feat: Enhance model and texture loading with improved error handling and new features

- Introduced `LoadedModel` and `LoadedTexture` structs for better encapsulation of model and texture data.
- Added functions to load models and textures from archives, including support for resolving textures based on materials and wear entries.
- Implemented error handling for missing textures, materials, and wear entries.
- Updated the rendering pipeline to support texture loading and binding, including command-line arguments for texture customization.
- Enhanced the `texm` crate with new decoding capabilities for various pixel formats, including indexed textures.
- Added tests for texture decoding and loading to ensure reliability and correctness.
- Updated documentation to reflect changes in the material and texture resolution process.

2 files changed, 635 insertions, 22 deletions

diff --git a/crates/render-demo/src/lib.rs b/crates/render-demo/src/lib.rs
index 4c73c09..c5c72b5 100644
--- a/crates/render-demo/src/lib.rs
+++ b/crates/render-demo/src/lib.rs
@@ -1,13 +1,25 @@
 use msh_core::{parse_model_payload, Model};
-use nres::Archive;
-use std::path::Path;
+use nres::{Archive, EntryRef};
+use std::path::{Path, PathBuf};
+use texm::{decode_mip_rgba8, parse_texm};
+
+const WEAR_KIND: u32 = 0x5241_4557;
+const MAT0_KIND: u32 = 0x3054_414D;
 
 #[derive(Debug)]
 pub enum Error {
     Nres(nres::error::Error),
     Msh(msh_core::error::Error),
+    Texm(texm::error::Error),
+    Io(std::io::Error),
     NoMshEntries,
     ModelNotFound(String),
+    NoTexmEntries,
+    TextureNotFound(String),
+    MaterialNotFound(String),
+    WearNotFound(String),
+    InvalidWear(String),
+    InvalidMaterial(String),
 }
 
 impl From<nres::error::Error> for Error {
@@ -22,9 +34,38 @@ impl From<msh_core::error::Error> for Error {
     }
 }
 
+impl From<texm::error::Error> for Error {
+    fn from(value: texm::error::Error) -> Self {
+        Self::Texm(value)
+    }
+}
+
+impl From<std::io::Error> for Error {
+    fn from(value: std::io::Error) -> Self {
+        Self::Io(value)
+    }
+}
+
 pub type Result<T> = core::result::Result<T, Error>;
 
-pub fn load_model_from_archive(path: &Path, model_name: Option<&str>) -> Result<Model> {
+#[derive(Clone, Debug)]
+pub struct LoadedModel {
+    pub name: String,
+    pub model: Model,
+}
+
+#[derive(Clone, Debug)]
+pub struct LoadedTexture {
+    pub name: String,
+    pub width: u32,
+    pub height: u32,
+    pub rgba8: Vec<u8>,
+}
+
+pub fn load_model_with_name_from_archive(
+    path: &Path,
+    model_name: Option<&str>,
+) -> Result<LoadedModel> {
     let archive = Archive::open_path(path)?;
     let mut msh_entries = Vec::new();
     for entry in archive.entries() {
@@ -46,8 +87,313 @@ pub fn load_model_from_archive(path: &Path, model_name: Option<&str>) -> Result<
         msh_entries[0].0
     };
 
