From 83ddbda90b503d5bfb497bc762b57653354ef5be Mon Sep 17 00:00:00 2001
From: MihailRis <mexaruc@gmail.com>
Date: Sun, 3 Nov 2024 13:05:42 +0300
Subject: [PATCH] implement entity-bound emitters

---
 src/graphics/render/Emitter.cpp           | 12 +++++++++---
 src/graphics/render/Emitter.hpp           |  3 +++
 src/graphics/render/ParticlesRenderer.cpp | 13 +++++++++----
 3 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/src/graphics/render/Emitter.cpp b/src/graphics/render/Emitter.cpp
index ea64a93d..6a7dacd8 100644
--- a/src/graphics/render/Emitter.cpp
+++ b/src/graphics/render/Emitter.cpp
@@ -6,15 +6,19 @@
 
 #include "window/Camera.hpp"
 #include "graphics/core/Texture.hpp"
+#include "objects/Entities.hpp"
+#include "world/Level.hpp"
 
 Emitter::Emitter(
+    const Level& level,
     std::variant<glm::vec3, entityid_t> origin,
     Particle prototype,
     const Texture* texture,
     float spawnInterval,
     int count
 )
-    : origin(std::move(origin)),
+    : level(level),
+      origin(std::move(origin)),
       prototype(std::move(prototype)),
       texture(texture),
       spawnInterval(spawnInterval),
@@ -38,8 +42,10 @@ void Emitter::update(
     glm::vec3 position {};
     if (auto staticPos = std::get_if<glm::vec3>(&origin)) {
         position = *staticPos;
-    } else {
-        // TODO: implement for entity origin
+    } else if (auto entityId = std::get_if<entityid_t>(&origin)) {
+        if (auto entity = level.entities->get(*entityId)) {
+            position = entity->getTransform().pos;
+        }
     }
     if (glm::distance2(position, cameraPosition) > maxDistance * maxDistance) {
         if (count > 0) {
diff --git a/src/graphics/render/Emitter.hpp b/src/graphics/render/Emitter.hpp
index b8783ea8..884ba11e 100644
--- a/src/graphics/render/Emitter.hpp
+++ b/src/graphics/render/Emitter.hpp
@@ -9,6 +9,7 @@
 #include "maths/UVRegion.hpp"
 #include "maths/util.hpp"
 
+class Level;
 class Emitter;
 
 struct Particle {
@@ -36,6 +37,7 @@ struct ParticleBehaviour {
 };
 
 class Emitter {
+    const Level& level;
     /// @brief Static position or entity
     std::variant<glm::vec3, entityid_t> origin;
     /// @brief Particle prototype
@@ -60,6 +62,7 @@ public:
     ParticleBehaviour behaviour;
 
     Emitter(
+        const Level& level,
         std::variant<glm::vec3, entityid_t> origin,
         Particle prototype,
         const Texture* texture,
diff --git a/src/graphics/render/ParticlesRenderer.cpp b/src/graphics/render/ParticlesRenderer.cpp
index f9c2e4d1..0ad5c1d5 100644
--- a/src/graphics/render/ParticlesRenderer.cpp
+++ b/src/graphics/render/ParticlesRenderer.cpp
@@ -19,10 +19,15 @@ ParticlesRenderer::ParticlesRenderer(
     : batch(std::make_unique<MainBatch>(1024)),
       level(level),
       settings(settings) {
-    auto region = util::get_texture_region(assets, "blocks:grass_top", "");
-    emitters.push_back(std::make_unique<Emitter>(glm::vec3(0, 80, 0), Particle {
-        nullptr, 0, glm::vec3(), glm::vec3(), 5.0f, region.region
-    }, region.texture, 0.002f, -1));
+    auto region = util::get_texture_region(assets, "blocks:grass_side", "");
+    emitters.push_back(std::make_unique<Emitter>(
+        level,
+        glm::vec3(0, 80, 0),
+        Particle {nullptr, 0, glm::vec3(), glm::vec3(), 5.0f, region.region},
+        region.texture,
+        0.002f,
+        -1
+    ));
 }
 
 ParticlesRenderer::~ParticlesRenderer() = default;