common_preinit: call glutInit in macOS

Call glutInit for macOS. This is rather a workaround to fix a problem
when running 'uv --capabilities' with RTDXT and Syphon. Initialization
of GLUT in Syphon then fails because glutInit is skipped since NSApp is
a non-NULL (from initialization of GL context). Further GLUT call then
fail.

src/gl_context.c

@@ -57,6 +57,10 @@
 #include "debug.h"
 #include "gl_context.h"
 
+#if defined HAVE_GL && !defined HAVE_MACOSX
+#  include <GL/glut.h>
+#endif
+
 /**
  * @brief initializes specified OpenGL context
  *
@@ -226,4 +230,18 @@ void gl_context_make_current(struct gl_context *context)
 #endif
 }
 
+void uvGlutInit(int *argcp, char **argv)
+{
+#ifdef HAVE_GL
+# ifdef HAVE_MACOSX
+        macGlutInit(argcp, argv);
+# else
+        glutInit(argcp, argv);
+# endif
+#else
+        UNUSED(argcp);
+        UNUSED(argv);
+#endif
+}
+
 #endif /* defined HAVE_MACOSX || (defined HAVE_LINUX && defined HAVE_LIBGLEW) */

src/gl_context.h

@@ -127,6 +127,7 @@ static void gl_check_error()
 
 GLuint glsl_compile_link(const char *vprogram, const char *fprogram);
 
+void uvGlutInit(int *argcp, char **argv);
 
 #ifdef __cplusplus
 }

src/host.cpp

@@ -77,6 +77,10 @@
 #define X11_LIB_NAME "libX11.so.6"
 #endif
 
+#if defined HAVE_GL && defined HAVE_MACOSX
+#include <GLUT/glut.h>
+#endif
+
 #ifdef USE_MTRACE
 #include <mcheck.h>
 #endif
@@ -216,6 +220,10 @@ struct init_data *common_preinit(int argc, char *argv[])
         }
 #endif
 
+#if defined HAVE_GL && defined HAVE_MACOSX
+        glutInit(&uv_argc, uv_argv);
+#endif
+
 #ifdef WIN32
         WSADATA wsaData;
         int err = WSAStartup(MAKEWORD(2, 2), &wsaData);

src/mac_gl_common.h

@@ -43,4 +43,5 @@ int get_mac_kernel_version_major();
 void *mac_gl_init(mac_opengl_version_t);
 void mac_gl_free(void *);
 void mac_gl_make_current(void *);
+void macGlutInit(int *argcp, char **argv);
 

src/mac_gl_common.m

@@ -58,7 +58,7 @@
 #include <sys/sysctl.h>
 #include <string.h>
 #include <stdlib.h>
-
+#include <GLUT/glut.h>
 
 #ifndef __MAC_10_11
 #warning "You are compling on pre-10.7 Mac OS X version. Core OpenGL 3.2 profile won't work"
@@ -207,3 +207,10 @@ void mac_gl_make_current(void * state)
 }
 @end
 
+void macGlutInit(int *argcp, char **argv)
+{
+        if (NSApp == nil) {
+                glutInit(argcp, argv);
+        }
+}
+

src/video_capture/syphon.mm

@@ -328,7 +328,7 @@ static void syphon_mainloop(void *state)
         state_global = (struct state_vidcap_syphon *) state;
         struct state_vidcap_syphon *s = state_global;
 
-        glutInit(&uv_argc, uv_argv);
+        uvGlutInit(&uv_argc, uv_argv);
         glutInitDisplayMode(GLUT_RGB);
         s->window = glutCreateWindow("dummy Syphon client window");
         glutHideWindow();

src/video_display/gl.cpp

@@ -1160,7 +1160,7 @@ static bool display_gl_init_opengl(struct state_gl *s)
         glutInitErrorFunc(glut_init_error_callback);
         if (setjmp(error_env) == 0) {
 #endif
-                glutInit(&uv_argc, uv_argv);
+                uvGlutInit(&uv_argc, uv_argv);
 #ifdef FREEGLUT
         } else {
                 exit_uv(EXIT_FAIL_DISPLAY);