# OpenGL errors on Windows

**URL:** <https://forum.juce.com/t/opengl-errors-on-windows/35317>\
**Category:** Windows\
**Created:** [September 20, 2019, 4:08pm UTC](https://forum.juce.com/t/opengl-errors-on-windows/35317 "2019-09-20T16:08:36Z")\
**Posts on this page:** 11\
**Page:** 1

<div class="post-metadata">

**Author:** ![adamwilson](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/adamwilson/32/1387_2.png) [@adamwilson](https://forum.juce.com/u/adamwilson)\
**Post date:** [September 20, 2019, 4:08pm UTC](https://forum.juce.com/t/opengl-errors-on-windows/35317/1 "2019-09-20T16:08:37Z")

</div>

I’m compiling an OpenGL app on Windows 10 with VS2019.

I am getting a load of errors e.g.

```auto
identifier "GLsizeiptr" is undefined
identifier "GL_STREAM_DRAW" is undefined
identifier "GL_STATIC_DRAW" is undefined
identifier "GL_ARRAY_BUFFER" is undefined

```

I’ve set `OPENGL3=1` in Projucer Preprocessor Definitions.

Anything else I might have missed?

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<div class="post-metadata">

**Author:** ![jrlanglois](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/jrlanglois/32/21372_2.png) [@jrlanglois](https://forum.juce.com/u/jrlanglois)\
**Post date:** [September 20, 2019, 4:45pm UTC](https://forum.juce.com/t/opengl-errors-on-windows/35317/2 "2019-09-20T16:45:35Z")

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I don’t see any other configuration needed in my projects to make that work. Also, `JUCE_OPENGL3=1` is the macro.

You sure this line is active in `juce_MissingGLDefinitions.h` ?

```auto
#if JUCE_WINDOWS && ! defined (GL_TEXTURE0)

```

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<div class="post-metadata">

**Author:** ![adamwilson](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/adamwilson/32/1387_2.png) [@adamwilson](https://forum.juce.com/u/adamwilson)\
**Post date:** [September 20, 2019, 9:42pm UTC](https://forum.juce.com/t/opengl-errors-on-windows/35317/3 "2019-09-20T21:42:52Z")

</div>

Yes I am using `JUCE_OPENGL3=1`, that was a typo.

It also looks like those definitions are set:

![59](https://us1.discourse-cdn.com/flex026/uploads/juce/original/2X/c/c16a3e6be8037906d8f3b078b696d2a9d628aba4.png)

---

<div class="post-metadata">

**Author:** ![adamwilson](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/adamwilson/32/1387_2.png) [@adamwilson](https://forum.juce.com/u/adamwilson)\
**Post date:** [September 23, 2019, 1:33pm UTC](https://forum.juce.com/t/opengl-errors-on-windows/35317/4 "2019-09-23T13:33:00Z")

</div>

The strange thing is that I can inspect the missing values:

 ![48](https://us1.discourse-cdn.com/flex026/uploads/juce/original/2X/a/a7dcdf58842b7810ec6e1e40c29bf5086c9f81cb.png)

---

<div class="post-metadata">

**Author:** ![adamwilson](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/adamwilson/32/1387_2.png) [@adamwilson](https://forum.juce.com/u/adamwilson)\
**Post date:** [September 23, 2019, 1:42pm UTC](https://forum.juce.com/t/opengl-errors-on-windows/35317/5 "2019-09-23T13:42:32Z")

</div>

Looks like adding the `juce` namespace to all the GL definitions is the solution. This code resides in a module, if that makes a difference…

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<div class="post-metadata">

**Author:** ![jrlanglois](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/jrlanglois/32/21372_2.png) [@jrlanglois](https://forum.juce.com/u/jrlanglois)\
**Post date:** [September 23, 2019, 4:46pm UTC](https://forum.juce.com/t/opengl-errors-on-windows/35317/6 "2019-09-23T16:46:55Z")

</div>

My guess is that you don’t have `DONT_SET_USING_JUCE_NAMESPACE=1` defined or you have it disabled?

Regardless, the reason this is an issue is that it’s entirely a non-standard way of going about. Everything that is a macro should remain that way, because OpenGL is fundamentally standardised as a C API.

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<div class="post-metadata">

**Author:** ![adamwilson](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/adamwilson/32/1387_2.png) [@adamwilson](https://forum.juce.com/u/adamwilson)\
**Post date:** [September 23, 2019, 8:21pm UTC](https://forum.juce.com/t/opengl-errors-on-windows/35317/7 "2019-09-23T20:21:18Z")

</div>

No, can’t see `DONT_SET_USING_JUCE_NAMESPACE` set anywhere…

However to get it working on both platforms I had to add `using namespace juce` to the top of the `.cpp` file containing the OpenGL calls. While adding `juce::` to the beginning of the OpenGL definitions worked on Windows it failed on macOS.

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<div class="post-metadata">

**Author:** ![PluginPenguin](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/pluginpenguin/32/10203_2.png) [@PluginPenguin](https://forum.juce.com/u/PluginPenguin)\
**Post date:** [September 24, 2019, 9:36am UTC](https://forum.juce.com/t/opengl-errors-on-windows/35317/8 "2019-09-24T09:36:50Z")

</div>

Looking at the code, I see that it is a problem coming from my realtime visualization module 😉

I tested all my code on Mac OS and iOS only so far and I do all my projects with `DONT_SET_USING_JUCE_NAMESPACE` turned on as I avoid `using namespace` at all costs – mainly because I know that people round here will read the code that might not be familiar with JUCE, so they will see immediately that I used a class from this framework. This means if I use any JUCE class or function in my code, I always prepend the `juce::` namespace, as I do with all other namespaces that might occur in my project.

