From 0cd5136fdb53c47dcc246bc09a4bdeb99c132d70 Mon Sep 17 00:00:00 2001
From: MihailRis <mexaruc@gmail.com>
Date: Mon, 4 Nov 2024 14:41:52 +0300
Subject: [PATCH] feat: emitters random access & add ParticlesRenderer.gc()

---
 src/graphics/render/ParticlesRenderer.cpp | 36 +++++++++++++++++++++--
 src/graphics/render/ParticlesRenderer.hpp | 17 +++++++++--
 src/typedefs.hpp                          |  1 +
 3 files changed, 49 insertions(+), 5 deletions(-)

diff --git a/src/graphics/render/ParticlesRenderer.cpp b/src/graphics/render/ParticlesRenderer.cpp
index a15e75a8..d377773e 100644
--- a/src/graphics/render/ParticlesRenderer.cpp
+++ b/src/graphics/render/ParticlesRenderer.cpp
@@ -1,5 +1,7 @@
 #include "ParticlesRenderer.hpp"
 
+#include <set>
+
 #include "assets/Assets.hpp"
 #include "assets/assets_util.hpp"
 #include "graphics/core/Shader.hpp"
@@ -119,7 +121,7 @@ void ParticlesRenderer::render(const Camera& camera, float delta) {
 
     auto iter = emitters.begin();
     while (iter != emitters.end()) {
-        auto& emitter = **iter;
+        auto& emitter = *iter->second;
         auto texture = emitter.getTexture();
         const auto& found = particles.find(texture);
         std::vector<Particle>* vec;
@@ -138,6 +140,34 @@ void ParticlesRenderer::render(const Camera& camera, float delta) {
     }
 }
 
-void ParticlesRenderer::add(std::unique_ptr<Emitter> emitter) {
-    emitters.push_back(std::move(emitter));
+void ParticlesRenderer::gc() {
+    std::set<Emitter*> usedEmitters;
+    for (const auto& [_, vec] : particles) {
+        for (const auto& particle : vec) {
+            usedEmitters.insert(particle.emitter);
+        }
+    }
+    auto iter = emitters.begin();
+    while (iter != emitters.end()) {
+        auto emitter = iter->second.get();
+        if (usedEmitters.find(emitter) == usedEmitters.end()) {
+            iter = emitters.erase(iter);
+        } else {
+            iter++;
+        }
+    }
+}
+
+Emitter* ParticlesRenderer::getEmitter(u64id_t id) const {
+    const auto& found = emitters.find(id);
+    if (found == emitters.end()) {
+        return nullptr;
+    }
+    return found->second.get();
+}
+
+u64id_t ParticlesRenderer::add(std::unique_ptr<Emitter> emitter) {
+    u64id_t uid = nextEmitter++;
+    emitters[uid] = std::move(emitter);
+    return uid;
 }
diff --git a/src/graphics/render/ParticlesRenderer.hpp b/src/graphics/render/ParticlesRenderer.hpp
index 27877959..46509d96 100644
--- a/src/graphics/render/ParticlesRenderer.hpp
+++ b/src/graphics/render/ParticlesRenderer.hpp
@@ -5,6 +5,7 @@
 #include <unordered_map>
 
 #include "Emitter.hpp"
+#include "typedefs.hpp"
 
 class Texture;
 class Assets;
@@ -18,9 +19,11 @@ class ParticlesRenderer {
     const Assets& assets;
     const GraphicsSettings* settings;
     std::unordered_map<const Texture*, std::vector<Particle>> particles;
-    std::vector<std::unique_ptr<Emitter>> emitters;
     std::unique_ptr<MainBatch> batch;
 
+    std::unordered_map<u64id_t, std::unique_ptr<Emitter>> emitters;
+    u64id_t nextEmitter = 1;
+
     void renderParticles(const Camera& camera, float delta);
 public:
     ParticlesRenderer(
@@ -32,7 +35,17 @@ public:
 
     void render(const Camera& camera, float delta);
 
-    void add(std::unique_ptr<Emitter> emitter);
+    u64id_t add(std::unique_ptr<Emitter> emitter);
+
+    /// @brief Perform garbage collection (remove extra dead emitters).
+    /// @note Emitters are deleting without GC when there's no particles with same
+    /// texture left.
+    /// @note Currently unused
+    void gc();
+
+    /// @brief Get emitter by UID
+    /// @return Emitter or nullptr
+    Emitter* getEmitter(u64id_t id) const;
 
     static size_t visibleParticles;
     static size_t aliveEmitters;
diff --git a/src/typedefs.hpp b/src/typedefs.hpp
index 3925d277..b3266aea 100644
--- a/src/typedefs.hpp
+++ b/src/typedefs.hpp
@@ -12,6 +12,7 @@ using integer_t = int64_t;
 using number_t = double;
 
 using uint = unsigned int;
+using u64id_t = uint64_t;
 
 /// @brief use for bytes arrays
 using ubyte = uint8_t;