/xbmc/screensavers/rsxs-0.9/src/hyperspace/spline.cc
http://github.com/xbmc/xbmc · C++ · 155 lines · 95 code · 22 blank · 38 comment · 4 complexity · e4d143141fa89ae05061152a114f0e5b MD5 · raw file
- /*
- * Really Slick XScreenSavers
- * Copyright (C) 2002-2006 Michael Chapman
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- *
- *****************************************************************************
- *
- * This is a Linux port of the Really Slick Screensavers,
- * Copyright (C) 2005 Terence M. Welsh, available from www.reallyslick.com
- */
- #include <common.hh>
- #include <spline.hh>
- #include <vector.hh>
- namespace Spline {
- unsigned int points;
- float step;
- std::vector<float> _phase;
- std::vector<float> _rate;
- std::vector<Vector> _moveXYZ;
- std::vector<Vector> _baseXYZ;
- std::vector<Vector> _XYZ;
- std::vector<Vector> _baseDir;
- std::vector<Vector> _dir;
- Vector interpolate(const Vector&, const Vector&, const Vector&, const Vector&, float);
- };
- void Spline::init(unsigned int length) {
- // 6 is the minimum number of points necessary for a tunnel to have one segment
- points = (length < 6 ? 6 : length);
- step = 0.0f;
- stdx::construct_n(_phase, points);
- stdx::construct_n(_rate, points);
- stdx::construct_n(_moveXYZ, points);
- stdx::construct_n(_baseXYZ, points);
- stdx::construct_n(_XYZ, points);
- stdx::construct_n(_baseDir, points);
- stdx::construct_n(_dir, points);
- _baseXYZ[points - 2].z() = 4.0f;
- for (unsigned int i = 0; i < points; ++i)
- makeNewPoint();
- }
- void Spline::makeNewPoint() {
- // shift points to rear of path
- std::rotate(_baseXYZ.begin(), _baseXYZ.begin() + 1, _baseXYZ.end());
- std::rotate(_moveXYZ.begin(), _moveXYZ.begin() + 1, _moveXYZ.end());
- std::rotate(_XYZ.begin(), _XYZ.begin() + 1, _XYZ.end());
- std::rotate(_phase.begin(), _phase.begin() + 1, _phase.end());
- std::rotate(_rate.begin(), _rate.begin() + 1, _rate.end());
- // make vector to new point
- int lastPoint = points - 1;
- float tempX = _baseXYZ[lastPoint - 1].x() - _baseXYZ[lastPoint - 2].x();
- float tempZ = _baseXYZ[lastPoint - 1].z() - _baseXYZ[lastPoint - 2].z();
- // find good angle
- float turnAngle;
- float pathAngle = std::atan2(tempX, tempZ);
- float distSquared =
- _baseXYZ[lastPoint].x() * _baseXYZ[lastPoint].x() +
- _baseXYZ[lastPoint].z() * _baseXYZ[lastPoint].z();
- if (distSquared > 10000.0f) {
- float angleToCenter = std::atan2(-_baseXYZ[lastPoint].x(), -_baseXYZ[lastPoint].z());
- turnAngle = angleToCenter - pathAngle;
- if (turnAngle > M_PI)
- turnAngle -= M_PI * 2.0f;
- if (turnAngle < -M_PI)
- turnAngle += M_PI * 2.0f;
- turnAngle = Common::clamp(turnAngle, -0.7f, 0.7f);
- } else
- turnAngle = Common::randomFloat(1.4f) - 0.7f;
- // rotate new point to some new position
- float ca = std::cos(turnAngle);
- float sa = std::cos(turnAngle);
- _baseXYZ[lastPoint].set(tempX * ca + tempZ * sa, 0.0f, tempX * -sa + tempZ * ca);
- // normalize and set length of vector
- // make it at least length 2, which is the grid size of the goo
- float lengthener = (Common::randomFloat(6.0f) + 2.0f) / _baseXYZ[lastPoint].length();
- _baseXYZ[lastPoint] *= lengthener;
- // make new movement vector proportional to base vector
- _moveXYZ[lastPoint].set(
- Common::randomFloat(0.25f) * -_baseXYZ[lastPoint].z(),
- 0.3f,
- Common::randomFloat(0.25f) * -_baseXYZ[lastPoint].x()
- );
- // add vector to previous point to get new point
- _baseXYZ[lastPoint] += Vector(
- _baseXYZ[lastPoint - 1].x(),
- 0.0f,
- _baseXYZ[lastPoint - 1].z()
- );
- // make new phase and movement rate
- _phase[lastPoint] = Common::randomFloat(M_PI * 2);
- _rate[lastPoint] = Common::randomFloat(1.0f);
- // reset base direction vectors
- _baseDir.front() = _baseXYZ[1] - _baseXYZ[points - 1];
- std::transform(
- _baseXYZ.begin() + 2, _baseXYZ.end(),
- _baseXYZ.begin(), _baseDir.begin() + 1,
- std::minus<Vector>()
- );
- _baseDir.back() = _baseXYZ[0] - _baseXYZ[points - 2];
- }
- Vector Spline::at(unsigned int section, float where) {
- section = Common::clamp(section, 1u, points - 3);
- return interpolate(_XYZ[section - 1], _XYZ[section], _XYZ[section + 1], _XYZ[section + 2], where);
- }
- Vector Spline::direction(unsigned int section, float where) {
- section = Common::clamp(section, 1u, points - 3);
- Vector direction(interpolate(_dir[section - 1], _dir[section], _dir[section + 1], _dir[section + 2], where));
- direction.normalize();
- return direction;
- }
- // Here's a little calculus that takes 4 points
- // and interpolates smoothly between the second and third
- // depending on the value of where which can be 0.0 to 1.0.
- // The slope at b is estimated using a and c. The slope at c
- // is estimated using b and d.
- Vector Spline::interpolate(const Vector& a, const Vector& b, const Vector& c, const Vector& d, float where) {
- return
- (((b * 3.0f) + d - a - (c * 3.0f)) * (where * where * where)) * 0.5f +
- (((a * 2.0f) - (b * 5.0f) + (c * 4.0f) - d) * (where * where)) * 0.5f +
- ((c - a) * where) * 0.5f +
- b;
- }