fyrox-impl 1.0.1

// Copyright (c) 2019-present Dmitry Stepanov and Fyrox Engine contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

#![allow(missing_docs)]

use std::{
    fmt::Display,
    path::{Path, PathBuf},
    sync::LazyLock,
};

use crate::{
    asset::{manager::ResourceManager, state::LoadError, untyped::ResourceKind, Resource},
    core::{algebra::Vector4, color::Color, log::Log},
    material::{
        shader::{Shader, ShaderResource},
        Material, MaterialProperty, MaterialResource,
    },
    resource::{
        model::MaterialSearchOptions,
        texture::{Texture, TextureError, TextureImportOptions, TextureResource},
    },
};
use gltf::{buffer::View, image, Document};

use super::uri;

type Result<T> = std::result::Result<T, GltfMaterialError>;

use crate::resource::texture::TextureMagnificationFilter as FyroxMagFilter;
use crate::resource::texture::TextureMinificationFilter as FyroxMinFilter;
use gltf::texture::MagFilter as GltfMagFilter;
use gltf::texture::MinFilter as GltfMinFilter;

pub static GLTF_SHADER: LazyLock<BuiltInResource<Shader>> = LazyLock::new(|| {
    BuiltInResource::new(
        "GltfShader",
        embedded_data_source!("gltf_standard.shader"),
        |data| {
            ShaderResource::new_ok(
                uuid!("33ee0142-f345-4c0a-9aca-d1f684a3485b"),
                ResourceKind::External,
                Shader::from_string_bytes(data).unwrap(),
            )
        },
    )
});

fn convert_mini(filter: GltfMinFilter) -> FyroxMinFilter {
    match filter {
        GltfMinFilter::Linear => FyroxMinFilter::Linear,
        GltfMinFilter::Nearest => FyroxMinFilter::Nearest,
        GltfMinFilter::LinearMipmapLinear => FyroxMinFilter::LinearMipMapLinear,
        GltfMinFilter::NearestMipmapLinear => FyroxMinFilter::NearestMipMapLinear,
        GltfMinFilter::LinearMipmapNearest => FyroxMinFilter::LinearMipMapNearest,
        GltfMinFilter::NearestMipmapNearest => FyroxMinFilter::NearestMipMapNearest,
    }
}

fn convert_mag(filter: GltfMagFilter) -> FyroxMagFilter {
    match filter {
        GltfMagFilter::Linear => FyroxMagFilter::Linear,
        GltfMagFilter::Nearest => FyroxMagFilter::Nearest,
    }
}

use crate::material::{MaterialResourceBinding, MaterialTextureBinding};
use crate::resource::texture::TextureWrapMode as FyroxWrapMode;
use fyrox_core::Uuid;
use fyrox_resource::builtin::BuiltInResource;
use fyrox_resource::embedded_data_source;
use gltf::texture::WrappingMode as GltfWrapMode;
use uuid::uuid;

fn convert_wrap(mode: GltfWrapMode) -> FyroxWrapMode {
    match mode {
        GltfWrapMode::Repeat => FyroxWrapMode::Repeat,
        GltfWrapMode::ClampToEdge => FyroxWrapMode::ClampToEdge,
        GltfWrapMode::MirroredRepeat => FyroxWrapMode::MirroredRepeat,
    }
}

#[derive(Debug)]
#[allow(dead_code)]
pub enum GltfMaterialError {
    ShaderLoadFailed,
    InvalidIndex,
    UnsupportedURI(Box<str>),
    TextureNotFound(Box<str>),
    Load(LoadError),
    Base64(base64::DecodeError),
    Texture(TextureError),
}

impl std::error::Error for GltfMaterialError {}

impl Display for GltfMaterialError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            GltfMaterialError::ShaderLoadFailed => f.write_str("Shader load failed"),
            GltfMaterialError::InvalidIndex => f.write_str("Invalid material index"),
            GltfMaterialError::UnsupportedURI(uri) => {
                write!(f, "Unsupported material URI {uri:?}")
            }
            GltfMaterialError::TextureNotFound(uri) => write!(f, "Texture not found: {uri:?}"),
            GltfMaterialError::Load(error) => Display::fmt(error, f),
            GltfMaterialError::Base64(error) => Display::fmt(error, f),
            GltfMaterialError::Texture(error) => Display::fmt(error, f),
        }
    }
}

impl From<LoadError> for GltfMaterialError {
    fn from(error: LoadError) -> Self {
        GltfMaterialError::Load(error)
    }
}

impl From<base64::DecodeError> for GltfMaterialError {
    fn from(error: base64::DecodeError) -> Self {
        GltfMaterialError::Base64(error)
    }
}

impl From<TextureError> for GltfMaterialError {
    fn from(error: TextureError) -> Self {
        GltfMaterialError::Texture(error)
    }
}

pub enum SourceImage<'a> {
    External(&'a str),
    View(&'a [u8]),
    Embedded(Vec<u8>),
}

pub fn decode_base64(source: &str) -> Result<Vec<u8>> {
    Ok(uri::decode_base64(source)?)
}

