From be83a08c3b2fd624ef1b0deaa6c24bbc857dd9f9 Mon Sep 17 00:00:00 2001
From: Tom Poole <thomas.poole@roli.com>
Date: Fri, 1 Feb 2019 13:00:08 +0000
Subject: [PATCH] Added an assertion to check the OpenGL swap interval on MacOS

---
 modules/juce_core/containers/juce_AbstractFifo.h | 2 +-
 modules/juce_opengl/native/juce_OpenGL_osx.h     | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/modules/juce_core/containers/juce_AbstractFifo.h b/modules/juce_core/containers/juce_AbstractFifo.h
index e1aaedcb6f..ef001e6bb6 100644
--- a/modules/juce_core/containers/juce_AbstractFifo.h
+++ b/modules/juce_core/containers/juce_AbstractFifo.h
@@ -331,7 +331,7 @@ inline void AbstractFifo::ScopedReadWrite<AbstractFifo::ReadOrWrite::write>::fin
 {
     f.finishedWrite (num);
 }
-    
+
 template<>
 inline void AbstractFifo::ScopedReadWrite<AbstractFifo::ReadOrWrite::read>::prepare (AbstractFifo& f, int num) noexcept
 {
diff --git a/modules/juce_opengl/native/juce_OpenGL_osx.h b/modules/juce_opengl/native/juce_OpenGL_osx.h
index 651b4f88f1..ea209d8293 100644
--- a/modules/juce_opengl/native/juce_OpenGL_osx.h
+++ b/modules/juce_opengl/native/juce_OpenGL_osx.h
@@ -200,6 +200,10 @@ public:
 
     bool setSwapInterval (int numFramesPerSwap)
     {
+        // The macOS OpenGL programming guide says that numFramesPerSwap
+        // can only be 0 or 1.
+        jassert (isPositiveAndBelow (numFramesPerSwap, 2));
+
         minSwapTimeMs = (numFramesPerSwap * 1000) / 60;
 
         [renderContext setValues: (const GLint*) &numFramesPerSwap