+    let target_name = archive
+        .get(target_id)
+        .map(|entry| entry.meta.name.clone())
+        .unwrap_or_else(|| String::from("<unknown>"));
     let payload = archive.read(target_id)?;
-    Ok(parse_model_payload(payload.as_slice())?)
+    Ok(LoadedModel {
+        name: target_name,
+        model: parse_model_payload(payload.as_slice())?,
+    })
+}
+
+pub fn load_model_from_archive(path: &Path, model_name: Option<&str>) -> Result<Model> {
+    Ok(load_model_with_name_from_archive(path, model_name)?.model)
+}
+
+pub fn load_texture_from_archive(path: &Path, texture_name: Option<&str>) -> Result<LoadedTexture> {
+    let archive = Archive::open_path(path)?;
+    if let Some(name) = texture_name {
+        return load_texture_from_archive_by_name(&archive, name);
+    }
+
+    let mut texm_entries = archive
+        .entries()
+        .filter(|entry| entry.meta.kind == texm::TEXM_MAGIC)
+        .collect::<Vec<_>>();
+    if texm_entries.is_empty() {
+        return Err(Error::NoTexmEntries);
+    }
+    texm_entries.sort_by(|a, b| {
+        a.meta
+            .name
+            .to_ascii_lowercase()
+            .cmp(&b.meta.name.to_ascii_lowercase())
+    });
+    let first = texm_entries[0];
+    decode_texture_entry(&archive, first)
+}
+
+pub fn resolve_texture_for_model(
+    model_archive_path: &Path,
+    model_entry_name: &str,
+    texture_name_override: Option<&str>,
+    textures_archive_override: Option<&Path>,
+    material_archive_override: Option<&Path>,
+    wear_entry_override: Option<&str>,
+) -> Result<Option<LoadedTexture>> {
+    if let Some(name) = texture_name_override {
+        return load_texture_by_name_from_candidate_archives(
+            name,
+            candidate_texture_archives(model_archive_path, textures_archive_override),
+        )
+        .map(Some);
+    }
+
+    let wear_entry_name = if let Some(name) = wear_entry_override {
+        name.to_string()
+    } else {
+        derive_wear_entry_name(model_entry_name).ok_or_else(|| {
+            Error::WearNotFound(format!(
+                "cannot derive WEAR name from model '{model_entry_name}'"
+            ))
+        })?
+    };
+
+    let model_archive = Archive::open_path(model_archive_path)?;
+    let wear_materials = parse_wear_material_names(
+        read_entry_by_name_kind(&model_archive, &wear_entry_name, WEAR_KIND)?
+            .0
+            .as_slice(),
+    )?;
+    let Some(primary_material) = wear_materials.first() else {
+        return Ok(None);
+    };
+
+    let material_path = if let Some(path) = material_archive_override {
+        path.to_path_buf()
+    } else {
+        sibling_archive_path(model_archive_path, "material.lib")
+            .ok_or_else(|| Error::MaterialNotFound(String::from("material.lib")))?
+    };
+    let material_archive = Archive::open_path(&material_path)?;
+    let material_entry = find_material_entry_with_fallback(&material_archive, primary_material)?;
+    let material_payload = material_archive.read(material_entry.id)?.into_owned();
+    let texture_name =
+        parse_primary_texture_name_from_mat0(&material_payload, material_entry.meta.attr2)?;
+    let Some(texture_name) = texture_name else {
+        return Ok(None);
+    };
+
+    let texture = load_texture_by_name_from_candidate_archives(
+        &texture_name,
+        candidate_texture_archives(model_archive_path, textures_archive_override),
+    )?;
+    Ok(Some(texture))
+}
+
+fn load_texture_by_name_from_candidate_archives(
+    texture_name: &str,
+    archives: Vec<PathBuf>,
+) -> Result<LoadedTexture> {
+    let mut last_not_found = None;
+    for archive_path in archives {
+        if !archive_path.is_file() {
+            continue;
+        }
+        let archive = Archive::open_path(&archive_path)?;
+        match load_texture_from_archive_by_name(&archive, texture_name) {
+            Ok(texture) => return Ok(texture),
+            Err(Error::TextureNotFound(name)) => {
+                last_not_found = Some(name);
+            }
+            Err(other) => return Err(other),
+        }
+    }
+
+    Err(Error::TextureNotFound(
+        last_not_found.unwrap_or_else(|| texture_name.to_string()),
+    ))
+}
+
+fn candidate_texture_archives(
+    model_archive_path: &Path,
+    textures_archive_override: Option<&Path>,
+) -> Vec<PathBuf> {
+    if let Some(path) = textures_archive_override {
+        return vec![path.to_path_buf()];
+    }
+
+    let mut out = Vec::new();
+    if let Some(path) = sibling_archive_path(model_archive_path, "textures.lib") {
+        out.push(path);
+    }
+    if let Some(path) = sibling_archive_path(model_archive_path, "lightmap.lib") {
+        out.push(path);
+    }
+    out
+}
+
+fn sibling_archive_path(model_archive_path: &Path, name: &str) -> Option<PathBuf> {
+    let parent = model_archive_path.parent()?;
+    Some(parent.join(name))
+}
+
+fn derive_wear_entry_name(model_entry_name: &str) -> Option<String> {
+    let stem = model_entry_name.rsplit_once('.').map(|(left, _)| left)?;
+    Some(format!("{stem}.wea"))
+}
+
+fn read_entry_by_name_kind(
+    archive: &Archive,
+    name: &str,
+    expected_kind: u32,
+) -> Result<(Vec<u8>, String)> {
+    let Some(id) = archive.find(name) else {
+        return Err(Error::WearNotFound(name.to_string()));
