renderscript/include/rs_quaternion.rsh

/*
 * Copyright (C) 2015 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.
 */

// Don't edit this file!  It is auto-generated by frameworks/rs/api/generate.sh.

/*
 * rs_quaternion.rsh: Quaternion Functions
 *
 * The following functions manipulate quaternions.
 */

#ifndef RENDERSCRIPT_RS_QUATERNION_RSH
#define RENDERSCRIPT_RS_QUATERNION_RSH

/*
 * rsQuaternionAdd: Add two quaternions
 *
 * Adds two quaternions, i.e. *q += *rhs;
 *
 * Parameters:
 *   q: Destination quaternion to add to.
 *   rhs: Quaternion to add.
 */
static inline void __attribute__((overloadable))
    rsQuaternionAdd(rs_quaternion* q, const rs_quaternion* rhs) {
    q->w *= rhs->w;
    q->x *= rhs->x;
    q->y *= rhs->y;
    q->z *= rhs->z;
}

/*
 * rsQuaternionConjugate: Conjugate a quaternion
 *
 * Conjugates the quaternion.
 *
 * Parameters:
 *   q: Quaternion to modify.
 */
static inline void __attribute__((overloadable))
    rsQuaternionConjugate(rs_quaternion* q) {
    q->x = -q->x;
    q->y = -q->y;
    q->z = -q->z;
}

/*
 * rsQuaternionDot: Dot product of two quaternions
 *
 * Returns the dot product of two quaternions.
 *
 * Parameters:
 *   q0: First quaternion.
 *   q1: Second quaternion.
 */
static inline float __attribute__((overloadable))
    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;
}

/*
 * rsQuaternionGetMatrixUnit: Get a rotation matrix from a quaternion
 *
 * Computes a rotation matrix from the normalized quaternion.
 *
 * Parameters:
 *   m: Resulting matrix.
 *   q: Normalized quaternion.
 */
static inline void __attribute__((overloadable))
    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;
}

/*
 * rsQuaternionLoadRotateUnit: Quaternion that represents a rotation about an arbitrary unit vector
 *
 * Loads a quaternion that represents a rotation about an arbitrary unit vector.
 *
 * Parameters:
 *   q: Destination quaternion.
 *   rot: Angle to rotate by, in radians.
 *   x: X component of the vector.
 *   y: Y component of the vector.
 *   z: Z component of the vector.
 */
static inline void __attribute__((overloadable))
    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;
}

/*
 * rsQuaternionSet: Create a quaternion
 *
 * Creates a quaternion from its four components or from another quaternion.
 *
 * Parameters:
 *   q: Destination quaternion.
 *   w: W component.
 *   x: X component.
 *   y: Y component.
 *   z: Z component.
 *   rhs: Source quaternion.
 */
static inline 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;
}

static inline 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;
}

/*
 * rsQuaternionLoadRotate: Create a rotation quaternion
 *
 * Loads a quaternion that represents a rotation about an arbitrary vector
 * (doesn't have to be unit)
 *
 * Parameters:
 *   q: Destination quaternion.
 *   rot: Angle to rotate by.
 *   x: X component of a vector.
 *   y: Y component of a vector.
 *   z: Z component of a vector.
 */
static inline void __attribute__((overloadable))
    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);
}

/*
 * rsQuaternionNormalize: Normalize a quaternion
 *
 * Normalizes the quaternion.
 *
 * Parameters:
 *   q: Quaternion to normalize.
 */
static inline void __attribute__((overloadable))
    rsQuaternionNormalize(rs_quaternion* q) {
    const float len = rsQuaternionDot(q, q);
    if (len != 1) {
        const float recipLen = 1.f / sqrt(len);
        q->w *= recipLen;
        q->x *= recipLen;
        q->y *= recipLen;
        q->z *= recipLen;
    }
}

/*
 * rsQuaternionMultiply: Multiply a quaternion by a scalar or another quaternion
 *
 * Multiplies a quaternion by a scalar or by another quaternion, e.g
 * *q = *q * scalar; or *q = *q * *rhs;.
 *
 * Parameters:
 *   q: Destination quaternion.
 *   scalar: Scalar to multiply the quaternion by.
 *   rhs: Quaternion to multiply the destination quaternion by.
 */
static inline void __attribute__((overloadable))
    rsQuaternionMultiply(rs_quaternion* q, float scalar) {
    q->w *= scalar;
    q->x *= scalar;
    q->y *= scalar;
    q->z *= scalar;
}

static inline 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);
}

/*
 * rsQuaternionSlerp: Spherical linear interpolation between two quaternions
 *
 * Performs spherical linear interpolation between two quaternions.
 *
 * Parameters:
 *   q: Result quaternion from the interpolation.
 *   q0: First input quaternion.
 *   q1: Second input quaternion.
 *   t: How much to interpolate by.
 */
static inline void __attribute__((overloadable))
    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);
}

#endif // RENDERSCRIPT_RS_QUATERNION_RSH