Implement HDRI skybox support

.gitattributes

@@ -1 +1,2 @@
 assets/models/* filter=lfs diff=lfs merge=lfs -text
+assets/exr/* filter=lfs diff=lfs merge=lfs -text

Cargo.lock

@@ -130,6 +130,12 @@ version = "0.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9e1b586273c5702936fe7b7d6896644d8be71e6314cfe09d3167c95f712589e8"
 
+[[package]]
+name = "bit_field"
+version = "0.10.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e4b40c7323adcfc0a41c4b88143ed58346ff65a288fc144329c5c45e05d70c6"
+
 [[package]]
 name = "bitflags"
 version = "1.3.2"
@@ -319,12 +325,37 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9dd111b7b7f7d55b72c0a6ae361660ee5853c9af73f70c3c2ef6858b950e2e51"
+dependencies = [
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
+dependencies = [
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "crossbeam-utils"
 version = "0.8.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d0a5c400df2834b80a4c3327b3aad3a4c4cd4de0629063962b03235697506a28"
 
+[[package]]
+name = "crunchy"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "460fbee9c2c2f33933d720630a6a0bac33ba7053db5344fac858d4b8952d77d5"
+
 [[package]]
 name = "cursor-icon"
 version = "1.2.0"
@@ -384,6 +415,21 @@ dependencies = [
  "windows-sys 0.60.2",
 ]
 
+[[package]]
+name = "exr"
+version = "1.73.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f83197f59927b46c04a183a619b7c29df34e63e63c7869320862268c0ef687e0"
+dependencies = [
+ "bit_field",
+ "half",
+ "lebe",
+ "miniz_oxide",
+ "rayon-core",
+ "smallvec",
+ "zune-inflate",
+]
+
 [[package]]
 name = "fdeflate"
 version = "0.3.7"
@@ -603,6 +649,16 @@ dependencies = [
  "gl_generator",
 ]
 
+[[package]]
+name = "half"
+version = "2.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "459196ed295495a68f7d7fe1d84f6c4b7ff0e21fe3017b2f283c6fac3ad803c9"
+dependencies = [
+ "cfg-if",
+ "crunchy",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.14.5"
@@ -636,12 +692,14 @@ checksum = "fc0fef456e4baa96da950455cd02c081ca953b141298e41db3fc7e36b1da849c"
 
 [[package]]
 name = "image"
-version = "0.25.6"
+version = "0.25.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "db35664ce6b9810857a38a906215e75a9c879f0696556a39f59c62829710251a"
+checksum = "529feb3e6769d234375c4cf1ee2ce713682b8e76538cb13f9fc23e1400a591e7"
 dependencies = [
  "bytemuck",
  "byteorder-lite",
+ "exr",
+ "moxcms",
  "num-traits",
  "png",
  "zune-core",
@@ -769,6 +827,12 @@ version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
 
+[[package]]
+name = "lebe"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a79a3332a6609480d7d0c9eab957bca6b455b91bb84e66d19f5ff66294b85b8"
+
 [[package]]
 name = "libc"
 version = "0.2.174"
@@ -864,6 +928,16 @@ version = "0.5.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e53debba6bda7a793e5f99b8dacf19e626084f525f7829104ba9898f367d85ff"
 
+[[package]]
+name = "moxcms"
+version = "0.7.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddd32fa8935aeadb8a8a6b6b351e40225570a37c43de67690383d87ef170cd08"
+dependencies = [
+ "num-traits",
+ "pxfm",
+]
+
 [[package]]
 name = "ndk"
 version = "0.9.0"
@@ -1267,11 +1341,11 @@ checksum = "7edddbd0b52d732b21ad9a5fab5c704c14cd949e5e9a1ec5929a24fded1b904c"
 
 [[package]]
 name = "png"
-version = "0.17.16"
+version = "0.18.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "82151a2fc869e011c153adc57cf2789ccb8d9906ce52c0b39a6b5697749d7526"
+checksum = "97baced388464909d42d89643fe4361939af9b7ce7a31ee32a168f832a70f2a0"
 dependencies = [
- "bitflags 1.3.2",
+ "bitflags 2.9.1",
  "crc32fast",
  "fdeflate",
  "flate2",
@@ -1310,6 +1384,15 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "pxfm"
+version = "0.1.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "83f9b339b02259ada5c0f4a389b7fb472f933aa17ce176fd2ad98f28bb401fde"
+dependencies = [
+ "num-traits",
+]
+
 [[package]]
 name = "quick-xml"
 version = "0.37.5"
@@ -1388,9 +1471,11 @@ name = "raidillon_glium"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "exr",
  "glam",
  "glium",
  "gltf",
+ "image",
  "imgui",
  "imgui-glium-renderer",
  "imgui-winit-support",
@@ -1419,6 +1504,16 @@ version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "20675572f6f24e9e76ef639bc5552774ed45f1c30e2951e1e99c59888861c539"
 