+    };
+    let Some(entry) = archive.get(id) else {
+        return Err(Error::WearNotFound(name.to_string()));
+    };
+    if entry.meta.kind != expected_kind {
+        return Err(Error::WearNotFound(name.to_string()));
+    }
+    let payload = archive.read(id)?.into_owned();
+    Ok((payload, entry.meta.name.clone()))
+}
+
+fn find_material_entry_with_fallback<'a>(
+    archive: &'a Archive,
+    requested_name: &str,
+) -> Result<EntryRef<'a>> {
+    if let Some(id) = archive.find(requested_name) {
+        if let Some(entry) = archive.get(id) {
+            if entry.meta.kind == MAT0_KIND {
+                return Ok(entry);
+            }
+        }
+    }
+
+    if let Some(id) = archive.find("DEFAULT") {
+        if let Some(entry) = archive.get(id) {
+            if entry.meta.kind == MAT0_KIND {
+                return Ok(entry);
+            }
+        }
+    }
+
+    let Some(entry) = archive.entries().find(|entry| entry.meta.kind == MAT0_KIND) else {
+        return Err(Error::MaterialNotFound(requested_name.to_string()));
+    };
+    Ok(entry)
+}
+
+fn parse_wear_material_names(payload: &[u8]) -> Result<Vec<String>> {
+    let text = String::from_utf8_lossy(payload).replace('\r', "");
+    let mut lines = text.lines();
+    let Some(first) = lines.next() else {
+        return Err(Error::InvalidWear(String::from("WEAR payload is empty")));
+    };
+    let count = first
+        .trim()
+        .parse::<usize>()
+        .map_err(|_| Error::InvalidWear(format!("invalid wearCount line: '{first}'")))?;
+    if count == 0 {
+        return Err(Error::InvalidWear(String::from("wearCount must be > 0")));
+    }
+
+    let mut materials = Vec::with_capacity(count);
+    for idx in 0..count {
+        let Some(line) = lines.next() else {
+            return Err(Error::InvalidWear(format!(
+                "missing material line {idx} of {count}"
+            )));
+        };
+        let mut parts = line.split_whitespace();
+        let _legacy = parts
+            .next()
+            .ok_or_else(|| Error::InvalidWear(format!("invalid material line {idx}: '{line}'")))?;
+        let name = parts
+            .next()
+            .ok_or_else(|| Error::InvalidWear(format!("invalid material line {idx}: '{line}'")))?;
+        materials.push(name.to_string());
+    }
+
+    Ok(materials)
+}
+
+fn parse_primary_texture_name_from_mat0(payload: &[u8], attr2: u32) -> Result<Option<String>> {
+    if payload.len() < 4 {
+        return Err(Error::InvalidMaterial(String::from(
+            "MAT0 payload is too small for header",
+        )));
+    }
+    let phase_count = u16::from_le_bytes([payload[0], payload[1]]) as usize;
+    if phase_count == 0 {
+        return Ok(None);
+    }
+
+    let mut offset = 4usize;
+    if attr2 >= 2 {
+        offset = offset
+            .checked_add(2)
+            .ok_or_else(|| Error::InvalidMaterial(String::from("MAT0 offset overflow")))?;
+    }
+    if attr2 >= 3 {
+        offset = offset
+            .checked_add(4)
+            .ok_or_else(|| Error::InvalidMaterial(String::from("MAT0 offset overflow")))?;
+    }
+    if attr2 >= 4 {
+        offset = offset
+            .checked_add(4)
+            .ok_or_else(|| Error::InvalidMaterial(String::from("MAT0 offset overflow")))?;
+    }
+
+    for phase in 0..phase_count {
+        let phase_off = offset
+            .checked_add(phase.checked_mul(34).ok_or_else(|| {
+                Error::InvalidMaterial(String::from("MAT0 phase offset overflow"))
+            })?)
+            .ok_or_else(|| Error::InvalidMaterial(String::from("MAT0 phase offset overflow")))?;
+        let phase_end = phase_off
+            .checked_add(34)
+            .ok_or_else(|| Error::InvalidMaterial(String::from("MAT0 phase offset overflow")))?;
+        let Some(rec) = payload.get(phase_off..phase_end) else {
+            return Err(Error::InvalidMaterial(format!(
+                "MAT0 phase {phase} is out of bounds"
+            )));
+        };
+        let name_raw = &rec[18..34];
+        let name_end = name_raw
+            .iter()
+            .position(|&b| b == 0)
+            .unwrap_or(name_raw.len());
+        let name = String::from_utf8_lossy(&name_raw[..name_end])
+            .trim()
+            .to_string();
+        if !name.is_empty() {
+            return Ok(Some(name));
+        }
+    }
+
+    Ok(None)
+}
+
+fn load_texture_from_archive_by_name(archive: &Archive, name: &str) -> Result<LoadedTexture> {
+    let Some(id) = archive.find(name) else {
+        return Err(Error::TextureNotFound(name.to_string()));
+    };
+    let Some(entry) = archive.get(id) else {
+        return Err(Error::TextureNotFound(name.to_string()));
+    };
+    if entry.meta.kind != texm::TEXM_MAGIC {
+        return Err(Error::TextureNotFound(name.to_string()));
+    }
+    decode_texture_entry(archive, entry)
+}
+
+fn decode_texture_entry(archive: &Archive, entry: EntryRef<'_>) -> Result<LoadedTexture> {
+    let payload = archive.read(entry.id)?.into_owned();
+    let parsed = parse_texm(&payload)?;
+    let decoded = decode_mip_rgba8(&parsed, &payload, 0)?;
+    Ok(LoadedTexture {
+        name: entry.meta.name.clone(),
+        width: decoded.width,
+        height: decoded.height,
+        rgba8: decoded.rgba8,
+    })
 }
 
