point_particle_emitter2.h

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// Copyright (c) 2018 Doyub Kim
//
// I am making my contributions/submissions to this project solely in my
// personal capacity and am not conveying any rights to any intellectual
// property of any third parties.
 
#ifndef INCLUDE_JET_POINT_PARTICLE_EMITTER2_H_
#define INCLUDE_JET_POINT_PARTICLE_EMITTER2_H_
 
#include <jet/particle_emitter2.h>
#include <limits>
#include <random>
 
namespace jet {
 
class PointParticleEmitter2 final : public ParticleEmitter2 {
 public:
    class Builder;
 
    PointParticleEmitter2(
        const Vector2D& origin,
        const Vector2D& direction,
        double speed,
        double spreadAngleInDegrees,
        size_t maxNumOfNewParticlesPerSec = 1,
        size_t maxNumOfParticles = std::numeric_limits<size_t>::max(),
        uint32_t seed = 0);
 
    size_t maxNumberOfNewParticlesPerSecond() const;
 
    void setMaxNumberOfNewParticlesPerSecond(size_t rate);
 
    size_t maxNumberOfParticles() const;
 
    void setMaxNumberOfParticles(size_t maxNumberOfParticles);
 
    static Builder builder();
 
 private:
    std::mt19937 _rng;
 
    double _firstFrameTimeInSeconds = 0.0;
    size_t _numberOfEmittedParticles = 0;
 
    size_t _maxNumberOfNewParticlesPerSecond;
    size_t _maxNumberOfParticles;
 
    Vector2D _origin;
    Vector2D _direction;
    double _speed;
    double _spreadAngleInRadians;
 
    void onUpdate(
        double currentTimeInSeconds,
        double timeIntervalInSeconds) override;
 
    void emit(
        Array1<Vector2D>* newPositions,
        Array1<Vector2D>* newVelocities,
        size_t maxNewNumberOfParticles);
 
    double random();
};
 
typedef std::shared_ptr<PointParticleEmitter2> PointParticleEmitter2Ptr;
 
 
class PointParticleEmitter2::Builder final {
 public:
    Builder& withOrigin(const Vector2D& origin);
 
    Builder& withDirection(const Vector2D& direction);
 
    Builder& withSpeed(double speed);
 
    Builder& withSpreadAngleInDegrees(double spreadAngleInDegrees);
 
    Builder& withMaxNumberOfNewParticlesPerSecond(
        size_t maxNumOfNewParticlesPerSec);
 
    Builder& withMaxNumberOfParticles(size_t maxNumberOfParticles);
 
    Builder& withRandomSeed(uint32_t seed);
 
    PointParticleEmitter2 build() const;
 
    PointParticleEmitter2Ptr makeShared() const;
 
 private:
    size_t _maxNumberOfNewParticlesPerSecond = 1;
    size_t _maxNumberOfParticles = kMaxSize;
    Vector2D _origin{0, 0};
    Vector2D _direction{0, 1};
    double _speed = 1.0;
    double _spreadAngleInDegrees = 90.0;
    uint32_t _seed = 0;
};
 
}  // namespace jet
 
#endif  // INCLUDE_JET_POINT_PARTICLE_EMITTER2_H_