multiplayer

# Multiplayer Game Development > Networking architecture and synchronization principles. --- ## 1. Architecture Selection ### Decision Tree ``` What type of multiplayer? │ ├── Competitive / Real-time │ └── Dedicated Server (authoritative) │ ├── Cooperative / Casual │ └── Host-based (one player is server) │ ├── Turn-based │ └── Client-server (simple) │ └── Massive (MMO) └── Distributed servers ``` ### Comparison | Architecture | Latency | Cost | Security | |--------------|---------|------|----------| | **Dedicated** | Low | High | Strong | | **P2P** | Variable | Low | Weak | | **Host-based** | Medium | Low | Medium | --- ## 2. Synchronization Principles ### State vs Input | Approach | Sync What | Best For | |----------|-----------|----------| | **State Sync** | Game state | Simple, few objects | | **Input Sync** | Player inputs | Action games | | **Hybrid** | Both | Most games | ### Lag Compensation | Technique | Purpose | |-----------|---------| | **Prediction** | Client predicts server | | **Interpolation** | Smooth remote players | | **Reconciliation** | Fix mispredictions | | **Lag compensation** | Rewind for hit detection | --- ## 3. Network Optimization ### Bandwidth Reduction | Technique | Savings | |-----------|---------| | **Delta compression** | Send only changes | | **Quantization** | Reduce precision | | **Priority** | Important data first | | **Area of interest** | Only nearby entities | ### Update Rates | Type | Rate | |------|------| | Position | 20-60 Hz | | Health | On change | | Inventory | On change | | Chat | On send | --- ## 4. Security Principles ### Server Authority ``` Client: "I hit the enemy" Server: Validate → did projectile actually hit? → was player in valid state? → was timing possible? ``` ### Anti-Cheat | Cheat | Prevention | |-------|------------| | Speed hack | Server validates movement | | Aimbot | Server validates sight line | | Item dupe | Server owns inventory | | Wall hack | Don't send hidden data | --- ## 5. Matchmaking ### Considerations | Factor | Impact | |--------|--------| | **Skill** | Fair matches | | **Latency** | Playable connection | | **Wait time** | Player patience | | **Party size** | Group play | --- ## 6. Anti-Patterns | ❌ Don't | ✅ Do | |----------|-------| | Trust the client | Server is authority | | Send everything | Send only necessary | | Ignore latency | Design for 100-200ms | | Sync exact positions | Interpolate/predict | --- > **Remember:** Never trust the client. The server is the source of truth.