 #[cfg(test)]
@@ -98,6 +444,19 @@ mod tests {
         None
     }
 
+    fn game_root() -> Option<PathBuf> {
+        let path = Path::new(env!("CARGO_MANIFEST_DIR"))
+            .join("..")
+            .join("..")
+            .join("testdata")
+            .join("Parkan - Iron Strategy");
+        if path.is_dir() {
+            Some(path)
+        } else {
+            None
+        }
+    }
+
     #[test]
     fn load_model_from_real_archive() {
         let Some(path) = archive_with_msh() else {
@@ -110,4 +469,59 @@ mod tests {
         assert!(!model.positions.is_empty());
         assert!(!model.indices.is_empty());
     }
+
+    #[test]
+    fn resolve_texture_for_real_model_via_wear_and_material() {
+        let Some(root) = game_root() else {
+            eprintln!(
+                "skipping resolve_texture_for_real_model_via_wear_and_material: no game root"
+            );
+            return;
+        };
+        let archive = root.join("animals.rlb");
+        if !archive.is_file() {
+            eprintln!("skipping resolve_texture_for_real_model_via_wear_and_material: missing animals.rlb");
+            return;
+        }
+
+        let loaded = load_model_with_name_from_archive(&archive, Some("A_L_01.msh"))
+            .unwrap_or_else(|err| {
+                panic!(
+                    "failed to load model A_L_01.msh from {}: {err:?}",
+                    archive.display()
+                )
+            });
+        let texture = resolve_texture_for_model(&archive, &loaded.name, None, None, None, None)
+            .unwrap_or_else(|err| panic!("failed to resolve texture for {}: {err:?}", loaded.name))
+            .expect("texture must be resolved for A_L_01.msh");
+        assert!(texture.width > 0 && texture.height > 0);
+        assert_eq!(
+            texture.rgba8.len(),
+            usize::try_from(texture.width)
+                .ok()
+                .and_then(|w| usize::try_from(texture.height).ok().map(|h| w * h * 4))
+                .unwrap_or(0)
+        );
+    }
+
+    #[test]
+    fn load_first_texture_from_real_archive() {
+        let Some(root) = game_root() else {
+            eprintln!("skipping load_first_texture_from_real_archive: no game root");
+            return;
+        };
+        let archive = root.join("textures.lib");
+        if !archive.is_file() {
+            eprintln!("skipping load_first_texture_from_real_archive: missing textures.lib");
+            return;
+        }
+        let texture = load_texture_from_archive(&archive, None).unwrap_or_else(|err| {
+            panic!(
+                "failed to load first texture from {}: {err:?}",
+                archive.display()
+            )
+        });
+        assert!(texture.width > 0 && texture.height > 0);
+        assert!(!texture.rgba8.is_empty());
+    }
 }
diff --git a/crates/render-demo/src/main.rs b/crates/render-demo/src/main.rs
index 5bb0a58..bb826d5 100644
--- a/crates/render-demo/src/main.rs
+++ b/crates/render-demo/src/main.rs
@@ -1,6 +1,6 @@
 use glow::HasContext as _;
-use render_core::{build_render_mesh, compute_bounds};
-use render_demo::load_model_from_archive;
+use render_core::{build_render_mesh, compute_bounds_for_mesh};
+use render_demo::{load_model_with_name_from_archive, resolve_texture_for_model, LoadedTexture};
 use std::path::{Path, PathBuf};
 use std::time::Instant;
 
