test: add a 10-line example program that computes Pi to the 150th digit.

.gitignore

@@ -59,5 +59,6 @@ test/testsuite
 test/benchsuite
 test/quad
 test/sandbox
+test/math/pi
 tools/make-font
 # Our data

configure.ac

@@ -322,6 +322,7 @@ AC_CONFIG_FILES(
  [Makefile
   src/Makefile
   test/Makefile
+  test/math/Makefile
   gfx/Makefile
   gfx/font/Makefile
   tools/Makefile

src/real.h

@@ -23,8 +23,6 @@ namespace lol
 
 class real
 {
-    static int const BIGITS = 32;
-
 public:
     inline real() { }
 
@@ -60,6 +58,11 @@ public:
     void print() const;
 
 private:
+    /* XXX: changing this requires tuning real::fres (the number of
+     * Newton-Raphson iterations) and real::print (the number of printed
+     * digits) */
+    static int const BIGITS = 32;
+
     uint32_t m_size;
     uint32_t m_signexp;
     uint16_t m_mantissa[BIGITS];

test/Makefile.am

@@ -1,4 +1,6 @@
 
+SUBDIRS = math
+
 AM_CPPFLAGS = -I$(top_srcdir)/src
 
 bench: benchsuite$(EXEEXT)

test/math/Makefile.am

@@ -0,0 +1,17 @@
+
+AM_CPPFLAGS = -I$(top_srcdir)/src
+
+all-local: $(noinst_PROGRAMS)
+	test x$(MAKE_FSELF) = xno || make_fself pi$(EXEEXT) pi.self
+
+CLEANFILES = $(noinst_PROGRAMS:%$(EXEEXT)=%.self) \
+             $(noinst_PROGRAMS:%$(EXEEXT)=%.elf) \
+             $(noinst_PROGRAMS:%$(EXEEXT)=%.exe)
+
+noinst_PROGRAMS = pi
+
+pi_SOURCES = pi.cpp
+pi_CPPFLAGS = @LOL_CFLAGS@ @PIPI_CFLAGS@
+pi_LDFLAGS = $(top_builddir)/src/liblol.a @LOL_LIBS@ @PIPI_LIBS@
+pi_DEPENDENCIES = $(top_builddir)/src/liblol.a
+

test/math/pi.cpp

@@ -0,0 +1,37 @@
+//
+// Lol Engine - Sample math program: compute Pi
+//
+// Copyright: (c) 2005-2011 Sam Hocevar <sam@hocevar.net>
+//   This program is free software; you can redistribute it and/or
+//   modify it under the terms of the Do What The Fuck You Want To
+//   Public License, Version 2, as published by Sam Hocevar. See
+//   http://sam.zoy.org/projects/COPYING.WTFPL for more details.
+//
+
+#if defined HAVE_CONFIG_H
+#   include "config.h"
+#endif
+
+#include "core.h"
+
+using namespace lol;
+
+int main(int argc, char **argv)
+{
+    /* Approximate Pi using Machin's formula: 16*atan(1/5)-4*atan(1/239) */
+    real sum = 0.0, x0 = 5.0, x1 = 239.0;
+    real const m0 = -x0 * x0, m1 = -x1 * x1, r16 = 16.0, r4 = 4.0;
+
+    /* Degree 240 is required for 512-bit mantissa precision */
+    for (int i = 1; i < 240; i += 2)
+    {
+        sum += r16 / (x0 * (real)i) - r4 / (x1 * (real)i);
+        x0 *= m0;
+        x1 *= m1;
+    }
+
+    sum.print();
+
+    return EXIT_SUCCESS;
+}
+