208 lines
6.5 KiB
C
208 lines
6.5 KiB
C
/* ------------------------------------------------------------------------- */
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static int _glewExtensionCompare(const char *s1, const char *s2)
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{
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/* http://www.chanduthedev.com/2012/07/strcmp-implementation-in-c.html */
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while (*s1 || *s2)
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{
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if (*s1 > *s2)
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return 1;
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if (*s1 < *s2)
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return -1;
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s1++;
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s2++;
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}
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return 0;
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}
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static ptrdiff_t _glewBsearchExtension(const char* name)
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{
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ptrdiff_t lo = 0, hi = sizeof(_glewExtensionLookup) / sizeof(char*) - 2;
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while (lo <= hi)
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{
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ptrdiff_t mid = (lo + hi) / 2;
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const int cmp = _glewExtensionCompare(name, _glewExtensionLookup[mid]);
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if (cmp < 0) hi = mid - 1;
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else if (cmp > 0) lo = mid + 1;
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else return mid;
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}
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return -1;
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}
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static GLboolean *_glewGetExtensionString(const char *name)
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{
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ptrdiff_t n = _glewBsearchExtension(name);
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if (n >= 0) return &_glewExtensionString[n];
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return NULL;
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}
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static GLboolean *_glewGetExtensionEnable(const char *name)
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{
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ptrdiff_t n = _glewBsearchExtension(name);
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if (n >= 0) return _glewExtensionEnabled[n];
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return NULL;
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}
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static const char *_glewNextSpace(const char *i)
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{
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const char *j = i;
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if (j)
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while (*j!=' ' && *j) ++j;
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return j;
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}
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static const char *_glewNextNonSpace(const char *i)
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{
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const char *j = i;
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if (j)
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while (*j==' ') ++j;
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return j;
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}
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GLboolean GLEWAPIENTRY glewGetExtension (const char* name)
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{
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GLboolean *enable = _glewGetExtensionString(name);
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if (enable)
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return *enable;
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return GL_FALSE;
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}
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/* ------------------------------------------------------------------------- */
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typedef const GLubyte* (GLAPIENTRY * PFNGLGETSTRINGPROC) (GLenum name);
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typedef void (GLAPIENTRY * PFNGLGETINTEGERVPROC) (GLenum pname, GLint *params);
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static GLenum GLEWAPIENTRY glewContextInit ()
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{
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PFNGLGETSTRINGPROC getString;
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const GLubyte* s;
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GLuint dot;
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GLint major, minor;
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size_t n;
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#ifdef _WIN32
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getString = glGetString;
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#else
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getString = (PFNGLGETSTRINGPROC) glewGetProcAddress((const GLubyte*)"glGetString");
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if (!getString)
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return GLEW_ERROR_NO_GL_VERSION;
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#endif
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/* query opengl version */
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s = getString(GL_VERSION);
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dot = _glewStrCLen(s, '.');
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if (dot == 0)
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return GLEW_ERROR_NO_GL_VERSION;
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major = s[dot-1]-'0';
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minor = s[dot+1]-'0';
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if (minor < 0 || minor > 9)
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minor = 0;
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if (major<0 || major>9)
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return GLEW_ERROR_NO_GL_VERSION;
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if (major == 1 && minor == 0)
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{
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return GLEW_ERROR_GL_VERSION_10_ONLY;
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}
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else
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{