@@ -14,6 +14,15 @@ struct Args {
     capture: Option<PathBuf>,
     angle: Option<f32>,
     spin_rate: f32,
+    texture: Option<String>,
+    texture_archive: Option<PathBuf>,
+    material_archive: Option<PathBuf>,
+    wear: Option<String>,
+    no_texture: bool,
+}
+
+struct GpuTexture {
+    handle: glow::NativeTexture,
 }
 
 fn parse_args() -> Result<Args, String> {
@@ -26,6 +35,11 @@ fn parse_args() -> Result<Args, String> {
     let mut capture = None;
     let mut angle = None;
     let mut spin_rate = 0.35f32;
+    let mut texture = None;
+    let mut texture_archive = None;
+    let mut material_archive = None;
+    let mut wear = None;
+    let mut no_texture = false;
 
     let mut it = std::env::args().skip(1);
     while let Some(arg) = it.next() {
@@ -104,6 +118,33 @@ fn parse_args() -> Result<Args, String> {
                     .parse::<f32>()
                     .map_err(|_| String::from("invalid --spin-rate value"))?;
             }
+            "--texture" => {
+                let value = it
+                    .next()
+                    .ok_or_else(|| String::from("missing value for --texture"))?;
+                texture = Some(value);
+            }
+            "--texture-archive" => {
+                let value = it
+                    .next()
+                    .ok_or_else(|| String::from("missing value for --texture-archive"))?;
+                texture_archive = Some(PathBuf::from(value));
+            }
+            "--material-archive" => {
+                let value = it
+                    .next()
+                    .ok_or_else(|| String::from("missing value for --material-archive"))?;
+                material_archive = Some(PathBuf::from(value));
+            }
+            "--wear" => {
+                let value = it
+                    .next()
+                    .ok_or_else(|| String::from("missing value for --wear"))?;
+                wear = Some(value);
+            }
+            "--no-texture" => {
+                no_texture = true;
+            }
             "--help" | "-h" => {
                 print_help();
                 std::process::exit(0);
@@ -125,6 +166,11 @@ fn parse_args() -> Result<Args, String> {
         capture,
         angle,
         spin_rate,
+        texture,
+        texture_archive,
+        material_archive,
+        wear,
+        no_texture,
     })
 }
 
@@ -133,6 +179,7 @@ fn print_help() {
         "parkan-render-demo --archive <path> [--model <name.msh>] [--lod N] [--group N] [--width W] [--height H]"
     );
     eprintln!("                  [--capture <out.png>] [--angle RAD] [--spin-rate RAD_PER_SEC]");
+    eprintln!("                  [--texture <name>] [--texture-archive <path>] [--material-archive <path>] [--wear <name.wea>] [--no-texture]");
 }
 
