Compiled files include comments

[jmgomezpoveda]

What happened?

Looking at both my output files compiled through vite using cesiumjs as a dependency, as well as the pre-compiled file (node_modules/cesium/Build/Cesium/Cesium.js), I see they contain a huge amount of comments. vite does not remove them since they are found in pre-embedded strings.

For example:

// To deal with smaller values of PRIMARY_STEPS (e.g. 4)
// we implement a split strategy: sky or horizon.
// For performance reasons, instead of a if/else branch
// a soft choice is implemented through a weight 0.0 <= w_stop_gt_lprl <= 1.0
float x = 1e-7 * primaryRayAtmosphereIntersect.stop / length(primaryRayLength);
// Value close to 0.0: close to the horizon
// Value close to 1.0: above in the sky
float w_stop_gt_lprl = 0.5 * (1.0 + czm_approximateTanh(x));

This increases the output file size, which is really important when downloading over the net. Would it be possible to strip those comments?

Reproduction steps

1. Open node_modules/cesium/Build/Cesium/Cesium.js
2. Look for /*, /*! or //

Sandcastle example

No response

Environment

Browser: n/a
CesiumJS Version: 1.136
Operating System: n/a

[donmccurdy]

An option pre-built for esbuild is:

https://github.com/vanruesc/esbuild-plugin-glsl

Another option, three.js uses a custom (regex-based) Rollup plugin defined here, which could be adapted to other build tools:

https://github.com/mrdoob/three.js/blob/dev/utils/build/rollup.config.js#L4-L36

---

UPDATE: Oops, I see there's already a plugin installed for stripping comments from GLSL:

cesium/scripts/build.js

Line 11 in ea5f4d9

import glslStripComments from "glsl-strip-comments";

Perhaps this has broken, or isn't being applied to the files that Vite is resolving — that may need some investigation.

[donmccurdy]

What appears to be happening is that when running npm run build-release, the task 'buildEngine' is not called with the minify:true option here...

cesium/gulpfile.js

Lines 420 to 442 in ea5f4d9

	export const buildRelease = gulp.series(
	buildEngine,
	buildWidgets,
	// Generate Build/CesiumUnminified
	function buildCesiumForNode() {
	return buildCesium({
	minify: false,
	removePragmas: false,
	node: true,
	sourcemap: false,
	});
	},
	// Generate Build/Cesium
	function buildMinifiedCesiumForNode() {
	return buildCesium({
	development: false,
	minify: true,
	removePragmas: true,
	node: true,
	sourcemap: false,
	});
	},
	);

... without which the shader minification does not run. A later stage of processing minifies the javascript regardless. If we force this option on, it does affect the unminified build (would need to build twice to avoid that?) but results in a smaller minzipped build:

npm run build-release
npx gzip-size-cli Build/Cesium/Cesium.js

Before: 1.69 MB
After: 1.64 MB

[ggetz]

I also noticed the release size increasing more than expected recently—If stripping comments as part of the release process was broken, it could certainly be a contributing factor.

[jjspace]

I definitely agree this can be improved. I think we've wanted to improve how we handle shaders in general for a little while now. However I do want to level set that this is how the shaders have been included in the Cesium.js file since version 1.100 so I would not consider it part of the "release size increasing more than expected recently"

[ggetz]

Just to be clear—We have a script that strips the comments from the shaders. The problem appears to be that it isn't running properly for the minified release build.