Start refactoring RS headerfiles for docs.
Change-Id: Ieb7797601f94beec2835e1d936dc2dd0c38cb48c
diff --git a/scriptc/rs_quaternion.rsh b/scriptc/rs_quaternion.rsh
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+/*
+ * 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_matrix.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;
+}
+
+/**
+ * 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) {
+ q->w = -q->x*rhs->x - q->y*rhs->y - q->z*rhs->z + q->w*rhs->w;
+ q->x = q->x*rhs->w + q->y*rhs->z - q->z*rhs->y + q->w*rhs->x;
+ q->y = -q->x*rhs->z + q->y*rhs->w + q->z*rhs->x + q->w*rhs->y;
+ q->z = q->x*rhs->y - q->y*rhs->x + q->z*rhs->w + q->w*rhs->z;
+}
+
+/**
+ * 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);
+ }
+}
+
+/**
+ * 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 x2 = 2.0f * q->x * q->x;
+ float y2 = 2.0f * q->y * q->y;
+ float z2 = 2.0f * q->z * q->z;
+ float xy = 2.0f * q->x * q->y;
+ float wz = 2.0f * q->w * q->z;
+ float xz = 2.0f * q->x * q->z;
+ float wy = 2.0f * q->w * q->y;
+ float wx = 2.0f * q->w * q->x;
+ float yz = 2.0f * q->y * q->z;
+
+ m->m[0] = 1.0f - y2 - z2;
+ m->m[1] = xy - wz;
+ m->m[2] = xz + wy;
+ m->m[3] = 0.0f;
+
+ m->m[4] = xy + wz;
+ m->m[5] = 1.0f - x2 - z2;
+ m->m[6] = yz - wx;
+ m->m[7] = 0.0f;
+
+ m->m[8] = xz - wy;
+ m->m[9] = yz - wx;
+ m->m[10] = 1.0f - x2 - y2;
+ m->m[11] = 0.0f;
+
+ m->m[12] = 0.0f;
+ m->m[13] = 0.0f;
+ m->m[14] = 0.0f;
+ m->m[15] = 1.0f;
+}
+
+#endif
+