From 7b752703ea8cad4176db24a704ddf6162c92da31 Mon Sep 17 00:00:00 2001
From: nullprop <git@nullprop.sh>
Date: Fri, 10 Nov 2023 01:50:30 +0200
Subject: [PATCH] Tweak fog light falloff & density

---
 res/shaders/constants.wgsl |  2 +-
 res/shaders/fog.wgsl       | 22 +++++++++++-----------
 src/core/pass.rs           |  5 ++++-
 src/core/state.rs          |  8 ++++++--
 4 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/res/shaders/constants.wgsl b/res/shaders/constants.wgsl
index b584400..298919c 100644
--- a/res/shaders/constants.wgsl
+++ b/res/shaders/constants.wgsl
@@ -8,6 +8,6 @@ const INV_SHADOW_SAMPLES = 1.0 / 25.0;
 const FOG_MAX_STEPS = 20;
 const FOG_MAX_DIST = 300.0;
 const FOG_SCALE = 0.01;
-const FOG_DENSITY = 1.0;
+const FOG_DENSITY = 2.0;
 const FOG_ALPHA = 1.0;
 const FOG_BLEND_DIST = 10.0;
diff --git a/res/shaders/fog.wgsl b/res/shaders/fog.wgsl
index 67fb450..510da2f 100644
--- a/res/shaders/fog.wgsl
+++ b/res/shaders/fog.wgsl
@@ -63,7 +63,7 @@ var s_roughness_metalness: sampler;
 fn fog_noise(pos: vec3<f32>) -> f32 {
     var p = pos * FOG_SCALE;
     p.x += global_uniforms.time * 0.01;
-    p.y += global_uniforms.time * 0.1;
+    p.y += global_uniforms.time * 0.2;
     p.z += sin(global_uniforms.time * 0.1) * 0.1;
     return fbm(p);
 }
@@ -112,12 +112,12 @@ fn fs_main(vert: FogVertexOutput) -> @location(0) vec4<f32> {
     let distance_to_volume = length(cam_to_volume);
     let direction = cam_to_volume / distance_to_volume;
     // FIXME: t_geometry_depth is 0
-//    let geometry_depth = scene_depth(vert.clip_position) - distance_to_volume;
-//    if (geometry_depth <= 0.0)
-//    {
-//        return vec4<f32>(0.0);
-//    }
-    let geometry_depth = 3000.0;
+    var geometry_depth = scene_depth(vert.clip_position) - distance_to_volume;
+    geometry_depth = 3000.0;
+    if (geometry_depth <= 0.0)
+    {
+        return vec4<f32>(0.0);
+    }
     let density = ray_march(vert.world_position.xyz, direction, geometry_depth);
 
     var in_light = 0.0;
@@ -149,16 +149,16 @@ fn fs_main(vert: FogVertexOutput) -> @location(0) vec4<f32> {
         in_light = 1.0;
     }
 
-    var color = vec3<f32>(0.5, 0.5, 0.5);
+    var base_color = vec3<f32>(mix(0.8, 0.4, density));
     let ambient_strength = 0.02;
-    let ambient_color = color * ambient_strength;
+    let ambient_color = base_color * ambient_strength;
 
     var radiance = vec3<f32>(0.0);
     if (in_light > 0.0) {
         // attenuation
         let light_dist = length(light.position - vert.world_position.xyz);
-        let coef_a = 0.0;
-        let coef_b = 1.0;
+        let coef_a = 2.0;
+        let coef_b = 4.0;
         let light_attenuation = 1.0 / (1.0 + coef_a * light_dist + coef_b * light_dist * light_dist);
 
         radiance = light.color.rgb * light.color.a * light_attenuation * in_light;
diff --git a/src/core/pass.rs b/src/core/pass.rs
index 2b07e01..4ad60e0 100644
--- a/src/core/pass.rs
+++ b/src/core/pass.rs
@@ -21,6 +21,7 @@ impl RenderPass {
         is_shadow: bool,
         has_transparency: bool,
         write_depth: bool,
+        cull_mode: Option<wgpu::Face>,
     ) -> Self {
         let layout = device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
             label: Some((label.to_owned() + " pipeline Layout").as_str()),
@@ -42,6 +43,7 @@ impl RenderPass {
             is_shadow,
             has_transparency,
             write_depth,
+            cull_mode,
         );
 
         Self { pipeline }
@@ -58,6 +60,7 @@ impl RenderPass {
         is_shadow: bool,
         has_transparency: bool,
         write_depth: bool,
+        cull_mode: Option<wgpu::Face>,
     ) -> wgpu::RenderPipeline {
         let shader = device.create_shader_module(shader);
 
@@ -101,7 +104,7 @@ impl RenderPass {
                 topology: wgpu::PrimitiveTopology::TriangleList,
                 strip_index_format: None,
                 front_face: wgpu::FrontFace::Ccw,
-                cull_mode: Some(wgpu::Face::Back),
+                cull_mode: cull_mode,
                 // Setting this to anything other than Fill requires Features::NON_FILL_POLYGON_MODE
                 polygon_mode: wgpu::PolygonMode::Fill,
                 // Requires Features::DEPTH_CLIP_CONTROL
diff --git a/src/core/state.rs b/src/core/state.rs
index 33d17a4..f605f2d 100644
--- a/src/core/state.rs
+++ b/src/core/state.rs
@@ -156,7 +156,7 @@ impl State {
             config.width,
             config.height,
             1,
-            wgpu::TextureUsages::RENDER_ATTACHMENT | wgpu::TextureUsages::TEXTURE_BINDING | wgpu::TextureUsages::COPY_DST,
+            wgpu::TextureUsages::RENDER_ATTACHMENT | wgpu::TextureUsages::TEXTURE_BINDING,
             true,
         );
 
@@ -445,6 +445,7 @@ impl State {
             true,
             false,
             true,
+            Some(wgpu::Face::Back),
         );
 
         let geometry_pass = RenderPass::new(
@@ -464,6 +465,7 @@ impl State {
             false,
             false,
             true,
+            Some(wgpu::Face::Back),
         );
 
         let light_debug_pass = RenderPass::new(
@@ -478,6 +480,7 @@ impl State {
             false,
             false,
             true,
+            Some(wgpu::Face::Back),
         );
 
         let fog_pass = RenderPass::new(
@@ -497,6 +500,7 @@ impl State {
             false,
             true,
             false,
+            Some(wgpu::Face::Back),
         );
 
         Self {
@@ -548,7 +552,7 @@ impl State {
                 self.config.width,
                 self.config.height,
                 1,
-                wgpu::TextureUsages::RENDER_ATTACHMENT | wgpu::TextureUsages::TEXTURE_BINDING | wgpu::TextureUsages::COPY_DST,
+                wgpu::TextureUsages::RENDER_ATTACHMENT | wgpu::TextureUsages::TEXTURE_BINDING,
                 true,
             );
         }