/// Extract a list of [MaterialResource] from the give glTF document, if that document contains any.
/// The resulting list of materials is guaranteed to be the same length as the list of materials
/// in the document so that an index into the document's list of materials will be the same as the index
/// of the matching MaterialResource in the returned list. This is important since the glTF document
/// refers to materials by index.
///
/// * `doc`: The document in which to find the materials.
///
/// * `textures`: A slice containing a [TextureResource] for every texture defined in the document, in that order, so that
/// a texture can be looked up using the index of a texture within the document. Materials in glTF specify their target
/// textures by their index within the node list of the document, and these indices need to be translated into handles.
///
/// * `buffers`: A slice containing a list of byte-vectors, one for each buffer in the glTF document.
/// Animations in glTF make reference to data stored in the document's list of buffers by index.
/// This slcie allows an index into the document's list of buffers to be translated into actual bytes of data.
///
/// * `resource_manager`: A [ResourceManager] makes it possible to access shaders and create materials.
pub async fn import_materials(
    gltf: &Document,
    textures: &[TextureResource],
) -> Result<Vec<MaterialResource>> {
    let mut result: Vec<MaterialResource> = Vec::with_capacity(gltf.materials().len());
    for mat in gltf.materials() {
        match import_material(mat, textures).await {
            Ok(res) => result.push(res),
            Err(err) => {
                Log::err(format!("glTF material failed to import. Reason: {err:?}"));
                result.push(MaterialResource::new_ok(
                    Uuid::new_v4(),
                    ResourceKind::Embedded,
                    Material::default(),
                ));
            }
        }
    }
    Ok(result)
}

async fn import_material(
    mat: gltf::Material<'_>,
    textures: &[TextureResource],
) -> Result<MaterialResource> {
    let shader: ShaderResource = GLTF_SHADER.resource.clone();
    if !shader.is_ok() {
        return Err(GltfMaterialError::ShaderLoadFailed);
    }
    let mut result: Material = Material::from_shader(shader);
    let pbr = mat.pbr_metallic_roughness();
    if let Some(tex) = pbr.base_color_texture() {
        set_texture(
            &mut result,
            "diffuseTexture",
            textures,
            tex.texture().index(),
        )?;
    }
    if let Some(tex) = mat.normal_texture() {
        set_texture(
            &mut result,
            "normalTexture",
            textures,
            tex.texture().index(),
        )?;
    }
    if let Some(tex) = pbr.metallic_roughness_texture() {
        set_texture(
            &mut result,
            "metallicRoughnessTexture",
            textures,
            tex.texture().index(),
        )?;
    }
    if let Some(tex) = mat.emissive_texture() {
        set_texture(
            &mut result,
            "emissionTexture",
            textures,
            tex.texture().index(),
        )?;
    }
    if let Some(tex) = mat.occlusion_texture() {
        set_texture(&mut result, "aoTexture", textures, tex.texture().index())?;
    }
    set_material_color(
        &mut result,
        "diffuseColor",
        Vector4::<f32>::from(pbr.base_color_factor()).into(),
    );
    let mut emission_strength = mat.emissive_factor();
    let emission_factor = mat.emissive_strength().unwrap_or(1.0);
    for c in emission_strength.iter_mut() {
        *c *= emission_factor;
    }
    set_material_vector3(&mut result, "emissionStrength", emission_strength);
    set_material_scalar(&mut result, "metallicFactor", pbr.metallic_factor());
    set_material_scalar(&mut result, "roughnessFactor", pbr.roughness_factor());
    Ok(Resource::new_ok(
        Uuid::new_v4(),
        ResourceKind::Embedded,
        result,
    ))
}

fn set_material_scalar(material: &mut Material, name: &'static str, value: f32) {
    let value: MaterialProperty = MaterialProperty::Float(value);
    material.set_property(name, value);
}

fn set_material_color(material: &mut Material, name: &'static str, color: Color) {
    let value: MaterialProperty = MaterialProperty::Color(color);
    material.set_property(name, value);
}

fn set_material_vector3(material: &mut Material, name: &'static str, vector: [f32; 3]) {
    let value: MaterialProperty = MaterialProperty::Vector3(vector.into());
    material.set_property(name, value);
}

