puzzles: fix a few things

- old acos() function was broken, replaced with a call to atan2(); this fixes "Cube!"
- Makefile extended to support building "unfinished games", but not enabled
- a backdrop issue fixed in rockbox.c

Change-Id: I9393e958d43de32f4ccf18e1cb409f75c2e1ed3c

1 files changed, 2 insertions, 93 deletions

diff --git a/apps/plugins/puzzles/rbwrappers.c b/apps/plugins/puzzles/rbwrappers.c
index b553a66dfc..2762194de3 100644
--- a/apps/plugins/puzzles/rbwrappers.c
+++ b/apps/plugins/puzzles/rbwrappers.c
@@ -1013,101 +1013,10 @@ float sqrt_wrapper(float x)
         return z;
 }
 
-/* @(#)e_acos.c 1.3 95/01/18 */
-/*
- * ====================================================
- * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
- *
- * Developed at SunSoft, a Sun Microsystems, Inc. business.
- * Permission to use, copy, modify, and distribute this
- * software is freely granted, provided that this notice
- * is preserved.
- * ====================================================
- */
-
-/* __ieee754_acos(x)
- * Method :
- *      acos(x)  = pi/2 - asin(x)
- *      acos(-x) = pi/2 + asin(x)
- * For |x|<=0.5
- *      acos(x) = pi/2 - (x + x*x^2*R(x^2))     (see asin.c)
- * For x>0.5
- *      acos(x) = pi/2 - (pi/2 - 2asin(sqrt((1-x)/2)))
- *              = 2asin(sqrt((1-x)/2))
- *              = 2s + 2s*z*R(z)        ...z=(1-x)/2, s=sqrt(z)
- *              = 2f + (2c + 2s*z*R(z))
- *     where f=hi part of s, and c = (z-f*f)/(s+f) is the correction term
- *     for f so that f+c ~ sqrt(z).
- * For x<-0.5
- *      acos(x) = pi - 2asin(sqrt((1-|x|)/2))
- *              = pi - 0.5*(s+s*z*R(z)), where z=(1-|x|)/2,s=sqrt(z)
- *
- * Special cases:
- *      if x is NaN, return x itself;
- *      if |x|>1, return NaN with invalid signal.
- *
- * Function needed: sqrt
- */
-
-#ifdef __STDC__
-static const double
-#else
-static double
-#endif
-pio2_hi =  1.57079632679489655800e+00, /* 0x3FF921FB, 0x54442D18 */
-pio2_lo =  6.12323399573676603587e-17, /* 0x3C91A626, 0x33145C07 */
-pS0 =  1.66666666666666657415e-01, /* 0x3FC55555, 0x55555555 */
-pS1 = -3.25565818622400915405e-01, /* 0xBFD4D612, 0x03EB6F7D */
-pS2 =  2.01212532134862925881e-01, /* 0x3FC9C155, 0x0E884455 */
-pS3 = -4.00555345006794114027e-02, /* 0xBFA48228, 0xB5688F3B */
-pS4 =  7.91534994289814532176e-04, /* 0x3F49EFE0, 0x7501B288 */
-pS5 =  3.47933107596021167570e-05, /* 0x3F023DE1, 0x0DFDF709 */
-qS1 = -2.40339491173441421878e+00, /* 0xC0033A27, 0x1C8A2D4B */
-qS2 =  2.02094576023350569471e+00, /* 0x40002AE5, 0x9C598AC8 */
-qS3 = -6.88283971605453293030e-01, /* 0xBFE6066C, 0x1B8D0159 */
-qS4 =  7.70381505559019352791e-02; /* 0x3FB3B8C5, 0xB12E9282 */
-
+/* hack, simple trig */
 double acos_wrapper(double x)
 {
-        double z,p,q,r,w,s,c,df;
-        int hx,ix;
-        hx = __HI(x);
-        ix = hx&0x7fffffff;
-        if(ix>=0x3ff00000) {    /* |x| >= 1 */
-            if(((ix-0x3ff00000)|__LO(x))==0) {  /* |x|==1 */
-                if(hx>0) return 0.0;            /* acos(1) = 0  */
-                else return pi+2.0*pio2_lo;     /* acos(-1)= pi */
-            }
-            return (x-x)/(x-x);         /* acos(|x|>1) is NaN */
-        }
-        if(ix<0x3fe00000) {     /* |x| < 0.5 */
-            if(ix<=0x3c600000) return pio2_hi+pio2_lo;/*if|x|<2**-57*/
-            z = x*x;
-            p = z*(pS0+z*(pS1+z*(pS2+z*(pS3+z*(pS4+z*pS5)))));
-            q = one+z*(qS1+z*(qS2+z*(qS3+z*qS4)));
-            r = p/q;
-            return pio2_hi - (x - (pio2_lo-x*r));
-        } else  if (hx<0) {             /* x < -0.5 */
-            z = (one+x)*0.5;
-            p = z*(pS0+z*(pS1+z*(pS2+z*(pS3+z*(pS4+z*pS5)))));
-            q = one+z*(qS1+z*(qS2+z*(qS3+z*qS4)));
-            s = sqrt_wrapper(z);
-            r = p/q;
-            w = r*s-pio2_lo;
-            return pi - 2.0*(s+w);
-        } else {                        /* x > 0.5 */
-            z = (one-x)*0.5;
-            s = sqrt_wrapper(z);
-            df = s;
-            __LO(df) = 0;
-            c  = (z-df*df)/(s+df);
-            p = z*(pS0+z*(pS1+z*(pS2+z*(pS3+z*(pS4+z*pS5)))));
-            q = one+z*(qS1+z*(qS2+z*(qS3+z*qS4)));
-            r = p/q;
-            w = r*s+c;
-            return 2.0*(df+w);
-        }
-
+    return atan2_wrapper(sqrt_wrapper(1.0 - x * x), x);
 }
 
 /*