+[[package]]
+name = "rayon-core"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "22e18b0f0062d30d4230b2e85ff77fdfe4326feb054b9783a3460d8435c8ab91"
+dependencies = [
+ "crossbeam-deque",
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.4.1"
@@ -2408,6 +2503,15 @@ version = "0.4.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3f423a2c17029964870cfaabb1f13dfab7d092a62a29a89264f4d36990ca414a"
 
+[[package]]
+name = "zune-inflate"
+version = "0.2.54"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "73ab332fe2f6680068f3582b16a24f90ad7096d5d39b974d1c0aff0125116f02"
+dependencies = [
+ "simd-adler32",
+]
+
 [[package]]
 name = "zune-jpeg"
 version = "0.4.20"

assets/shaders/skybox.frag

@@ -17,6 +17,7 @@ vec2 sample_spherical_map(vec3 v) {
 
 void main() {
     vec2 uv = sample_spherical_map(normalize(direction));
+    uv.y = 1.0 - uv.y;
     vec3 color = texture(equirect, uv).rgb;
     frag_color = vec4(color, 1.0);
 }

game/src/main.rs

@@ -101,8 +101,8 @@ fn main() {
         let platform = GliumPlatform::initialize(
             engine,
             "Raidillon".to_string(),
-            1920,
+            2560,
-            1080,
+            1440,
         );
         platform.run()
     };

glium_platform/Cargo.toml

@@ -18,3 +18,5 @@ indexmap = "2.10.0"
 imgui = "0.12.0"
 imgui-winit-support = "0.13.0"
 imgui-glium-renderer = "0.13.0"
+exr = "1.73.0"
+image = { version = "0.25.8", default-features = false, features = ["exr"] }

glium_platform/src/platform.rs

@@ -14,8 +14,9 @@ use raidillon_core::engine::EngineTrait;
 use raidillon_core::time;
 use raidillon_core::time::Time;
 use crate::render::debug_ui::ImguiBridge;
-use crate::render::BasicMeshRenderingSystem;
+use crate::render::{BasicMeshRenderingSystem, SkyboxRenderingSystem};
 use crate::GliumAssetManager;
+use glam::Vec3;
 
 pub struct GliumPlatform<E: EngineTrait<PlatformCtx = PlatformContext>> {
     event_loop: EventLoop<()>,
@@ -44,7 +45,8 @@ impl<E: EngineTrait<PlatformCtx = PlatformContext>> Platform<E> for GliumPlatfor
         let time_cfg = time::Config::default();
         let time = time::Time::new(time_cfg);
 
-        // Install rendering systems
+        // Install rendering systems in order
+        rendering_system_manager.add::<SkyboxRenderingSystem>(&display, &window);
         rendering_system_manager.add::<BasicMeshRenderingSystem>(&display, &window);
         rendering_system_manager.add::<ImguiBridge>(&display, &window);
 
@@ -95,12 +97,14 @@ impl<E: EngineTrait<PlatformCtx = PlatformContext>> Platform<E> for GliumPlatfor
                             asset_manager: self.asset_manager.clone(),
                             window: &mut self.window,
                             debug_ui_buffer,
+                            env_light_dir: Vec3::new(0.0, -1.0, 0.0),
                         };
 
                         self.rendering_system_manager
                             .systems
                             .values_mut()
                             .for_each(|system| system.render(&mut context));
+
                         target.finish().unwrap();
                     }
                     _ => {},

glium_platform/src/render/basic.rs

@@ -55,14 +55,8 @@ impl RenderingSystem for BasicMeshRenderingSystem {
             }
         };
 
