Michael Herzog Mugen87

I ❤️ three.js

Mugen87 / packing.js

Last active June 30, 2026 13:09

Packing/unpacking routines for RGB9E5 usage in WebGL/WebGPU.

	// reference https://registry.khronos.org/OpenGL/extensions/EXT/EXT_texture_shared_exponent.txt

	const RGB9E5_MANTISSA_BITS = 9;
	const RGB9E5_EXP_BIAS = 15;
	const RGB9E5_MAX_VALID_BIASED_EXP = 31;

	const MAX_RGB9E5_EXP = ( RGB9E5_MAX_VALID_BIASED_EXP - RGB9E5_EXP_BIAS );
	const RGB9E5_MANTISSA_VALUES = ( 1 << RGB9E5_MANTISSA_BITS );
	const MAX_RGB9E5_MANTISSA = ( RGB9E5_MANTISSA_VALUES - 1 );
	const MAX_RGB9E5 = ( ( MAX_RGB9E5_MANTISSA ) / RGB9E5_MANTISSA_VALUES * ( 1 << MAX_RGB9E5_EXP ) );