From 07fc3656274117c211ca0d6a54926d390a4d9b68 Mon Sep 17 00:00:00 2001
From: metamuffin <metamuffin@disroot.org>
Date: Fri, 14 Mar 2025 17:45:19 +0100
Subject: initial work on gltf exports

---
 src/classes/mesh.rs | 41 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 39 insertions(+), 2 deletions(-)

(limited to 'src/classes/mesh.rs')

diff --git a/src/classes/mesh.rs b/src/classes/mesh.rs
index f0b2173..f828b7c 100644
--- a/src/classes/mesh.rs
+++ b/src/classes/mesh.rs
@@ -1,7 +1,8 @@
 use super::streaminginfo::StreamingInfo;
 use crate::object::{Value, parser::FromValue};
 use anyhow::{Result, anyhow, bail};
-use glam::Mat4;
+use glam::{Mat4, Vec3, Vec3A};
+use log::debug;
 use serde::Serialize;
 use std::mem::transmute;
 
@@ -154,7 +155,7 @@ impl VertexData {
         let component_offset = channel.offset as usize;
         let component_size = channel.format.component_size();
         let (offset, stride) = self.stream_layout()[channel.stream as usize];
-
+        debug!("reading {channel:?} vertex channel (stride={stride}, offset={offset})");
         let mut out = Vec::new();
         for vi in 0..self.vertex_count as usize {
             for di in 0..channel.dimension as usize {
@@ -178,6 +179,42 @@ impl VertexData {
         }
         Some((channel.dimension as usize, out))
     }
+    pub fn read_channel_vec<T: VectorType>(
+        &self,
+        channel: VertexDataChannel,
+    ) -> Result<Option<Vec<T>>> {
+        let Some((dim, data)) = self.read_channel(channel) else {
+            return Ok(None);
+        };
+        if dim != T::DIM {
+            bail!(
+                "dimension mismatch reading {channel:?} channel ({} != {})",
+                dim,
+                T::DIM
+            );
+        }
+        Ok(Some(VectorType::convert_array(data)))
+    }
+}
+
+pub trait VectorType: Sized {
+    const DIM: usize;
+    fn convert_array(a: Vec<f32>) -> Vec<Self>;
+}
+impl VectorType for Vec3A {
+    const DIM: usize = 3;
+    fn convert_array(a: Vec<f32>) -> Vec<Self> {
+        a.into_iter()
+            .array_chunks()
+            .map(Vec3A::from_array)
+            .collect()
+    }
+}
+impl VectorType for Vec3 {
+    const DIM: usize = 3;
+    fn convert_array(a: Vec<f32>) -> Vec<Self> {
+        a.into_iter().array_chunks().map(Vec3::from_array).collect()
+    }
 }
 
 impl FromValue for ChannelInfo {
-- 
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