-        // Direction from the light source (0,+Y) towards the scene.
+        // Use HDR-derived environment light direction if provided, otherwise default to downward
-        let light_dir: Vec3 = Vec3::new(0.0, -1.0, 0.0).normalize();
+        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();
-        // let any_ref: &dyn Any = &**asset_manager;
-        // if let Some(glium_manager) = any_ref.downcast_ref::<GliumAssetManager>() {
-        //     &glium_manager.models;
-        // }
 
         let asset_manager = ctx.asset_manager.borrow();
 

glium_platform/src/render/mod.rs

@@ -1,4 +1,6 @@
 mod basic;
 pub mod debug_ui;
+mod skybox;
 
 pub use basic::BasicMeshRenderingSystem;
+pub use skybox::SkyboxRenderingSystem;

glium_platform/src/render/skybox.rs

@@ -0,0 +1,149 @@
+use std::path::PathBuf;
+use std::rc::Rc;
+use std::cell::RefCell;
+use glium::{Display, Program, Surface, VertexBuffer, IndexBuffer, implement_vertex};
+use glium::glutin::surface::WindowSurface;
+use glium::index::PrimitiveType;
+use glium::texture::{RawImage2d, SrgbTexture2d, Texture2d};
+use glium::uniform;
+use glam::{Mat4, Vec2, Vec3};
+use raidillon_assets::include_shader;
+use crate::system::RenderingContext;
+use crate::RenderingSystem;
+
+#[derive(Copy, Clone)]
+struct SkyboxVertex { position: [f32; 3] }
+implement_vertex!(SkyboxVertex, position);
+
+pub struct SkyboxRenderingSystem {
+	program: Program,
+	quad_vb: VertexBuffer<SkyboxVertex>,
+	quad_ib: IndexBuffer<u16>,
+	/// Equirectangular HDR image, tonemapped to sRGB for skybox view
+	equirect_srgb: SrgbTexture2d,
+	/// Dominant light direction estimated from HDRI
+	light_dir: Vec3,
+}
+
+impl SkyboxRenderingSystem {
+	fn build_cube(display: &Display<WindowSurface>) -> (VertexBuffer<SkyboxVertex>, IndexBuffer<u16>) {
+		// Unit cube centered at origin
+		let p = &[
+			[-1.0, -1.0, -1.0], [ 1.0, -1.0, -1.0], [ 1.0,  1.0, -1.0], [-1.0,  1.0, -1.0], // back
+			[-1.0, -1.0,  1.0], [ 1.0, -1.0,  1.0], [ 1.0,  1.0,  1.0], [-1.0,  1.0,  1.0], // front
+		];
+		let verts = vec![
+			SkyboxVertex { position: p[0] }, SkyboxVertex { position: p[1] }, SkyboxVertex { position: p[2] }, SkyboxVertex { position: p[3] }, // back
+			SkyboxVertex { position: p[4] }, SkyboxVertex { position: p[5] }, SkyboxVertex { position: p[6] }, SkyboxVertex { position: p[7] }, // front
+		];
+		let idx: [u16; 36] = [
+			// back face
+			0,1,2,  2,3,0,
+			// front face
+			4,6,5,  6,4,7,
+			// left face
+			0,3,7,  7,4,0,
+			// right face
+			1,5,6,  6,2,1,
+			// bottom face
+			0,4,5,  5,1,0,
+			// top face
+			3,2,6,  6,7,3,
+		];
+		(
+			VertexBuffer::new(display, &verts).unwrap(),
+			IndexBuffer::new(display, PrimitiveType::TrianglesList, &idx).unwrap(),
+		)
+	}
+
+	fn load_hdr_equirect_and_analyze(display: &Display<WindowSurface>, path: &std::path::Path) -> (SrgbTexture2d, Vec3) {
+		// Use image crate to decode EXR as f32 RGB
+		let dyn_img = image::ImageReader::open(path).expect("open exr").with_guessed_format().expect("guess format").decode().expect("decode exr");
+		let hdr = dyn_img.to_rgb32f();
+		let (width, height) = hdr.dimensions();
+		let width = width as usize; let height = height as usize;
+		let mut dir_accum = Vec3::ZERO;
+		let mut weight_sum = 0.0f32;
+		for y in 0..height {
+			let v = (y as f32 + 0.5) / height as f32;
+			let theta = (v - 0.5) * std::f32::consts::PI;
+			let lat_weight = theta.cos().max(0.0);
+			for x in 0..width {
+				let u = (x as f32 + 0.5) / width as f32;
+				let phi = (u - 0.5) * 2.0 * std::f32::consts::PI;
+				let px = hdr.get_pixel(x as u32, y as u32).0;
+				let rgb = Vec3::new(px[0], px[1], px[2]);
