From 7134bd0f1b1dfd54c41856c463e779484526c99a Mon Sep 17 00:00:00 2001
From: ed <eddavies95@gmail.com>
Date: Wed, 23 Jan 2019 10:43:28 +0000
Subject: [PATCH] VST:  Add juce_shouldDoubleScaleNativeGLWindow() method to
 ensure that OpenGL plug-ins running in hiDPI Cubase 10 on Windows are
 correctly scaled

---
 .../utility/juce_PluginUtilities.cpp                | 12 ++++++++++++
 modules/juce_opengl/native/juce_OpenGL_win32.h      | 13 +++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/modules/juce_audio_plugin_client/utility/juce_PluginUtilities.cpp b/modules/juce_audio_plugin_client/utility/juce_PluginUtilities.cpp
index 9b5c214f06..b9e97ee9d0 100644
--- a/modules/juce_audio_plugin_client/utility/juce_PluginUtilities.cpp
+++ b/modules/juce_audio_plugin_client/utility/juce_PluginUtilities.cpp
@@ -43,6 +43,18 @@ AudioProcessor::WrapperType PluginHostType::jucePlugInClientCurrentWrapperType =
  bool juce_isRunningInUnity()    { return PluginHostType::getPluginLoadedAs() == AudioProcessor::wrapperType_Unity; }
 #endif
 
+#if JUCE_MODULE_AVAILABLE_juce_opengl
+ bool juce_shouldDoubleScaleNativeGLWindow()
+ {
+     auto wrapperType = PluginHostType::getPluginLoadedAs();
+
+     if (wrapperType == AudioProcessor::wrapperType_VST || wrapperType == AudioProcessor::wrapperType_VST3)
+         return getHostType().type == PluginHostType::SteinbergCubase10;
+
+     return false;
+ }
+#endif
+
 #ifndef JUCE_VST3_CAN_REPLACE_VST2
  #define JUCE_VST3_CAN_REPLACE_VST2 1
 #endif
diff --git a/modules/juce_opengl/native/juce_OpenGL_win32.h b/modules/juce_opengl/native/juce_OpenGL_win32.h
index 03f6f9ef12..a0811b6a95 100644
--- a/modules/juce_opengl/native/juce_OpenGL_win32.h
+++ b/modules/juce_opengl/native/juce_OpenGL_win32.h
@@ -30,6 +30,12 @@ namespace juce
 extern ComponentPeer* createNonRepaintingEmbeddedWindowsPeer (Component&, void* parent);
 extern bool shouldScaleGLWindow (void* hwnd);
 
+#if JUCE_MODULE_AVAILABLE_juce_audio_plugin_client && (JucePlugin_Build_VST || JucePlugin_Build_VST3)
+ bool juce_shouldDoubleScaleNativeGLWindow();
+#else
+ bool juce_shouldDoubleScaleNativeGLWindow()  { return false; }
+#endif
+
 //==============================================================================
 class OpenGLContext::NativeContext
    #if JUCE_WIN_PER_MONITOR_DPI_AWARE
@@ -191,6 +197,9 @@ private:
             {
                 auto newScale = peer->getPlatformScaleFactor();
 
+                if (juce_shouldDoubleScaleNativeGLWindow())
+                    newScale *= newScale;
+
                 if (! approximatelyEqual (newScale, nativeScaleFactor))
                 {
                     nativeScaleFactor = newScale;
@@ -220,6 +229,10 @@ private:
            #if JUCE_WIN_PER_MONITOR_DPI_AWARE
             safeComponent = Component::SafePointer<Component> (&component);
             nativeScaleFactor = peer->getPlatformScaleFactor();
+
+            if (juce_shouldDoubleScaleNativeGLWindow())
+                nativeScaleFactor *= nativeScaleFactor;
+
             startTimer (50);
            #endif