float x, y, z, w;
} cgm_quat;
+/* vectors */
+static inline void cgm_vzero(cgm_vec3 *v);
+static inline void cgm_vone(cgm_vec3 *v);
+
static inline void cgm_vadd(cgm_vec3 *a, const cgm_vec3 *b);
static inline void cgm_vsub(cgm_vec3 *a, const cgm_vec3 *b);
static inline void cgm_vmul(cgm_vec3 *a, const cgm_vec3 *b);
static inline float cgm_vdist_sq(const cgm_vec3 *a, const cgm_vec3 *b);
static inline void cgm_vnormalize(cgm_vec3 *v);
+/* quaternions */
+static inline void cgm_qident(cgm_quat *q);
+
+static inline void cgm_qneg(cgm_quat *q);
+static inline void cgm_qadd(cgm_quat *a, const cgm_quat *b);
+static inline void cgm_qsub(cgm_quat *a, const cgm_quat *b);
+static inline void cgm_qmul(cgm_quat *a, const cgm_quat *b);
+
+static inline float cgm_qlength(const cgm_quat *q);
+static inline float cgm_qlength_sq(const cgm_quat *q);
+
+static inline void cgm_qnormalize(cgm_quat *q);
+
+static inline void cgm_qconjugate(cgm_quat *q);
+static inline void cgm_qinvert(cgm_quat *q);
+
+static inline void cgm_qrot_axis(cgm_quat *q, float axis, float x, float y, float z);
+static inline void cgm_qrot_quat(cgm_quat *q, const cgm_quat *rq);
+
+static inline void cgm_qmatrix(float *mat, const cgm_quat *q);
+
+static inline void cgm_qslerp(cgm_quat *res, const cgm_quat *a, const cgm_quat *b, float t);
+
#include "cgmath.inl"
#endif /* CGMATH_H_ */
+static inline void cgm_vzero(cgm_vec3 *v)
+{
+ v->x = v->y = v->z = 0.0f;
+}
+
+static inline void cgm_vone(cgm_vec3 *v)
+{
+ v->x = v->y = v->z = 1.0f;
+}
+
static inline void cgm_vadd(cgm_vec3 *a, const cgm_vec3 *b)
{
a->x += b->x;
v->z *= s;
}
}
+
+static inline void cgm_qident(cgm_quat *q)
+{
+ q->x = q->y = q->z = 0.0f;
+ q->w = 1.0f;
+}
+
+static inline void cgm_qneg(cgm_quat *q)
+{
+ q->x = -q->x;
+ q->y = -q->y;
+ q->z = -q->z;
+ q->w = -q->w;
+}
+
+static inline void cgm_qadd(cgm_quat *a, const cgm_quat *b)
+{
+ a->x += b->x;
+ a->y += b->y;
+ a->z += b->z;
+ a->w += b->w;
+}
+
+static inline void cgm_qsub(cgm_quat *a, const cgm_quat *b)
+{
+ a->x -= b->x;
+ a->y -= b->y;
+ a->z -= b->z;
+ a->w -= b->w;
+}
+
+static inline void cgm_qmul(cgm_quat *a, const cgm_quat *b)
+{
+ float axb_x = a->y * b->z - a->z * b->y;
+ float axb_y = a->z * b->x - a->x * b->z;
+ float axb_z = a->x * b->y - a->y * b->x;
+
+ float im_x = a->w * b->x + b->w * a->x + axb_x;
+ float im_y = a->w * b->y + b->w * a->y + axb_y;
+ float im_z = a->w * b->z + b->w * a->z + axb_z;
+
+ a->w = a->w * b->w - (a->x * b->x + a->y * b->y + a->z * b->z);
+ a->x = im_x;
+ a->y = im_y;
+ a->z = im_z;
+}
+
+static inline float cgm_qlength(const cgm_quat *q)
+{
+ return sqrt(q->x * q->x + q->y * q->y + q->z * q->z + q->w * q->w);
+}
+
+static inline float cgm_qlength_sq(const cgm_quat *q)