 fn main() {
@@ -152,24 +199,34 @@ fn main() {
 }
 
 fn run(args: Args) -> Result<(), String> {
-    let model = load_model_from_archive(&args.archive, args.model.as_deref()).map_err(|err| {
-        format!(
-            "failed to load model from archive {}: {err:?}",
-            args.archive.display()
-        )
-    })?;
-
-    let mesh = build_render_mesh(&model, args.lod, args.group);
+    let loaded_model = load_model_with_name_from_archive(&args.archive, args.model.as_deref())
+        .map_err(|err| {
+            format!(
+                "failed to load model from archive {}: {err:?}",
+                args.archive.display()
+            )
+        })?;
+    let mesh = build_render_mesh(&loaded_model.model, args.lod, args.group);
     if mesh.vertices.is_empty() {
         return Err(format!(
             "model has no renderable triangles for lod={} group={}",
             args.lod, args.group
         ));
     }
-    let Some((bounds_min, bounds_max)) = compute_bounds(&mesh.vertices) else {
+    let Some((bounds_min, bounds_max)) = compute_bounds_for_mesh(&mesh.vertices) else {
         return Err(String::from("failed to compute mesh bounds"));
     };
 
+    let resolved_texture = resolve_texture(&args, &loaded_model.name)?;
+    if let Some(tex) = resolved_texture.as_ref() {
+        println!(
+            "resolved texture '{}' ({}x{})",
+            tex.name, tex.width, tex.height
+        );
+    } else {
+        println!("texture path disabled or unresolved; rendering with fallback color");
+    }
+
     let center = [
         0.5 * (bounds_min[0] + bounds_max[0]),
         0.5 * (bounds_min[1] + bounds_max[1]),
@@ -224,9 +281,13 @@ fn run(args: Args) -> Result<(), String> {
         video.gl_set_swap_interval(1)
     };
 
-    let mut vertices_flat = Vec::with_capacity(mesh.vertices.len() * 3);
-    for pos in &mesh.vertices {
-        vertices_flat.extend_from_slice(pos);
+    let mut vertex_data = Vec::with_capacity(mesh.vertices.len() * 5);
+    for vertex in &mesh.vertices {
+        vertex_data.push(vertex.position[0]);
+        vertex_data.push(vertex.position[1]);
+        vertex_data.push(vertex.position[2]);
+        vertex_data.push(vertex.uv0[0]);
+        vertex_data.push(vertex.uv0[1]);
     }
 
     let gl = unsafe {
@@ -235,27 +296,41 @@ fn run(args: Args) -> Result<(), String> {
 
     let program = unsafe { create_program(&gl)? };
     let u_mvp = unsafe { gl.get_uniform_location(program, "u_mvp") };
+    let u_use_tex = unsafe { gl.get_uniform_location(program, "u_use_tex") };
+    let u_tex = unsafe { gl.get_uniform_location(program, "u_tex") };
     let a_pos = unsafe { gl.get_attrib_location(program, "a_pos") }
         .ok_or_else(|| String::from("shader attribute a_pos is missing"))?;
+    let a_uv = unsafe { gl.get_attrib_location(program, "a_uv") }
+        .ok_or_else(|| String::from("shader attribute a_uv is missing"))?;
 
     let vbo = unsafe { gl.create_buffer().map_err(|e| e.to_string())? };
     unsafe {
         gl.bind_buffer(glow::ARRAY_BUFFER, Some(vbo));
         gl.buffer_data_u8_slice(
             glow::ARRAY_BUFFER,
-            cast_slice_u8(&vertices_flat),
+            cast_slice_u8(&vertex_data),
             glow::STATIC_DRAW,
         );
         gl.bind_buffer(glow::ARRAY_BUFFER, None);
     }
 
+    let gpu_texture = if let Some(texture) = resolved_texture.as_ref() {
+        Some(unsafe { create_texture(&gl, texture)? })
+    } else {
+        None
+    };
+
     let result = if let Some(capture_path) = args.capture.as_ref() {
         run_capture(
             &gl,
             program,
             u_mvp.as_ref(),
+            u_use_tex.as_ref(),
+            u_tex.as_ref(),
             a_pos,
+            a_uv,
             vbo,
+            gpu_texture.as_ref(),
             mesh.vertices.len(),
             &args,
             center,
@@ -269,8 +344,12 @@ fn run(args: Args) -> Result<(), String> {
             &gl,
             program,
             u_mvp.as_ref(),
+            u_use_tex.as_ref(),
+            u_tex.as_ref(),
             a_pos,
+            a_uv,
             vbo,
+            gpu_texture.as_ref(),
             mesh.vertices.len(),
             &args,
             center,
@@ -279,6 +358,9 @@ fn run(args: Args) -> Result<(), String> {
     };
 
