second commit

Net.h

@@ -24,6 +24,25 @@ struct NetUpdate {
     NetState state;
 };
 
+// A shockwave explosion. Every machine applies the launch to its own player, since remote
+// players are only puppets here. Blasts are re-sent a few times (UDP) and de-duplicated on receive.
+struct NetBlast {
+    uint8_t   sender = 0;  // filled in by the host; ignored on send
+    uint32_t  id = 0;      // filled in by SendBlast
+    glm::vec3 center = glm::vec3(0.0f);
+    float     radius = 0.0f;
+    float     power = 0.0f;
+};
+
+// Damage dealt to another player. Each machine owns its own player's health, so the shooter
+// aims locally and sends this to the victim, who applies it. Re-sent a few times and de-duplicated.
+struct NetHit {
+    uint8_t   sender = 0;  // filled in by the host
+    uint32_t  id = 0;      // filled in by SendHit
+    int       damage = 0;
+    glm::vec3 knockback = glm::vec3(0.0f);  // added to the victim's velocity
+};
+
 class Lan {
 public:
     enum class Mode { Off, Host, Client };
@@ -44,7 +63,14 @@ public:
     // Call once per frame with our own state.
     void Send(const NetState& state);
     // Drains all waiting packets and appends the other players' newest states to 'out'.
-    void Receive(std::vector<NetUpdate>& out);
+    // If 'blasts' is given, new (de-duplicated) shockwave blasts from other players are appended to it.
+    // 'hits' gets damage aimed at us (de-duplicated).
+    void Receive(std::vector<NetUpdate>& out, std::vector<NetBlast>* blasts = nullptr,
+                 std::vector<NetHit>* hits = nullptr);
+    // Damage another player. 'target' is the id from their NetUpdate (the host is 0).
+    void SendHit(uint8_t target, const NetHit& hit);
+    // Tell the other players about a blast we caused. Sent over the next few Send() calls.
+    void SendBlast(const NetBlast& blast);
 
     // Host: at least one player has joined. Client: the host has been heard from in the last 2 s.
     bool IsConnected() const;