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particle system - alpha depends on relative life

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This commit is contained in:
Mikulas Florek 2015-11-09 22:13:17 +01:00
parent 4ffa6b5318
commit fa4735e3eb
2 changed files with 31 additions and 6 deletions
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34
src/renderer/particle_system.cpp
View file

@ -72,7 +72,19 @@ const uint32_t ParticleEmitter::LinearMovementModule::s_type = Lumix::crc32("lin
ParticleEmitter::AlphaModule::AlphaModule(ParticleEmitter& emitter)
: ModuleBase(emitter)
, m_values(emitter.getAllocator())
{
m_values.resize(10);
m_values[0] = 0.33f;
m_values[1] = 0.66f;
m_values[2] = 0.8f;
m_values[3] = 0.7f;
m_values[4] = 0.6f;
m_values[5] = 0.5f;
m_values[6] = 0.4f;
m_values[7] = 0.3f;
m_values[8] = 0.15f;
m_values[9] = 0.0f;
}
@ -81,9 +93,16 @@ void ParticleEmitter::AlphaModule::update(float time_delta)
if (m_emitter.m_alpha.empty()) return;
float* alpha = &m_emitter.m_alpha[0];
float* rel_life = &m_emitter.m_rel_life[0];
int size = m_values.size() - 1;
float float_size = (float)size;
for (int i = 0, c = m_emitter.m_alpha.size(); i < c; ++i)
{
alpha[i] = Math::minValue(m_emitter.m_life[i], 1.0f);
float float_idx = float_size * rel_life[i];
int idx = (int)float_idx;
int next_idx = Math::minValue(idx + 1, size);
float w = float_idx - idx;
alpha[i] = m_values[idx] * (1 - w) + m_values[next_idx] * w;
}
}
@ -130,6 +149,7 @@ float Interval::getRandom() const
ParticleEmitter::ParticleEmitter(Entity entity, Universe& universe, IAllocator& allocator)
: m_next_spawn_time(0)
, m_allocator(allocator)
, m_rel_life(allocator)
, m_life(allocator)
, m_modules(allocator)
, m_position(allocator)
@ -179,6 +199,7 @@ void ParticleEmitter::spawnParticle()
m_rotation.push(0);
m_rotational_speed.push(0);
m_life.push(m_initial_life.getRandom());
m_rel_life.push(0.0f);
m_alpha.push(1);
m_velocity.push(Vec3(0, 0, 0));
m_size.push(m_initial_size.getRandom());
@ -202,6 +223,7 @@ void ParticleEmitter::destroyParticle(int index)
module->destoryParticle(index);
}
m_life.eraseFast(index);
m_rel_life.eraseFast(index);
m_position.eraseFast(index);
m_velocity.eraseFast(index);
m_rotation.eraseFast(index);
@ -213,13 +235,13 @@ void ParticleEmitter::destroyParticle(int index)
void ParticleEmitter::updateLives(float time_delta)
{
for (int i = 0, c = m_life.size(); i < c; ++i)
for (int i = 0, c = m_rel_life.size(); i < c; ++i)
{
float life = m_life[i];
life -= time_delta;
m_life[i] = life;
float rel_life = m_rel_life[i];
rel_life += time_delta / m_life[i];
m_rel_life[i] = rel_life;
if (life < 0)
if (rel_life > 1)
{
destroyParticle(i);
--i;

3
src/renderer/particle_system.h
View file

@ -87,6 +87,8 @@ public:
uint32_t getType() const override { return s_type; }
static const uint32_t s_type;
Array<float> m_values;
};
@ -115,6 +117,7 @@ public:
void addModule(ModuleBase* module);
public:
Array<float> m_rel_life;
Array<float> m_life;
Array<float> m_size;
Array<Vec3> m_position;