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Add dot/cross

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This commit is contained in:
Miloslav Číž 2019-06-06 00:13:11 +02:00
parent 16ecb29675
commit c48d868007
1 changed files with 42 additions and 7 deletions
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47
small3dlib.h
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@ -282,6 +282,8 @@ S3L_Unit S3L_vec3Length(S3L_Vec4 v);
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);
static inline S3L_Unit S3L_dotProductVec3(S3L_Vec4 a, S3L_Vec4 b);
#define S3L_logVec4(v)\
printf("Vec4: %d %d %d %d\n",((v).x),((v).y),((v).z),((v).w))
@ -454,6 +456,10 @@ static inline S3L_Unit S3L_cos(S3L_Unit x);
S3L_Unit S3L_vec3Length(S3L_Vec4 v);
S3L_Unit S3L_sqrt(S3L_Unit value);
/** Computes a normalized normal of given triangle. */
void S3L_triangleNormal(S3L_Vec4 t0, S3L_Vec4 t1, S3L_Vec4 t2,
S3L_Vec4 *n);
/** Interpolated between two values, v1 and v2, in the same ratio as t is to
tMax. Does NOT prevent zero division. */
static inline S3L_Unit S3L_interpolate(
@ -753,6 +759,33 @@ void S3L_initMat4(S3L_Mat4 *m)
#undef S
}
S3L_Unit S3L_dotProductVec3(S3L_Vec4 a, S3L_Vec4 b)
{
return (a.x * b.x + a.y * b.y + a.z * b.z) / S3L_FRACTIONS_PER_UNIT;
}
void S3L_crossProduct(S3L_Vec4 a, S3L_Vec4 b, S3L_Vec4 *result)
{
result->x = a.y * b.z - a.z * b.y;
result->y = a.z * b.x - a.x * b.z;
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)
{
t1.x = t1.x - t0.x;
t1.y = t1.y - t0.y;
t1.z = t1.z - t0.z;
t2.x = t2.x - t0.x;
t2.y = t2.y - t0.y;
t2.z = t2.z - t0.z;
S3L_crossProduct(t1,t2,n);
S3L_normalizeVec3(n);
}
void S3L_vec4Xmat4(S3L_Vec4 *v, S3L_Mat4 *m)
{
S3L_Vec4 vBackup;
@ -765,10 +798,10 @@ void S3L_vec4Xmat4(S3L_Vec4 *v, S3L_Mat4 *m)
// TODO: try alternative operation orders to optimize
#define dotCol(col)\
(vBackup.x * (*m)[col][0]) / S3L_FRACTIONS_PER_UNIT +\
(vBackup.y * (*m)[col][1]) / S3L_FRACTIONS_PER_UNIT +\
(vBackup.z * (*m)[col][2]) / S3L_FRACTIONS_PER_UNIT +\
(vBackup.w * (*m)[col][3]) / S3L_FRACTIONS_PER_UNIT
((vBackup.x * (*m)[col][0]) +\
(vBackup.y * (*m)[col][1]) +\
(vBackup.z * (*m)[col][2]) +\
(vBackup.w * (*m)[col][3])) / S3L_FRACTIONS_PER_UNIT
v->x = dotCol(0);
v->y = dotCol(1);
@ -1099,7 +1132,7 @@ void S3L_lookAt(S3L_Vec4 pointFrom, S3L_Vec4 pointTo, S3L_Transform3D *t)
S3L_Unit dx = v.x;
S3L_Unit l = S3L_vec2Length(v);
dx = (v.x * S3L_FRACTIONS_PER_UNIT) / l; // normalize
dx = (v.x * S3L_FRACTIONS_PER_UNIT) / S3L_nonZero(l); // normalize
t->rotation.y = S3L_asin(dx);
@ -1109,7 +1142,9 @@ void S3L_lookAt(S3L_Vec4 pointFrom, S3L_Vec4 pointTo, S3L_Transform3D *t)
v.x = pointTo.y - pointFrom.y;
v.y = l;
dx = (v.x * S3L_FRACTIONS_PER_UNIT) / S3L_vec2Length(v);
l = S3L_vec2Length(v);
dx = (v.x * S3L_FRACTIONS_PER_UNIT) / S3L_nonZero(l);
t->rotation.x = S3L_asin(dx);
}