From f4701c7d3b69cdcf784282e385f3afcb83ae7010 Mon Sep 17 00:00:00 2001
From: Ryan Friedman <ryanfriedman5410+github@gmail.com>
Date: Sat, 27 Jan 2024 16:24:59 -0700
Subject: [PATCH] Fix regression with default value

* Infinite rate would crash, now it has special handling

Signed-off-by: Ryan Friedman <ryanfriedman5410+github@gmail.com>
---
 src/CameraZoomPlugin.cc | 43 +++++++++++++++++++++++------------------
 1 file changed, 24 insertions(+), 19 deletions(-)

diff --git a/src/CameraZoomPlugin.cc b/src/CameraZoomPlugin.cc
index 944a8d1..f2c2d29 100644
--- a/src/CameraZoomPlugin.cc
+++ b/src/CameraZoomPlugin.cc
@@ -440,36 +440,41 @@ void CameraZoomPlugin::PreUpdate(
     std::numeric_limits<double>::epsilon())
     return;
 
-  // This is the amount of time passed since the last update.
-  const auto dt = _info.dt;
-  // How many meters the focal length could change per update loop
-  const auto maxFocalLengthChange = this->impl->slewRate *
-    std::chrono::duration<double>(dt).count();
   const auto curFocalLength = cameraSdf->LensFocalLength();
 
   // This value should be static every iteration.
   const auto sensorWidth = CameraZoomPlugin::Impl::SensorWidth(
-      curFocalLength, oldHfov);
-
+    curFocalLength, oldHfov);
   const auto goalFocalLength = CameraZoomPlugin::Impl::FovToFocalLength(
-      sensorWidth, this->impl->goalHfov);
-  // How many meters the focal length should change this iteration
-  const auto deltaFL = std::min(maxFocalLengthChange,
-    std::abs(curFocalLength - goalFocalLength));
+    sensorWidth, this->impl->goalHfov);
 
-  // Update rendering camera with the latest focal length.
   double newFocalLength;
-  if (goalFocalLength > curFocalLength)
-  {
-    newFocalLength = curFocalLength + deltaFL;
-  }
-  else
-  {
-    newFocalLength = curFocalLength - deltaFL;
+  if (std::isfinite(this->impl->slewRate)) {
+    // This is the amount of time passed since the last update.
+    const auto dt = _info.dt;
+    // How many meters the focal length could change per update loop
+    const auto maxFocalLengthChange = this->impl->slewRate *
+      std::chrono::duration<double>(dt).count();
+
+    // How many meters the focal length should change this iteration
+    const auto deltaFL = std::min(maxFocalLengthChange,
+      std::abs(curFocalLength - goalFocalLength));
+
+    if (goalFocalLength > curFocalLength)
+    {
+      newFocalLength = curFocalLength + deltaFL;
+    }
+    else
+    {
+      newFocalLength = curFocalLength - deltaFL;
+    }
+  } else {
+    newFocalLength = goalFocalLength;
   }
 
   const auto newHfov = CameraZoomPlugin::Impl::FocalLengthToFov(
       sensorWidth, newFocalLength);
+  // Update rendering camera with the latest focal length.
   cameraSdf->SetHorizontalFov(newHfov);
   _ecm.SetChanged(cameraEntity, components::Camera::typeId,
     ComponentState::OneTimeChange);