initial commit.

1 files changed, 115 insertions, 0 deletions

diff --git a/maths.c b/maths.c
new file mode 100644
index 0000000..d0bccf3
--- /dev/null
+++ b/maths.c
@@ -0,0 +1,115 @@
+#include "maths.h"
+
+#define sin_table_count 256
+
+static const int sin_table[sin_table_count] = {
+	0, 25, 50, 75,
+	100, 125, 150, 175,
+	200, 224, 249, 273,
+	297, 321, 345, 369,
+	392, 415, 438, 460,
+	483, 505, 526, 548,
+	569, 590, 610, 630,
+	650, 669, 688, 706,
+	724, 742, 759, 775,
+	792, 807, 822, 837,
+	851, 865, 878, 891,
+	903, 915, 926, 936,
+	946, 955, 964, 972,
+	980, 987, 993, 999,
+	1004, 1009, 1013, 1016,
+	1019, 1021, 1023, 1024,
+	1024, 1024, 1023, 1021,
+	1019, 1016, 1013, 1009,
+	1004, 999, 993, 987,
+	980, 972, 964, 955,
+	946, 936, 926, 915,
+	903, 891, 878, 865,
+	851, 837, 822, 807,
+	792, 775, 759, 742,
+	724, 706, 688, 669,
+	650, 630, 610, 590,
+	569, 548, 526, 505,
+	483, 460, 438, 415,
+	392, 369, 345, 321,
+	297, 273, 249, 224,
+	200, 175, 150, 125,
+	100, 75, 50, 25,
+	0, -25, -50, -75,
+	-100, -125, -150, -175,
+	-200, -224, -249, -273,
+	-297, -321, -345, -369,
+	-392, -415, -438, -460,
+	-483, -505, -526, -548,
+	-569, -590, -610, -630,
+	-650, -669, -688, -706,
+	-724, -742, -759, -775,
+	-792, -807, -822, -837,
+	-851, -865, -878, -891,
+	-903, -915, -926, -936,
+	-946, -955, -964, -972,
+	-980, -987, -993, -999,
+	-1004, -1009, -1013, -1016,
+	-1019, -1021, -1023, -1024,
+	-1024, -1024, -1023, -1021,
+	-1019, -1016, -1013, -1009,
+	-1004, -999, -993, -987,
+	-980, -972, -964, -955,
+	-946, -936, -926, -915,
+	-903, -891, -878, -865,
+	-851, -837, -822, -807,
+	-792, -775, -759, -742,
+	-724, -706, -688, -669,
+	-650, -630, -610, -590,
+	-569, -548, -526, -505,
+	-483, -460, -438, -415,
+	-392, -369, -345, -321,
+	-297, -273, -249, -224,
+	-200, -175, -150, -125,
+	-100, -75, -50, -25
+};
+
+int fsqrt(int n) {
+	int lo, hi, mid, i, mm;
+	if (n <= 0) { return -1; }
+	lo = mini(1, n);
+	hi = maxi(1, n);
+	while ((100 << fbits * lo * lo) >> fbits * 2)
+		lo *= (10 << fbits) >> fbits;
+	while ((5 * hi * hi) >> fbits * 2 > n)
+		hi *= (1 << fbits) / 10;
+	for (i = 0; i < 100; i++) {
+		mid = ((lo + hi) * (1 << fbits)) / (2 << fbits);
+		mm = mid * mid >> fbits;
+		if (mm == n) return mid;
+		if (mm > n)  hi = mid;
+		else         lo = mid;
+	}
+	return mid;
+}
+
+int absolute(int x) {
+	return x >= 0 ? x : -x;
+}
+
+int fsin(int t) {
+	int index, sign;
+	sign = t >= 0 ? 1 : -1;
+	t = absolute(t);
+	index = (t * (sin_table_count) / ((1 << fbits) * 2));
+	index = index % sin_table_count;
+	return (sign * sin_table[index]) / 2;
+}
+
+int fcos(int t) {
+	return fsin((1 << fbits) / 2 - t);
+}
+
+int ftan(int t) {
+	return (fsin(t) << fbits) / fcos(t);
+}
+
+int flerp(int a, int b, int t) {
+	return a + ((t * (b - a)) >> fbits);
+}
+