#[allow(dead_code)]
fn set_material_vector4(material: &mut Material, name: &'static str, vector: [f32; 4]) {
    let value: MaterialProperty = MaterialProperty::Vector4(vector.into());
    material.set_property(name, value);
}

fn set_texture(
    material: &mut Material,
    name: &'static str,
    textures: &[TextureResource],
    index: usize,
) -> Result<()> {
    let tex: TextureResource = textures
        .get(index)
        .ok_or(GltfMaterialError::InvalidIndex)?
        .clone();
    material.bind(
        name,
        MaterialResourceBinding::Texture(MaterialTextureBinding { value: Some(tex) }),
    );
    Ok(())
}

pub fn import_images<'a, 'b>(
    gltf: &'a Document,
    buffers: &'b [Vec<u8>],
) -> Result<Vec<SourceImage<'b>>>
where
    'a: 'b,
{
    let mut result: Vec<SourceImage> = Vec::new();
    for image in gltf.images() {
        match image.source() {
            image::Source::Uri { uri, mime_type: _ } => result.push(import_image_from_uri(uri)?),
            image::Source::View { view, mime_type: _ } => {
                result.push(import_image_from_view(view, buffers)?)
            }
        }
    }
    Ok(result)
}

fn import_image_from_uri(uri: &str) -> Result<SourceImage> {
    let parsed_uri = uri::parse_uri(uri);
    match parsed_uri.scheme {
        uri::Scheme::Data if parsed_uri.data.is_some() => Ok(SourceImage::Embedded(decode_base64(
            parsed_uri.data.unwrap(),
        )?)),
        uri::Scheme::None => Ok(SourceImage::External(uri)),
        _ => Err(GltfMaterialError::UnsupportedURI(uri.into())),
    }
}

fn import_image_from_view<'a>(view: View, buffers: &'a [Vec<u8>]) -> Result<SourceImage<'a>> {
    let offset: usize = view.offset();
    let length: usize = view.length();
    let buf: &Vec<u8> = buffers
        .get(view.buffer().index())
        .ok_or(GltfMaterialError::InvalidIndex)?;
    Ok(SourceImage::View(&buf[offset..offset + length]))
}

pub struct TextureContext<'a> {
    pub resource_manager: &'a ResourceManager,
    pub model_path: &'a Path,
    pub search_options: &'a MaterialSearchOptions,
}

pub async fn import_textures<'a>(
    gltf: &'a Document,
    images: &[SourceImage<'a>],
    context: TextureContext<'a>,
) -> Result<Vec<TextureResource>> {
    let mut result: Vec<TextureResource> = Vec::with_capacity(gltf.textures().len());
    for tex in gltf.textures() {
        let sampler = tex.sampler();
        let source = tex.source();
        let image = images
            .get(source.index())
            .ok_or(GltfMaterialError::InvalidIndex)?;
        match image {
            SourceImage::Embedded(data) => result.push(import_embedded_texture(sampler, data)?),
            SourceImage::View(data) => result.push(import_embedded_texture(sampler, data)?),
            SourceImage::External(filename) => {
                import_external_texture(filename, &context).await?;
            } // result.push(import_external_texture(filename, &context).await?),
        }
    }
    Ok(result)
}

fn import_embedded_texture(
    sampler: gltf::texture::Sampler,
    data: &[u8],
) -> Result<TextureResource> {
    let mut options = TextureImportOptions::default();
    if let Some(filter) = sampler.min_filter() {
        options.set_minification_filter(convert_mini(filter));
    }
    if let Some(filter) = sampler.mag_filter() {
        options.set_magnification_filter(convert_mag(filter));
    }
    options.set_s_wrap_mode(convert_wrap(sampler.wrap_s()));
    options.set_t_wrap_mode(convert_wrap(sampler.wrap_t()));
    let tex = Texture::load_from_memory(data, options)?;
    Ok(Resource::new_ok(
        Uuid::new_v4(),
        ResourceKind::Embedded,
        tex,
    ))
}

async fn import_external_texture(
    filename: &str,
    context: &TextureContext<'_>,
) -> Result<TextureResource> {
    let path = search_for_path(filename, context)
        .await
        .ok_or_else(|| GltfMaterialError::TextureNotFound(filename.into()))?;
    Ok(context.resource_manager.request(path))
}

async fn search_for_path(filename: &str, context: &TextureContext<'_>) -> Option<PathBuf> {
    match context.search_options {
        MaterialSearchOptions::MaterialsDirectory(ref directory) => Some(directory.join(filename)),
        MaterialSearchOptions::RecursiveUp => {
            let io = context.resource_manager.resource_io();
            let mut texture_path = None;
            let mut path: PathBuf = context.model_path.to_owned();
            while let Some(parent) = path.parent() {
                let candidate = parent.join(filename);
                if io.exists(&candidate).await {
                    texture_path = Some(candidate);
                    break;
                }
                path.pop();
            }
            texture_path
        }
        MaterialSearchOptions::WorkingDirectory => {
            let io = context.resource_manager.resource_io();
            let mut texture_path = None;
            let path = Path::new(".");
            if let Ok(iter) = io.walk_directory(path, usize::MAX).await {
                for dir in iter {
                    if io.is_dir(&dir).await {
                        let candidate = dir.join(filename);
                        if candidate.exists() {
                            texture_path = Some(candidate);
                            break;
                        }
                    }
                }
            }
            texture_path
        }
        MaterialSearchOptions::UsePathDirectly => Some(filename.into()),
    }
}