490 lines
20 KiB
C++
490 lines
20 KiB
C++
/* OpenSceneGraph example, osgparticle.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <osgViewer/Viewer>
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#include <osgViewer/ViewerEventHandlers>
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#include <osg/Group>
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#include <osg/Geode>
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#include <osgParticle/Particle>
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#include <osgParticle/ParticleSystem>
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#include <osgParticle/ParticleSystemUpdater>
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#include <osgParticle/ModularEmitter>
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#include <osgParticle/ModularProgram>
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#include <osgParticle/RandomRateCounter>
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#include <osgParticle/SectorPlacer>
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#include <osgParticle/RadialShooter>
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#include <osgParticle/AccelOperator>
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#include <osgParticle/FluidFrictionOperator>
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//////////////////////////////////////////////////////////////////////////////
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// CUSTOM OPERATOR CLASS
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//////////////////////////////////////////////////////////////////////////////
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// This class demonstrates Operator subclassing. This way you can create
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// custom operators to apply your motion effects to the particles. See docs
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// for more details.
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class VortexOperator: public osgParticle::Operator {
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public:
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VortexOperator()
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: osgParticle::Operator(), center_(0, 0, 0), axis_(0, 0, 1), intensity_(0.1f) {}
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VortexOperator(const VortexOperator ©, const osg::CopyOp ©op = osg::CopyOp::SHALLOW_COPY)
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: osgParticle::Operator(copy, copyop), center_(copy.center_), axis_(copy.axis_), intensity_(copy.intensity_) {}
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META_Object(osgParticle, VortexOperator);
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void setCenter(const osg::Vec3 &c)
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{
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center_ = c;
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}
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void setAxis(const osg::Vec3 &a)
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{
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axis_ = a / a.length();
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}
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// this method is called by ModularProgram before applying
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// operators on the particle set via the operate() method.
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void beginOperate(osgParticle::Program *prg)
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{
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// we have to check whether the reference frame is RELATIVE_RF to parents
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// or it's absolute; in the first case, we must transform the vectors
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// from local to world space.
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if (prg->getReferenceFrame() == osgParticle::Program::RELATIVE_RF) {
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// transform the center point (full transformation)
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xf_center_ = prg->transformLocalToWorld(center_);
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// transform the axis vector (only rotation and scale)
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xf_axis_ = prg->rotateLocalToWorld(axis_);
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} else {
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xf_center_ = center_;
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xf_axis_ = axis_;
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}
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}
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// apply a vortex-like acceleration. This code is not optimized,
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// it's here only for demonstration purposes.
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void operate(osgParticle::Particle *P, double dt)
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{
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float l = xf_axis_ * (P->getPosition() - xf_center_);
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osg::Vec3 lc = xf_center_ + xf_axis_ * l;
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osg::Vec3 R = P->getPosition() - lc;
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osg::Vec3 v = (R ^ xf_axis_) * P->getMassInv() * intensity_;
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// compute new position
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osg::Vec3 newpos = P->getPosition() + v * dt;
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// update the position of the particle without modifying its
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// velocity vector (this is unusual, normally you should call
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// the Particle::setVelocity() or Particle::addVelocity()
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// methods).
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P->setPosition(newpos);
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}
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protected:
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virtual ~VortexOperator() {}
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private:
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osg::Vec3 center_;
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osg::Vec3 xf_center_;
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osg::Vec3 axis_;
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osg::Vec3 xf_axis_;
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float intensity_;
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};
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//////////////////////////////////////////////////////////////////////////////
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// SIMPLE PARTICLE SYSTEM CREATION
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//////////////////////////////////////////////////////////////////////////////
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osgParticle::ParticleSystem *create_simple_particle_system(osg::Group *root)
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{
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// Ok folks, this is the first particle system we build; it will be
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// very simple, with no textures and no special effects, just default
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// values except for a couple of attributes.
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// First of all, we create the ParticleSystem object; it will hold
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// our particles and expose the interface for managing them; this object
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// is a Drawable, so we'll have to add it to a Geode later.
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osgParticle::ParticleSystem *ps = new osgParticle::ParticleSystem;
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// As for other Drawable classes, the aspect of graphical elements of
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// ParticleSystem (the particles) depends on the StateAttribute's we
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// give it. The ParticleSystem class has an helper function that let
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// us specify a set of the most common attributes: setDefaultAttributes().
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// This method can accept up to three parameters; the first is a texture
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// name (std::string), which can be empty to disable texturing, the second
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// sets whether particles have to be "emissive" (additive blending) or not;
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// the third parameter enables or disables lighting.
