239 lines
6.8 KiB
C
239 lines
6.8 KiB
C
/* -*- tab-width: 4; -*- */
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/* vi: set sw=2 ts=4 expandtab textwidth=70: */
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/*
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* Copyright 2017-2020 Mark Callow.
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @internal
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* @file
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* @~English
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*
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* @brief Retrieve OpenGL function pointers needed by libktx
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*/
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#define UNIX 0
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#define MACOS 0
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#define WINDOWS 0
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#define IOS 0
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#if defined(_WIN32)
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#undef WINDOWS
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#define WINDOWS 1
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#endif
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#if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__bsdi__) || defined(__DragonFly__)
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#undef UNIX
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#define UNIX 1
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#endif
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#if defined(linux) || defined(__linux) || defined(__linux__)
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#undef UNIX
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#define UNIX 1
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#endif
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#if defined(__APPLE__) && defined(__x86_64__)
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#undef MACOS
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#define MACOS 1
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#endif
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#if defined(__APPLE__) && (defined(__arm64__) || defined (__arm__))
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#undef IOS
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#define IOS 1
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#endif
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#if defined(__EMSCRIPTEN__)
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#define WEB 1
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#endif
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#if (IOS + MACOS + UNIX + WINDOWS + WEB) > 1
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#error "Multiple OS\'s defined"
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#endif
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#if WINDOWS
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#define WINDOWS_LEAN_AND_MEAN
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#include <windows.h>
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#else
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#include <dlfcn.h>
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#include <stdlib.h>
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#endif
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#define NO_SHORTCUTS
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#include "gl_funcs.h"
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#if WINDOWS
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#define GetOpenGLModuleHandle(flags) ktxFindOpenGL()
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static HMODULE ktxOpenGLModuleHandle;
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static PFNGLGETPROCADDRESS pfnWglGetProcAddress;
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PFNVOIDFUNCTION
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defaultGLGetProcAddress(const char* proc)
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{
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PFNVOIDFUNCTION pfnGLProc = NULL;
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if (pfnWglGetProcAddress)
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pfnGLProc = pfnWglGetProcAddress(proc);
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if (!pfnGLProc) {
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pfnGLProc = (PFNVOIDFUNCTION)GetProcAddress(ktxOpenGLModuleHandle,
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proc);
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}
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return pfnGLProc;
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}
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#elif MACOS || UNIX || IOS
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// Using NULL returns a handle that can be used to search the process that
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// loaded us and any other libraries it has loaded. That's all we need to
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// search as the app is responsible for creating the GL context so it must
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// be there.
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#define GetOpenGLModuleHandle(flags) dlopen(NULL, flags)
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static void* ktxOpenGLModuleHandle;
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PFNVOIDFUNCTION
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defaultGLGetProcAddress(const char* proc)
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{
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return dlsym(ktxOpenGLModuleHandle, proc);
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}
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#elif WEB
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extern void* emscripten_GetProcAddress(const char *name_);
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#define GetOpenGLModuleHandle(flag) (void*)0x0000ffff // Value doesn't matter.
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void* ktxOpenGLModuleHandle;
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#define defaultGLGetProcAddress ((PFNGLGETPROCADDRESS)emscripten_GetProcAddress)
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#else
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#error "Don\'t know how to load symbols on this OS."
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#endif
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static bool openGLLoaded = false;
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static const char* noloadmsg = "Could not load OpenGL command: %s!\n";
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/* Define pointers for functions libktx is using. */
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struct glFuncPtrs gl;
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#define GL_FUNCTION(type, func, required) \
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gl.func = (type)pfnGLGetProcAddress(#func); \
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if ( !gl.func && required) { \
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fprintf(stderr, noloadmsg, #func); \
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return KTX_NOT_FOUND; \
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}
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#if WINDOWS
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static HMODULE
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ktxFindOpenGL() {
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HMODULE module = 0;
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BOOL found;
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// Use GetModule not LoadLibrary so we only succeed if the process
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// has already loaded some OpenGL library.
