Initial revisions.

diff --git a/Makefile.am b/Makefile.am
new file mode 100644 (file)
index 0000000..128a56d
--- /dev/null
+++ b/Makefile.am
@@ -0,0 +1,15 @@
+if HAVE_DAYLIGHT
+DEFS += -DHAVE_DAYLIGHT
+endif
+
+if HAVE_TIMEZONE
+DEFS += -DHAVE_TIMEZONE
+endif
+
+bin_PROGRAMS = est-epsilon gl-info test-mktime
+
+est_epsilon_SOURCES = est-epsilon.c
+
+gl_info_SOURCES = gl-info.c
+
+test_mktime_SOURCES = test-mktime.cxx

diff --git a/est-epsilon.c b/est-epsilon.c
new file mode 100644 (file)
index 0000000..ea4fa35
--- /dev/null
+++ b/est-epsilon.c
@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <GL/glut.h>
+
+int main() {
+    GLfloat a, t;
+
+    a = 1.0;
+
+    do {
+       printf("a = %.10f\n", a);
+       a = a / 2.0;
+       t = 1.0 + a;
+    } while ( t > 1.0 );
+
+    a = a + a;
+
+    printf("Estimated GLfloat epsilon = %.10f\n", a);
+
+    return(0);
+}

diff --git a/gl-info.c b/gl-info.c
new file mode 100644 (file)
index 0000000..1e3d914
--- /dev/null
+++ b/gl-info.c
@@ -0,0 +1,98 @@
+/*
+From: Steve Baker <sbaker@link.com>
+Sender: root@fatcity.com
+To: OPENGL-GAMEDEV-L <OPENGL-GAMEDEV-L@fatcity.com>
+Subject: Re: Win32 OpenGL Resource Page
+Date: Fri, 24 Apr 1998 07:33:51 -0800
+*/
+
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+#ifdef HAVE_WINDOWS_H
+#  include <windows.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <GL/glut.h>
+
+void getPrints ( GLenum token, char *string )
+{
+  printf ( "%s = \"%s\"\n", string, glGetString ( token ) ) ;
+}
+
+void getPrint2f ( GLenum token, char *string )
+{
+  GLfloat f[2] ;
+  glGetFloatv ( token, f ) ;
+  printf ( "%s = %g,%g\n", string, f[0],f[1] ) ;
+}
+
+void getPrintf ( GLenum token, char *string )
+{
+  GLfloat f ;
+  glGetFloatv ( token, &f ) ;
+  printf ( "%s = %g\n", string, f ) ;
+}
+
+void getPrint2i ( GLenum token, char *string )
+{
+  GLint i[2] ;
+  glGetIntegerv ( token, i ) ;
+  printf ( "%s = %d,%d\n", string, i[0],i[1] ) ;
+}
+
+void getPrinti ( GLenum token, char *string )
+{
+  GLint i ;
+  glGetIntegerv ( token, &i ) ;
+  printf ( "%s = %d\n", string, i ) ;
+}
+
+int main ( int argc, char **argv )
+{
+  glutInit            ( &argc, argv ) ;
+  glutInitDisplayMode ( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH ) ;
+  glutCreateWindow    ( "You should never see this window!"  ) ;
+
+  getPrints ( GL_VENDOR      , "GL_VENDOR"     ) ;
+  getPrints ( GL_RENDERER    , "GL_RENDERER"   ) ;
+  getPrints ( GL_VERSION     , "GL_VERSION"    ) ;
+  getPrints ( GL_EXTENSIONS  , "GL_EXTENSIONS" ) ;
+
+  getPrinti ( GL_RED_BITS    , "GL_RED_BITS"   ) ;
+  getPrinti ( GL_GREEN_BITS  , "GL_GREEN_BITS" ) ;
