prettier-plugin-glsl
v0.2.0
Published
Prettier (https://prettier.io) plugin for GLSL (OpenGL Shading Language).
Downloads
13,372
Readme
prettier-plugin-glsl
This is a plugin for Prettier (version 3.x), the opinionated code formatter, for GLSL, the shading language used in WebGL and other places. It uses a custom parser based on Chevrotain and does not require any external dependencies.
NB: this is still in active development, breaking/formatting changes may be included in any version.
Formatting
This plugin tries to match the formatting rules for JavaScript as closely as possible. Issues or PRs which make the formatting closer to JavaScript are welcome.
Formatting of macros
This plugin will attempt to parse #define
macros as top-level declarations,
statements or expressions. If successful, these will be formatted as usual.
For example,
#define MAX3(genType) genType max3(genType a, genType b, genType c) { /* comment */ return max(max(a, b), c); }
will be formatted as:
#define MAX3(genType) \
genType max3(genType a, genType b, genType c) { \
/* comment */ \
return max(max(a, b), c); \
}
Formatting of comments
Comments which start with /**
will be passed to the markdown formatter.
For an example, see ./builtins.glsl.
Installation
npm install --save-dev prettier-plugin-glsl
Prettier will automatically pick up the plugin. The following extensions will be recognized as GLSL files by default.
.fp
.frag
.frg
.fs
.fsh
.fshader
.geo
.geom
.glsl
.glslf
.glslv
.gs
.gshader
.rchit
.rmiss
.shader
.tesc
.tese
.vert
.vrx
.vsh
.vshader
Note that .frag
files are recognized as JavaScript files by default. Add the
following to your Prettier configuration to format them as GLSL.
"overrides": [{"files": ["*.frag"], "options": {"parser": "glsl-parser"}}]
Limitations due to preprocessor
As GLSL includes a C++-style preprocessor, this presents some difficulties when formatting. For example, the plugin does not attempt to be able to format crazy (but technically valid) constructs such as:
#define LBRACE {
void main() LBRACE
}
Instead, the plugin effectively treats preprocessor directives such as #define
as their own statements. This covers most cases, for example, the following
works fine:
#define AA 2
#define ZERO (min(iFrame, 0))
void main() {
// ...
#if AA > 1
for (int m = ZERO; m < AA; m++)
for (int n = ZERO; n < AA; n++) {
// pixel coordinates
vec2 o = vec2(float(m), float(n)) / float(AA) - 0.5;
vec2 p = (2.0 * (fragCoord + o) - iResolution.xy) / iResolution.y;
#else
vec2 p = (2.0 * fragCoord - iResolution.xy) / iResolution.y;
#endif
// use p
#if AA > 1
}
tot /= float(AA * AA);
#endif
}
However, the following does not, as the #else
and #endif
are treated as the
bodies of the if-statement, which leads to the else
following a {}
block
instead of an if block, which is invalid.
#if FOO
if (a())
#else
if (b())
#endif
{ }
else
{ }
In general this approach works well. Of the top 100 Shadertoy shaders, 145/152 compilation units (95%) can be formatted without any changes.
- 1 has actually invalid code. (It doesn't cause compilation errors as it is
excluded via
#if/#endif
.) - 1 uses a not self-contained function macro. (It requires a specific token before its call.)
- 4 mix
#if/#else/#endif
andif/else
which leads to issues as above. - 1 uses complicated macro constructions to compose music.