Particles

#include "atlas/particle.h"

// Create emitter with max particle count
ParticleEmitter emitter(200);

// Set position
emitter.setPosition({0.0f, 2.0f, 0.0f});

// Initialize GPU buffers
emitter.initialize();

// Add to scene
window.addObject(&emitter);

emitter.setEmissionType(ParticleEmissionType::Fountain);
emitter.setDirection({0.0f, 1.0f, 0.0f});  // Upward
emitter.setSpawnRadius(0.5f);              // Radius around origin

emitter.setEmissionType(ParticleEmissionType::Ambient);
emitter.setSpawnRadius(5.0f);  // Large spawn area

ParticleSettings settings;
settings.minLifetime = 1.0f;      // Min lifetime in seconds
settings.maxLifetime = 3.0f;      // Max lifetime in seconds
settings.minSize = 0.05f;         // Min particle size
settings.maxSize = 0.1f;          // Max particle size
settings.fadeSpeed = 0.5f;        // Alpha fade rate
settings.gravity = -9.81f;        // Gravitational force
settings.spread = 1.0f;           // Velocity spread
settings.speedVariation = 0.5f;   // Speed randomization

emitter.setParticleSettings(settings);

emitter.setSpawnRate(20.0f);  // 20 particles/second

// Continuous emission (default)
emitter.emitContinuously();

// Single burst then stop
emitter.emitOnce();

// Manual burst
emitter.emitBurst(50);  // Emit 50 particles immediately

// Start/stop emission
emitter.startEmission();
emitter.stopEmission();

emitter.setColor(Color(1.0f, 0.5f, 0.2f, 1.0f));  // Orange tint

// Create or load texture
Texture particleTexture = Texture::fromResourceName(
    "ParticleSprite",
    TextureType::Color
);

// Attach to emitter
emitter.attachTexture(particleTexture);
emitter.enableTexture();

Texture rainStreak = Texture::createRainStreak(64, 256);
emitter.attachTexture(rainStreak);
emitter.enableTexture();

struct Particle {
    Position3d position;   // Current position
    Magnitude3d velocity;  // Velocity vector
    Color color;           // Particle color
    float life;            // Current life (seconds)
    float maxLife;         // Maximum life (seconds)
    float size;            // Size/scale
    bool active;           // Is particle alive?
};

ParticleEmitter fire(500);
fire.setPosition({0.0f, 0.0f, 0.0f});
fire.setEmissionType(ParticleEmissionType::Fountain);
fire.setDirection({0.0f, 1.0f, 0.0f});
fire.setSpawnRadius(0.3f);
fire.setSpawnRate(100.0f);

ParticleSettings fireSettings;
fireSettings.minLifetime = 0.5f;
fireSettings.maxLifetime = 1.5f;
fireSettings.minSize = 0.1f;
fireSettings.maxSize = 0.3f;
fireSettings.fadeSpeed = 2.0f;
fireSettings.gravity = -2.0f;  // Slight upward force
fireSettings.spread = 0.3f;
fireSettings.speedVariation = 0.8f;
fire.setParticleSettings(fireSettings);

fire.setColor(Color(1.0f, 0.5f, 0.1f, 1.0f));  // Orange-red
fire.initialize();
window.addObject(&fire);

ParticleEmitter snow(1000);
snow.setPosition({0.0f, 10.0f, 0.0f});
snow.setEmissionType(ParticleEmissionType::Ambient);
snow.setSpawnRadius(10.0f);
snow.setSpawnRate(50.0f);

ParticleSettings snowSettings;
snowSettings.minLifetime = 5.0f;
snowSettings.maxLifetime = 8.0f;
snowSettings.minSize = 0.02f;
snowSettings.maxSize = 0.05f;
snowSettings.fadeSpeed = 0.2f;
snowSettings.gravity = -1.0f;  // Gentle fall
snowSettings.spread = 2.0f;
snowSettings.speedVariation = 0.3f;
snow.setParticleSettings(snowSettings);

snow.setColor(Color::white());
snow.initialize();
window.addObject(&snow);

ParticleEmitter rain(2000);
rain.setPosition({0.0f, 20.0f, 0.0f});
rain.setEmissionType(ParticleEmissionType::Ambient);
rain.setSpawnRadius(15.0f);
rain.setSpawnRate(200.0f);

ParticleSettings rainSettings;
rainSettings.minLifetime = 2.0f;
rainSettings.maxLifetime = 4.0f;
rainSettings.minSize = 0.03f;
rainSettings.maxSize = 0.05f;
rainSettings.fadeSpeed = 0.5f;
rainSettings.gravity = -20.0f;  // Fast fall
rainSettings.spread = 0.5f;
rainSettings.speedVariation = 0.2f;
rain.setParticleSettings(rainSettings);

// Use streak texture for rain
Texture rainStreak = Texture::createRainStreak(64, 256);
rain.attachTexture(rainStreak);
rain.enableTexture();
rain.setColor(Color(0.7f, 0.7f, 0.9f, 0.6f));  // Light blue, transparent

rain.initialize();
window.addObject(&rain);

ParticleEmitter explosion(300);
explosion.setPosition({5.0f, 2.0f, 0.0f});
explosion.setEmissionType(ParticleEmissionType::Fountain);
explosion.setSpawnRadius(0.1f);

ParticleSettings explosionSettings;
explosionSettings.minLifetime = 0.5f;
explosionSettings.maxLifetime = 1.0f;
explosionSettings.minSize = 0.1f;
explosionSettings.maxSize = 0.4f;
explosionSettings.fadeSpeed = 3.0f;
explosionSettings.gravity = -5.0f;
explosionSettings.spread = 3.0f;     // Wide spread
explosionSettings.speedVariation = 1.5f;  // High variation
explosion.setParticleSettings(explosionSettings);

explosion.setColor(Color(1.0f, 0.7f, 0.2f, 1.0f));  // Bright orange
explosion.initialize();

// Emit once as a burst
explosion.emitOnce();
window.addObject(&explosion);

void ParticleEmitter::render(
    float dt,
    std::shared_ptr<opal::CommandBuffer> commandBuffer,
    bool updatePipeline
) override;