[Openexr-devel] fix for ImathPlatform.h for Win32 (MSVC): M_PI / M_PI_2 / ...

[Ger Hobbelt]

Since the M_PI and M_PI_2 constants are lacking with MSVC (Microsoft
Visual C++) unless you define an extension define (see code below) and
one of the sources in CVS requires the M_PI_2 constant which wasn't in
there, here's a fix for that.

diff included below.

Ger



--- \\Debbie\ger\prj\1original\OpenEXR\src\IlmBase\Imath\ImathPlatform.h        
2006-12-09
00:23:08.000000000 +-0200
+++ \\Debbie\ger\prj\3actual\OpenEXR\IlmBase\Imath\ImathPlatform.h      
2008-06-17
22:15:23.000000000 +-0200
@@ -43,19 +43,97 @@
 //
 //     This file contains functions and constants which aren't
 //     provided by the system libraries, compilers, or includes on
 //     certain platforms.
 //----------------------------------------------------------------------------

+#if defined(_MSC_VER)
+/* [i_a] MSVC again: see the comment from Microsoft's math.h below (MSVC2005).
+
+   Other compilers may also lack M_PI / M_PI_2 which both are used in the
+   OpenEXR (test) code.
+
+   Microsoft says:
+
+       Define _USE_MATH_DEFINES before including math.h to expose these macro
+       definitions for common math constants.  These are placed under an #ifdef
+       since these commonly-defined names are not part of the C/C++ standards.
+
+   End of quote.
+
+   The other defines have been added for completeness sake (they exist on
+   BSD and Linux at least and other code may expect these).
+
+   Microsoft doesn't define M_2PI ever, other compilers may lack some of these
+   too, hence the sequence as it is: load math.h, then see what's
lacking still.
+*/
+#define _USE_MATH_DEFINES 1
+#endif
+
 #include <math.h>

-#if defined _WIN32 || defined _WIN64
+// #if defined _WIN32 || defined _WIN64 -- [i_a] some other platforms
(MingW?) don't have this either, it seems.
     #ifndef M_PI
-        #define M_PI 3.14159265358979323846
+        #define M_PI    3.14159265358979323846 /* pi */
     #endif
+
+       #ifndef M_PI_2
+        #define M_PI_2  1.57079632679489661923 /* pi/2 */
+    #endif
+
+/* Some extra useful constants.  */
+
+#ifndef M_E
+#define M_E            2.7182818284590452354   /* e */
 #endif
+
+#ifndef M_LOG2E
+#define M_LOG2E        1.4426950408889634074   /* log_2 e */
+#endif
+
+#ifndef M_LOG10E
+#define M_LOG10E       0.43429448190325182765  /* log_10 e */
+#endif
+
+#ifndef M_LN2
+#define M_LN2          0.69314718055994530942  /* log_e 2 */
+#endif
+
+#ifndef M_LN10
+#define M_LN10         2.30258509299404568402  /* log_e 10 */
+#endif
+
+#ifndef M_PI_4
+#define M_PI_4         0.78539816339744830962  /* pi/4 */
+#endif
+
+#ifndef M_1_PI
+#define M_1_PI         0.31830988618379067154  /* 1/pi */
+#endif
+
+#ifndef M_2_PI
+#define M_2_PI         0.63661977236758134308  /* 2/pi */
+#endif
+
+#ifndef M_2_SQRTPI
+#define M_2_SQRTPI     1.12837916709551257390  /* 2/sqrt(pi) */
+#endif
+
+#ifndef M_SQRT2
+#define M_SQRT2        1.41421356237309504880  /* sqrt(2) */
+#endif
+
+#ifndef M_SQRT1_2
+#define M_SQRT1_2      0.70710678118654752440  /* 1/sqrt(2) */
+#endif
+
+#ifndef M_2PI
+#define M_2PI           6.283185307179586232    /* 2*pi  */
+#endif
+
+// #endif

 //-----------------------------------------------------------------------------
 //
 //    Fixes for the "restrict" keyword.  These #ifdef's for detecting
 //    compiler versions courtesy of Boost's select_compiler_config.hpp;
 //    here is the copyright notice for that file:



-- 
Met vriendelijke groeten / Best regards,

Ger Hobbelt

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