a tool and a helper to statically analyze shader sources

[hajimehoshi]

Operating System

• Windows
• macOS
• Linux
• FreeBSD
• OpenBSD
• Android
• iOS
• Nintendo Switch
• PlayStation 5
• Xbox
• Web Browsers

What feature would you like to be added?

In order to introduce shader precompilation, we need to know what shader sources are used. We have to list them before the compilation. Listing them by users would not be a good solution since unknown dependencies might use shaders internally, and users couldn't know them.

In order to resolve this issue, what about this?

1. Introduce a new function ebiten.RegisterShader(src []byte) (or string?). This function is just a marker and does nothing.
2. Introduce a new tool to analyaze all the source of a specified package and its dependencies, list all the invocations of RegisterShader, and output them as JSON or something.

Libralies using shaders would have to call RegisterShader to precompile the shader source, but it should be much better than having to export shader sources as a public API.

Why is this needed?

No response

[hajimehoshi]

Probably commenting is better since any library can prepare this without waiting for Ebitengine 2.9.

//ebitengine:shader
const superUltraShader = "package main

func Fragment(..."

[hajimehoshi]

Add a new field to provide compilation results like GLSL, HLSL, and MSL.

See also: 48f79af

[hajimehoshi]

Hmm, this tool doesn't work well with embedded Kage files. What should we do?

var (
	//go:embed default.go
	default_go []byte

	//go:embed texel.go
	texel_go []byte

	//go:embed lighting.go
	lighting_go []byte

	//go:embed radialblur.go
	radialblur_go []byte

	//go:embed chromaticaberration.go
	chromaticaberration_go []byte

	//go:embed dissolve.go
	dissolve_go []byte

	//go:embed water.go
	water_go []byte
)

[hajimehoshi]

Let's add another directive like ebitengine:embeddedshader for embedded files and iterate all the embedded files.

[hajimehoshi]

I changed the directives like these:

• //ebitengine:shadersource for consntant values
• //ebitengine:shaderfile [pattern] for files

[hajimehoshi]

Hmm, a directive inside a function should be ignored, but it is pretty tricky to get only top-level comments from *ast.File.

func foo() {
	// Non top-level files are ignored.

	//ebitengine:shaderfile *_notkage.go
}

See also:

• https://cs.opensource.google/go/go/+/master:src/go/build/read.go;drc=bdbc5ca1bd0547d91441c4785854c82dbd852443;bpv=0;bpt=1;l=190
• https://cs.opensource.google/go/go/+/master:src/cmd/compile/internal/noder/noder.go;l=457;drc=bdbc5ca1bd0547d91441c4785854c82dbd852443;bpv=1;bpt=1