sync code with last improvements from OpenBSD

xserver/hw/xwin/glx/glthunk.c

@@ -0,0 +1,87 @@
+/*
+ * File: glthunk.c
+ * Purpose: cdecl thunk wrapper library for Win32 stdcall OpenGL library
+ *
+ * Copyright (c) Jon TURNEY 2009,2013
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE ABOVE LISTED COPYRIGHT HOLDER(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+// define USE_OPENGL32 makes gl.h declare gl*() function prototypes with stdcall linkage,
+// so our generated wrappers will correctly link with the functions in opengl32.dll
+#define USE_OPENGL32
+
+#ifdef HAVE_XWIN_CONFIG_H
+#include <xwin-config.h>
+#endif
+
+#include <X11/Xwindows.h>
+
+#define GL_GLEXT_LEGACY
+#include <GL/gl.h>
+#undef GL_ARB_imaging
+#undef GL_VERSION_1_3
+#include <GL/glext.h>
+
+static PROC
+glWinResolveHelper(PROC * cache, const char *symbol)
+{
+    PROC proc = NULL;
+
+    /* If not yet cached, call wglGetProcAddress */
+    if ((*cache) == NULL) {
+        proc = wglGetProcAddress(symbol);
+        if (proc == NULL) {
+            (*cache) = (PROC) - 1;
+        }
+        else {
+            (*cache) = proc;
+        }
+    }
+    /* Cached wglGetProcAddress failure */
+    else if ((*cache) == (PROC) - 1) {
+        proc = 0;
+    }
+    /* Cached wglGetProcAddress result */
+    else {
+        proc = (*cache);
+    }
+
+    return proc;
+}
+
+#define RESOLVE_RET(proctype, symbol, retval) \
+    static PROC cache = NULL; \
+    __stdcall proctype proc = (proctype)glWinResolveHelper(&cache, symbol); \
+    if (proc == NULL) { \
+        return retval; \
+    }
+
+#define RESOLVE(proctype, symbol) RESOLVE_RET(proctype, symbol,)
+
+#define RESOLVED_PROC(proctype) proc
+
+/*
+  Include generated cdecl wrappers for stdcall gl*() functions in opengl32.dll
+
+  OpenGL 1.2 and upward is treated as extensions, function address must
+  found using wglGetProcAddress(), but also stdcall so still need wrappers...
+*/
+
+#include "generated_gl_thunks.ic"