vector ops

v3.h

@@ -0,0 +1,99 @@
+/** \file
+ * 3D point operations.
+ */
+#ifndef _papercraft_v3_h_
+#define _papercraft_v3_h_
+
+#include <math.h>
+
+#define EPS 0.0001
+
+
+typedef struct
+{
+	float p[3];
+} v3_t;
+
+
+static inline int
+v3_eq(
+	const v3_t * v1,
+	const v3_t * v2
+)
+{
+	float dx = v1->p[0] - v2->p[0];
+	float dy = v1->p[1] - v2->p[1];
+	float dz = v1->p[2] - v2->p[2];
+
+	if (-EPS < dx && dx < EPS
+	&&  -EPS < dy && dy < EPS
+	&&  -EPS < dz && dz < EPS)
+		return 1;
+
+	return 0;
+}
+
+
+static inline double
+v3_len(
+	const v3_t * const v0,
+	const v3_t * const v1
+)
+{
+	float dx = v0->p[0] - v1->p[0];
+	float dy = v0->p[1] - v1->p[1];
+	float dz = v0->p[2] - v1->p[2];
+
+	return sqrt(dx*dx + dy*dy + dz*dz);
+}
+
+
+static inline v3_t
+v3_sub(
+	v3_t a,
+	v3_t b
+)
+{
+	v3_t c = { .p = {
+		a.p[0] - b.p[0],
+		a.p[1] - b.p[1],
+		a.p[2] - b.p[2],
+	} };
+	return c;
+}
+
+
+static inline float
+v3_dot(
+	v3_t a,
+	v3_t b
+)
+{
+	return a.p[0]*b.p[0] + a.p[1]*b.p[1] + a.p[2]*b.p[2];
+}
+
+
+static inline v3_t
+v3_cross(
+	v3_t u,
+	v3_t v
+)
+{
+	float u1 = u.p[0];
+	float u2 = u.p[1];
+	float u3 = u.p[2];
+
+	float v1 = v.p[0];
+	float v2 = v.p[1];
+	float v3 = v.p[2];
+
+	v3_t c = { .p = {
+		u2*v3 - u3*v2,
+		u3*v1 - u1*v3,
+		u1*v2 - u2*v1,
+	}};
+
+	return c;
+}
+
+#endif