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ps->setDefaultAttributes("", true, false);
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// Now that our particle system is set we have to create an emitter, that is
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// an object (actually a Node descendant) that generate new particles at
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// each frame. The best choice is to use a ModularEmitter, which allow us to
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// achieve a wide variety of emitting styles by composing the emitter using
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// three objects: a "counter", a "placer" and a "shooter". The counter must
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// tell the ModularEmitter how many particles it has to create for the
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// current frame; then, the ModularEmitter creates these particles, and for
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// each new particle it instructs the placer and the shooter to set its
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// position vector and its velocity vector, respectively.
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// By default, a ModularEmitter object initializes itself with a counter of
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// type RandomRateCounter, a placer of type PointPlacer and a shooter of
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// type RadialShooter (see documentation for details). We are going to leave
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// these default objects there, but we'll modify the counter so that it
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// counts faster (more particles are emitted at each frame).
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osgParticle::ModularEmitter *emitter = new osgParticle::ModularEmitter;
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// the first thing you *MUST* do after creating an emitter is to set the
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// destination particle system, otherwise it won't know where to create
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// new particles.
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emitter->setParticleSystem(ps);
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// Ok, get a pointer to the emitter's Counter object. We could also
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// create a new RandomRateCounter object and assign it to the emitter,
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// but since the default counter is already a RandomRateCounter, we
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// just get a pointer to it and change a value.
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osgParticle::RandomRateCounter *rrc =
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static_cast<osgParticle::RandomRateCounter *>(emitter->getCounter());
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// Now set the rate range to a better value. The actual rate at each frame
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// will be chosen randomly within that range.
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rrc->setRateRange(20, 30); // generate 20 to 30 particles per second
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// The emitter is done! Let's add it to the scene graph. The cool thing is
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// that any emitter node will take into account the accumulated local-to-world
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// matrix, so you can attach an emitter to a transform node and see it move.
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root->addChild(emitter);
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// Ok folks, we have almost finished. We don't add any particle modifier
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// here (see ModularProgram and Operator classes), so all we still need is
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// to create a Geode and add the particle system to it, so it can be
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// displayed.
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// add the ParticleSystem to the scene graph
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root->addChild(ps);
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return ps;
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}
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//////////////////////////////////////////////////////////////////////////////
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// COMPLEX PARTICLE SYSTEM CREATION
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//////////////////////////////////////////////////////////////////////////////
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osgParticle::ParticleSystem *create_complex_particle_system(osg::Group *root)
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{
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// Are you ready for a more complex particle system? Well, read on!
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// Now we take one step we didn't before: create a particle template.
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// A particle template is simply a Particle object for which you set
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// the desired properties (see documentation for details). When the
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// particle system has to create a new particle and it's been assigned
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// a particle template, the new particle will inherit the template's
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// properties.
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// You can even assign different particle templates to each emitter; in
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// this case, the emitter's template will override the particle system's
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// default template.
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osgParticle::Particle ptemplate;
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ptemplate.setLifeTime(3); // 3 seconds of life
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// the following ranges set the envelope of the respective
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// graphical properties in time.
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ptemplate.setSizeRange(osgParticle::rangef(0.75f, 3.0f));
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ptemplate.setAlphaRange(osgParticle::rangef(0.0f, 1.5f));
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ptemplate.setColorRange(osgParticle::rangev4(
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osg::Vec4(1, 0.5f, 0.3f, 1.5f),
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osg::Vec4(0, 0.7f, 1.0f, 0.0f)));
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// these are physical properties of the particle
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ptemplate.setRadius(0.05f); // 5 cm wide particles
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ptemplate.setMass(0.05f); // 50 g heavy
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// As usual, let's create the ParticleSystem object and set its
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// default state attributes. This time we use a texture named
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// "smoke.rgb", you can find it in the data distribution of OSG.
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// We turn off the additive blending, because smoke has no self-
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// illumination.
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osgParticle::ParticleSystem *ps = new osgParticle::ParticleSystem;
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ps->setDefaultAttributes("Images/smoke.rgb", false, false);
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// assign the particle template to the system.
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ps->setDefaultParticleTemplate(ptemplate);
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// now we have to create an emitter; this will be a ModularEmitter, for which
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// we define a RandomRateCounter as counter, a SectorPlacer as placer, and
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// a RadialShooter as shooter.
