[Bf-blender-cvs] [6af0434] master: Workaround for glew initialization bug

[Campbell Barton]

Commit: 6af043424d20fb144c477591f5fc645d562ddd99
Author: Campbell Barton
Date:   Mon Oct 12 21:58:57 2015 +1100
Branches: master
https://developer.blender.org/rB6af043424d20fb144c477591f5fc645d562ddd99

Workaround for glew initialization bug

It turns out libGL from Intel crashes when calling glxewInit (where mesa, nvidia work fine),
unfortunately the only option without making larger changes to glew,
is to inline the parts of glew we're using - before the glx context is created.

===================================================================

M	intern/ghost/intern/GHOST_ContextGLX.cpp

===================================================================

diff --git a/intern/ghost/intern/GHOST_ContextGLX.cpp b/intern/ghost/intern/GHOST_ContextGLX.cpp
index c431e7e..0ee8da1 100644
--- a/intern/ghost/intern/GHOST_ContextGLX.cpp
+++ b/intern/ghost/intern/GHOST_ContextGLX.cpp
@@ -40,6 +40,14 @@
 #include <cstdio>
 #include <cstring>
 
+/* needed for intel drivers (works w/ mesa-swrast & nvidia) */
+#define USE_GLXEW_INIT_WORKAROUND
+
+#ifdef USE_GLXEW_INIT_WORKAROUND
+static GLuint _glewStrLen(const GLubyte *s);
+static GLboolean _glewSearchExtension(const char *name, const GLubyte *start, const GLubyte *end);
+#endif
+
 #ifdef WITH_GLEW_MX
 GLXEWContext *glxewContext = NULL;
 #endif
@@ -153,9 +161,54 @@ GHOST_TSuccess GHOST_ContextGLX::initializeDrawingContext()
 	XIOErrorHandler old_handler_io = XSetIOErrorHandler(GHOST_X11_ApplicationIOErrorHandler);
 #endif
 
+
+
+	/* -------------------------------------------------------------------- */
+	/* Begin Inline Glew  */
+
+#ifdef USE_GLXEW_INIT_WORKAROUND
+	const GLubyte *extStart = (GLubyte *)"";
+	const GLubyte *extEnd;
+	if (glXQueryExtension(m_display, NULL, NULL)) {
+		extStart = (const GLubyte *)glXGetClientString(m_display, GLX_EXTENSIONS);
+		if ((extStart == NULL) ||
+		    (glXChooseFBConfig = (PFNGLXCHOOSEFBCONFIGPROC)glXGetProcAddressARB(
+		             (const GLubyte *)"glXChooseFBConfig")) == NULL ||
+		    (glXCreateContextAttribsARB = (PFNGLXCREATECONTEXTATTRIBSARBPROC)glXGetProcAddressARB(
+		             (const GLubyte *)"glXCreateContextAttribsARB")) == NULL)
+		{
+			extStart = (GLubyte *)"";
+		}
+	}
+	extEnd = extStart + _glewStrLen(extStart);
+
+#undef GLXEW_ARB_create_context
+	const bool GLXEW_ARB_create_context =
+	        _glewSearchExtension("GLX_ARB_create_context", extStart, extEnd);
+#undef GLXEW_ARB_create_context_profile
+	const bool GLXEW_ARB_create_context_profile =
+	        _glewSearchExtension("GLX_ARB_create_context_profile", extStart, extEnd);
+#undef GLXEW_ARB_create_context_robustness
+const bool GLXEW_ARB_create_context_robustness =
+	        _glewSearchExtension("GLX_ARB_create_context_robustness", extStart, extEnd);
+#ifdef WITH_GLEW_ES
+#undef GLXEW_EXT_create_context_es_profile
+	const bool GLXEW_EXT_create_context_es_profile =
+	        _glewSearchExtension("GLX_EXT_create_context_es_profile", extStart, extEnd);
+#undef GLXEW_EXT_create_context_es2_profile
+	const bool GLXEW_EXT_create_context_es2_profile =
+	        _glewSearchExtension("GLX_EXT_create_context_es2_profile", extStart, extEnd);
+#endif  /* WITH_GLEW_ES */
+
+	/* End Inline Glew */
+	/* -------------------------------------------------------------------- */
+#else
 	/* important to initialize only glxew (_not_ glew),
 	 * since this breaks w/ Mesa's `swrast`, see: T46431 */
 	glxewInit();
+#endif  /* USE_GLXEW_INIT_WORKAROUND */
+
+
 
 	if (GLXEW_ARB_create_context) {
 		int profileBitCore   = m_contextProfileMask & GLX_CONTEXT_CORE_PROFILE_BIT_ARB;
@@ -411,3 +464,45 @@ int GHOST_X11_GL_GetAttributes(
 
 	return i;
 }
+
+
+/* excuse inlining part of glew */
+#ifdef USE_GLXEW_INIT_WORKAROUND
+static GLuint _glewStrLen(const GLubyte *s)
+{
+	GLuint i = 0;
+	if (s == NULL) return 0;
+	while (s[i] != '\0') i++;
+	return i;
+}
+
+static GLuint _glewStrCLen(const GLubyte *s, GLubyte c)
+{
+	GLuint i = 0;
+	if (s == NULL) return 0;
+	while (s[i] != '\0' && s[i] != c) i++;
+	return (s[i] == '\0' || s[i] == c) ? i : 0;
+}
+
+static GLboolean _glewStrSame(const GLubyte *a, const GLubyte *b, GLuint n)
+{
+	GLuint i = 0;
+	if (a == NULL || b == NULL)
+		return (a == NULL && b == NULL && n == 0) ? GL_TRUE : GL_FALSE;
+	while (i < n && a[i] != '\0' && b[i] != '\0' && a[i] == b[i]) i++;
+	return i == n ? GL_TRUE : GL_FALSE;
+}
+
+static GLboolean _glewSearchExtension(const char *name, const GLubyte *start, const GLubyte *end)
+{
+	const GLubyte *p;
+	GLuint len = _glewStrLen((const GLubyte *)name);
+	p = start;
+	while (p < end) {
+		GLuint n = _glewStrCLen(p, ' ');
+		if (len == n && _glewStrSame((const GLubyte *)name, p, n)) return GL_TRUE;
+		p += n + 1;
+	}
+	return GL_FALSE;
+}
+#endif  /* USE_GLXEW_INIT_WORKAROUND */
\ No newline at end of file