diff --git a/small3dlib.h b/small3dlib.h index f39c782..5d8d603 100644 --- a/small3dlib.h +++ b/small3dlib.h @@ -319,7 +319,12 @@ static inline void S3L_setVec4(S3L_Vec4 *v, S3L_Unit x, S3L_Unit y, static inline void S3L_vec3Add(S3L_Vec4 *result, S3L_Vec4 added); static inline void S3L_vec3Sub(S3L_Vec4 *result, S3L_Vec4 substracted); S3L_Unit S3L_vec3Length(S3L_Vec4 v); + +/** Normalizes Vec3. Note that this function tries to normalize correctly rather + than quickly! If you need to normalize quickly, do it yourself in a way that + best fits your case. */ void S3L_normalizeVec3(S3L_Vec4 *v); + S3L_Unit S3L_vec2Length(S3L_Vec4 v); void S3L_normalizeVec2(S3L_Vec4 *v); void S3L_crossProduct(S3L_Vec4 a, S3L_Vec4 b, S3L_Vec4 *result); @@ -954,8 +959,7 @@ void S3L_crossProduct(S3L_Vec4 a, S3L_Vec4 b, S3L_Vec4 *result) result->z = a.x * b.y - a.y * b.x; } -void S3L_triangleNormal(S3L_Vec4 t0, S3L_Vec4 t1, S3L_Vec4 t2, - S3L_Vec4 *n) +void S3L_triangleNormal(S3L_Vec4 t0, S3L_Vec4 t1, S3L_Vec4 t2, S3L_Vec4 *n) { #define antiOverflow 32 @@ -970,6 +974,7 @@ void S3L_triangleNormal(S3L_Vec4 t0, S3L_Vec4 t1, S3L_Vec4 t2, #undef antiOverflow S3L_crossProduct(t1,t2,n); + S3L_normalizeVec3(n); } @@ -1449,14 +1454,22 @@ S3L_Unit S3L_vec2Length(S3L_Vec4 v) void S3L_normalizeVec3(S3L_Vec4 *v) { #define SCALE 16 + #define LIMIT 16 - v->x *= SCALE; - v->y *= SCALE; - v->z *= SCALE; - - // ^ This pre-scale prevents inaccuracy with very small vectors ([1,1,1]). + /* Here we try to decide if the vector is too small and would cause + inaccurate result due to very its inaccurate length. If so, we scale + it up. We can't scale up everything as big vectors overflow in length + calculations. */ + + if (S3L_abs(v->x + v->y + v->z) < LIMIT) + { + v->x *= SCALE; + v->y *= SCALE; + v->z *= SCALE; + } #undef SCALE + #undef LIMIT S3L_Unit l = S3L_vec3Length(*v);