From cf6a8e98ebb793c0eb886292d4ab4d390a9e7f0f Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Mon, 31 Aug 2020 09:47:30 +0300
Subject: [PATCH] Change spherical camera: now X is right, Y is forward, Z is
 up

---
 libs/geom/include/psemek/geom/camera.hpp | 6 ++++--
 libs/geom/source/camera.cpp              | 8 ++++++--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/libs/geom/include/psemek/geom/camera.hpp b/libs/geom/include/psemek/geom/camera.hpp
index 7969bcff..976e9443 100644
--- a/libs/geom/include/psemek/geom/camera.hpp
+++ b/libs/geom/include/psemek/geom/camera.hpp
@@ -65,8 +65,10 @@ namespace psemek::geom
 	struct spherical_camera
 		: perspective_camera
 	{
-		// assumes up is +Y
-		//
+		// assumes up is +Z
+		// azimuthal angle is in XY plane
+		// both angles zero gives X right, Y forward, and Z up
+
 		float azimuthal_angle;
 		float elevation_angle;
 		float distance;
diff --git a/libs/geom/source/camera.cpp b/libs/geom/source/camera.cpp
index 1bb8ef7b..9b54a9f3 100644
--- a/libs/geom/source/camera.cpp
+++ b/libs/geom/source/camera.cpp
@@ -4,6 +4,8 @@
 #include <psemek/geom/perspective.hpp>
 #include <psemek/geom/translation.hpp>
 #include <psemek/geom/rotation.hpp>
+#include <psemek/geom/permutation.hpp>
+#include <psemek/geom/scale.hpp>
 #include <psemek/geom/homogeneous.hpp>
 
 #include <cmath>
@@ -98,8 +100,10 @@ namespace psemek::geom
 	{
 		return
 			  translation<float, 3>({0.f, 0.f, -distance}).homogeneous_matrix()
-			* homogeneous(plane_rotation<float, 3>(1, 2, elevation_angle).matrix())
-			* homogeneous(plane_rotation<float, 3>(2, 0, azimuthal_angle).matrix())
+			* homogeneous(swap<float, 3>(1, 2).matrix())
+			* homogeneous(scale<float, 3>({1.f, -1.f, 1.f}).matrix())
+			* homogeneous(plane_rotation<float, 3>(2, 1, elevation_angle).matrix())
+			* homogeneous(plane_rotation<float, 3>(1, 0, azimuthal_angle).matrix())
 			* translation<float, 3>({ -target[0], -target[1], -target[2] }).homogeneous_matrix()
 			;
 	}