From 15445c990e42486ba33faca7f36e2ad04943115f Mon Sep 17 00:00:00 2001
From: robtfm <50659922+robtfm@users.noreply.github.com>
Date: Thu, 29 Jun 2023 01:28:34 +0100
Subject: [PATCH] fix prepass normal_mapping (#8978)

# Objective

#5703 caused the normal prepass to fail as the prepass uses
`pbr_functions::apply_normal_mapping`, which uses
`mesh_view_bindings::view` to determine mip bias, which conflicts with
`prepass_bindings::view`.

## Solution

pass the mip bias to the `apply_normal_mapping` function explicitly.
---
 assets/shaders/array_texture.wgsl             | 1 +
 crates/bevy_pbr/src/render/pbr.wgsl           | 1 +
 crates/bevy_pbr/src/render/pbr_functions.wgsl | 3 ++-
 crates/bevy_pbr/src/render/pbr_prepass.wgsl   | 1 +
 4 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/assets/shaders/array_texture.wgsl b/assets/shaders/array_texture.wgsl
index 17c714f420742..4650491724d23 100644
--- a/assets/shaders/array_texture.wgsl
+++ b/assets/shaders/array_texture.wgsl
@@ -44,6 +44,7 @@ fn fragment(
 #endif
 #endif
         mesh.uv,
+        view.mip_bias,
     );
     pbr_input.V = fns::calculate_view(mesh.world_position, pbr_input.is_orthographic);
 
diff --git a/crates/bevy_pbr/src/render/pbr.wgsl b/crates/bevy_pbr/src/render/pbr.wgsl
index 245a822c09e89..cdb9586d435d2 100644
--- a/crates/bevy_pbr/src/render/pbr.wgsl
+++ b/crates/bevy_pbr/src/render/pbr.wgsl
@@ -131,6 +131,7 @@ fn fragment(
 #ifdef VERTEX_UVS
             uv,
 #endif
+            view.mip_bias,
         );
 #endif
 
diff --git a/crates/bevy_pbr/src/render/pbr_functions.wgsl b/crates/bevy_pbr/src/render/pbr_functions.wgsl
index 393ff2728dffa..4e9fce0242e40 100644
--- a/crates/bevy_pbr/src/render/pbr_functions.wgsl
+++ b/crates/bevy_pbr/src/render/pbr_functions.wgsl
@@ -70,6 +70,7 @@ fn apply_normal_mapping(
 #ifdef VERTEX_UVS
     uv: vec2<f32>,
 #endif
+    mip_bias: f32,
 ) -> vec3<f32> {
     // NOTE: The mikktspace method of normal mapping explicitly requires that the world normal NOT
     // be re-normalized in the fragment shader. This is primarily to match the way mikktspace
@@ -94,7 +95,7 @@ fn apply_normal_mapping(
 #ifdef VERTEX_UVS
 #ifdef STANDARDMATERIAL_NORMAL_MAP
     // Nt is the tangent-space normal.
-    var Nt = textureSampleBias(pbr_bindings::normal_map_texture, pbr_bindings::normal_map_sampler, uv, view_bindings::view.mip_bias).rgb;
+    var Nt = textureSampleBias(pbr_bindings::normal_map_texture, pbr_bindings::normal_map_sampler, uv, mip_bias).rgb;
     if (standard_material_flags & pbr_types::STANDARD_MATERIAL_FLAGS_TWO_COMPONENT_NORMAL_MAP) != 0u {
         // Only use the xy components and derive z for 2-component normal maps.
         Nt = vec3<f32>(Nt.rg * 2.0 - 1.0, 0.0);
diff --git a/crates/bevy_pbr/src/render/pbr_prepass.wgsl b/crates/bevy_pbr/src/render/pbr_prepass.wgsl
index b5103e73a9ab1..542e540309a5c 100644
--- a/crates/bevy_pbr/src/render/pbr_prepass.wgsl
+++ b/crates/bevy_pbr/src/render/pbr_prepass.wgsl
@@ -107,6 +107,7 @@ fn fragment(in: FragmentInput) -> FragmentOutput {
 #ifdef VERTEX_UVS
             in.uv,
 #endif // VERTEX_UVS
+            bevy_pbr::prepass_bindings::view.mip_bias,
         );
 
         out.normal = vec4(normal * 0.5 + vec3(0.5), 1.0);