euler stuff

diff --git a/vg_m.h b/vg_m.h
index 6d86177894e97f75273c7f67e9c6b4be0bd0e2e2..46cf38c173d09111ed17fc86176707ece7249845 100644 (file)
--- a/vg_m.h
+++ b/vg_m.h
@@ -540,6 +540,34 @@ static void v3_tangent_basis( v3f n, v3f tx, v3f ty ){
    v3_cross( n, tx, ty );
 }
 
+/*
+ * Compute yaw and pitch based of a normalized vector representing forward
+ * forward: -z
+ * result -> (YAW,PITCH,0.0)
+ */
+static void v3_angles( v3f v, v3f out_angles ){
+   float yaw = atan2f( v[0], -v[2] ),
+       pitch = atan2f( 
+                   -v[1], 
+                   sqrtf(
+                     v[0]*v[0] + v[2]*v[2]
+                   )
+               );
+
+   out_angles[0] = yaw;
+   out_angles[1] = pitch;
+   out_angles[2] = 0.0f;
+}
+
+/*
+ * Compute the forward vector from (YAW,PITCH,ROLL)
+ * forward: -z
+ */
+static void v3_angles_vector( v3f angles, v3f out_v ){
+   out_v[0] =  sinf( angles[0] ) * cosf( angles[1] );
+   out_v[1] = -sinf( angles[1] );
+   out_v[2] = -cosf( angles[0] ) * cosf( angles[1] );
+}
 
 /*
  * -----------------------------------------------------------------------------