From 8596c4c54e8570e5e24f969277c2288536ddecea Mon Sep 17 00:00:00 2001
From: Jan Hohenheim <jan@hohenheim.ch>
Date: Fri, 16 Feb 2024 17:53:15 +0100
Subject: [PATCH 01/10] Add support for KHR_texture_transform

Co-authored-by: Al McElrath <hello@yrns.org>
---
 crates/bevy_gltf/Cargo.toml                   |  1 +
 crates/bevy_gltf/src/loader.rs                | 34 +++++++++++++++----
 crates/bevy_pbr/src/pbr_material.rs           |  9 ++++-
 crates/bevy_pbr/src/render/pbr_fragment.wgsl  |  2 +-
 .../src/render/pbr_prepass_functions.wgsl     |  3 +-
 crates/bevy_pbr/src/render/pbr_types.wgsl     |  2 ++
 6 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/crates/bevy_gltf/Cargo.toml b/crates/bevy_gltf/Cargo.toml
index 78306fd6db3a9..322ec50447749 100644
--- a/crates/bevy_gltf/Cargo.toml
+++ b/crates/bevy_gltf/Cargo.toml
@@ -43,6 +43,7 @@ gltf = { version = "1.4.0", default-features = false, features = [
   "KHR_materials_volume",
   "KHR_materials_unlit",
   "KHR_materials_emissive_strength",
+  "KHR_texture_transform",
   "extras",
   "extensions",
   "names",
diff --git a/crates/bevy_gltf/src/loader.rs b/crates/bevy_gltf/src/loader.rs
index ff1aced2f680b..072076030c42e 100644
--- a/crates/bevy_gltf/src/loader.rs
+++ b/crates/bevy_gltf/src/loader.rs
@@ -8,7 +8,7 @@ use bevy_ecs::entity::EntityHashMap;
 use bevy_ecs::{entity::Entity, world::World};
 use bevy_hierarchy::{BuildWorldChildren, WorldChildBuilder};
 use bevy_log::{error, warn};
-use bevy_math::{Mat4, Vec3};
+use bevy_math::{Mat3, Mat4, Vec3};
 use bevy_pbr::{
     AlphaMode, DirectionalLight, DirectionalLightBundle, PbrBundle, PointLight, PointLightBundle,
     SpotLight, SpotLightBundle, StandardMaterial, MAX_JOINTS,
@@ -38,7 +38,7 @@ use bevy_utils::{HashMap, HashSet};
 use gltf::{
     accessor::Iter,
     mesh::{util::ReadIndices, Mode},
-    texture::{MagFilter, MinFilter, WrappingMode},
+    texture::{MagFilter, MinFilter, TextureTransform, WrappingMode},
     Material, Node, Primitive, Semantic,
 };
 use serde::{Deserialize, Serialize};
@@ -791,6 +791,15 @@ async fn load_image<'a, 'b>(
     }
 }
 
+/// Converts [`TextureTransform`] to [`Mat3`].
+fn texture_transform_mat3(texture_transform: TextureTransform) -> Mat3 {
+    Mat3::from_scale_angle_translation(
+        texture_transform.scale().into(),
+        -texture_transform.rotation(),
+        texture_transform.offset().into(),
+    )
+}
+
 /// Loads a glTF material as a bevy [`StandardMaterial`] and returns it.
 fn load_material(
     material: &Material,
@@ -803,10 +812,16 @@ fn load_material(
 
         // TODO: handle missing label handle errors here?
         let color = pbr.base_color_factor();
-        let base_color_texture = pbr.base_color_texture().map(|info| {
-            // TODO: handle info.tex_coord() (the *set* index for the right texcoords)
-            texture_handle(load_context, &info.texture())
-        });
+        let (base_color_texture, uv_transform) = pbr
+            .base_color_texture()
+            .map(|info| {
+                // TODO: handle info.tex_coord() (the *set* index for the right texcoords)
+                let texture = texture_handle(load_context, &info.texture());
+                let uv_transform = info.texture_transform().map(texture_transform_mat3);
+                (texture, uv_transform)
+            })
+            .unzip();
+        let uv_transform = uv_transform.flatten().unwrap_or_default();
 
         let normal_map_texture: Option<Handle<Image>> =
             material.normal_texture().map(|normal_texture| {
@@ -817,6 +832,9 @@ fn load_material(
 
         let metallic_roughness_texture = pbr.metallic_roughness_texture().map(|info| {
             // TODO: handle info.tex_coord() (the *set* index for the right texcoords)
+            if info.texture_transform().map(texture_transform_mat3) != Some(uv_transform) {
+                warn!("Only one texture transform is supported");
+            }
             texture_handle(load_context, &info.texture())
         });
 
@@ -830,6 +848,9 @@ fn load_material(
         let emissive_texture = material.emissive_texture().map(|info| {
             // TODO: handle occlusion_texture.tex_coord() (the *set* index for the right texcoords)
             // TODO: handle occlusion_texture.strength() (a scalar multiplier for occlusion strength)
+            if info.texture_transform().map(texture_transform_mat3) != Some(uv_transform) {
+                warn!("Only one texture transform is supported");
+            }
             texture_handle(load_context, &info.texture())
         });
 