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// Check current module to see if we are statically linked to GL.
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found = GetModuleHandleExA(
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GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
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(LPCSTR)ktxFindOpenGL,
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&module
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);
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if (found) {
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if (GetProcAddress(module, "glGetError") != NULL)
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return module;
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}
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// Not statically linked. See what dll the process has loaded.
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// Emulators probably also have opengl32.lib loaded so check that last.
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found = GetModuleHandleExA(
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0,
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"libGLESv2.dll",
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&module
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);
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if (found) return module;
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found = GetModuleHandleExA(
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0,
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"libGLES_CM.dll",
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&module
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);
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if (found) return module;
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found = GetModuleHandleExA(
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0,
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"opengl32.dll",
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&module
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);
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if (found) {
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// Need wglGetProcAddr for non-OpenGL-2 functions.
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#ifdef __clang__
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#pragma clang diagnostic push
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#pragma clang diagnostic ignored "-Wcast-function-type-mismatch"
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#endif
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pfnWglGetProcAddress =
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(PFNGLGETPROCADDRESS)GetProcAddress(module,
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"wglGetProcAddress");
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#ifdef __clang__
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#pragma clang diagnostic pop
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#endif
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if (pfnWglGetProcAddress != NULL)
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return module;
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}
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return 0;
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}
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#endif
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ktx_error_code_e
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ktxLoadOpenGLLibrary(void)
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{
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if (openGLLoaded)
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return KTX_SUCCESS;
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// Look for OpenGL module and set up default GetProcAddress.
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ktxOpenGLModuleHandle = GetOpenGLModuleHandle(RTLD_LAZY);
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if (ktxOpenGLModuleHandle == NULL) {
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fprintf(stderr, "OpenGL lib not linked or loaded by application.\n");
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// Normal use is for this constructor to be called by an
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// application that has completed OpenGL initialization. In that
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// case the only cause for failure would be a coding error in our
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// library loading. The only other cause would be an application
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// calling GLUpload without having initialized OpenGL.
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#if defined(DEBUG)
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abort();
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#else
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return KTX_LIBRARY_NOT_LINKED; // So release version doesn't crash.
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#endif
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}
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return KTX_SUCCESS;
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}
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/**
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* @ingroup ktx\_glloader
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* @~English
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* @brief Load pointers for the GL functions used by the ktxTexture\*\_GLUpload functions.
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*
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* Should be called by an application before its first call to a
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* ktxTexture\*\_GLUpload function, passing a pointer to the GLGetProcAddress function
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* provided by whatever OpenGL framework it is using. For backward
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* compatibility, the ktxTexture\*\_GLUpload functions call this with a NULL pointer causing an
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* attempt to load the pointers from the program module using
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* @c dlsym (GNU/Linux, macOS), @c wglGetProcAddr and @c GetProcAddr (Windows)
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* or @c emscripten_GetProcAddress (Web). This works with the vast majority of
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* OpenGL implementations but issues have been seen on Fedora systems
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* particularly with NVIDIA hardware. For full robustness, applications should
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* call this function.
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*
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* @param [in] pfnGLGetProcAddress pointer to function for retrieving pointers
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* to GL functions. If NULL, retrieval is
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* attempted using system dependent generic
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* functions.
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*/
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ktx_error_code_e
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ktxLoadOpenGL(PFNGLGETPROCADDRESS pfnGLGetProcAddress)
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{
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if (openGLLoaded)
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return KTX_SUCCESS;
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if (!pfnGLGetProcAddress) {
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ktx_error_code_e result = ktxLoadOpenGLLibrary();
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if (result != KTX_SUCCESS) {
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return result;
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}
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pfnGLGetProcAddress = defaultGLGetProcAddress;
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}
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// Load function pointers
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#include "gl_funclist.inl"
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openGLLoaded = true;
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return KTX_SUCCESS;
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}
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#undef GL_FUNCTION
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