+{
+ return q->x * q->x + q->y * q->y + q->z * q->z + q->w * q->w;
+}
+
+static inline void cgm_qnormalize(cgm_quat *q)
+{
+ float len = cgm_qlength(q);
+ if(len != 0.0f) {
+ float inv_len = 1.0f / len;
+ q->x *= inv_len;
+ q->y *= inv_len;
+ q->z *= inv_len;
+ q->w *= inv_len;
+ }
+}
+
+static inline void cgm_qconjugate(cgm_quat *q)
+{
+ q->x = -q->x;
+ q->y = -q->y;
+ q->z = -q->z;
+}
+
+static inline void cgm_qinvert(cgm_quat *q)
+{
+ cgm_qconjugate(q);
+ float len_sq = cgm_qlength_sq(q);
+ if(len_sq != 0.0) {
+ float s = 1.0f / len_sq;
+ q->x *= s;
+ q->y *= s;
+ q->z *= s;
+ q->w *= s;
+ }
+}
+
+static inline void cgm_qrot_axis(cgm_quat *q, float angle, float x, float y, float z)
+{
+ float half_angle = angle * 0.5f;
+ float sin_ha = sin(half_angle);
+ q->w = cos(half_angle);
+ q->x = x * sin_ha;
+ q->y = y * sin_ha;
+ q->z = z * sin_ha;
+}
+
+static inline void cgm_qrot_quat(cgm_quat *q, const cgm_quat *rq)
+{
+ cgm_quat qrot = *rq;
+ cgm_quat rqconj = *rq;
+ cgm_qconjugate(&rqconj);
+ cgm_qmul(&qrot, q);
+ cgm_qmul(&qrot, &rqconj);
+ *q = qrot;
+}
+
+static inline void cgm_qmatrix(float *mat, const cgm_quat *q)
+{
+ float xsq2 = 2.0f * q->x * q->x;
+ float ysq2 = 2.0f * q->y * q->y;
+ float zsq2 = 2.0f * q->z * q->z;
+ float sx = 1.0f - ysq2 - zsq2;
+ float sy = 1.0f - xsq2 - zsq2;
+ float sz = 1.0f - xsq2 - ysq2;
+
+ mat[0] = sx;
+ mat[1] = 2.0f * q->x * q->y + 2.0f * q->w * q->z;
+ mat[2] = 2.0f * q->z * q->x - 2.0f * q->w * q->y;
+ mat[3] = 0.0f;
+
+ mat[4] = 2.0f * q->x * q->y - 2.0f * q->w * q->z;
+ mat[5] = sy;
+ mat[6] = 2.0f * q->y * q->z + 2.0f * q->w * q->x;
+ mat[7] = 0.0f;
+
+ mat[8] = 2.0f * q->z * q->x + 2.0f * q->w * q->y;
+ mat[9] = 2.0f * q->y * q->z - 2.0f * q->w * q->x;
+ mat[10] = sz;
+ mat[11] = 0.0f;
+
+ mat[12] = mat[13] = mat[14] = 0.0f;
+ mat[15] = 1.0f;
+}
+
+static inline void cgm_qslerp(cgm_quat *res, const cgm_quat *a, const cgm_quat *b, float t)
+{
+ cgm_quat qa = *a;
+ float dot = a->x * b->x + a->y * b->y + a->z * b->z + a->w * b->w;
+ float angle, sin_angle, ta, tb;
+
+ if(dot < 0.0f) {
+ /* make sure we interpolate across the shortest arc */
+ qa.x = -qa.x;
+ qa.y = -qa.y;
+ qa.z = -qa.z;
+ qa.w = -qa.w;
+ dot = -dot;
+ }
+
+ /* clamp dot to [-1, 1] in order to avoid domain errors in acos */
+ if(dot < -1.0f) dot = -1.0f;
+ if(dot > 1.0f) dot = 1.0f;
+ angle = acos(dot);
+ sin_angle = sin(angle);
+
+ if(sin_angle == 0.0f) {
+ /* use linear interpolation to avoid div/zero */
+ ta = 1.0f - t;
+ tb = t;
+ } else {
+ ta = sin((1.0f - t) * angle) / sin_angle;
+ tb = sin(t * angle) / sin_angle;
+ }
+
+ res->x = a->x * ta + b->x * tb;
+ res->y = a->y * ta + b->y * tb;
+ res->z = a->z * ta + b->z * tb;
+ res->w = a->w * ta + b->w * tb;
+}