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#include <math/quat.h>
#include <math/float.h>
#include "test.h"
#include <stdio.h>
static const float eps = 1e-7;
static inline void print_quat(quat q) {
printf("{ %f, %f, %f, %f }\n", q.x, q.y, q.z, q.w);
}
static inline void print_vec3(vec3 v) {
printf("{ %f, %f, %f }\n", v.x, v.y, v.z);
}
/// Slerp between two vectors forming an acute angle.
TEST_CASE(quat_slerp_acute_angle) {
const R angle1 = 0;
const R angle2 = PI / 4;
const R t = 0.5;
const quat a = qmake_rot(angle1, 0, 0, 1);
const quat b = qmake_rot(angle2, 0, 0, 1);
const quat c = qslerp(a, b, t);
const vec3 result = qrot(c, vec3_make(1, 0, 0));
const R angle3 = lerp(angle1, angle2, t);
const vec3 expected = vec3_make(cos(angle3), sin(angle3), 0.0);
TEST_TRUE(vec3_eq(result, expected, eps));
}
/// Slerp between two vectors forming an obtuse angle (negative dot product).
///
/// The interpolation must follow the shortest path between both vectors.
TEST_CASE(quat_slerp_obtuse_angle) {
const R angle1 = 0;
const R angle2 = 3 * PI / 4;
const R t = 0.5;
const quat a = qmake_rot(angle1, 0, 0, 1);
const quat b = qmake_rot(angle2, 0, 0, 1);
const quat c = qslerp(a, b, t);
const vec3 result = qrot(c, vec3_make(1, 0, 0));
const R angle3 = lerp(angle1, angle2, t);
const vec3 expected = vec3_make(cos(angle3), sin(angle3), 0.0);
TEST_TRUE(vec3_eq(result, expected, eps));
}
/// Slerp between two vectors forming a reflex angle.
///
/// The interpolation must follow the shortest path between both vectors.
TEST_CASE(quat_slerp_reflex_angle) {
const R angle1 = 0;
const R angle2 = 5 * PI / 4;
const R t = 0.5;
const quat a = qmake_rot(angle1, 0, 0, 1);
const quat b = qmake_rot(angle2, 0, 0, 1);
const quat c = qslerp(a, b, t);
const vec3 result = qrot(c, vec3_make(1, 0, 0));
// Because it's a reflex angle, we expect the rotation to follow the short
// path from 'a' down clockwise to 'b'. Could add +PI to the result of lerp(),
// but that adds more error than negating cos and sin.
const R angle3 = lerp(angle1, angle2, t);
const vec3 expected = vec3_make(-cos(angle3), -sin(angle3), 0.0);
TEST_TRUE(vec3_eq(result, expected, eps));
}
TEST_CASE(quat_mat4_from_quat) {
const R angle = PI / 8;
const quat q = qmake_rot(angle, 0, 0, 1);
const mat4 m = mat4_from_quat(q);
const vec3 p = mat4_mul_vec3(m, vec3_make(1, 0, 0), /*w=*/1);
TEST_TRUE(vec3_eq(p, vec3_make(cos(angle), sin(angle), 0), eps));
}
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