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

Comments

• KrankerApfel_

  August 2022 edited August 2022

  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 !

  0 · Share on Facebook
• ueno(staff)

  August 2022

  @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

  0 · Share on Facebook