Merge pull request #22 from t-mw/quat_mul_vec3_fix

Fix bug in quat_mul_vec3 caused by reuse of u and t in 'vec3_mul_cross'

1 files changed, 4 insertions, 3 deletions

diff --git a/linmath.h b/linmath.h
index d0e1f00..b368739 100644
--- a/linmath.h
+++ b/linmath.h
@@ -481,13 +481,14 @@ static inline void quat_mul_vec3(vec3 r, quat q, vec3 v)
 t = 2 * cross(q.xyz, v)
 v' = v + q.w * t + cross(q.xyz, t)
  */
-	vec3 t = {q[0], q[1], q[2]};
+	vec3 t;
+	vec3 q_xyz = {q[0], q[1], q[2]};
 	vec3 u = {q[0], q[1], q[2]};
 
-	vec3_mul_cross(t, t, v);
+	vec3_mul_cross(t, q_xyz, v);
 	vec3_scale(t, t, 2);
 
-	vec3_mul_cross(u, u, t);
+	vec3_mul_cross(u, q_xyz, t);
 	vec3_scale(t, t, q[3]);
 
 	vec3_add(r, v, t);