ldr123/unes

Nintendo Entertainment System emulator written in C# and run in Unity

UNES

UNES is an emulator plug-in that runs Nintendo Entertainment System Nintendo FC Game *.nes files in the Unity environment. The project is based on Emulator.NES to achieve cross-platform through Unity.

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• 1. Start
• 2. Load
  • 2.1. Resources loading
  • 2.2. FileStream loading
• 3. Configuration
  • 3.1. Filter Mode
  • 3.2. Logic Thread
  • 3.3. Input Config
• 4. input
• 5. API
  • 5.1. Boot
  • 5.2. Save
  • 5.3. Load
• 6. Mapper
• 7. Problem

1. Start

• 1. Create a new or select a GameObject in the scene and add the UNESBehaviour component.
• 2. Create a new RenderTexture to render the game screen.
• 3. Use any way you want to display the RenderTexture file in the game.
• 4. Use the default input method or realize custom input on demand.
• 5. Implement the loading of *.nes files on demand to obtain byte[] format data.
• 6. Call the UNESBehaviour.Boot(byte[] romData) interface to start the game.

2. Load

2.1. Resources loading

If you need to use the Resources.Load() interface to load the ROM file, you need to pay attention to changing the .nes extension to .bytes, and then use the following method to load:

var bytes = Resources.Load<TextAsset>(romPath).bytes;
UNES.BootRom(bytes);

2.2. FileStream loading

If you use the method of loading the original file byte stream, you can directly call the UNESBehaviour.Boot(byte[] romData) interface.

3. Configuration

3.1. Filter Mode

Filter mode of game screen rendering:

Mode	Description
Point	Texture pixels become blocky at close range.
Bilinear	Bilinear bilinear filtering-averages the texture samples.
Trilinear	Trilinear Trilinear filtering-averages texture samples and blends between mipmap levels.

For detailed explanation, please refer to FilterMode

3.2. Logic Thread

If the Logic Thread option is turned on, the simulation calculations of the CPU and PPU parts will be executed by other thread, and the Unity main thread is only responsible for reading the status data to refresh the game screen, which can significantly increase the number of frames.

3.3. Input Config

Customize the physical keyboard keys corresponding to the native keys.

4. input

Default configuration control method:

Native buttons	Operation buttons
Start	Num1
Select	Num2
Up	Up Arrow
Down	Down Arrow
Left	Left Arrow
Right	Right Arrow
A	A
B	S

5. API

5.1. Boot

Obtain the byte array format of the original ROM file in any way for the emulator to start:

public void Boot(byte[] romData);

5.2. Save

The simulator itself only provides the data of the current running state, and does not provide the persistence implementation of the data file. Need to realize the preservation of archived data by oneself.

public byte[] GetSaveData();

5.3. Load

Obtain archive file data in any way for the emulator to restore game progress:

public void LoadSaveData(byte[] saveData);

6. Mapper

There are many Mapper extension formats in NES, and the implemented part of the project implementation can theoretically support most common games.

0	NROM
1	MMC1
2	UxROM
3	CNROM
4	MMC3
7	AxROM
9	MMC2 (Mike Tyson's Punch-Out!!)
10	MMC4
11	Color Dreams
66	GxROM
71	Camerica
79	NINA-003-006
94	Senjou no Ookami
140	Jaleco
155	MMC1A
180	Crazy Climber
206	DxROM

7. Problem

• Audio APU simulation is not implemented.
• Only realize Unity basic input system and pure keyboard operation mode.
• Not all Mappers are implemented.
• The performance of the PPU simulation part is low, and the frame number is unstable on the low-end mobile devices.