playcanvas/build/playcanvas/src/scene/shader-lib/wgsl/chunks/gsplat/vert/gsplatSH.js

PlayCanvas WebGL game engine

var gsplatSHVS = `
#if SH_BANDS > 0
fn unpack111011s(bits: u32) -> vec3f {
	return (vec3f((vec3<u32>(bits) >> vec3<u32>(21u, 11u, 0u)) & vec3<u32>(0x7ffu, 0x3ffu, 0x7ffu)) / vec3f(2047.0, 1023.0, 2047.0)) * 2.0 - 1.0;
}
struct ScaleAndSH {
	scale: f32,
	a: vec3f,
	b: vec3f,
	c: vec3f
};
fn fetchScale(t_in: vec4<u32>) -> ScaleAndSH {
	var result: ScaleAndSH;
	result.scale = bitcast<f32>(t_in.x);
	result.a = unpack111011s(t_in.y);
	result.b = unpack111011s(t_in.z);
	result.c = unpack111011s(t_in.w);
	return result;
}
struct SH {
	a: vec3f,
	b: vec3f,
	c: vec3f,
	d: vec3f
};
fn fetch4(t_in: vec4<u32>) -> SH {
	var result: SH;
	result.a = unpack111011s(t_in.x);
	result.b = unpack111011s(t_in.y);
	result.c = unpack111011s(t_in.z);
	result.d = unpack111011s(t_in.w);
	return result;
}
fn fetch1(t_in: u32) -> vec3f {
	return unpack111011s(t_in);
}
#if SH_BANDS == 1
	var splatSH_1to3: texture_2d<u32>;
	fn readSHData(source: ptr<function, SplatSource>, sh: ptr<function, array<vec3f, 3>>, scale: ptr<function, f32>) {
		let result = fetchScale(textureLoad(splatSH_1to3, source.uv, 0));
		*scale = result.scale;
		sh[0] = result.a;
		sh[1] = result.b;
		sh[2] = result.c;
	}
#elif SH_BANDS == 2
	var splatSH_1to3: texture_2d<u32>;
	var splatSH_4to7: texture_2d<u32>;
	var splatSH_8to11: texture_2d<u32>;
	fn readSHData(source: ptr<function, SplatSource>, sh: ptr<function, array<vec3f, 8>>, scale: ptr<function, f32>) {
		let first: ScaleAndSH = fetchScale(textureLoad(splatSH_1to3, source.uv, 0));
		*scale = first.scale;
		sh[0] = first.a;
		sh[1] = first.b;
		sh[2] = first.c;
		let second: SH = fetch4(textureLoad(splatSH_4to7, source.uv, 0));
		sh[3] = second.a;
		sh[4] = second.b;
		sh[5] = second.c;
		sh[6] = second.d;
		sh[7] = fetch1(textureLoad(splatSH_8to11, source.uv, 0).x);
	}
#else
	var splatSH_1to3: texture_2d<u32>;
	var splatSH_4to7: texture_2d<u32>;
	var splatSH_8to11: texture_2d<u32>;
	var splatSH_12to15: texture_2d<u32>;
	fn readSHData(source: ptr<function, SplatSource>, sh: ptr<function, array<vec3f, 15>>, scale: ptr<function, f32>) {
		let first: ScaleAndSH = fetchScale(textureLoad(splatSH_1to3, source.uv, 0));
		*scale = first.scale;
		sh[0] = first.a;
		sh[1] = first.b;
		sh[2] = first.c;
		let second: SH = fetch4(textureLoad(splatSH_4to7, source.uv, 0));
		sh[3] = second.a;
		sh[4] = second.b;
		sh[5] = second.c;
		sh[6] = second.d;
		let third: SH = fetch4(textureLoad(splatSH_8to11, source.uv, 0));
		sh[7] = third.a;
		sh[8] = third.b;
		sh[9] = third.c;
		sh[10] = third.d;
		let fourth: SH = fetch4(textureLoad(splatSH_12to15, source.uv, 0));
		sh[11] = fourth.a;
		sh[12] = fourth.b;
		sh[13] = fourth.c;
		sh[14] = fourth.d;
	}
#endif
#endif
`;

export { gsplatSHVS as default };