From 204329d2aa498b1fbf78a7cc75975bc545daf85b Mon Sep 17 00:00:00 2001
From: En Yi <en.yi@tutanota.com>
Date: Wed, 24 Apr 2024 21:47:58 +0800
Subject: [PATCH] Use float for timing in particle system

Also, update the assets_loader due to this
---
 engine/particle_sys.c  | 18 +++++++++++-------
 engine/particle_sys.h  |  8 ++++----
 scenes/assets_loader.c |  2 +-
 3 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/engine/particle_sys.c b/engine/particle_sys.c
index acc7da4..e5cbf81 100644
--- a/engine/particle_sys.c
+++ b/engine/particle_sys.c
@@ -1,8 +1,8 @@
 #include "particle_sys.h"
 #include "assets.h"
+#include "raymath.h"
 #include <string.h>
 #include <stdlib.h>
-#include <math.h>
 
 void init_particle_system(ParticleSystem_t* system)
 {
@@ -30,9 +30,9 @@ static inline float generate_randrange(float lo, float hi)
 
 static inline void spawn_particle(ParticleEmitter_t* emitter, uint32_t idx)
 {
-    uint32_t lifetime = (emitter->config->particle_lifetime[1] - emitter->config->particle_lifetime[0]);
+    float lifetime = (emitter->config->particle_lifetime[1] - emitter->config->particle_lifetime[0]);
     emitter->particles[idx].timer = emitter->config->particle_lifetime[0];
-    emitter->particles[idx].timer += rand() % lifetime;
+    emitter->particles[idx].timer += lifetime * rand()/ (float)RAND_MAX;
     emitter->particles[idx].alive = true;
 
     float angle = generate_randrange(emitter->config->launch_range[0], emitter->config->launch_range[1]);
@@ -92,7 +92,7 @@ void play_emitter_handle(ParticleSystem_t* system, uint16_t handle)
         {
             // TODO: deal with stream type
             //spawn_particle(emitter, 0);
-            uint32_t incr = 0;
+            float incr = 0;
             for (uint32_t i = 0; i < emitter->n_particles; ++i)
             {
                 emitter->particles[i].timer = incr;
@@ -179,9 +179,9 @@ void update_particle_system(ParticleSystem_t* system, float delta_time)
                 }
 
             }
-            // Lifetime update
-            if (emitter->particles[i].timer > 0) emitter->particles[i].timer--;
-            if (emitter->particles[i].timer == 0)
+
+            emitter->particles[i].timer -= delta_time;
+            if (emitter->particles[i].timer <= 0.0f)
             {
                 if (emitter->particles[i].spawned)
                 {
@@ -222,6 +222,10 @@ void update_particle_system(ParticleSystem_t* system, float delta_time)
             {
                 emitter->finished = true;
             }
+        }
+
+        if (emitter->finished)
+        {
             system->emitter_list[prev_idx].next = system->emitter_list[emitter_idx].next;
             system->emitter_list[emitter_idx].next = 0;
             system->emitter_list[emitter_idx].playing = false;
diff --git a/engine/particle_sys.h b/engine/particle_sys.h
index beab1a0..591d948 100644
--- a/engine/particle_sys.h
+++ b/engine/particle_sys.h
@@ -22,7 +22,7 @@ typedef struct Particle
     float rotation;
     float angular_vel;
     float size;
-    uint32_t timer;
+    float timer;
     bool alive;
     bool spawned;
 }Particle_t;
@@ -38,8 +38,8 @@ typedef struct EmitterConfig
     float speed_range[2];
     float angle_range[2];
     float rotation_range[2];
-    uint32_t particle_lifetime[2];
-    uint32_t initial_spawn_delay;
+    float particle_lifetime[2];
+    float initial_spawn_delay;
     PartEmitterType_t type;
     bool one_shot;
 }EmitterConfig_t;
@@ -51,7 +51,7 @@ struct ParticleEmitter
     Vector2 position;
     Particle_t particles[MAX_PARTICLES];
     uint32_t n_particles;
-    uint32_t timer;
+    float timer;
     bool finished;
     bool active;
     void* user_data;
diff --git a/scenes/assets_loader.c b/scenes/assets_loader.c
index fcaff98..cc57211 100644
--- a/scenes/assets_loader.c
+++ b/scenes/assets_loader.c
@@ -41,7 +41,7 @@ static bool parse_emitter_info(char* emitter_info_str, EmitterConfig_t* conf)
     char emitter_type;
     uint8_t one_shot;
     int data_count = sscanf(
-        emitter_info_str, "%c,%f-%f,%f-%f,%f-%f,%f-%f,%u-%u,%u,%c",
+        emitter_info_str, "%c,%f-%f,%f-%f,%f-%f,%f-%f,%f-%f,%f,%c",
         &emitter_type,
         conf->launch_range, conf->launch_range + 1,
         conf->speed_range, conf->speed_range + 1,