Effects And Shaders

Overview

A core element of Microsoft XNA is the effect system which is used for all rendering.

For MonoGame we have the burden of supporting stock and custom effects for desktop GLSL, mobile GLSL, DirectX HLSL, and custom formats like that of the PlayStation Suite. There currently is no effect system or shader language that supports all the platforms we require forcing us to build a new custom effect system.

MGFX

MGFX is MonoGame's own "FX" runtime and file format which has the following core goals:

• Support a similar technique, passes, shaders structure as Microsoft FX files.
• Have a textual format for ease of editing.
• Have a compiled and optimized binary format for runtime use.
• Be cross-platform and support multiple shader languages and bytecodes.
• Easy to extend for future platforms and features.

2MGFX

Currently the 2MGFX tool is used to build a MonoGame Effect from an input Microsoft FX or MGFX file. You can find pre-built binaries in the 'Tools\bin' folder and the source in 'Tools\2MGFX'.

NOTE: At this time 2MGFX only supports FX files as input as the textual format is not yet complete.

Stock Effects

The following stock effects in MonoGame and fully supported on all current platforms:

• BasicEffect
• AlphaTestEffect
• DualTextureEffect
• EnvironmentMapEffect
• SkinnedEffect

Under the hood these effects use the same system and tools as one would for a custom Effect. The source and pre-compiled versions of these effects can be found in the 'MonoGame.Framework\Graphics\Effect\Resources' folder.

If your game requires an extra little bit of performance you can easily hand edit the existing effects to remove unnecessary features or optimize for specific hardware and rebuild them with the MGFX tool.

Custom Effects

To use an XNA custom effect with MonoGame you may need to make a few changes to the FX

To use a custom effect with MonoGame you must process your effect with the 2MGFX tool. You must use the /XNB option which forces it to generate an XNB wrapper around the effect for inclusion into your project.

Roadmap

There is still work to be done for better support of custom effects and shaders in MonoGame:

• Implement textual MGFX format for direct editing of effects.
• Make MGEffectProcessor which can be used from the content pipeline.
• Make automated tests for custom effects.
• Support PlayStation Suite shaders in MGFX tools and formats.
• Expose a API from MonoGame which can be used for low level access to shaders.
• String table all strings stored in MGFX files to save more space.
• Support pre-compiled GLSL assembly instead of GLSL code.