+VG_STATIC void line_tangent_basis( v3f n, v3f tx, v3f ty )
+{
+ /* Compute tangent basis (box2d) */
+ if( fabsf( n[0] ) >= 0.57735027f )
+ {
+ tx[0] = n[1];
+ tx[1] = -n[0];
+ tx[2] = 0.0f;
+ }
+ else
+ {
+ tx[0] = 0.0f;
+ tx[1] = n[2];
+ tx[2] = -n[1];
+ }
+
+ v3_normalize( tx );
+ v3_cross( n, tx, ty );
+}
+
+VG_STATIC void vg_line_arrow( line_co co, line_co dir, float size, u32 colour )
+{
+ v3f p1, tx, ty, p2, p3;
+ v3_muladds( co, dir, size, p1 );
+ line_tangent_basis( dir, tx, ty );
+
+ v3_muladds( p1, dir, -size * 0.125f, p2 );
+ v3_muladds( p2, ty, size * 0.125f, p3 );
+ v3_muladds( p2, ty, -size * 0.125f, p2 );
+
+ vg_line( co, p1, colour );
+ vg_line( p1, p2, colour );
+ vg_line( p1, p3, colour );
+}
+