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osgParticle::ModularEmitter *emitter = new osgParticle::ModularEmitter;
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emitter->setParticleSystem(ps);
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// setup the counter
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osgParticle::RandomRateCounter *counter = new osgParticle::RandomRateCounter;
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counter->setRateRange(60, 60);
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emitter->setCounter(counter);
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// setup the placer; it will be a circle of radius 5 (the particles will
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// be placed inside this circle).
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osgParticle::SectorPlacer *placer = new osgParticle::SectorPlacer;
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placer->setCenter(8, 0, 10);
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placer->setRadiusRange(2.5, 5);
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placer->setPhiRange(0, 2 * osg::PI); // 360 angle to make a circle
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emitter->setPlacer(placer);
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// now let's setup the shooter; we use a RadialShooter but we set the
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// initial speed to zero, because we want the particles to fall down
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// only under the effect of the gravity force. Since we se the speed
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// to zero, there is no need to setup the shooting angles.
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osgParticle::RadialShooter *shooter = new osgParticle::RadialShooter;
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shooter->setInitialSpeedRange(0, 0);
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emitter->setShooter(shooter);
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// add the emitter to the scene graph
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root->addChild(emitter);
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// WELL, we got our particle system and a nice emitter. Now we want to
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// simulate the effect of the earth gravity, so first of all we have to
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// create a Program. It is a particle processor just like the Emitter
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// class, but it allows to modify particle properties *after* they have
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// been created.
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// The ModularProgram class can be thought as a sequence of operators,
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// each one performing some actions on the particles. So, the trick is:
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// create the ModularProgram object, create one or more Operator objects,
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// add those operators to the ModularProgram, and finally add the
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// ModularProgram object to the scene graph.
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// NOTE: since the Program objects perform actions after the particles
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// have been emitted by one or more Emitter objects, all instances of
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// Program (and its descendants) should be placed *after* the instances
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// of Emitter objects in the scene graph.
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osgParticle::ModularProgram *program = new osgParticle::ModularProgram;
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program->setParticleSystem(ps);
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// create an operator that simulates the gravity acceleration.
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osgParticle::AccelOperator *op1 = new osgParticle::AccelOperator;
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op1->setToGravity();
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program->addOperator(op1);
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// now create a custom operator, we have defined it before (see
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// class VortexOperator).
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VortexOperator *op2 = new VortexOperator;
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op2->setCenter(osg::Vec3(8, 0, 0));
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program->addOperator(op2);
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// let's add a fluid operator to simulate air friction.
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osgParticle::FluidFrictionOperator *op3 = new osgParticle::FluidFrictionOperator;
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op3->setFluidToAir();
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program->addOperator(op3);
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// add the program to the scene graph
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root->addChild(program);
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// add the particle system to the scene graph.
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root->addChild(ps);
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return ps;
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}
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//////////////////////////////////////////////////////////////////////////////
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// ANIMATED PARTICLE SYSTEM CREATION
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//////////////////////////////////////////////////////////////////////////////
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osgParticle::ParticleSystem *create_animated_particle_system(osg::Group *root)
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{
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// Now we will create a particle system that uses two emitters to
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// display two animated particles, one showing an explosion, the other
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// a smoke cloud. A particle system can only use one texture, so
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// the animations for both particles are stored in a single bitmap.
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// The frames of the animation are stored in tiles. For each particle
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// template, the start and end tile of their animation have to be given.
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// The example file used here has 64 tiles, stored in eight rows with
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// eight images each.
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// First create a prototype for the explosion particle.
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osgParticle::Particle pexplosion;
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// The frames of the explosion particle are played from birth to
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// death of the particle. So if lifetime is one second, all 16 images
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// of the particle are shown in this second.
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pexplosion.setLifeTime(1);
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// some other particle properties just as in the last example.
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pexplosion.setSizeRange(osgParticle::rangef(0.75f, 3.0f));
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pexplosion.setAlphaRange(osgParticle::rangef(0.5f, 1.0f));
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pexplosion.setColorRange(osgParticle::rangev4(
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osg::Vec4(1, 1, 1, 1),
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osg::Vec4(1, 1, 1, 1)));
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pexplosion.setRadius(0.05f);
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pexplosion.setMass(0.05f);
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// This command sets the animation tiles to be shown for the particle.
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// The first two parameters define the tile layout of the texture image.
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// 8, 8 means the texture has eight rows of tiles with eight columns each.
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// 0, 15 defines the start and end tile
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pexplosion.setTextureTileRange(8, 8, 0, 15);
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// The smoke particle is just the same, only plays another tile range.