     unsafe {
+        if let Some(texture) = gpu_texture {
+            gl.delete_texture(texture.handle);
+        }
         gl.delete_buffer(vbo);
         gl.delete_program(program);
     }
@@ -286,13 +368,82 @@ fn run(args: Args) -> Result<(), String> {
     result
 }
 
+fn resolve_texture(args: &Args, model_name: &str) -> Result<Option<LoadedTexture>, String> {
+    if args.no_texture {
+        return Ok(None);
+    }
+
+    match resolve_texture_for_model(
+        &args.archive,
+        model_name,
+        args.texture.as_deref(),
+        args.texture_archive.as_deref(),
+        args.material_archive.as_deref(),
+        args.wear.as_deref(),
+    ) {
+        Ok(texture) => Ok(texture),
+        Err(err) => {
+            if args.texture.is_some()
+                || args.texture_archive.is_some()
+                || args.material_archive.is_some()
+                || args.wear.is_some()
+            {
+                Err(format!("failed to resolve texture: {err:?}"))
+            } else {
+                eprintln!(
+                    "warning: auto texture resolve failed ({err:?}), fallback to solid color"
+                );
+                Ok(None)
+            }
+        }
+    }
+}
+
+unsafe fn create_texture(
+    gl: &glow::Context,
+    texture: &LoadedTexture,
+) -> Result<GpuTexture, String> {
+    let handle = gl.create_texture().map_err(|e| e.to_string())?;
+    gl.bind_texture(glow::TEXTURE_2D, Some(handle));
+    gl.tex_parameter_i32(
+        glow::TEXTURE_2D,
+        glow::TEXTURE_MIN_FILTER,
+        glow::LINEAR as i32,
+    );
+    gl.tex_parameter_i32(
+        glow::TEXTURE_2D,
+        glow::TEXTURE_MAG_FILTER,
+        glow::LINEAR as i32,
+    );
+    gl.tex_parameter_i32(glow::TEXTURE_2D, glow::TEXTURE_WRAP_S, glow::REPEAT as i32);
+    gl.tex_parameter_i32(glow::TEXTURE_2D, glow::TEXTURE_WRAP_T, glow::REPEAT as i32);
+    gl.pixel_store_i32(glow::UNPACK_ALIGNMENT, 1);
+    gl.tex_image_2d(
+        glow::TEXTURE_2D,
+        0,
+        glow::RGBA as i32,
+        texture.width.min(i32::MAX as u32) as i32,
+        texture.height.min(i32::MAX as u32) as i32,
+        0,
+        glow::RGBA,
+        glow::UNSIGNED_BYTE,
+        glow::PixelUnpackData::Slice(Some(texture.rgba8.as_slice())),
+    );
+    gl.bind_texture(glow::TEXTURE_2D, None);
+    Ok(GpuTexture { handle })
+}
+
 #[allow(clippy::too_many_arguments)]
 fn run_capture(
     gl: &glow::Context,
     program: glow::NativeProgram,
     u_mvp: Option<&glow::NativeUniformLocation>,
+    u_use_tex: Option<&glow::NativeUniformLocation>,
+    u_tex: Option<&glow::NativeUniformLocation>,
     a_pos: u32,
+    a_uv: u32,
     vbo: glow::NativeBuffer,
+    texture: Option<&GpuTexture>,
     vertex_count: usize,
     args: &Args,
     center: [f32; 3],
@@ -306,8 +457,12 @@ fn run_capture(
             gl,
             program,
             u_mvp,
+            u_use_tex,
+            u_tex,
             a_pos,
+            a_uv,
             vbo,
+            texture,
             vertex_count,
             args.width,
             args.height,
@@ -328,8 +483,12 @@ fn run_interactive(
     gl: &glow::Context,
     program: glow::NativeProgram,
     u_mvp: Option<&glow::NativeUniformLocation>,
+    u_use_tex: Option<&glow::NativeUniformLocation>,
+    u_tex: Option<&glow::NativeUniformLocation>,
     a_pos: u32,
+    a_uv: u32,
     vbo: glow::NativeBuffer,
+    texture: Option<&GpuTexture>,
     vertex_count: usize,
     args: &Args,
     center: [f32; 3],
@@ -359,7 +518,21 @@ fn run_interactive(
         let mvp = compute_mvp(w, h, center, camera_distance, angle);
 
