Improve particle system

Add support for texture and rotation

engine/particle_sys.c

@@ -52,6 +52,8 @@ void add_particle_emitter(ParticleSystem_t* system, const ParticleEmitter_t* in_
         emitter->particles[i].velocity.x = speed * cos(angle);
         emitter->particles[i].velocity.y = speed * sin(angle);
         emitter->particles[i].position = emitter->position;
+        emitter->particles[i].rotation = angle;
+        emitter->particles[i].angular_vel = -10 + 20 * (float)rand() / (float)RAND_MAX;
     }
 }
 void update_particle_system(ParticleSystem_t* system)
@@ -110,11 +112,33 @@ void draw_particle_system(ParticleSystem_t* system)
     {
         ParticleEmitter_t* emitter = system->emitters + emitter_idx;
 
-        for (uint32_t i = 0; i < emitter->n_particles; ++i)
+        Particle_t* part = emitter->particles;
+        for (uint32_t i = 0; i < emitter->n_particles; ++i, ++part)
         {
-            if (emitter->particles[i].alive)
+            if (part->alive)
             {
-                DrawCircleV(emitter->particles[i].position, 5, BLACK);
+                if (emitter->tex == NULL)
+                {
+                    DrawCircleV(part->position, 5, BLACK);
+                }
+                else
+                {
+                    Rectangle source = {
+                        0.0f, 0.0f,
+                        (float)emitter->tex->width, (float)emitter->tex->height
+                    };
+                    
+                    Rectangle dest = {
+                        part->position.x, part->position.y,
+                        (float)emitter->tex->width, (float)emitter->tex->height
+                    };
+                    Vector2 origin = { (float)emitter->tex->width / 2, (float)emitter->tex->height / 2 };
+                    DrawTexturePro(
+                        *emitter->tex,
+                        source, dest, origin,
+                        part->rotation, WHITE
+                    );
+                }
             }
         }
         emitter_idx = system->emitter_list[emitter_idx].next;

engine/particle_sys.h

@@ -13,11 +13,11 @@ typedef enum PartEmitterType
 
 typedef struct Particle
 {
-    Texture2D* tex;
     Vector2 position;
     Vector2 velocity;
     Vector2 accleration;
     float rotation;
+    float angular_vel;
     float size;
     uint32_t timer;
     bool alive;
@@ -41,6 +41,7 @@ typedef struct ParticleEmitter
     Vector2 position;
     Particle_t particles[MAX_PARTICLES];
     uint32_t n_particles;
+    Texture2D* tex;
     uint32_t timer;
     bool one_shot;
     bool finished;

particle_test.c

@@ -10,6 +10,8 @@ void simple_particle_system_update(Particle_t* part, void* user_data)
 {
 
     float delta_time = DELTA_T; // TODO: Will need to think about delta time handling
+    part->rotation += part->angular_vel;
+
     part->velocity =
         Vector2Add(
             part->velocity,
@@ -49,6 +51,7 @@ int main(void)
     static ParticleSystem_t part_sys = {0};
 
     init_particle_system(&part_sys);
+    Texture2D tex = LoadTexture("res/bomb.png");
 
     EmitterConfig_t conf ={
         .launch_range = {0, 360},
@@ -61,6 +64,7 @@ int main(void)
         .config = conf,
         .n_particles = MAX_PARTICLES,
         .one_shot = true,
+        .tex = &tex,
     };
 
     bool key_press = false;
@@ -83,5 +87,7 @@ int main(void)
             draw_particle_system(&part_sys);
         EndDrawing();
     } 
+    UnloadTexture(tex);
     CloseWindow();
+    deinit_particle_system(&part_sys);
 }