1 files changed, 26 insertions, 0 deletions

diff --git a/maths.c b/maths.c
index 74d682d..f6f1912 100644
--- a/maths.c
+++ b/maths.c
@@ -64,6 +64,15 @@ void init_maths(void) {
 	mtx_cpy(mtx_stack[0], m);
 }
 
+int fpow(int a, int p) {
+	int r = a;
+	p--;
+	while (p--) {
+		r = (r * a) >> fbits;
+	}
+	return r;
+}
+
 int* mtx_iden(int* m) {
 	register int o = f1;
 	m[0]  = o;
@@ -228,6 +237,23 @@ int* vec_cpy(int* d, const int* s, int c) {
 	return d;
 }
 
+int* vec_ref(int* d, const int* i, const int* n, int c) {
+	int r, j;
+	int dp = 2 * vec_dot(n, i, c);
+	for (j = r = 0; j < c; j++) {
+		d[j] = i[j] - ((dp * n[j]) >> fbits);
+	}
+	return d;
+}
+
+int vec_dot(const int* a, const int* b, int d) {
+	int r, i;
+	for (i = r = 0; i < d; i++) {
+		r += a[i] * b[i] >> fbits;
+	}
+	return r;
+}
+
 void persp(int* v, int asp) {
 	v[2] += !v[2];
 	v[0] = ((v[0] << fbits) / v[2]);