         unsafe {
-            draw_frame(gl, program, u_mvp, a_pos, vbo, vertex_count, w, h, &mvp);
+            draw_frame(
+                gl,
+                program,
+                u_mvp,
+                u_use_tex,
+                u_tex,
+                a_pos,
+                a_uv,
+                vbo,
+                texture,
+                vertex_count,
+                w,
+                h,
+                &mvp,
+            );
         }
         window.gl_swap_window();
     }
@@ -389,8 +562,12 @@ unsafe fn draw_frame(
     gl: &glow::Context,
     program: glow::NativeProgram,
     u_mvp: Option<&glow::NativeUniformLocation>,
+    u_use_tex: Option<&glow::NativeUniformLocation>,
+    u_tex: Option<&glow::NativeUniformLocation>,
     a_pos: u32,
+    a_uv: u32,
     vbo: glow::NativeBuffer,
+    texture: Option<&GpuTexture>,
     vertex_count: usize,
     width: u32,
     height: u32,
@@ -409,16 +586,30 @@ unsafe fn draw_frame(
     gl.use_program(Some(program));
     gl.uniform_matrix_4_f32_slice(u_mvp, false, mvp);
 
+    let texture_enabled = texture.is_some();
+    gl.uniform_1_f32(u_use_tex, if texture_enabled { 1.0 } else { 0.0 });
+    if let Some(tex) = texture {
+        gl.active_texture(glow::TEXTURE0);
+        gl.bind_texture(glow::TEXTURE_2D, Some(tex.handle));
+        gl.uniform_1_i32(u_tex, 0);
+    } else {
+        gl.bind_texture(glow::TEXTURE_2D, None);
+    }
+
     gl.bind_buffer(glow::ARRAY_BUFFER, Some(vbo));
     gl.enable_vertex_attrib_array(a_pos);
-    gl.vertex_attrib_pointer_f32(a_pos, 3, glow::FLOAT, false, 12, 0);
+    gl.vertex_attrib_pointer_f32(a_pos, 3, glow::FLOAT, false, 20, 0);
+    gl.enable_vertex_attrib_array(a_uv);
+    gl.vertex_attrib_pointer_f32(a_uv, 2, glow::FLOAT, false, 20, 12);
     gl.draw_arrays(
         glow::TRIANGLES,
         0,
         vertex_count.min(i32::MAX as usize) as i32,
     );
+    gl.disable_vertex_attrib_array(a_uv);
     gl.disable_vertex_attrib_array(a_pos);
     gl.bind_buffer(glow::ARRAY_BUFFER, None);
+    gl.bind_texture(glow::TEXTURE_2D, None);
     gl.use_program(None);
 }
 
@@ -475,16 +666,24 @@ fn save_png(path: &Path, width: u32, height: u32, rgba: Vec<u8>) -> Result<(), S
 unsafe fn create_program(gl: &glow::Context) -> Result<glow::NativeProgram, String> {
     let vs_src = r#"
 attribute vec3 a_pos;
+attribute vec2 a_uv;
 uniform mat4 u_mvp;
+varying vec2 v_uv;
 void main() {
+    v_uv = a_uv;
     gl_Position = u_mvp * vec4(a_pos, 1.0);
 }
 "#;
 
     let fs_src = r#"
 precision mediump float;
+uniform sampler2D u_tex;
+uniform float u_use_tex;
+varying vec2 v_uv;
 void main() {
-    gl_FragColor = vec4(0.85, 0.90, 1.00, 1.0);
+    vec4 base = vec4(0.85, 0.90, 1.00, 1.0);
+    vec4 texColor = texture2D(u_tex, v_uv);
+    gl_FragColor = mix(base, texColor, u_use_tex);
 }
 "#;