From 52494a680cf73e2f3f46d20bb4f10aeb214c40fb Mon Sep 17 00:00:00 2001
From: MihailRis <mexaruc@gmail.com>
Date: Mon, 23 Dec 2024 17:26:22 +0300
Subject: [PATCH] upgrade emitters garbage collection

---
 src/graphics/render/Emitter.cpp           |  7 ++++++-
 src/graphics/render/Emitter.hpp           |  6 ++++++
 src/graphics/render/ParticlesRenderer.cpp | 20 +++++++++-----------
 3 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/src/graphics/render/Emitter.cpp b/src/graphics/render/Emitter.cpp
index ff8413d5..88951588 100644
--- a/src/graphics/render/Emitter.cpp
+++ b/src/graphics/render/Emitter.cpp
@@ -19,7 +19,7 @@ Emitter::Emitter(
 )
     : level(level),
       origin(std::move(origin)),
-      prototype({this, 0, glm::vec3(), preset.velocity, preset.lifetime, region}),
+      prototype({this, 0, {}, preset.velocity, preset.lifetime, region}),
       texture(texture),
       count(count),
       preset(std::move(preset)) {
@@ -113,6 +113,7 @@ void Emitter::update(
         if (count > 0) {
             count--;
         }
+        refCount++;
     }
 }
 
@@ -124,6 +125,10 @@ bool Emitter::isDead() const {
     return count == 0;
 }
 
+bool Emitter::isReferred() const {
+    return refCount > 0;
+}
+
 const EmitterOrigin& Emitter::getOrigin() const {
     return origin;
 }
diff --git a/src/graphics/render/Emitter.hpp b/src/graphics/render/Emitter.hpp
index b2a371ad..ce1ec8f4 100644
--- a/src/graphics/render/Emitter.hpp
+++ b/src/graphics/render/Emitter.hpp
@@ -54,6 +54,9 @@ class Emitter {
 
     util::PseudoRandom random;
 public:
+    /// @brief Number of references (alive particles)
+    int refCount = 0;
+    /// @brief Particle settings
     ParticlesPreset preset;
 
     Emitter(
@@ -86,6 +89,9 @@ public:
     /// @return true if the emitter has spawned all particles
     bool isDead() const;
 
+    /// @return true if there is at least one alive referring particle left
+    bool isReferred() const;
+
     const EmitterOrigin& getOrigin() const;
 
     void setOrigin(const EmitterOrigin& origin);
diff --git a/src/graphics/render/ParticlesRenderer.cpp b/src/graphics/render/ParticlesRenderer.cpp
index f3a30cdd..e96eb615 100644
--- a/src/graphics/render/ParticlesRenderer.cpp
+++ b/src/graphics/render/ParticlesRenderer.cpp
@@ -63,7 +63,8 @@ void ParticlesRenderer::renderParticles(const Camera& camera, float delta) {
         auto iter = vec.begin();
         while (iter != vec.end()) {
             auto& particle = *iter;
-            auto& preset = particle.emitter->preset;
+            auto& emitter = *particle.emitter;
+            auto& preset = emitter.preset;
 
             if (!preset.frames.empty()) {
                 float time = preset.lifetime - particle.lifetime;
@@ -137,6 +138,7 @@ void ParticlesRenderer::renderParticles(const Camera& camera, float delta) {
             );
             if (particle.lifetime <= 0.0f) {
                 iter = vec.erase(iter);
+                emitter.refCount--;
             } else {
                 iter++;
             }
@@ -159,19 +161,15 @@ void ParticlesRenderer::render(const Camera& camera, float delta) {
     auto iter = emitters.begin();
     while (iter != emitters.end()) {
         auto& emitter = *iter->second;
+        if (emitter.isDead() && !emitter.isReferred()) {
+            // destruct Emitter only when there is no particles spawned by it
+            iter = emitters.erase(iter);
+            continue;
+        }
         auto texture = emitter.getTexture();
         const auto& found = particles.find(texture);
         std::vector<Particle>* vec;
-        if (found == particles.end()) {
-            if (emitter.isDead()) {
-                // destruct Emitter only when there is no particles spawned by it
-                iter = emitters.erase(iter);
-                continue;
-            }
-            vec = &particles[texture];
-        } else {
-            vec = &found->second;
-        }
+        vec = &particles[texture];
         emitter.update(delta, camera.position, *vec);
         iter++;
     }