Implement feature to start and stop emitter

engine/particle_sys.c

@@ -61,15 +61,35 @@ uint16_t load_in_particle_emitter(ParticleSystem_t* system, const ParticleEmitte
     {
         system->emitters[idx].n_particles = MAX_PARTICLES;
     }
+    system->emitter_list[idx].playing = false;
     return idx;
 }
 
 void play_emitter_handle(ParticleSystem_t* system, uint16_t handle)
 {
     if (handle == 0) return;
+    if (!system->emitter_list[handle].playing)
+    {
+        ParticleEmitter_t* emitter = system->emitters + handle;
+        if (emitter->config->type == EMITTER_BURST)
+        {
+            for (uint32_t i = 0; i < emitter->n_particles; ++i)
+            {
+                spawn_particle(emitter, i);
+            }
+        }
+        else if (emitter->config->type == EMITTER_STREAM)
+        {
+            // TODO: deal with stream type
+            //spawn_particle(emitter, 0);
+        }
         system->emitter_list[system->tail_idx].next = handle;
         system->tail_idx = handle;
         system->emitter_list[handle].next = 0;
+        system->emitter_list[handle].playing = true;
+    }
+    system->emitters[handle].active = true;
+
 }
 
 // An emitter cannot be unloaded or paused mid-way when particles to still
@@ -77,10 +97,18 @@ void play_emitter_handle(ParticleSystem_t* system, uint16_t handle)
 void pause_emitter_handle(ParticleSystem_t* system, uint16_t handle)
 {
     if (handle == 0) return;
+    if (!system->emitter_list[handle].playing) return;
     
     system->emitters[handle].active = false;
 }
 
+void update_emitter_handle_position(ParticleSystem_t* system, EmitterHandle handle, Vector2 pos)
+{
+    if (handle == 0) return;
+    
+    system->emitters[handle].position = pos;
+}
+
 void unload_emitter_handle(ParticleSystem_t* system, uint16_t handle)
 {
     if (handle == 0) return;
@@ -94,17 +122,6 @@ void play_particle_emitter(ParticleSystem_t* system, const ParticleEmitter_t* in
     uint16_t idx = load_in_particle_emitter(system, in_emitter);
     if (idx == 0) return;
 
-    ParticleEmitter_t* emitter = system->emitters + idx;
-    // Generate particles based on type
-    // Burst type need to generate all at once
-    // TODO: stream type need to generate one at a time
-    if (emitter->config->type == EMITTER_BURST)
-    {
-        for (uint32_t i = 0; i < emitter->n_particles; ++i)
-        {
-            spawn_particle(emitter, i);
-        }
-    }
     play_emitter_handle(system, idx);
 }
 
@@ -134,29 +151,32 @@ void update_particle_system(ParticleSystem_t* system)
                 if (emitter->particles[i].timer == 0)
                 {
                     emitter->particles[i].alive = false;
-                    inactive_count++;
                 }
-                // TODO: If streaming and not one shot, immediately revive the particle
+            }
+
+            if (!emitter->particles[i].alive)
+            {
+                if (emitter->config->one_shot || !emitter->active)
+                {
+                    inactive_count++;
                 }
                 else
                 {
-                inactive_count++;
+                    // If not one shot, immediately revive the particle
+                    spawn_particle(emitter, i); 
+                }
             }
         }
         if (inactive_count == emitter->n_particles)
         {
-            // TODO: If burst and not one shot, revive all particles
+            // Stop playing only if all particles is inactive
-            emitter->active = false;
-        }
-
-        if (!emitter->active)
-        {
             if (!emitter->finished && emitter->config->one_shot)
             {
                 emitter->finished = true;
             }
             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;
             if (system->tail_idx == emitter_idx)
             {
                 system->tail_idx = prev_idx;

engine/particle_sys.h

@@ -11,8 +11,9 @@ typedef uint16_t EmitterHandle;
 
 typedef enum PartEmitterType
 {
-    EMITTER_BURST = 0,
+    EMITTER_UNKNOWN = 0,
-    EMITTER_UNKNOWN,
+    EMITTER_BURST,
+    EMITTER_STREAM,
 } PartEmitterType_t;
 
 typedef struct Particle
@@ -56,6 +57,7 @@ typedef struct ParticleEmitter
 typedef struct IndexList
 {
     uint32_t next;
+    bool playing;
 }IndexList_t;
 
 typedef struct ParticleSystem
@@ -77,6 +79,7 @@ void play_particle_emitter(ParticleSystem_t* system, const ParticleEmitter_t* in
 EmitterHandle load_in_particle_emitter(ParticleSystem_t* system, const ParticleEmitter_t* in_emitter);
 void play_emitter_handle(ParticleSystem_t* system, EmitterHandle handle);
 void pause_emitter_handle(ParticleSystem_t* system, EmitterHandle handle);
+void update_emitter_handle_position(ParticleSystem_t* system, EmitterHandle handle, Vector2 pos);
 void unload_emitter_handle(ParticleSystem_t* system, EmitterHandle handle);
 
 void update_particle_system(ParticleSystem_t* system);

particle_test.c

@@ -69,6 +69,7 @@ int main(void)
         .launch_range = {0, 360},
         .speed_range = {400, 2000},
         .particle_lifetime = {30, 110},
+        .type = EMITTER_BURST,
     };
 
     ParticleEmitter_t emitter = {
@@ -78,20 +79,59 @@ int main(void)
         .spr = (tex.width == 0) ? NULL : &spr,
     };
 
+    EmitterConfig_t conf2 ={
+        .one_shot = false,
+        .launch_range = {0, 360},
+        .speed_range = {300, 800},
+        .particle_lifetime = {15, 30},
+        .type = EMITTER_BURST,
+    };
+
+    ParticleEmitter_t emitter2 = {
+        .config = &conf2,
+        .n_particles = MAX_PARTICLES,
+        .update_func = &simple_particle_system_update,
+        .spr = (tex.width == 0) ? NULL : &spr,
+    };
+
+    EmitterHandle han = load_in_particle_emitter(&part_sys, &emitter2);
+    assert(han != 0);
+
     bool key_press = false;
+    uint8_t key2_press = 0;
     char text_buffer[32];
     while(!WindowShouldClose())
     {
+        Vector2 mouse_pos = GetMousePosition();
         if (IsMouseButtonPressed(MOUSE_LEFT_BUTTON))
         {
             key_press = true;
         }
         else if (key_press && IsMouseButtonReleased(MOUSE_BUTTON_LEFT))
         {
-            emitter.position = GetMousePosition();
+            emitter.position = mouse_pos;
             play_particle_emitter(&part_sys, &emitter);
             key_press = false;
         }
+
+        key2_press <<= 1;
+        key2_press |= IsMouseButtonDown(MOUSE_RIGHT_BUTTON)? 1: 0;
+        key2_press &= 0b11;
+
+        if (key2_press == 0b01)
+        {
+            update_emitter_handle_position(&part_sys, han, mouse_pos);
+            play_emitter_handle(&part_sys, han);
+        }
+        else if(key2_press == 0b11)
+        {
+            update_emitter_handle_position(&part_sys, han, mouse_pos);
+        }
+        else if (key2_press == 0b10)
+        {
+            pause_emitter_handle(&part_sys, han);
+        }
+
         update_particle_system(&part_sys);
         sprintf(text_buffer, "free: %u", get_number_of_free_emitter(&part_sys));
         BeginDrawing();