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GLEW_VERSION_4_6 = ( major > 4 ) || ( major == 4 && minor >= 6 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_4_5 = GLEW_VERSION_4_4 == GL_TRUE || ( major == 4 && minor >= 5 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_4_4 = GLEW_VERSION_4_5 == GL_TRUE || ( major == 4 && minor >= 4 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_4_3 = GLEW_VERSION_4_4 == GL_TRUE || ( major == 4 && minor >= 3 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_4_2 = GLEW_VERSION_4_3 == GL_TRUE || ( major == 4 && minor >= 2 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_4_1 = GLEW_VERSION_4_2 == GL_TRUE || ( major == 4 && minor >= 1 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_4_0 = GLEW_VERSION_4_1 == GL_TRUE || ( major == 4 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_3_3 = GLEW_VERSION_4_0 == GL_TRUE || ( major == 3 && minor >= 3 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_3_2 = GLEW_VERSION_3_3 == GL_TRUE || ( major == 3 && minor >= 2 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_3_1 = GLEW_VERSION_3_2 == GL_TRUE || ( major == 3 && minor >= 1 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_3_0 = GLEW_VERSION_3_1 == GL_TRUE || ( major == 3 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_2_1 = GLEW_VERSION_3_0 == GL_TRUE || ( major == 2 && minor >= 1 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_2_0 = GLEW_VERSION_2_1 == GL_TRUE || ( major == 2 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_1_5 = GLEW_VERSION_2_0 == GL_TRUE || ( major == 1 && minor >= 5 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_1_4 = GLEW_VERSION_1_5 == GL_TRUE || ( major == 1 && minor >= 4 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_1_3 = GLEW_VERSION_1_4 == GL_TRUE || ( major == 1 && minor >= 3 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_1_2_1 = GLEW_VERSION_1_3 == GL_TRUE ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_1_2 = GLEW_VERSION_1_2_1 == GL_TRUE || ( major == 1 && minor >= 2 ) ? GL_TRUE : GL_FALSE;
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GLEW_VERSION_1_1 = GLEW_VERSION_1_2 == GL_TRUE || ( major == 1 && minor >= 1 ) ? GL_TRUE : GL_FALSE;
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}
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for (n = 0; n < sizeof(_glewExtensionString) / sizeof(_glewExtensionString[0]); ++n)
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_glewExtensionString[n] = GL_FALSE;
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if (GLEW_VERSION_3_0)
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{
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GLint n = 0;
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GLint i;
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PFNGLGETINTEGERVPROC getIntegerv;
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PFNGLGETSTRINGIPROC getStringi;
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const char *ext;
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GLboolean *enable;
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#ifdef _WIN32
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getIntegerv = glGetIntegerv;
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#else
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getIntegerv = (PFNGLGETINTEGERVPROC) glewGetProcAddress((const GLubyte*)"glGetIntegerv");
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#endif
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if (getIntegerv)
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getIntegerv(GL_NUM_EXTENSIONS, &n);
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/* glGetStringi is OpenGL 3.0 */
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getStringi = (PFNGLGETSTRINGIPROC) glewGetProcAddress((const GLubyte*)"glGetStringi");
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if (getStringi)
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for (i = 0; i<n; ++i)
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{
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ext = (const char *) getStringi(GL_EXTENSIONS, i);
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/* Based on extension string(s), glewGetExtension purposes */
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enable = _glewGetExtensionString(ext);
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if (enable)
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*enable = GL_TRUE;
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/* Based on extension string(s), experimental mode, glewIsSupported purposes */
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enable = _glewGetExtensionEnable(ext);
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if (enable)
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*enable = GL_TRUE;
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}
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}
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else
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{
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const char *extensions;
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const char *end;
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const char *i;
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const char *j;
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char ext[128];
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GLboolean *enable;
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extensions = (const char *) getString(GL_EXTENSIONS);
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if (extensions)
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{
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end = extensions + _glewStrLen((const GLubyte *) extensions);
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for (i=extensions; i<end; i = j + 1)
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{
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i = _glewNextNonSpace(i);
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j = _glewNextSpace(i);
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/* Copy extension into NUL terminated string */
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if (j-i >= (ptrdiff_t) sizeof(ext))
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continue;
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_glewStrCopy(ext, i, ' ');
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/* Based on extension string(s), glewGetExtension purposes */
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enable = _glewGetExtensionString(ext);
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if (enable)
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*enable = GL_TRUE;
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/* Based on extension string(s), experimental mode, glewIsSupported purposes */
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enable = _glewGetExtensionEnable(ext);
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if (enable)
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*enable = GL_TRUE;
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}
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}
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}
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