Is that possible to use Glad instead of Glew ? (C++/OpenGL)

KrankerApfel_

Hi people !

I try to add Cubism 4 R4 to my C++/OpenGL project.
I already use Glad, so I would like to use Cubism Core and Cubism Framework with Glad instead of Glew.

Must I rewrite Framework with Glad or is there another way to switch the lib to Glad ?
Is Core compatible with Glad or is that an obligation to use Glew ?

Thank you for reading me ~

KrankerApfel_

Okay, so this night I tried to modify the Native SDK Sample Demo for OpenGL (with CSM_TARGET_WIN_GL i.e. for Windows) and it works, but there are some things I don't understand and I'm afraid it will cause problems later. I am a beginner in OpenGL so maybe my questions are stupid.

Here what I do to switch the OpenGL Demo sample from Glew to Glad :


1) Delete glew folder and add glad one in the project include directory.
2) Replace each #include <GL/glew.h> by #include <glad/glad.h> in Framework and
Demo project.
3) Write #define GL_TEXTURE_MAX_ANISOTROPY_EXT 0x84FE in CubismRenderer_OpenGLES2.cpp. ( Normally this should be defined in glad.h but I don't know which extension to check in https://glad.dav1d.de to add it to the loader)
4) In CubismRenderer_OpenGLES2.cpp I remove a part of the GL functions in InitializeGLFunction() Because some macros that begins with PFNGL wasn't found. Here below all the lines I deleted :

 glGenFramebuffers = (PFNGLGENFRAMEBUFFERSEXTPROC)WinGlGetProcAddress("glGenFramebuffers");
    glGenRenderbuffers = (PFNGLGENRENDERBUFFERSEXTPROC)WinGlGetProcAddress("glGenRenderbuffers");
    glBindFramebuffer = (PFNGLBINDFRAMEBUFFEREXTPROC)WinGlGetProcAddress("glBindFramebuffer");
    glFramebufferTexture2D = (PFNGLFRAMEBUFFERTEXTURE2DEXTPROC)WinGlGetProcAddress("glFramebufferTexture2D");
    glDeleteFramebuffers = (PFNGLDELETEFRAMEBUFFERSEXTPROC)WinGlGetProcAddress("glDeleteFramebuffers");
    glBindRenderbuffer = (PFNGLBINDRENDERBUFFEREXTPROC)WinGlGetProcAddress("glBindRenderbuffer");
    glDeleteRenderbuffers = (PFNGLDELETERENDERBUFFERSEXTPROC)WinGlGetProcAddress("glDeleteRenderbuffers");

    glRenderbufferStorage = (PFNGLRENDERBUFFERSTORAGEEXTPROC)WinGlGetProcAddress("glRenderbufferStorage");
    glFramebufferRenderbuffer = (PFNGLFRAMEBUFFERRENDERBUFFEREXTPROC)WinGlGetProcAddress("glFramebufferRenderbuffer");
    glCheckFramebufferStatus = (PFNGLCHECKFRAMEBUFFERSTATUSEXTPROC)WinGlGetProcAddress("glCheckFramebufferStatus");

My questions and worries :


A ) Why the function InitializeGlFunctions() is needed ? Isn't that the job of Glew or Glad to load and initialize the OpenGL function ?

B ) Are PFNGLCHECKFRAMEBUFFERSTATUSEXTPROC and other macros I deleted define by Glew, by Windows or by the GPU driver ? What happend if I don't intialize them with WinGlGetProcAddress("gl_function_name") ?

C ) What are the extension I need to add to glad on the loader website to get GL_TEXTURE_MAX_ANISOTROPY_EXT ? Is That the another name for ARB_texture_filter_anisotropic ?

Thank you for reading me !

ueno(staff)

@KrankerApfel_
Thank you for your continued use of our product.

Since we do not know the specifications of GLAD, please contact GLAD officials or developers for more information.

A ) Why the function InitializeGlFunctions() is needed ? Isn't that the job of Glew or Glad to load and initialize the OpenGL function ?
This is necessary because it specifies the setting values during initialization.

B ) Are PFNGLCHECKFRAMEBUFFERSTATUSEXTPROC and other macros I deleted define by Glew, by Windows or by the GPU driver ? What happend if I don't intialize them with WinGlGetProcAddress("gl_function_name") ?
In GLEW, macros such as PFNGLCHECKFRAMEBUFFERSTATUSEXTPROC are defined in glew.h.
If not initialized with WinGlGetProcAddress, the rendering process may fail.
https://docs.microsoft.com/ja-jp/windows/win32/api/wingdi/nf-wingdi-wglgetprocaddress
GLAD requires that you prepare the appropriate loader yourself.

C ) What are the extension I need to add to glad on the loader website to get GL_TEXTURE_MAX_ANISOTROPY_EXT ? Is That the another name for ARB_texture_filter_anisotropic ?
I think it is possible to use it by adding ARB_texture_filter_anisotropic, but please check the glad.c generated by you for details.

hope that helps!
Live2D Cubism Support