From 0a0f4093618074e4be59e4108404fd1369d71eda Mon Sep 17 00:00:00 2001
From: "S. Gilles" <sgilles@math.umd.edu>
Date: Thu, 26 Jan 2017 02:00:31 -0500
Subject: [PATCH] Fix up trig constants

 o Remove useless sine/cosine precalculations

 o Add M_PI, since GCC (or glibc?) is inconsistent on whether the
   default options in the Makefile bring it in.
---
 ui-sdl.c | 30 +++---------------------------
 1 file changed, 3 insertions(+), 27 deletions(-)

diff --git a/ui-sdl.c b/ui-sdl.c
index 7e8cfc8..a9c82c2 100644
--- a/ui-sdl.c
+++ b/ui-sdl.c
@@ -31,7 +31,9 @@
 
 #define TICKS_PER_FRAME (1000 / 60)
 
-#define TRIG_PRECALC_NUM 4
+#ifndef M_PI
+#define M_PI (3.14159265358979323846)
+#endif
 
 /* What clicking does */
 static enum ui_action {
@@ -242,29 +244,6 @@ static uint_fast8_t save_load_delay;
 /* If something needs to be freed next frame, but not before */
 static void *free_this;
 
-/* sine tables */
-static double precalc_sins[TRIG_PRECALC_NUM];
-
-/* cosine tables */
-static double precalc_coss[TRIG_PRECALC_NUM];
-
-/* Precalculate sines and cosines */
-static void precalc_trig(void)
-{
-        precalc_coss[0] = 0.0;
-        precalc_sins[0] = 1.0;
-
-        for (size_t j = 1; j < TRIG_PRECALC_NUM - 1; ++j) {
-                double theta = (M_PI * j) / (2 * (TRIG_PRECALC_NUM - 1));
-
-                precalc_sins[j] = sin(theta);
-                precalc_coss[j] = cos(theta);
-        }
-
-        precalc_coss[TRIG_PRECALC_NUM - 1] = 0.0;
-        precalc_sins[TRIG_PRECALC_NUM - 1] = 1.0;
-}
-
 /* GCD */
 static int gcd(uint_fast8_t x, uint_fast8_t y)
 {
@@ -840,9 +819,6 @@ int ui_init(struct quiver *i_q)
         eq_len = 2;
         eq_head = 0;
         eq_tail = 0;
-
-        /* Sines and cosines for drawing circles */
-        precalc_trig();
 done:
 
         return ret;
-- 
2.11.4.GIT