From 6c94102afc70ce28eee3d17aad997a056aaf9195 Mon Sep 17 00:00:00 2001 From: Silas Bartha Date: Fri, 11 Oct 2024 19:01:52 -0400 Subject: gltf, wav, and binary codecs --- src/gltf/extras.rs | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 src/gltf/extras.rs (limited to 'src/gltf/extras.rs') diff --git a/src/gltf/extras.rs b/src/gltf/extras.rs new file mode 100644 index 0000000..eade453 --- /dev/null +++ b/src/gltf/extras.rs @@ -0,0 +1,91 @@ +use std::borrow::Cow; + +use base64::Engine; +use gltf::Gltf; +use serde_json::{json, value::to_raw_value, Value}; + +use crate::{Codec, Error}; + +/// Codec for embedding data in a GLTF file "extras" entry. It uses the extras entry in the first +/// scene in the file and stores the data as base64. +#[derive(Default)] +pub struct ExtrasEntryCodec; + +impl Codec for ExtrasEntryCodec { + fn encode(&self, carrier: &[u8], payload: &[u8]) -> Result, crate::Error> { + let gltf = match Gltf::from_slice(carrier) { + Ok(gltf) => gltf, + Err(e) => return Err(Error::DependencyError(e.to_string())), + }; + + let mut json = gltf.document.into_json(); + let mut scene = json.scenes.remove(0); + let mut extras = match serde_json::from_str::(scene.extras.clone().unwrap_or(to_raw_value(&json!({})).unwrap()).get()) { + Ok(extras) => extras, + Err(e) => return Err(Error::DependencyError(e.to_string())), + }; + match &mut extras { + Value::Object(object) => { + let base64_payload = base64::engine::general_purpose::STANDARD.encode(payload); + object.insert("occule".into(), Value::String(base64_payload)); + }, + _ => return Err(Error::DataInvalid("Carrier has extras in non-object format, not gonna mess with that.".into())) + } + let extras = match to_raw_value(&extras) { + Ok(raw) => Some(raw), + Err(e) => return Err(Error::DependencyError(e.to_string())), + }; + scene.extras = extras; + json.scenes.insert(0, scene); + let json_string = match gltf_json::serialize::to_string(&json) { + Ok(json_string) => json_string, + Err(e) => return Err(Error::DependencyError(e.to_string())), + }; + + let mut glb = match gltf::binary::Glb::from_slice(carrier) { + Ok(glb) => glb, + Err(e) => return Err(Error::DependencyError(e.to_string())), + }; + glb.header.length = (glb.header.length as usize - glb.json.len() + align_to_multiple_of_four(json_string.len())) as u32; + glb.json = Cow::Owned(json_string.into_bytes()); + + Ok(match glb.to_vec() { + Ok(vec) => vec, + Err(e) => return Err(Error::DependencyError(e.to_string())) + }) + } + + fn decode(&self, encoded: &[u8]) -> Result<(Vec, Vec), crate::Error> { + let gltf = match Gltf::from_slice(encoded) { + Ok(gltf) => gltf, + Err(e) => return Err(Error::DependencyError(e.to_string())), + }; + let mut json = gltf.document.into_json(); + let mut extras = match &json.scenes[0].extras { + Some(extras) => match serde_json::from_str::(extras.get()) { + Ok(Value::Object(value)) => value, + _ => return Err(Error::DataNotEncoded), + }, + None => return Err(Error::DataNotEncoded), + }; + let payload = match extras.remove("occule".into()) { + Some(Value::String(payload)) => match base64::engine::general_purpose::STANDARD.decode(payload) { + Ok(payload) => payload, + Err(e) => return Err(Error::DependencyError(e.to_string())), + }, + _ => return Err(Error::DataNotEncoded), + }; + + json.scenes[0].extras = match to_raw_value(&Value::Object(extras)) { + Ok(extras) => Some(extras), + Err(e) => return Err(Error::DependencyError(e.to_string())) + }; + + // TODO: remove payload from carrier + Ok((encoded.to_vec(), payload)) + } +} + +fn align_to_multiple_of_four(n: usize) -> usize { + (n + 3) & !3 +} -- cgit v1.2.3