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<p class="MsoNormal"><span lang="PL" style="mso-fareast-language:EN-US">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="PL" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">I don’t have much ES2 experience, so I cannot really answer 1). But I think I can somewhat answer 2) based on Windows OpenGL knowledge.<br>
<br>
This might be a situation similar to how Windows handles GL contexts. When you create a context in modern GL (3.0 and onwards, aka. Core) you must acquire some newer GL/WGL calls which can create such context. These calls are GL extensions, so to get them you
need to be able to call `wglGetProcAddress()`. To be able to call `wglGetProcAddress()` on Windows you need to first make any GL context current. Core WGL exposes calls to create a 1.1 Context, but they require a window.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">As such, usual path to get a 3.0 Context on Windows is as follows:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">- Create a dummy/invisible window<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">- Use a dummy window to create 1.1 Context (aka false context)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">- Make 1.1 false context current<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">- Fetch necessary functions via `wglGetProcAddress()`<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">- Create a proper 3.0 Context and make It current<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">For reference, Khronos Wiki mentions this briefly:
<a href="https://www.khronos.org/opengl/wiki/Creating_an_OpenGL_Context_(WGL)#Create_a_False_Context">
https://www.khronos.org/opengl/wiki/Creating_an_OpenGL_Context_(WGL)#Create_a_False_Context</a><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">I think on Linux and with GLX such behavior is not required (AFAIK glXGetProcAddress could fetch GL/GLX extensions without a current context), but to keep it consistent on all platforms
ES2 seems to follow this path regardless.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">BRs,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Lukasz<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> openjfx-dev <openjfx-dev-retn@openjdk.org>
<b>On Behalf Of </b>Thiago Milczarek Sayão<br>
<b>Sent:</b> Friday, 20 October 2023 22:38<br>
<b>To:</b> openjfx-dev <openjfx-dev@openjdk.org><br>
<b>Subject:</b> Exploring the prism es2 land - couple of questions<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Hi,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I have some questions on prism es2.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">1) Why is a Context created on each platform GLFactory if there is a GLContext?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">2) What is the use of the Dummy Window?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I'm working on using EGL instead of GLX, so it will work on Wayland.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thanks.<o:p></o:p></p>
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