From c50de96acf58288d04673800a401a84207ce4a4e Mon Sep 17 00:00:00 2001
From: Paris DOUADY <paris.douady@hotmail.fr>
Date: Thu, 17 Aug 2023 12:53:42 +0200
Subject: [PATCH] tune lighting

---
 assets/shaders/atmosphere.wgsl | 8 +++++++-
 assets/shaders/pbr/render.wgsl | 8 +++++---
 native_app/src/context.rs      | 2 +-
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/assets/shaders/atmosphere.wgsl b/assets/shaders/atmosphere.wgsl
index 34056827..a2d2a958 100644
--- a/assets/shaders/atmosphere.wgsl
+++ b/assets/shaders/atmosphere.wgsl
@@ -113,6 +113,12 @@ fn atmosphere(r: vec3<f32>, pSun: vec3<f32>) -> vec3<f32> {
         iTime += iStepSize;
     }
 
+    let backgroundLight: vec3<f32> = mix(vec3(0.0116, 0.027, 0.0423), // light blue (horizon)
+                                         vec3(0.0036, 0.013, 0.0194), // dark blue
+                                         saturate(2.0 * sqrt(r.z)))   // gradient
+                                          * 0.4                       // power
+                                          * smoothstep(-0.3, 0.1, r.z); // black at bottom
+
     // Calculate and return the final color.
-    return iSun * (pRlh * kRlh * totalRlh + pMie * kMie * totalMie);
+    return backgroundLight + iSun * (pRlh * kRlh * totalRlh + pMie * kMie * totalMie);
 }
diff --git a/assets/shaders/pbr/render.wgsl b/assets/shaders/pbr/render.wgsl
index 8d672e59..6e1699c0 100644
--- a/assets/shaders/pbr/render.wgsl
+++ b/assets/shaders/pbr/render.wgsl
@@ -158,10 +158,12 @@ fn render(sun: vec3<f32>,
     var dkD: vec3<f32> = 1.0 - dkS;
     dkD *= 1.0 - vec3(metallic);
 
-    let ambient: vec3<f32> = (0.2 * dkD * (0.15 + irradiance_diffuse) * albedo + specular) * ssao;
-    var color: vec3<f32>   = ambient + Lo * 4.0;
+    let ambient: vec3<f32> = (0.2 * dkD * (0.04 + irradiance_diffuse) * albedo + specular) * ssao;
+    var color: vec3<f32>   = ambient + Lo;
 
-    color = tonemap(color);
+    let autoexposure = 1.0 + smoothstep(0.0, 0.1, -sun.z) * 5.0;
+
+    color = tonemap(autoexposure * color);
 
     color += dither(position);
 
diff --git a/native_app/src/context.rs b/native_app/src/context.rs
index ed58c1c1..e45ab8fe 100644
--- a/native_app/src/context.rs
+++ b/native_app/src/context.rs
@@ -134,7 +134,7 @@ impl Context {
 
                         let params = self.gfx.render_params.value_mut();
                         params.time_always = (params.time_always + self.delta) % 3600.0;
-                        params.sun_col = sun.z.max(0.0).sqrt().sqrt() * LinearColor::new(1.0, 0.95 + sun.z * 0.05, 0.95 + sun.z * 0.05, 1.0);
+                        params.sun_col = 4.0 * sun.z.max(0.0).sqrt().sqrt() * LinearColor::new(1.0, 0.95 + sun.z * 0.05, 0.95 + sun.z * 0.05, 1.0);
                         let camera = state.uiw.read::<CameraHandler3D>();
                         params.cam_pos = camera.camera.eye();
                         params.cam_dir = -camera.camera.dir();