Making more progress on EXPERIMENTAL_HIGH_PRECISION_MATH_Q3MAP2_FIXES code.

- Setting EXPERIMENTAL_HIGH_PRECISION_MATH_Q3MAP2_FIXES to 1 (enabled).  I'll
turn this off before merging into trunk.

- In function MapPlaneFromPoints() in map.c, doing a bit tighter math when
EXPERIMENTAL_HIGH_PRECISION_MATH_Q3MAP2_FIXES is on.  This comes at the
expense of a few extra CPU cycles.  The signature of the function remains
the same.

- In VectorNormalize() in mathlib.c, fixing a cast of the return value.
I did not see compile warnings or runtime errors, but it seems wrong the
way it was.

- Adding VectorNormalizeAccu() in mathlib.c, for normalizing vectors built on
the high resolution data type.


git-svn-id: svn://svn.icculus.org/gtkradiant/GtkRadiant/branches/Rambetter-math-fix-experiments@395 8a3a26a2-13c4-0310-b231-cf6edde360e5

libs/mathlib.h

@@ -347,6 +347,7 @@ vec_accu_t Q_rintAccu(vec_accu_t val);
 
 void VectorCopyAccuToRegular(const vec3_accu_t in, vec3_t out);
 void VectorCopyRegularToAccu(const vec3_t in, vec3_accu_t out);
+vec_accu_t VectorNormalizeAccu(const vec3_accu_t in, vec3_accu_t out);
 
 #ifdef __cplusplus
 }

libs/mathlib/mathlib.c

@@ -150,7 +150,7 @@ vec_t VectorNormalize( const vec3_t in, vec3_t out ) {
 	out[1] = (vec_t) (y / length);
 	out[2] = (vec_t) (z / length);
 
-	return length;
+	return (vec_t) length;
 }
 
 vec_t ColorNormalize( const vec3_t in, vec3_t out ) {
@@ -722,3 +722,31 @@ void VectorCopyRegularToAccu(const vec3_t in, vec3_accu_t out)
 	out[1] = (vec_accu_t) in[1];
 	out[2] = (vec_accu_t) in[2];
 }
+
+/*
+=================
+VectorNormalizeAccu
+=================
+*/
+vec_accu_t VectorNormalizeAccu(const vec3_accu_t in, vec3_accu_t out)
+{
+	// The sqrt() function takes double as an input and returns double as an
+	// output according the the man pages on Debian and on FreeBSD.  Therefore,
+	// I don't see a reason why using a double outright (instead of using the
+	// vec_accu_t alias for example) could possibly be frowned upon.
+
+	vec_accu_t	length;
+
+	length = (vec_accu_t) sqrt((in[0] * in[0]) + (in[1] * in[1]) + (in[2] * in[2]));
+	if (length == 0)
+	{
+		VectorClear(out);
+		return 0;
+	}
+
+	out[0] = in[0] / length;
+	out[1] = in[1] / length;
+	out[2] = in[2] / length;
+
+	return length;
+}

tools/quake3/q3map2/map.c

@@ -280,6 +280,25 @@ takes 3 points and finds the plane they lie in
 
 int MapPlaneFromPoints( vec3_t *p )
 {
+#if EXPERIMENTAL_HIGH_PRECISION_MATH_Q3MAP2_FIXES
+	vec3_accu_t	paccu[3];
+	vec3_accu_t	t1, t2, normalAccu;
+	vec3_t		normal;
+	vec_t		dist;
+
+	VectorCopyRegularToAccu(p[0], paccu[0]);
+	VectorCopyRegularToAccu(p[1], paccu[1]);
+	VectorCopyRegularToAccu(p[2], paccu[2]);
+
+	VectorSubtractAccu(paccu[0], paccu[1], t1);
+	VectorSubtractAccu(paccu[2], paccu[1], t2);
+	CrossProductAccu(t1, t2, normalAccu);
+	VectorNormalizeAccu(normalAccu, normalAccu);
+	dist = (vec_t) DotProductAccu(paccu[0], normalAccu);
+	VectorCopyAccuToRegular(normalAccu, normal);
+
+	return FindFloatPlane(normal, dist, 3, p);
+#else
 	vec3_t	t1, t2, normal;
 	vec_t	dist;
 	
@@ -295,6 +314,7 @@ int MapPlaneFromPoints( vec3_t *p )
 	
 	/* store the plane */
 	return FindFloatPlane( normal, dist, 3, p );
+#endif
 }
 
 

tools/quake3/q3map2/q3map2.h

@@ -123,7 +123,7 @@ constants
 ------------------------------------------------------------------------------- */
 
 /* temporary hacks and tests (please keep off in SVN to prevent anyone's legacy map from screwing up) */
-#define EXPERIMENTAL_HIGH_PRECISION_MATH_Q3MAP2_FIXES	0
+#define EXPERIMENTAL_HIGH_PRECISION_MATH_Q3MAP2_FIXES	1
 
 /* general */
 #define MAX_QPATH				64