From 3d29a93885442478e1ae36bc16f624e474d36c10 Mon Sep 17 00:00:00 2001
From: Matthew Gordon <matthew@gordon.earth>
Date: Tue, 21 Jan 2025 20:14:52 -0400
Subject: [PATCH] Replace ambient coefficient with a no-shadow fill light

---
 src/app/dem_renderer/dem_renderer.wgsl | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/app/dem_renderer/dem_renderer.wgsl b/src/app/dem_renderer/dem_renderer.wgsl
index 9e91b6e..dab531a 100644
--- a/src/app/dem_renderer/dem_renderer.wgsl
+++ b/src/app/dem_renderer/dem_renderer.wgsl
@@ -96,9 +96,10 @@ fn fs_solid(vertex: VertexOutput) -> @location(0) vec4<f32> {
            let sun_direction =
              (uniforms.camera_to_world_matrix
               * vec4<f32>(sun_direction, 0.0)).xyz;
-           let lambertian_value = dot(hit_normal, sun_direction);
-           let ambient_strength = 0.25;
-           let l = ambient_strength + (1.0 - ambient_strength) * lambertian_value * shadow_value;
+           let sun_lambertian_value = dot(hit_normal, sun_direction);
+           let fill_lambertian_value = dot(hit_normal, sun_direction * vec3(1.0, -1.0, 1.0));
+           let fill_strength = 0.25;
+           let l = fill_strength * fill_lambertian_value + (1.0 - fill_strength) * sun_lambertian_value * shadow_value;
            color_accumulator += 0.25 * vec4<f32>(vec3<f32>(l), 1.0);
         }
     }