Add rotation

gamestate.c

@@ -2,28 +2,41 @@
 
 // do not use any global variables to process gamestate
 
-
-static void process_body(struct Body *body, float dt)
+static void integrate_acceleration(struct Body *body, float dt)
 {
-    V2 current = body->position;
-    body->position = V2add(body->position, V2sub(current, body->old_position));
-    body->position = V2add(body->position, V2scale(body->acceleration, dt*dt));
-    body->old_position = current;
-}
+    // position
+    {
+        V2 current = body->position;
+        body->position = V2add(body->position, V2sub(current, body->old_position));
+        body->position = V2add(body->position, V2scale(body->acceleration, dt * dt));
+        body->old_position = current;
+    }
 
+    // rotation
+    {
+        float current = body->rotation;
+        body->rotation = body->rotation + (current - body->old_rotation);
+        body->rotation = body->rotation + body->angular_acceleration * dt * dt;
+        body->old_rotation = current;
+    }
+}
 
-void process(struct GameState * gs, float dt) {
-    for(int i = 0; i < MAX_PLAYERS; i++)
+void process(struct GameState *gs, float dt)
+{
+    for (int i = 0; i < MAX_PLAYERS; i++)
     {
-        struct Player * p = &gs->players[i];
-        if(!p->connected)
+        struct Player *p = &gs->players[i];
+        if (!p->connected)
             continue;
         p->body.acceleration = V2scale(p->input, 5.0f);
-        process_body(&p->body, dt);
+        p->body.angular_acceleration = p->input.x * 10.0f;
+        integrate_acceleration(&p->body, dt);
     }
 
-    for(int i = 0; i < gs->num_boxes; i++)
+    for (int i = 0; i < gs->num_boxes; i++)
     {
-        process_body(&gs->boxes[i].body, dt);
+        integrate_acceleration(&gs->boxes[i].body, dt);
     }
+
+    
 }

main.c

@@ -195,7 +195,10 @@ static void frame(void)
             if (!p->connected)
                 continue;
             sgp_set_color(1.0f, 1.0f, 1.0f, 1.0f);
+            sgp_push_transform();
+            sgp_rotate_at(p->body.rotation,p->body.position.x, p->body.position.y);
             sgp_draw_filled_rect(p->body.position.x - halfbox, p->body.position.y - halfbox, BOX_SIZE, BOX_SIZE);
+            sgp_pop_transform();
         }
 
         // boxes

types.h

@@ -34,7 +34,12 @@ struct Body
 {
     P2 position;
     P2 old_position;
+
+    float rotation;
+    float old_rotation;
+
     V2 acceleration;
+    float angular_acceleration;
 };
 
 struct Player