Editing Openai/69676758-d944-8003-a3d4-835e33b4e372 (section)

=== Assistant: This is a good question, and it’s the right way to think if you want designs that actually ship. ===
This is a good question, and it’s the right way to think if you want designs that actually ship. The key is that you do not derive constraints from hardware first. You derive them from a performance budget, which is then mapped onto hardware classes.

Below is the correct, practical method used in real engines.

==== Everything flows from this. ====

Typical targets:
* 60 FPS → 16.67 ms per frame
* 120 FPS → 8.33 ms per frame
* 30 FPS → 33.3 ms per frame

This is your total budget for:
* CPU
* GPU
* synchronization
* OS overhead

If you don’t fix this, all other numbers are meaningless.

==== You never design for “a GPU”. You design for classes. ====

Example PC tiers:
* Minimum: 4-core CPU @ ~3 GHz, GTX 1060 / RX 580–class GPU
* Recommended: 6–8 core CPU, RTX 2060 / RX 6600–class GPU
* High-end: modern 8–12 core CPU, RTX 4070+

You do not need exact specs—only relative capability.

==== Example for 60 FPS: ====

===== - Total CPU frame time: ≤ 6–8 ms =====

Typical split:
* Gameplay logic: 1–2 ms
* Physics: 1–2 ms
* AI: 0.5–1.5 ms
* Rendering submission: 1–2 ms
* Misc (audio, scripting): ~1 ms

===== - Total GPU frame time: ≤ 10–12 ms =====

Split roughly into:
* Geometry / visibility: 2–4 ms
* Lighting / shading: 4–6 ms
* Post-processing: 1–2 ms
* UI / compositing: <1 ms

These are design targets, not measurements.

==== Now you can answer: ====

: 

===== Express limits as: =====
* Time per frame (ms)
* Operations per entity
* Entities per frame

Example:
* Enemy AI update: ≤ 0.02 ms per entity
* Physics objects: ≤ 1,000 active bodies
* Pathfinding: amortized over multiple frames

===== Express limits as: =====
* Draw calls
* Triangles / vertices
* Shader cost
* Overdraw
* Texture memory

Example:
* Character model: ≤ 50k triangles
* Screen-space effects: ≤ 2 ms GPU
* Particles: ≤ 100k sprites total

==== This is crucial. ====

Every mechanic must answer:
* What scales with entity count?
* What scales with screen resolution?
* What scales with view distance?

Example:
* Crowd system scales by: - LOD level - Animation update rate - AI tick frequency
* VFX scale by: - Resolution - Particle density - Shader quality

On paper, you write:

: 

==== Design for: ====
* Maximum enemies on screen
* Worst camera angle
* Maximum particle overlap
* Peak combat moments

If it fits worst-case, it fits everywhere else.

==== You cannot: ====
* Predict exact GPU ms costs
* Predict cache behavior
* Predict driver scheduling
* Predict shader compilation impact

That’s why:
* Paper design gives upper bounds
* Profiling later validates them

==== On paper, you don’t say: ====

: 

You say:

: 

That statement is meaningful, testable, and enforceable.

==== Design budgets in milliseconds, counts, and scaling rules — not hardware registers or specs. ====

That is the deepest level you can reliably go before you have a prototype.

If you want, I can help you build a one-page performance budget template you can reuse for any game concept.