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osgParticle::Particle psmoke = pexplosion;
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psmoke.setTextureTileRange(8, 8, 32, 45);
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// Create a single particle system for both particle types
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osgParticle::ParticleSystem *ps = new osgParticle::ParticleSystem;
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// Assign the tiled texture
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ps->setDefaultAttributes("Images/fireparticle8x8.png", false, false);
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// Create two emitters, one for the explosions, one for the smoke balls.
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osgParticle::ModularEmitter *emitter1 = new osgParticle::ModularEmitter;
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emitter1->setParticleSystem(ps);
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emitter1->setParticleTemplate(pexplosion);
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osgParticle::ModularEmitter *emitter2 = new osgParticle::ModularEmitter;
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emitter2->setParticleSystem(ps);
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emitter2->setParticleTemplate(psmoke);
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// create a counter each. We could reuse the counter for both emitters, but
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// then we could not control the ratio of smoke balls to explosions
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osgParticle::RandomRateCounter *counter1 = new osgParticle::RandomRateCounter;
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counter1->setRateRange(10, 10);
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emitter1->setCounter(counter1);
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osgParticle::RandomRateCounter *counter2 = new osgParticle::RandomRateCounter;
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counter2->setRateRange(3, 4);
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emitter2->setCounter(counter2);
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// setup a single placer for both emitters.
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osgParticle::SectorPlacer *placer = new osgParticle::SectorPlacer;
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placer->setCenter(-8, 0, 0);
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placer->setRadiusRange(2.5, 5);
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placer->setPhiRange(0, 2 * osg::PI); // 360 angle to make a circle
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emitter1->setPlacer(placer);
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emitter2->setPlacer(placer);
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// the shooter is reused for both emitters
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osgParticle::RadialShooter *shooter = new osgParticle::RadialShooter;
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shooter->setInitialSpeedRange(0, 0);
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// give particles a little spin
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shooter->setInitialRotationalSpeedRange(osgParticle::rangev3(
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osg::Vec3(0, 0, -1),
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osg::Vec3(0, 0, 1)));
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emitter1->setShooter(shooter);
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emitter2->setShooter(shooter);
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// add both emitters to the scene graph
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root->addChild(emitter1);
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root->addChild(emitter2);
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// create a program, just as before
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osgParticle::ModularProgram *program = new osgParticle::ModularProgram;
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program->setParticleSystem(ps);
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// create an operator that moves the particles upwards
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osgParticle::AccelOperator *op1 = new osgParticle::AccelOperator;
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op1->setAcceleration(osg::Vec3(0, 0, 2.0f));
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program->addOperator(op1);
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// add the program to the scene graph
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root->addChild(program);
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// create a Geode to contain our particle system.
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osg::Geode *geode = new osg::Geode;
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geode->addDrawable(ps);
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// add the geode to the scene graph.
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root->addChild(geode);
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return ps;
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}
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//////////////////////////////////////////////////////////////////////////////
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// MAIN SCENE GRAPH BUILDING FUNCTION
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//////////////////////////////////////////////////////////////////////////////
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void build_world(osg::Group *root)
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{
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// In this function we are going to create two particle systems;
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// the first one will be very simple, based mostly on default properties;
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// the second one will be a little bit more complex, showing how to
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// create custom operators.
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// To avoid inserting too much code in a single function, we have
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// splitted the work into two functions which accept a Group node as
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// parameter, and return a pointer to the particle system they created.
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osgParticle::ParticleSystem *ps1 = create_simple_particle_system(root);
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osgParticle::ParticleSystem *ps2 = create_complex_particle_system(root);
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osgParticle::ParticleSystem *ps3 = create_animated_particle_system(root);
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// Now that the particle systems and all other related objects have been
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// created, we have to add an "updater" node to the scene graph. This node
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// will react to cull traversal by updating the specified particles system.
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osgParticle::ParticleSystemUpdater *psu = new osgParticle::ParticleSystemUpdater;
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psu->addParticleSystem(ps1);
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psu->addParticleSystem(ps2);
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psu->addParticleSystem(ps3);
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// add the updater node to the scene graph
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root->addChild(psu);
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}
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//////////////////////////////////////////////////////////////////////////////
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// main()
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//////////////////////////////////////////////////////////////////////////////
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int main(int, char **)
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{
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// construct the viewer.
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osgViewer::Viewer viewer;
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osg::Group *root = new osg::Group;
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build_world(root);
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// add the stats handler
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viewer.addEventHandler(new osgViewer::StatsHandler);
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// add a viewport to the viewer and attach the scene graph.
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viewer.setSceneData(root);
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return viewer.run();
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}
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