readme.w32

著名SFC模拟器Snes9x的源代码。

Snes9x: The Portable Super Nintendo Entertainment System Emulator
=================================================================
v1.35 21-JAN-2001
=================

Home page: http://www.snes9x.com

Contents
========
Changes Since Last Release
Introduction
What's Emulated
What's Not
What You Will Need
Getting Started
Keyboard Controls
Joystick Support
Game Saving
Netplay Support
Cheat Support
Super FX
SA-1
C4
3dfx Support
Problems With ROMs
Sound Problems
Converting ROM Images
Speeding up the Emulation
Getting Help
Credits

Changes Since Last Release
==========================

Check the CHANGES file for a complete history of Snes9x changes between
versions.

Introduction
============

Snes9x is a portable, freeware Super Nintendo Entertainment System (SNES)
emulator. It basically allows you to play most games designed for the SNES
and Super Famicom Nintendo game systems on your PC or Workstation. The games
include some real gems that were only ever released in Japan.

Snes9x is the result of well over three years worth of part-time hacking,
coding, recoding, debugging, etc. Snes9x is coded in C++, with three assembler
CPU emulation cores on the i386 Linux, DOS and Windows ports.

Snes9x is better than a real SNES:
o Freeze a game at any position, then restore the game to that exact spot at
  a later date - ideal for saving a game just before a difficult bit.
o Built-in cheat cartridge.
o Built-in peripheral emulation. The SNES mouse, Multi-player 5 and SuperScope
  external add-ons are all emulated, they cost extra money with a real SNES.
o Stereo sound - yes I know the SNES produced stereo sound, but who actually
  paid the inflated price for the special lead just so you could hear it?
o No more cartridge contact cleaning!
o Some SNES hardware features that be turned on and off during game play,
  games might be using one of these features to deliberately make a section
  of the game more difficult. Easy, just turn the feature off!
o Networked game play on some ports.
o Speed up or slow down SNES games.
o Save screen shots to impress(?!) your friends. (Alt + PrtSc, then paste
  image into paint program, save or print from there)

Snes9x is worse than a real SNES:
o Unless your computer is very fast (Pentium II+), some games just can't
  hit every frame being rendered and the emulator starts to skip the drawing
  of some frames to keep the emulator running at a constant speed - to you
  it appears as if the graphics aren't moving as smoothly as they could.
o Not all games work; bugs and missing features cause some games to fail to
  work or renders them un-playable.
o You have to wait for your computer to boot before you can play games,
  no waiting on the real SNES!
o The SNES has an analogue low-pass sound filter that give a nice bass to
  all the sounds and music - Snes9x doesn't emulate this. If you have
  a posh sound card, you could try fiddling with it mixer controls to produce
  a similar effect. Turning on interpolated sound helps a lot.

What's Emulated
===============
- The 65c816 main CPU.
- The Sony SPC700 sound CPU.
- SNES variable length machine cycles.
- 8 channel DMA and H-DMA (raster effects).
- All background modes, 0 to 7.
- Sound DSP, with eight 16-bit, stereo channels, compressed samples, hardware
  attack-decay-sustain-release volume processing, echo, pitch modulation
  and digital FIR sound filter.
- 8x8, 16x8 and 16x16 tile sizes, flipped in either direction.
- 32x32, 32x64, 64x32 and 64x64 screen tile sizes.
- H-IRQ, V-IRQ and NMI.
- Mode 7 screen rotation, scaling and screen flipping.
- Vertical offset-per-tile in modes 2, and 4.
- Horizontal offset-per-tile in modes 2, 4 and 6.
- 256x224, 256x239, 512x224, 512x239, 512x448 and 512x478 SNES screen
  resolutions.
- Sub-screen and fixed colour blending effects.
- Mosaic effect.
- Single and dual graphic clip windows, with all four logic combination modes.
- Colour blending effects only inside or outside a window.
- 128 8x8, 16x16, 32x32 or 64x64 sprites, flipped in either direction.
- SNES palette changes during frame (15/16-bit internal rendering only).
- Direct colour mode - uses tile and palette-group data directly as RGB value.
- Super FX, a 21/10MHz RISC CPU found in the cartridge of several games.
- SA-1, a faster version of CPU found in the main SNES unit together with some
  custom game-accelerator hardware.
- C4, a custom Capcom chip used only in Megaman X2 and X3. Its a sprite scaler/
  rotator/line drawer/simple maths co-processor chip used to enhance some
  in-game effects.
- Partial DSP-1 support, enough to play Mario Kart.
- SNES mouse.
- SuperScope (light gun) emulated using computer mouse.
- Multi-player 5 - allowing up to five people to play games simultaneously on
  games that support that many players.
- Game-Genie and Action Replay cheat codes.
- Multiple ROM image formats, with or without a 512 byte copier header.
- Single or split images, compressed using gzip, and interleaved in one of two
  ways.
- Auto S-RAM (battery backed RAM) loading and saving.
- Freeze-game support, now portable between different Snes9x ports.
- Interpolated sound.

