/*
* Copyright (C) 2011 The Android Open Source Project
*
* 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.
*/
/** @file rs_quaternion.rsh
* \brief Quaternion routines
*
*
*/
#ifndef __RS_QUATERNION_RSH__
#define __RS_QUATERNION_RSH__
/**
* Set the quaternion components
* @param w component
* @param x component
* @param y component
* @param z component
*/
static void __attribute__((overloadable))
rsQuaternionSet(rs_quaternion *q, float w, float x, float y, float z) {
q->w = w;
q->x = x;
q->y = y;
q->z = z;
}
/**
* Set the quaternion from another quaternion
* @param q destination quaternion
* @param rhs source quaternion
*/
static void __attribute__((overloadable))
rsQuaternionSet(rs_quaternion *q, const rs_quaternion *rhs) {
q->w = rhs->w;
q->x = rhs->x;
q->y = rhs->y;
q->z = rhs->z;
}
/**
* Multiply quaternion by a scalar
* @param q quaternion to multiply
* @param s scalar
*/
static void __attribute__((overloadable))
rsQuaternionMultiply(rs_quaternion *q, float s) {
q->w *= s;
q->x *= s;
q->y *= s;
q->z *= s;
}
/**
* Add two quaternions
* @param q destination quaternion to add to
* @param rsh right hand side quaternion to add
*/
static void
rsQuaternionAdd(rs_quaternion *q, const rs_quaternion *rhs) {
q->w *= rhs->w;
q->x *= rhs->x;
q->y *= rhs->y;
q->z *= rhs->z;
}
/**
* Loads a quaternion that represents a rotation about an arbitrary unit vector
* @param q quaternion to set
* @param rot angle to rotate by
* @param x component of a vector
* @param y component of a vector
* @param x component of a vector
*/
static void
rsQuaternionLoadRotateUnit(rs_quaternion *q, float rot, float x, float y, float z) {
rot *= (float)(M_PI / 180.0f) * 0.5f;
float c = cos(rot);
float s = sin(rot);
q->w = c;
q->x = x * s;
q->y = y * s;
q->z = z * s;
}
/**
* Loads a quaternion that represents a rotation about an arbitrary vector
* (doesn't have to be unit)
* @param q quaternion to set
* @param rot angle to rotate by
* @param x component of a vector
* @param y component of a vector
* @param x component of a vector
*/
static void
rsQuaternionLoadRotate(rs_quaternion *q, float rot, float x, float y, float z) {
const float len = x*x + y*y + z*z;
if (len != 1) {
const float recipLen = 1.f / sqrt(len);
x *= recipLen;
y *= recipLen;
z *= recipLen;
}
rsQuaternionLoadRotateUnit(q, rot, x, y, z);
}
/**
* Conjugates the quaternion
* @param q quaternion to conjugate
*/
static void
rsQuaternionConjugate(rs_quaternion *q) {
q->x = -q->x;
q->y = -q->y;
q->z = -q->z;
}
/**
* Dot product of two quaternions
* @param q0 first quaternion
* @param q1 second quaternion
* @return dot product between q0 and q1
*/
static float
rsQuaternionDot(const rs_quaternion *q0, const rs_quaternion *q1) {
return q0->w*q1->w + q0->x*q1->x + q0->y*q1->y + q0->z*q1->z;
}
/**
* Normalizes the quaternion
* @param q quaternion to normalize
*/
static void
rsQuaternionNormalize(rs_quaternion *q) {
const float len = rsQuaternionDot(q, q);
if (len != 1) {
const float recipLen = 1.f / sqrt(len);
rsQuaternionMultiply(q, recipLen);
}
}
/**
* Multiply quaternion by another quaternion
* @param q destination quaternion
* @param rhs right hand side quaternion to multiply by
*/
static void __attribute__((overloadable))
rsQuaternionMultiply(rs_quaternion *q, const rs_quaternion *rhs) {
rs_quaternion qtmp;
rsQuaternionSet(&qtmp, q);
q->w = qtmp.w*rhs->w - qtmp.x*rhs->x - qtmp.y*rhs->y - qtmp.z*rhs->z;
q->x = qtmp.w*rhs->x + qtmp.x*rhs->w + qtmp.y*rhs->z - qtmp.z*rhs->y;
q->y = qtmp.w*rhs->y + qtmp.y*rhs->w + qtmp.z*rhs->x - qtmp.x*rhs->z;
q->z = qtmp.w*rhs->z + qtmp.z*rhs->w + qtmp.x*rhs->y - qtmp.y*rhs->x;
rsQuaternionNormalize(q);
}
/**
* Performs spherical linear interpolation between two quaternions
* @param q result quaternion from interpolation
* @param q0 first param
* @param q1 second param
* @param t how much to interpolate by
*/
static void
rsQuaternionSlerp(rs_quaternion *q, const rs_quaternion *q0, const rs_quaternion *q1, float t) {
if (t <= 0.0f) {
rsQuaternionSet(q, q0);
return;
}
if (t >= 1.0f) {
rsQuaternionSet(q, q1);
return;
}
rs_quaternion tempq0, tempq1;
rsQuaternionSet(&tempq0, q0);
rsQuaternionSet(&tempq1, q1);
float angle = rsQuaternionDot(q0, q1);
if (angle < 0) {
rsQuaternionMultiply(&tempq0, -1.0f);
angle *= -1.0f;
}
float scale, invScale;
if (angle + 1.0f > 0.05f) {
if (1.0f - angle >= 0.05f) {
float theta = acos(angle);
float invSinTheta = 1.0f / sin(theta);
scale = sin(theta * (1.0f - t)) * invSinTheta;
invScale = sin(theta * t) * invSinTheta;
} else {
scale = 1.0f - t;
invScale = t;
}
} else {
rsQuaternionSet(&tempq1, tempq0.z, -tempq0.y, tempq0.x, -tempq0.w);
scale = sin(M_PI * (0.5f - t));
invScale = sin(M_PI * t);
}
rsQuaternionSet(q, tempq0.w*scale + tempq1.w*invScale, tempq0.x*scale + tempq1.x*invScale,
tempq0.y*scale + tempq1.y*invScale, tempq0.z*scale + tempq1.z*invScale);
}
/**
* Computes rotation matrix from the normalized quaternion
* @param m resulting matrix
* @param p normalized quaternion
*/
static void rsQuaternionGetMatrixUnit(rs_matrix4x4 *m, const rs_quaternion *q) {
float xx = q->x * q->x;
float xy = q->x * q->y;
float xz = q->x * q->z;
float xw = q->x * q->w;
float yy = q->y * q->y;
float yz = q->y * q->z;
float yw = q->y * q->w;
float zz = q->z * q->z;
float zw = q->z * q->w;
m->m[0] = 1.0f - 2.0f * ( yy + zz );
m->m[4] = 2.0f * ( xy - zw );
m->m[8] = 2.0f * ( xz + yw );
m->m[1] = 2.0f * ( xy + zw );
m->m[5] = 1.0f - 2.0f * ( xx + zz );
m->m[9] = 2.0f * ( yz - xw );
m->m[2] = 2.0f * ( xz - yw );
m->m[6] = 2.0f * ( yz + xw );
m->m[10] = 1.0f - 2.0f * ( xx + yy );
m->m[3] = m->m[7] = m->m[11] = m->m[12] = m->m[13] = m->m[14] = 0.0f;
m->m[15] = 1.0f;
}
#endif