = 1.0;
+		else if (cos_theta < - 1.0)
+			cos_theta = -1.0;
+
 		el.nu= acos(cos_theta);
 	}