mirror of
https://github.com/Perlmint/glew-cmake.git
synced 2025-03-24 17:46:54 +00:00
63374ccd9c
git-svn-id: https://glew.svn.sourceforge.net/svnroot/glew/trunk/glew@299 783a27ee-832a-0410-bc00-9f386506c6dd
134 lines
3.4 KiB
C
134 lines
3.4 KiB
C
/* ------------------------------------------------------------------------- */
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/*
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* GLEW, just like OpenGL or GLU, does not rely on the standard C library.
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* These functions implement the functionality required in this file.
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*/
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static GLuint _glewStrLen (const GLubyte* s)
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{
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GLuint i=0;
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while (s+i != NULL && s[i] != '\0') i++;
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return i;
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}
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static GLuint _glewStrCLen (const GLubyte* s, GLubyte c)
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{
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GLuint i=0;
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while (s+i != NULL && s[i] != '\0' && s[i] != c) i++;
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return i;
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}
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static GLboolean _glewStrSame (const GLubyte* a, const GLubyte* b, GLuint n)
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{
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GLuint i=0;
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while (i < n && a+i != NULL && b+i != NULL && a[i] == b[i]) i++;
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return i == n;
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}
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/*
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* Search for name in the extensions string. Use of strstr()
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* is not sufficient because extension names can be prefixes of
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* other extension names. Could use strtok() but the constant
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* string returned by glGetString might be in read-only memory.
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*/
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GLboolean glewGetExtension (const char* name)
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{
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GLubyte* p;
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GLubyte* end;
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GLuint len = _glewStrLen((const GLubyte*)name);
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p = (GLubyte*)glGetString(GL_EXTENSIONS);
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if (0 == p) return GL_FALSE;
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end = p + _glewStrLen(p);
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while (p < end)
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{
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GLuint n = _glewStrCLen(p, ' ');
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if (len == n && _glewStrSame((const GLubyte*)name, p, n)) return GL_TRUE;
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p += n+1;
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}
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return GL_FALSE;
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}
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/* ------------------------------------------------------------------------- */
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#ifndef GLEW_MX
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static
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#endif
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GLenum glewContextInit (GLEW_CONTEXT_ARG_DEF_LIST)
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{
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const GLubyte* s;
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GLuint major, minor;
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/* query opengl version */
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s = glGetString(GL_VERSION);
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if (!s) return GLEW_ERROR_NO_GL_VERSION;
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major = _glewStrCLen(s, '.')-1;
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minor = _glewStrCLen(s, '.')+1;
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if (s+major == NULL
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|| s+minor-1 == NULL || s+minor == NULL
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|| (s[major] == 1 && s[minor] < '1'))
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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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if (s[major] >= '2')
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{
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GLEW_VERSION_1_1 = GL_TRUE;
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GLEW_VERSION_1_2 = GL_TRUE;
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GLEW_VERSION_1_3 = GL_TRUE;
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GLEW_VERSION_1_4 = GL_TRUE;
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GLEW_VERSION_1_5 = GL_TRUE;
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GLEW_VERSION_2_0 = GL_TRUE;
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}
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else
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{
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if (s[minor] >= '5')
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{
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GLEW_VERSION_1_1 = GL_TRUE;
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GLEW_VERSION_1_2 = GL_TRUE;
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GLEW_VERSION_1_3 = GL_TRUE;
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GLEW_VERSION_1_4 = GL_TRUE;
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GLEW_VERSION_1_5 = GL_TRUE;
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GLEW_VERSION_2_0 = GL_FALSE;
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}
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if (s[minor] == '4')
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{
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GLEW_VERSION_1_1 = GL_TRUE;
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GLEW_VERSION_1_2 = GL_TRUE;
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GLEW_VERSION_1_3 = GL_TRUE;
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GLEW_VERSION_1_4 = GL_TRUE;
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GLEW_VERSION_1_5 = GL_FALSE;
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GLEW_VERSION_2_0 = GL_FALSE;
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}
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if (s[minor] == '3')
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{
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GLEW_VERSION_1_1 = GL_TRUE;
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GLEW_VERSION_1_2 = GL_TRUE;
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GLEW_VERSION_1_3 = GL_TRUE;
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GLEW_VERSION_1_4 = GL_FALSE;
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GLEW_VERSION_1_5 = GL_FALSE;
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GLEW_VERSION_2_0 = GL_FALSE;
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}
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if (s[minor] == '2')
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{
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GLEW_VERSION_1_1 = GL_TRUE;
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GLEW_VERSION_1_2 = GL_TRUE;
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GLEW_VERSION_1_3 = GL_FALSE;
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GLEW_VERSION_1_4 = GL_FALSE;
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GLEW_VERSION_1_5 = GL_FALSE;
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GLEW_VERSION_2_0 = GL_FALSE;
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}
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if (s[minor] < '2')
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{
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GLEW_VERSION_1_1 = GL_TRUE;
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GLEW_VERSION_1_2 = GL_FALSE;
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GLEW_VERSION_1_3 = GL_FALSE;
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GLEW_VERSION_1_4 = GL_FALSE;
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GLEW_VERSION_1_5 = GL_FALSE;
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GLEW_VERSION_2_0 = GL_FALSE;
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}
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}
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}
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/* initialize extensions */
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