+  getPrinti ( GL_BLUE_BITS   , "GL_BLUE_BITS"  ) ;
+  getPrinti ( GL_ALPHA_BITS  , "GL_ALPHA_BITS" ) ;
+  getPrinti ( GL_DEPTH_BITS  , "GL_DEPTH_BITS" ) ;
+  getPrinti ( GL_INDEX_BITS  , "GL_INDEX_BITS" ) ;
+  getPrinti ( GL_STENCIL_BITS, "GL_STENCIL_BITS" ) ;
+
+  getPrinti ( GL_ACCUM_RED_BITS  , "GL_ACCUM_RED_BITS"   ) ;
+  getPrinti ( GL_ACCUM_GREEN_BITS, "GL_ACCUM_GREEN_BITS" ) ;
+  getPrinti ( GL_ACCUM_BLUE_BITS , "GL_ACCUM_BLUE_BITS"  ) ;
+  getPrinti ( GL_ACCUM_ALPHA_BITS, "GL_ACCUM_ALPHA_BITS" ) ;
+
+  getPrinti ( GL_AUX_BUFFERS, "GL_AUX_BUFFERS" ) ;
+
+  getPrinti ( GL_MAX_ATTRIB_STACK_DEPTH    , "GL_MAX_ATTRIB_STACK_DEPTH"     ) ;
+  getPrinti ( GL_MAX_NAME_STACK_DEPTH      , "GL_MAX_NAME_STACK_DEPTH"       ) ;
+  getPrinti ( GL_MAX_TEXTURE_STACK_DEPTH   , "GL_MAX_TEXTURE_STACK_DEPTH"    ) ;
+  getPrinti ( GL_MAX_PROJECTION_STACK_DEPTH, "GL_MAX_PROJECTION_STACK_DEPTH" ) ;
+  getPrinti ( GL_MAX_MODELVIEW_STACK_DEPTH , "GL_MAX_MODELVIEW_STACK_DEPTH"  ) ;
+
+  getPrinti ( GL_MAX_CLIP_PLANES    , "GL_MAX_CLIP_PLANES"     ) ;
+  getPrinti ( GL_MAX_EVAL_ORDER     , "GL_MAX_EVAL_ORDER"      ) ;
+  getPrinti ( GL_MAX_LIGHTS         , "GL_MAX_LIGHTS"          ) ;
+  getPrinti ( GL_MAX_LIST_NESTING   , "GL_MAX_LIST_NESTING"    ) ;
+  getPrinti ( GL_MAX_TEXTURE_SIZE   , "GL_MAX_TEXTURE_SIZE"    ) ;
+  getPrint2i( GL_MAX_VIEWPORT_DIMS  , "GL_MAX_VIEWPORT_DIMS"   ) ;
+
+  getPrintf ( GL_POINT_SIZE_GRANULARITY, "GL_POINT_SIZE_GRANULARITY" ) ;
+  getPrint2f( GL_POINT_SIZE_RANGE      , "GL_POINT_SIZE_RANGE" ) ;
+
+  return 0 ;
+}

diff --git a/test-mktime.cxx b/test-mktime.cxx
new file mode 100644 (file)
index 0000000..7602d17
--- /dev/null
+++ b/test-mktime.cxx
@@ -0,0 +1,137 @@
+// test the systems mktime() function
+
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+#include <math.h>
+#include <stdio.h>
+#include <time.h>
+
+#ifdef HAVE_SYS_TIMEB_H
+#  include <sys/types.h>
+#  include <sys/timeb.h> // for ftime() and struct timeb
+#endif
+#ifdef HAVE_UNISTD_H
+#  include <unistd.h>    // for gettimeofday()
+#endif
+#ifdef HAVE_SYS_TIME_H
+#  include <sys/time.h>  // for get/setitimer, gettimeofday, struct timeval
+#endif
+
+#define LST_MAGIC_TIME_1998 890481600
+
+
+// Fix up timezone if using ftime()
+long int fix_up_timezone( long int timezone_orig ) {
+#if !defined( HAVE_GETTIMEOFDAY ) && defined( HAVE_FTIME )
+    // ftime() needs a little extra help finding the current timezone
+    struct timeb current;
+    ftime(&current);
+    return( current.timezone * 60 );
+#else
+    return( timezone_orig );
+#endif
+}
+
+
+// Return time_t for Sat Mar 21 12:00:00 GMT
+//
+// I believe the mktime() has a SYSV vs. BSD behavior difference.
