OpenGL: Avoid enabling GL_TEXTURE_2D in core profile contexts

examples/GUI/OpenGLDemo.h

@@ -841,7 +841,9 @@ public:
         glEnable (GL_BLEND);
         glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
         glActiveTexture (GL_TEXTURE0);
-        glEnable (GL_TEXTURE_2D);
+
+        if (! openGLContext.isCoreProfile())
+            glEnable (GL_TEXTURE_2D);
 
         glViewport (0, 0,
                     roundToInt (desktopScale * (float) bounds.getWidth()),

modules/juce_opengl/juce_opengl.cpp

@@ -240,22 +240,6 @@ private:
     OpenGLTargetSaver& operator= (const OpenGLTargetSaver&);
 };
 
-static bool contextRequiresTexture2DEnableDisable()
-{
-   #if JUCE_OPENGL_ES
-    return false;
-   #else
-    clearGLError();
-    GLint mask = 0;
-    glGetIntegerv (GL_CONTEXT_PROFILE_MASK, &mask);
-
-    if (glGetError() == GL_INVALID_ENUM)
-        return true;
-
-    return (mask & (GLint) GL_CONTEXT_CORE_PROFILE_BIT) == 0;
-   #endif
-}
-
 } // namespace juce
 
 //==============================================================================

modules/juce_opengl/opengl/juce_OpenGLContext.cpp

@@ -537,7 +537,7 @@ public:
 
     void drawComponentBuffer()
     {
-        if (contextRequiresTexture2DEnableDisable())
+        if (! isCoreProfile())
             glEnable (GL_TEXTURE_2D);
 
        #if JUCE_WINDOWS
@@ -644,6 +644,7 @@ public:
         if (getOpenGLVersion() >= Version { 4, 3 } && glDebugMessageCallback != nullptr)
         {
             glEnable (GL_DEBUG_OUTPUT);
+            glEnable (GL_DEBUG_OUTPUT_SYNCHRONOUS);
             glDebugMessageCallback ([] (GLenum, GLenum type, GLuint, GLenum severity, GLsizei, const GLchar* message, const void*)
             {
                 // This may reiterate issues that are also flagged by JUCE_CHECK_OPENGL_ERROR.
@@ -674,6 +675,24 @@ public:
         return InitResult::success;
     }
 
+    bool isCoreProfile() const
+    {
+       #if JUCE_OPENGL_ES
+        return true;
+       #else
+        clearGLError();
+        GLint mask = 0;
+        glGetIntegerv (GL_CONTEXT_PROFILE_MASK, &mask);
+
+        // The context isn't aware of the profile mask, so it pre-dates the core profile
+        if (glGetError() == GL_INVALID_ENUM)
+            return false;
+
+        // Also assumes a compatibility profile if the mask is completely empty for some reason
+        return (mask & (GLint) GL_CONTEXT_CORE_PROFILE_BIT) != 0;
+       #endif
+    }
+
     /*  Returns true if the context requires a non-zero vertex array object (VAO) to be bound.
 
         If the context is a compatibility context, we can just pretend that VAOs don't exist,
@@ -686,16 +705,7 @@ public:
        #if JUCE_OPENGL_ES
         return false;
        #else
-        clearGLError();
-        GLint mask = 0;
-        glGetIntegerv (GL_CONTEXT_PROFILE_MASK, &mask);
-
-        // The context isn't aware of the profile mask, so it pre-dates the core profile
-        if (glGetError() == GL_INVALID_ENUM)
-            return false;
-
-        // Also assumes a compatibility profile if the mask is completely empty for some reason
-        return (mask & (GLint) GL_CONTEXT_CORE_PROFILE_BIT) != 0;
+        return isCoreProfile();
        #endif
     }
 
@@ -1443,6 +1453,12 @@ void* OpenGLContext::getRawContext() const noexcept
     return nativeContext != nullptr ? nativeContext->getRawContext() : nullptr;
 }
 
+bool OpenGLContext::isCoreProfile() const
+{
+    auto* c = getCachedImage();
+    return c != nullptr && c->isCoreProfile();
+}
+
 OpenGLContext::CachedImage* OpenGLContext::getCachedImage() const noexcept
 {
     if (auto* comp = getTargetComponent())

modules/juce_opengl/opengl/juce_OpenGLContext.h

@@ -133,7 +133,16 @@ public:
     /** Returns true if non-power-of-two textures are supported in this context. */
     bool isTextureNpotSupported() const;
 
-    /** OpenGL versions, used by setOpenGLVersionRequired(). */
+    /** OpenGL versions, used by setOpenGLVersionRequired().
+
+        The Core profile doesn't include some legacy functionality, including the
+        fixed-function pipeline.
+
+        The Compatibility profile is backwards-compatible, and includes functionality
+        deprecated in the Core profile. However, not all implementations provide
+        compatibility profiles targeting later versions of OpenGL. To run on the
+        broadest range of hardware, using the 3.2 Core profile is recommended.
+    */
     enum OpenGLVersion
     {
         defaultGLVersion = 0, ///< Whatever the device decides to give us, normally a compatibility profile
@@ -285,6 +294,12 @@ public:
     */
     void* getRawContext() const noexcept;
 
+    /** Returns true if this context is using the core profile.
+
+        @see OpenGLVersion
+    */
+    bool isCoreProfile() const;
+
     /** This structure holds a set of dynamically loaded GL functions for use on this context. */
     OpenGLExtensionFunctions extensions;
 

modules/juce_opengl/opengl/juce_OpenGLFrameBuffer.cpp

@@ -216,7 +216,9 @@ bool OpenGLFrameBuffer::initialise (OpenGLFrameBuffer& other)
         pimpl->bind();
 
        #if ! JUCE_ANDROID
-        glEnable (GL_TEXTURE_2D);
+        if (! pimpl->context.isCoreProfile())
+            glEnable (GL_TEXTURE_2D);
+
         clearGLError();
        #endif
         glBindTexture (GL_TEXTURE_2D, p->textureID);

modules/juce_opengl/opengl/juce_OpenGLGraphicsContext.cpp

@@ -1086,7 +1086,7 @@ struct StateHelpers
         GLuint currentTextureID[numTextures];
         int texturesEnabled = 0, currentActiveTexture = -1;
         const OpenGLContext& context;
-        const bool needsToEnableTexture = contextRequiresTexture2DEnableDisable();
+        const bool needsToEnableTexture = ! context.isCoreProfile();
 
         ActiveTextures& operator= (const ActiveTextures&);
     };
@@ -1784,7 +1784,10 @@ struct NonShaderContext   : public LowLevelGraphicsSoftwareRenderer
 
        #if ! JUCE_ANDROID
         target.context.extensions.glActiveTexture (GL_TEXTURE0);
-        glEnable (GL_TEXTURE_2D);
+
+        if (! target.context.isCoreProfile())
+            glEnable (GL_TEXTURE_2D);
+
         clearGLError();
        #endif