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//-----------------------------------------------------------------------------
// Name: quaternions.h
// Developer: Wolfire Games LLC
// Description:
// License: Read below
//-----------------------------------------------------------------------------
//
// Copyright 2022 Wolfire Games LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//-----------------------------------------------------------------------------
#pragma once
#include <Math/vec3math.h>
#include <Math/mat4.h>
#include <Math/mat3.h>
class quaternion {
public:
float entries[4];
quaternion& operator+=( const quaternion &b );
quaternion(bool Degree_Flag, vec3 Euler);
quaternion(float x, float y, float z, float w);
quaternion(vec4 AnAx); // vec4(vec3(axis), float angle [radians])
quaternion(const quaternion &other);
quaternion();
float& operator[](int which){ return entries[which]; }
const float& operator[](int which)const{ return entries[which]; }
};
float Length2(const quaternion& quat);
vec4 Quat_2_AA(quaternion Quat);
quaternion normalize(const quaternion &quat);
quaternion Quat_Mult(const quaternion &q1, const quaternion &q2);
quaternion QNormalize(quaternion Quat);
vec3 Quat2Vector(quaternion Quat);
void QuaternionInvert(quaternion * quat);
void QuaternionToAxisAngle(quaternion quat, vec3 * axis, float * angle);
quaternion QuaternionFromAxisAngle(vec3 axis, float angle);
quaternion QuaternionFromMat4(const mat4 &m);
mat4 Mat4FromQuaternion(const quaternion &Quat);
mat3 Mat3FromQuaternion(const quaternion &Quat);
quaternion invert(const quaternion &quat);
const quaternion operator*(const quaternion &a,
const quaternion &b);
bool operator!=(const quaternion &a,
const quaternion &b);
bool operator==(const quaternion &a,
const quaternion &b);
const quaternion operator+(const quaternion &a,
const quaternion &b);
const vec3 operator*(const quaternion &a,
const vec3 &b);
const quaternion operator*(const quaternion &a,
float b);
float dot( const quaternion &a, const quaternion &b );
quaternion Slerp(quaternion start, quaternion end, float t);
inline quaternion mix( const quaternion &a, const quaternion &b, float alpha )
{return Slerp(a,b,alpha);}
vec3 ASMult( quaternion a, vec3 b );
quaternion invert_by_val(quaternion quat);
void QuaternionMultiplyVector(const quaternion * quat, vec3 * vector);
inline vec3 QuaternionMultiplyVectorFast(const quaternion& quat, const vec3& vector) {
// Adapted from https://github.com/g-truc/glm/blob/master/glm/detail/type_quat.inl
// Also from Fabien Giesen, according to - https://blog.molecular-matters.com/2013/05/24/a-faster-quaternion-vector-multiplication/
vec3 quat_vector = *(vec3*)&quat.entries[0];
vec3 uv = cross(quat_vector, vector);
vec3 uuv = cross(quat_vector, uv);
return vector + ((uv * quat[3]) + uuv) * 2.0f;
}
inline vec3 TransformVec3(const vec3& scale, const quaternion& rotation, const vec3& translation, const vec3& vertex) {
vec3 result = vertex;
result *= scale;
result = QuaternionMultiplyVectorFast(rotation, result);
result += translation;
return result;
}
vec3 QuaternionToEuler(const quaternion& quat);
quaternion EulerToQuaternion(const vec3& euler);
inline std::ostream& operator<<(std::ostream& os, const quaternion& v )
{
os << "quat(" << v[0] << "," << v[1] << "," << v[2] << "," << v[3] << ")";
return os;
}
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