+//
+// The BSD style mktime() is nice because it returns its result
+// assuming you have specified the input time in GMT
+//
+// The SYSV style mktime() is a pain because it returns its result
+// assuming you have specified the input time in your local timezone.
+// Therefore you have to go to extra trouble to convert back to GMT.
+//
+// If you are having problems with incorrectly positioned astronomical
+// bodies, this is a really good place to start looking.
+
+time_t get_start_gmt(int year) {
+    struct tm mt;
+
+    // For now we assume that if daylight is not defined in
+    // /usr/include/time.h that we have a machine with a BSD behaving
+    // mktime()
+#   if !defined(HAVE_DAYLIGHT)
+#       define MK_TIME_IS_GMT 1
+#   endif
+
+    // timezone seems to work as a proper offset for Linux & Solaris
+#   if defined( __linux__ ) || defined( __sun__ ) 
+#       define TIMEZONE_OFFSET_WORKS 1
+#   endif
+
+    mt.tm_mon = 2;
+    mt.tm_mday = 21;
+    mt.tm_year = year;
+    mt.tm_hour = 12;
+    mt.tm_min = 0;
+    mt.tm_sec = 0;
+    mt.tm_isdst = -1; // let the system determine the proper time zone
+
+#   if defined( MK_TIME_IS_GMT )
+    return ( mktime(&mt) );
+#   else // ! defined ( MK_TIME_IS_GMT )
+
+    long int start = mktime(&mt);
+
+    printf("start1 = %ld\n", start);
+    printf("start2 = %s", ctime(&start));
+    printf("(tm_isdst = %d)\n", mt.tm_isdst);
+
+    timezone = fix_up_timezone( timezone );
+
+#   if defined( TIMEZONE_OFFSET_WORKS )
+    printf("start = %ld, timezone = %ld\n", start, timezone);
+    return( start - timezone );
+#   else // ! defined( TIMEZONE_OFFSET_WORKS )
+
+    daylight = mt.tm_isdst;
+    if ( daylight > 0 ) {
+       daylight = 1;
+    } else if ( daylight < 0 ) {
+       printf("OOOPS, problem in fg_time.cxx, no daylight savings info.\n");
+    }
+
+    long int offset = -(timezone / 3600 - daylight);
+
+    printf("  Raw time zone offset = %ld\n", timezone);
+    printf("  Daylight Savings = %d\n", daylight);
+    printf("  Local hours from GMT = %ld\n", offset);
+    
+    long int start_gmt = start - timezone + (daylight * 3600);
+    
+    printf("  March 21 noon (CST) = %ld\n", start);
+
+    return ( start_gmt );
+#   endif // ! defined( TIMEZONE_OFFSET_WORKS )
+#   endif // ! defined ( MK_TIME_IS_GMT )
+}
+
+
+int main() {
+    time_t start_gmt;
+
+    start_gmt = get_start_gmt(98);
+
+
+    if ( start_gmt == LST_MAGIC_TIME_1998 ) {
+#ifdef MK_TIME_IS_GMT
+       printf("mktime() assumes GMT on your system, lucky you!\n");
+#else
+       printf("mktime() assumes local time zone on your system, but we can\n");
+       printf("compensate just fine.\n");
+#endif
+    } else {
+       printf("There is likely a problem with mktime() on your system.\n");
+        printf("This will cause the sun/moon/stars/planets to be in the\n");
+       printf("wrong place in the sky and the rendered time of day will be\n");
+       printf("incorrect.\n\n");
+       printf("Please report this to curt@me.umn.edu so we can work to fix\n");
+       printf("the problem on your platform.\n");
+    }
+}