Now for reasons I don’t know, it seems like there was the need to define some of the Open GL macros for Windows that are missing on that platform (why??). So there is a header called `juce_MissingGLDefinitions.h` which contains

```auto
namespace juce
{
/** These are important openGL values that aren't defined by default
    by the GL headers on various platforms.
*/
enum MissingOpenGLDefinitions
{
   //...

   #if JUCE_WINDOWS && ! defined (GL_TEXTURE0)
    GL_OPERAND0_RGB = 0x8590,
    GL_OPERAND1_RGB = 0x8591,
    GL_OPERAND0_ALPHA = 0x8598,
    GL_OPERAND1_ALPHA = 0x8599,
    GL_SRC0_RGB = 0x8580,
    GL_SRC1_RGB = 0x8581,
    GL_SRC0_ALPHA = 0x8588,
    GL_SRC1_ALPHA = 0x8589,
    GL_TEXTURE0 = 0x84C0,
    GL_TEXTURE1 = 0x84C1,
    GL_TEXTURE2 = 0x84C2,
    GL_COMBINE = 0x8570,
    GL_COMBINE_RGB = 0x8571,
    GL_COMBINE_ALPHA = 0x8572,
    GL_PREVIOUS = 0x8578,
    GL_COMPILE_STATUS = 0x8B81,
    GL_LINK_STATUS = 0x8B82,
    GL_SHADING_LANGUAGE_VERSION = 0x8B8C,
    GL_FRAGMENT_SHADER = 0x8B30,
    GL_VERTEX_SHADER = 0x8B31,
    GL_ARRAY_BUFFER = 0x8892,
    GL_ELEMENT_ARRAY_BUFFER = 0x8893,
    GL_STATIC_DRAW = 0x88E4,
    GL_DYNAMIC_DRAW = 0x88E8,
    GL_STREAM_DRAW = 0x88E0,

    //...
   #endif
}
} // namespace juce

```

Now if we take e.g. `GL_STREAM_DRAW` and look where it is defined on Mac OS, we’ll find `#define GL_STREAM_DRAW 0x88E0` defined in the system header `gl3.h`. However on Windows there is the enum value `juce::MissingOpenGLDefinitions::GL_STREAM_DRAW` that holds this value, which can also be called by `juce::GL_STREAM_DRAW` and if you have set `using namespace juce` it just gets `GL_STREAM_DRAW` and therefore suddenly becomes silently exchangeable with the macro on the other platforms. This explains why adding that directive to the .cpp file solved the problem for you @adamski.

I personally think, declaring a missing macro as an enum inside a namespace with the assumtion that all users will have `using namespace juce` enabled globally is no good idea and a serious design flaw when the goal is to provide a framework that aims at writing portable code. Would love to hear from the JUCE team what they think about it and why they didn’t chose to declare the missing macros as macros? @ed95 @jules

---

<div class="post-metadata">

**Author:** ![adamwilson](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/adamwilson/32/1387_2.png) [@adamwilson](https://forum.juce.com/u/adamwilson)\
**Post date:** [September 24, 2019, 9:41am UTC](https://forum.juce.com/t/opengl-errors-on-windows/35317/9 "2019-09-24T09:41:33Z")

</div>

I came to the same conclusion as you. It seems like a strange design decision to treat platforms differently, which can lead to anomalies as I have found.

And yes it is coming from your OpenGL module 🙂 Thanks for confirming re: `DONT_SET_USING_JUCE_NAMESPACE` I could not find a reference to it in my project (which includes your module)

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<div class="post-metadata">

**Author:** ![adamwilson](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/adamwilson/32/1387_2.png) [@adamwilson](https://forum.juce.com/u/adamwilson)\
**Post date:** [September 24, 2019, 9:55am UTC](https://forum.juce.com/t/opengl-errors-on-windows/35317/10 "2019-09-24T09:55:35Z")

</div>

I also found an extra GL definition missing on Windows:

```cpp
#define GL_ALIASED_LINE_WIDTH_RANGE 0x846E

```

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<div class="post-metadata">

**Author:** ![reuk](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/reuk/32/21494_2.png) [@reuk](https://forum.juce.com/u/reuk)\
**Post date:** [May 24, 2021, 5:13pm UTC](https://forum.juce.com/t/opengl-errors-on-windows/35317/11 "2021-05-24T17:13:50Z")

</div>

I’ve made some changes to the way that we load OpenGL symbols which should solve some of the issues raised in this thread.

Given that the change is quite large, it’s currently on a feature branch: `generated-opengl-headers`. I’d really appreciate any feedback on this potential change, before we merge it to `develop`. As always, I’m happy to answer any questions you may have about this change.

Some more details can be found in this post: [FR: Wrangle a comprehensive set of OpenGL functions & macros - #5 by reuk](https://forum.juce.com/t/fr-wrangle-a-comprehensive-set-of-opengl-functions-macros/33158/5)