MAMEWorld Forums - EmuChat - MAME HLSL

> So, it seems that MAME is reading the .ini, applying the general mame config
> parameters, but ignoring the HLSL ones.
>
> Please forgive me if I have overlooked anything from the comments in the hlsl.json
> file.

Not entirely, but there's this comment block in mame.ini, above the HLSL settings:

Code:


#
# DIRECT3D POST-PROCESSING OPTIONS
#

Direct3D isn't an API (Application Programming Interface) that's available on Linux.

What's being missed is the context in which the term "HLSL" is used.

HLSL stands for "High Level Shader Language", and is a method for authoring shaders specifically used by Microsoft's DirectX API. When I initially added shader post-processing to MAME back in 2011, DirectX was the rendering API with which I was the most familiar, so that was what I went with. It was one single chain of effects, with no real ability to swap it out for other post-processing effects that various other emulators use.

About 5-6 years later, I had heard about a cross-platform rendering library called BGFX, which provides a common interface for talking to the wide variety of graphics APIs that exist nowadays: Direct3D 9 through 11 (now 12), OpenGL ES (used on mobile devices like cell phones), GLSL (an OpenGL-specific shader language), Vulkan (a next-generation rendering API developed by the same workgroup that created OpenGL), and Metal (Apple's own rendering API used on macOS and iOS).

So, I went and added a separate renderer module to MAME that talks to BGFX. Moreover, I opted to put the overall setup of the chain of shaders into external data files, so that there would be other options for post-processing as well. For example, you can specify "-bgfx_screen_chains crt-geom-deluxe" for a different CRT-simulation effect. Or you could specify "-bgfx_screen_chains super-eagle" for a particularly bad, but long-lived, smoothing effect.

When I added it, I also ported the same shader code that I used in the initial DirectX/HLSL backend over to BGFX's platform-agnostic shader language (which primarily resembles GLSL). Hence the filename, hlsl.json - it's designed to provide broadly the same visual output as running MAME with "-video d3d -hlsl" on a Windows system.

> I did find a section relating to "input" that almost seems like what I need to
> use, but it referred to something explicitly about the artwork folder and reading in
> an image file:
>
> // option (optional): The name of any MAME option, which will have its value fetched
> and used as the name of a PNG to load from the artwork directory.
> // value: Any valid MAME INI option name.

Yes, it has to do with reading in image files so that various post-processing chains available to BGFX can load externally-supplied images. You can see an example of some of those options in this section of mame.ini:

Code:


#
# BGFX POST-PROCESSING OPTIONS
#
bgfx_path                 bgfx
bgfx_backend              auto
bgfx_debug                0
bgfx_screen_chains        default
bgfx_shadow_mask          slot-mask.png
bgfx_lut                  lut-default.png
bgfx_avi_name             auto

> I have some custom hlsl settings for vertical games that I place in the vertical.ini
> for example and quite a lot of custom tweaks for specific games and drivers so if the
> json file can be modified in any way to read in the values from .ini files I am more
> than happy to go the legwork if I can figure out what it is I need to do

Since all the JSON files in the bgfx/chains/ directory do is contain the setup for the overall chain, and the unique setup for each effect pass, you can just open it in a text editor then save it as some other name.

The fastest way to do what you want to do, using vertical games as an example:
- Copy (don't rename) hlsl.json into hlsl_vertical.json
- Plug the HLSL settings from your vertical INI file into hlsl_vertical.json, as you did with the settings for horizontal games.
- Take the INI file that you're using for vertical games, and either modify (if it exists) or add (if it doesn't) the following line:

Code:


bgfx_screen_chains        hlsl_vertical

The same method should work for any other driver-specific or game-specific INIs you have: dupe the JSON, copy settings in, add or change the line pertaining to "bgfx_screen_chains" in the INI file.

If any of them are multi-screen games, be aware that you can (and should) specify the chain per-screen, delimited by commas. For example, on a game with two monitors, you should specify:

Code:


bgfx_screen_chains        hlsl_vertical,hlsl_vertical

This can (and should) be made easier, but the same thing about saving the settings sliders applies here, too: It was easy enough to add settings for HLSL to the INI file, since there was only ever that one effect available on Windows via Direct3D. Each option in the INI file requires several lines of code to be added to MAME itself, but that was simple enough since it was a known, unchanging target. Since you now have free selection of what chain you want to use, per-monitor, via BGFX, it's impossible to hard-code which settings are available in an INI file.

There's also eventually going to be a major re-write of MAME's underlying rendering architecture, since at the moment it's rather bad. So, at the moment I'm in something of a holding pattern when it comes to making any significant changes (beyond bugfixes) to the BGFX-based renderer, as in all likelihood both it and the Direct3D renderer will be going away eventually in favor of something more unified and better.