From 6d63c712218dc1d1feffad41506c2c5b022fd3f3 Mon Sep 17 00:00:00 2001
From: MihailRis <mexaruc@gmail.com>
Date: Sun, 3 Nov 2024 12:45:46 +0300
Subject: [PATCH] add Emitter maxDistance

---
 src/graphics/render/Emitter.cpp           | 23 +++++++++++++++++++++--
 src/graphics/render/Emitter.hpp           | 16 ++++++++++++----
 src/graphics/render/ParticlesRenderer.cpp |  2 +-
 3 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/src/graphics/render/Emitter.cpp b/src/graphics/render/Emitter.cpp
index e4fb9d47..ea64a93d 100644
--- a/src/graphics/render/Emitter.cpp
+++ b/src/graphics/render/Emitter.cpp
@@ -1,7 +1,10 @@
 #include "Emitter.hpp"
 
 #include <glm/gtc/random.hpp>
+#define GLM_ENABLE_EXPERIMENTAL
+#include <glm/gtx/norm.hpp>
 
+#include "window/Camera.hpp"
 #include "graphics/core/Texture.hpp"
 
 Emitter::Emitter(
@@ -24,8 +27,12 @@ const Texture* Emitter::getTexture() const {
     return texture;
 }
 
-void Emitter::update(float delta, std::vector<Particle>& particles) {
-    if (count == 0) {
+void Emitter::update(
+    float delta,
+    const glm::vec3& cameraPosition,
+    std::vector<Particle>& particles
+) {
+    if (count == 0 || (count == -1 && spawnInterval < FLT_EPSILON)) {
         return;
     }
     glm::vec3 position {};
@@ -34,6 +41,18 @@ void Emitter::update(float delta, std::vector<Particle>& particles) {
     } else {
         // TODO: implement for entity origin
     }
+    if (glm::distance2(position, cameraPosition) > maxDistance * maxDistance) {
+        if (count > 0) {
+            if (spawnInterval < FLT_EPSILON) {
+                count = 0;
+                return;
+            }
+            int skipped = timer / spawnInterval;
+            count = std::max(0, count - skipped);
+            timer -= skipped * spawnInterval;
+        }
+        return;
+    }
     timer += delta;
     while (count && timer > spawnInterval) {
         // spawn particle
diff --git a/src/graphics/render/Emitter.hpp b/src/graphics/render/Emitter.hpp
index 431d2e49..b8783ea8 100644
--- a/src/graphics/render/Emitter.hpp
+++ b/src/graphics/render/Emitter.hpp
@@ -15,6 +15,7 @@ struct Particle {
     /// @brief Pointer used to access common behaviour.
     /// Emitter must be utilized after all related particles despawn.
     Emitter* emitter;
+    /// @brief Some random integer for visuals configuration.
     int random;
     /// @brief Global position
     glm::vec3 position;
@@ -44,15 +45,17 @@ class Emitter {
     /// @brief Particles spawn interval
     float spawnInterval;
     /// @brief Number of particles should be spawned before emitter deactivation.
-    /// -1 is infinite
+    /// -1 is infinite.
     int count;
     /// @brief Spawn timer used to determine number of particles 
     /// to spawn on update. May be innacurate.
     float timer = 0.0f;
-    /// @brief Random velocity magnitude applying to spawned particles
+    /// @brief Random velocity magnitude applying to spawned particles.
     glm::vec3 explosion {8.0f};
+    /// @brief Max distance of actually spawning particles.
+    float maxDistance = 32.0f;
 
-    util::PseudoRandom random;    
+    util::PseudoRandom random;
 public:
     ParticleBehaviour behaviour;
 
@@ -71,8 +74,13 @@ public:
 
     /// @brief Update emitter and spawn particles
     /// @param delta delta time
+    /// @param cameraPosition current camera global position
     /// @param particles destination particles vector
-    void update(float delta, std::vector<Particle>& particles);    
+    void update(
+        float delta,
+        const glm::vec3& cameraPosition,
+        std::vector<Particle>& particles
+    );
 
     /// @brief Set initial random velocity magitude
     void setExplosion(const glm::vec3& magnitude);
diff --git a/src/graphics/render/ParticlesRenderer.cpp b/src/graphics/render/ParticlesRenderer.cpp
index e7b72c00..f9c2e4d1 100644
--- a/src/graphics/render/ParticlesRenderer.cpp
+++ b/src/graphics/render/ParticlesRenderer.cpp
@@ -119,7 +119,7 @@ void ParticlesRenderer::render(const Camera& camera, float delta) {
         } else {
             vec = &found->second;
         }
-        emitter.update(delta, *vec);
+        emitter.update(delta, camera.position, *vec);
         iter++;
     }
 }