windows build

[censuslogo] / src / cgmath / cgmquat.inl

diff --git a/src/cgmath/cgmquat.inl b/src/cgmath/cgmquat.inl
new file mode 100644 (file)
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+++ b/src/cgmath/cgmquat.inl
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+/* gph-cmath - C graphics math library
+ * Copyright (C) 2018 John Tsiombikas <nuclear@member.fsf.org>
+ *
+ * This program is free software. Feel free to use, modify, and/or redistribute
+ * it under the terms of the MIT/X11 license. See LICENSE for details.
+ * If you intend to redistribute parts of the code without the LICENSE file
+ * replace this paragraph with the full contents of the LICENSE file.
+ */
+static inline void cgm_qcons(cgm_quat *q, float x, float y, float z, float w)
+{
+       q->x = x;
+       q->y = y;
+       q->z = z;
+       q->w = w;
+}
+
+
+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 x, y, z, dot;
+       cgm_vec3 cross;
+
+       dot = a->x * b->x + a->y * b->y + a->z * b->z;
+       cgm_vcross(&cross, (cgm_vec3*)a, (cgm_vec3*)b);
+
+       x = a->w * b->x + b->w * a->x + cross.x;
+       y = a->w * b->y + b->w * a->y + cross.y;
+       z = a->w * b->z + b->w * a->z + cross.z;
+       a->w = a->w * b->w - dot;
+       a->x = x;
+       a->y = y;
+       a->z = 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 s = 1.0f / len;
+               q->x *= s;
+               q->y *= s;
+               q->z *= s;
+               q->w *= s;
+       }
+}
+
+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)
+{
+       float len_sq = cgm_qlength_sq(q);
+       cgm_qconjugate(q);
+       if(len_sq != 0.0f) {
+               float s = 1.0f / len_sq;
+               q->x *= s;
+               q->y *= s;
+               q->z *= s;
+               q->w *= s;
+       }
+}
+
+static inline void cgm_qrotation(cgm_quat *q, float angle, float x, float y, float z)
+{
+       float hangle = angle * 0.5f;
+       float sin_ha = sin(hangle);
+       q->w = cos(hangle);
+       q->x = x * sin_ha;
+       q->y = y * sin_ha;
+       q->z = z * sin_ha;
+}
+
+static inline void cgm_qrotate(cgm_quat *q, float angle, float x, float y, float z)
+{
+       cgm_quat qrot;
+       cgm_qrotation(&qrot, angle, x, y, z);
+       cgm_qmul(q, &qrot);
+}
+
+static inline void cgm_qslerp(cgm_quat *res, const cgm_quat *quat1, const cgm_quat *q2, float t)
+{
+       float angle, dot, a, b, sin_angle;
+       cgm_quat q1 = *quat1;
+
+       dot = quat1->x * q2->x + quat1->y * q2->y + quat1->z * q2->z + quat1->w * q2->w;
+       if(dot < 0.0f) {
+               /* make sure we inteprolate across the shortest arc */
+               cgm_qneg(&q1);
+               dot = -dot;
+       }
+
+       /* clamp dot to [-1, 1] in order to avoid domain errors in acos due to
+        * floating point imprecisions
+        */
+       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 */
+               a = 1.0f;
+               b = t;
+       } else {
+               a = sin((1.0f - t) * angle) / sin_angle;
+               b = sin(t * angle) / sin_angle;
+       }
+
+       res->x = q1.x * a + q2->x * b;
+       res->y = q1.y * a + q2->y * b;
+       res->z = q1.z * a + q2->z * b;
+       res->w = q1.w * a + q2->w * b;
+}
+
+static inline void cgm_qlerp(cgm_quat *res, const cgm_quat *a, const cgm_quat *b, float t)
+{
+       res->x = a->x + (b->x - a->x) * t;
+       res->y = a->y + (b->y - a->y) * t;
+       res->z = a->z + (b->z - a->z) * t;
+       res->w = a->w + (b->w - a->w) * t;
+}