What's Not
==========
- Only partial DSP1 support, enough to play Mario Kart but no more. The DSP1
  is a math co-processor chip that was inside the cartridge of some games,
  notably Mario Kart and Pilot Wings.
- Any other odd chips that manufactures sometimes placed inside the
  cartridge to enhance games and as a nice side-effect, also act as an 
  anti-piracy measure, e.g. S-DD1.
- Pseudo hi-res. mode - SNES hardware uses interpolation to give apparent
  increase in horizontal resolution, use one of the output image processing
  options to get the same effect.
- Mosaic effect on mode 7.
- A couple of SPC700 instructions that I can't work exactly out what they 
  should do.
- Fixed colour and mosaic effects in SNES hi-res. (512x448) modes.
- Offset-per-tile in mode 6. Luckily I haven't found a game that uses it, yet.

What You Will Need
==================

Windows 95, 98 or NT with at least DirectX 6 installed running on a modern,
fast (e.g. Pentium 200 or higher) computer with at least 32Mb of RAM. Some
games require another CPU to be emulated and/or make heavy use of colour
translucency effects, so an even faster computer may be required to get an
acceptable frame rate.

If you want SNES sound emulation, you'll need a DirectSound compatible sound
card - virtually all modern PCI sound cards are DirectSound compatible - or
use FMOD's older Windows WAVE sound driver.

Snes9x's full-screen mode uses DirectDraw to switch to the required resolution
and depth, but if you intend to use the Windowed mode, for maximum emulation 
speed you should have your desktop depth set to 256 colours if translucency
emulation and 16-bit rendering are switched off and not required, or hi-colour
mode (32768/65536 colours) if translucency effects are required.

If you have a Voodoo 3dfx card, Snes9x can use this hardware to stretch and
smooth the relatively lo-resolution SNES image to fill your computer screen.
Newer nvidia cards can do the same trick, just select stretch image option.
There are also two OpenGL display output modes that can stretch and smooth
the SNES image - but they both require a compatible, modern, fast 3d card and
a fast computer (400MHz +) to match.

Software
--------
Access to SNES ROM images in *.smc, *.sfc, *.fig or *.1, *.2, or sf32xxxa,
sf32xxxb, etc., format otherwise you will have nothing to run!

Some home-brewed ROM images can be downloaded from http://www.snes9x.com. To
find commercial games, you could try a web search engine and some imaginative
use of search strings, alternatively, I've heard http://www.cherryroms.com or
http://www.emuinfinity.com is good place to try. Please note, it is illegal in
most countries to have commercial ROM images without also owning the actual
SNES ROM cartridge.

Getting Started
===============

Launch Snes9x from the Windows Start menu if you used the package install
method; alternatively use Windows explorer to locate the directory where you
un-zipped the snes9xw.exe, fmod.dll and snes9xw.dll files and double-click on
the snes9xw.exe executable. You could create a shortcut to Snes9x and drag 
that icon out onto your desktop.

Loading Games
-------------
Use the Open option from the File menu to open the ROM load dialog. The dialog
allows you to browse your computer to locate the directory where you have
stored your SNES games. Double-click on a ROM image name or single-click and 
then press Load to load and start the game.

SNES ROM images come in lots of different formats, depending on the copier
device that was originally used to create the image amongst other things, and
sometimes Snes9x has trouble auto-detecting the exact ROM format. Try playing
around with the values of the combo boxes in the ROM load dialog if the game
doesn't appear to work after its been loaded. In particular, games that use
the Super FX RISC processor seem to be mostly in an odd interleaved format
that Snes9x has trouble auto-detecting; try selecting 'Interleave mode 2' from
the load ROM dialog if you have a Super FX game that isn't working.

SNES Joypad Emulation
---------------------
On a real SNES, players controlled games using an 8-button digital joy-pad; on
Snes9x you can use your computer's keyboard (the default) or any joystick
or controller device supported by Window's DirectInput. The default key
mapping for joy-pad 1 is:

'up arrow'              Up direction
'down arrow'            Down direction
'left arrow'            Left direction
'right arrow'           Right direction
'a'                     TL button
'z'                     TR button
's'                     X button
'x'                     Y button
'd'                     A button
'c'                     B button
'return'                Start button
'space'                 Select button

The real SNES allowed up to five joy-pads to be plugged in at once via a
special adaptor, although there are only a few games that actually supported
that many players. Having five people crowd around the keyboard would not be
much fun, and anyway, all keyboards have a limit on the number of keys that
can be pressed simultaneously and still be detected correctly; much better to
use multiple joysticks or NetPlay. 

Keyboard/Joystick Config
------------------------

Add support for your joystick and calibrate it using Windows' joystick applet
from the Windows control panel before starting Snes9x, then use Joy-pad 
Configuration dialog in Snes9x to customise the keyboard/joystick to SNES 
joy-pad mappings. The dialog is easy to use: select which SNES joy-pad you are
configuring using the combo box (#1 to #5), click on the text box next to the
'UP' SNES joy-pad button and then press the key on the keyboard or 
button on your joystick that you would like to perform the UP action. The
focus will automatically move on to the 'RIGHT' text box, press the key or
joystick button that you want to perform the RIGHT action, and so on until 
you've customised all the SNES joy-pad buttons.

If you're using the keyboard, you might want to also program four keys for
diagonal movement - I'm told it helps with beat-em-up type games. Click on the
each of the blue-coloured diagonal text boxes in turn and press a key on the
keyboard you would like to perform the action. Using the numeric keypad for
direction keys might be useful in this case.

Additional Keyboard Controls
============================

While the emulator is running:
'Escape'                Show/hide the menu-bar.
'Pause'                 Pause the emulator

Alt+'Return'            Toggle between full-screen and windowed mode.