raidillon/glium_platform/src/render/basic.rs

use std::any::Any;
use std::sync::{Arc, Mutex};
use glium::{uniform, Display, Program, Surface};
use glium::glutin::surface::WindowSurface;
use glium::texture::{RawImage2d, SrgbTexture2d};
use crate::{GliumAssetManager, RenderingSystem};
use crate::system::RenderingContext;
use raidillon_assets::include_shader;
pub use raidillon_platform::Camera;
use glam::Vec3;
use glium::uniforms::{MagnifySamplerFilter, MinifySamplerFilter, SamplerWrapFunction};
use winit::event::Event;
use winit::event_loop::EventLoop;
use raidillon_ecs::{Transform, ModelID};
use raidillon_ecs::components::ModelHandle;
use crate::model::Model;

/// A basic renderer pipeline step.
pub struct BasicMeshRenderingSystem {
    program: Program,
    white_tex: SrgbTexture2d,
    params: glium::DrawParameters<'static>,
}

impl RenderingSystem for BasicMeshRenderingSystem {
    fn initialize(display: &Display<WindowSurface>, _window: Arc<Mutex<glium::winit::window::Window>>, event_loop: &EventLoop<()>) -> Self {
        const VERT_SRC: &str = include_shader!("gl_textured.vert");
        const FRAG_SRC: &str = include_shader!("gl_textured.frag");

        let program = Program::from_source(display, VERT_SRC, FRAG_SRC, None).unwrap();

        let white_tex = {
            let data = vec![255u8, 255u8, 255u8, 255u8];
            let raw  = RawImage2d::from_raw_rgba(data, (1, 1));
            SrgbTexture2d::new(display, raw).unwrap()
        };

        let params = glium::DrawParameters {
            depth: glium::Depth {
                test: glium::draw_parameters::DepthTest::IfLess,
                write: true,
                .. Default::default()
            },
            .. Default::default()
        };

        Self {
            program, white_tex, params
        }
    }

    fn render(&mut self, ctx: &mut RenderingContext) {
        let cam = match ctx.scene.world.query::<&Camera>().iter().next() {
            Some((_, cam)) => *cam,
            None => {
                eprintln!("[renderer] No camera component found. Skipping frame");
                return;
            }
        };

        // Use HDR-derived environment light direction if provided, otherwise default to downward
        let light_dir: Vec3 = if ctx.env_light_dir.length_squared() > 0.0 { ctx.env_light_dir.normalize() } else { Vec3::new(0.0, -1.0, 0.0) };

        let asset_manager = ctx.asset_manager.borrow();

        for (_, (tr, mh)) in ctx.scene.world.query::<(&Transform, &ModelHandle)>().iter() {
            let model = match asset_manager.get_model(&mh.0) {
                Some(model) => model,
                _ => continue,
            };

            let model = match model.downcast_ref::<Model>() {
                Some(model) => model,
                None => continue,
            };

            let mesh = &model.mesh;
            let mat = &model.material;

            let tex_ref: &SrgbTexture2d = mat.base_color.as_ref().unwrap_or(&self.white_tex);

            let mut sampler = tex_ref.sampled();
            sampler = sampler.wrap_function(SamplerWrapFunction::Repeat);
            sampler = sampler.minify_filter(MinifySamplerFilter::Linear);
            sampler = sampler.magnify_filter(MagnifySamplerFilter::Linear);

            let c = mat.base_color_factor;

            let uniforms = uniform! {
                model:      tr.matrix().to_cols_array_2d(),
                view:       cam.view().to_cols_array_2d(),
                projection: cam.projection().to_cols_array_2d(),
                u_light:    [light_dir.x, light_dir.y, light_dir.z],
                tex:        sampler,
                color:      [c[0], c[1], c[2]],
                uv_offset:  [mat.uv_offset.x, mat.uv_offset.y],
                uv_scale:   [mat.uv_scale.x,  mat.uv_scale.y],
            };

            ctx.target.draw(
                &mesh.vbuf,
                &mesh.ibuf,
                &self.program,
                &uniforms,
                &self.params,
            ).unwrap();
        }
    }
}