+				let lum = 0.2126*rgb.x + 0.7152*rgb.y + 0.0722*rgb.z;
+				if lum > 0.0 {
+					let dir = Vec3::new(phi.cos()*theta.cos(), theta.sin(), phi.sin()*theta.cos());
+					let w = lum * lat_weight;
+					dir_accum += dir * w;
+					weight_sum += w;
+				}
+			}
+		}
+		let mut light_dir = if weight_sum > 0.0 { dir_accum / weight_sum } else { Vec3::new(0.0, -1.0, 0.0) };
+		if light_dir.length_squared() < 1e-6 { light_dir = Vec3::new(0.0,-1.0,0.0); }
+		light_dir = light_dir.normalize();
+
+		// Tonemap to sRGB
+		let mut srgb_bytes = Vec::with_capacity(width*height*4);
+		for y in 0..height {
+			for x in 0..width {
+				let px = hdr.get_pixel(x as u32, y as u32).0;
+				let mapped = Vec3::new(px[0], px[1], px[2]) / (Vec3::new(px[0], px[1], px[2]) + Vec3::ONE);
+				let srgb = mapped.powf(1.0/2.2);
+				srgb_bytes.extend_from_slice(&[
+					(srgb.x.clamp(0.0,1.0)*255.0) as u8,
+					(srgb.y.clamp(0.0,1.0)*255.0) as u8,
+					(srgb.z.clamp(0.0,1.0)*255.0) as u8,
+					255u8,
+				]);
+			}
+		}
+		let raw = RawImage2d::from_raw_rgba(srgb_bytes, (width as u32, height as u32));
+		let tex = SrgbTexture2d::new(display, raw).unwrap();
+		(tex, light_dir)
+	}
+}
+
+impl RenderingSystem for SkyboxRenderingSystem {
+	fn initialize(display: &Display<WindowSurface>, _window: &glium::winit::window::Window) -> Self {
+		const VERT_SRC: &str = include_shader!("skybox.vert");
+		const FRAG_SRC: &str = include_shader!("skybox.frag");
+		let program = Program::from_source(display, VERT_SRC, FRAG_SRC, None).unwrap();
+		let (quad_vb, quad_ib) = Self::build_cube(display);
+
+		// Load EXR from assets/exr
+		let manifest_dir = env!("CARGO_MANIFEST_DIR");
+		let path = std::path::Path::new(manifest_dir).join("../assets/exr/qwantani_sunset_puresky_2k.exr");
+		let (equirect_srgb, light_dir) = Self::load_hdr_equirect_and_analyze(display, &path);
+		Self { program, quad_vb, quad_ib, equirect_srgb, light_dir }
+	}
+
+	fn render(&mut self, ctx: &mut RenderingContext) {
+		// Provide view and projection without translation for skybox
+		let cam = match ctx.scene.world.query::<&raidillon_platform::Camera>().iter().next() {
+			Some((_, cam)) => *cam,
+			None => return,
+		};
+		let mut view = cam.view();
+		// remove translation from view matrix (only orientation)
+		view.col_mut(3).x = 0.0; view.col_mut(3).y = 0.0; view.col_mut(3).z = 0.0;
+		let uniforms = uniform! {
+			view:       view.to_cols_array_2d(),
+			projection: cam.projection().to_cols_array_2d(),
+			equirect:   &self.equirect_srgb,
+		};
+		let params = glium::DrawParameters { depth: glium::Depth { test: glium::draw_parameters::DepthTest::IfLessOrEqual, write: false, ..Default::default() }, ..Default::default() };
+		ctx.target.draw(&self.quad_vb, &self.quad_ib, &self.program, &uniforms, &params).ok();
+
+		// Share light direction with following passes
+		ctx.env_light_dir = self.light_dir;
+	}
+}
+
+// Provide a getter for light direction for other systems
+impl SkyboxRenderingSystem {
+	pub fn light_direction(&self) -> Vec3 { self.light_dir }
+}

glium_platform/src/system.rs

@@ -7,6 +7,7 @@ use glium::glutin::surface::WindowSurface;
 use raidillon_assets::ModelManagerRef;
 use raidillon_core::DebugUIBuffer;
 use raidillon_core::scene::Scene;
+use glam::Vec3;
 
 pub struct RenderingContext<'a> {
     pub scene: &'a Scene,
@@ -14,6 +15,7 @@ pub struct RenderingContext<'a> {
     pub window: &'a mut glium::winit::window::Window,
     pub asset_manager: ModelManagerRef,
     pub debug_ui_buffer: Rc<RefCell<DebugUIBuffer>>,
+    pub env_light_dir: Vec3,
 }
 
 /// The internal "rendering system" trait of glium_platform.