@@ -917,6 +938,7 @@ fn load_material(
             ),
             unlit: material.unlit(),
             alpha_mode: alpha_mode(material),
+            uv_transform,
             ..Default::default()
         }
     })
diff --git a/crates/bevy_pbr/src/pbr_material.rs b/crates/bevy_pbr/src/pbr_material.rs
index 25cb24fc14447..574468cc00053 100644
--- a/crates/bevy_pbr/src/pbr_material.rs
+++ b/crates/bevy_pbr/src/pbr_material.rs
@@ -1,5 +1,5 @@
 use bevy_asset::{Asset, Handle};
-use bevy_math::Vec4;
+use bevy_math::{Mat3, Vec4};
 use bevy_reflect::{std_traits::ReflectDefault, Reflect};
 use bevy_render::{
     color::Color, mesh::MeshVertexBufferLayout, render_asset::RenderAssets, render_resource::*,
@@ -472,6 +472,9 @@ pub struct StandardMaterial {
     /// Default is [`DEFAULT_PBR_DEFERRED_LIGHTING_PASS_ID`] for default
     /// PBR deferred lighting pass. Ignored in the case of forward materials.
     pub deferred_lighting_pass_id: u8,
+
+    /// Texture UV transform.
+    pub uv_transform: Mat3,
 }
 
 impl Default for StandardMaterial {
@@ -520,6 +523,7 @@ impl Default for StandardMaterial {
             parallax_mapping_method: ParallaxMappingMethod::Occlusion,
             opaque_render_method: OpaqueRendererMethod::Auto,
             deferred_lighting_pass_id: DEFAULT_PBR_DEFERRED_LIGHTING_PASS_ID,
+            uv_transform: Mat3::IDENTITY,
         }
     }
 }
@@ -632,6 +636,8 @@ pub struct StandardMaterialUniform {
     pub max_relief_mapping_search_steps: u32,
     /// ID for specifying which deferred lighting pass should be used for rendering this material, if any.
     pub deferred_lighting_pass_id: u32,
+    /// Texture UV transform.
+    pub uv_transform: Mat3,
 }
 
 impl AsBindGroupShaderType<StandardMaterialUniform> for StandardMaterial {
@@ -729,6 +735,7 @@ impl AsBindGroupShaderType<StandardMaterialUniform> for StandardMaterial {
             lightmap_exposure: self.lightmap_exposure,
             max_relief_mapping_search_steps: self.parallax_mapping_method.max_steps(),
             deferred_lighting_pass_id: self.deferred_lighting_pass_id as u32,
+            uv_transform: self.uv_transform,
         }
     }
 }
diff --git a/crates/bevy_pbr/src/render/pbr_fragment.wgsl b/crates/bevy_pbr/src/render/pbr_fragment.wgsl
index be759d38b573e..1b43d4a912cba 100644
--- a/crates/bevy_pbr/src/render/pbr_fragment.wgsl
+++ b/crates/bevy_pbr/src/render/pbr_fragment.wgsl
@@ -73,7 +73,7 @@ fn pbr_input_from_standard_material(
     let NdotV = max(dot(pbr_input.N, pbr_input.V), 0.0001);
 
 #ifdef VERTEX_UVS
-    var uv = in.uv;
+    var uv = (pbr_bindings::material.uv_transform * vec3(in.uv, 1.0)).xy;
 
 #ifdef VERTEX_TANGENTS
     if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_DEPTH_MAP_BIT) != 0u) {
diff --git a/crates/bevy_pbr/src/render/pbr_prepass_functions.wgsl b/crates/bevy_pbr/src/render/pbr_prepass_functions.wgsl
index 176c56aa1aba7..ee1bb45f3ebc0 100644
--- a/crates/bevy_pbr/src/render/pbr_prepass_functions.wgsl
+++ b/crates/bevy_pbr/src/render/pbr_prepass_functions.wgsl
@@ -18,8 +18,9 @@ fn prepass_alpha_discard(in: VertexOutput) {
     var output_color: vec4<f32> = pbr_bindings::material.base_color;
 
 #ifdef VERTEX_UVS
+    let uv = (pbr_bindings::material.uv_transform * vec3(in.uv, 1.0)).xy;
     if (pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_BASE_COLOR_TEXTURE_BIT) != 0u {
-        output_color = output_color * textureSampleBias(pbr_bindings::base_color_texture, pbr_bindings::base_color_sampler, in.uv, view.mip_bias);
+        output_color = output_color * textureSampleBias(pbr_bindings::base_color_texture, pbr_bindings::base_color_sampler, uv, view.mip_bias);
     }
 #endif // VERTEX_UVS
 
diff --git a/crates/bevy_pbr/src/render/pbr_types.wgsl b/crates/bevy_pbr/src/render/pbr_types.wgsl
index 72a70e45c840c..b90631380cefc 100644
--- a/crates/bevy_pbr/src/render/pbr_types.wgsl
+++ b/crates/bevy_pbr/src/render/pbr_types.wgsl
@@ -21,6 +21,7 @@ struct StandardMaterial {
     max_relief_mapping_search_steps: u32,
     /// ID for specifying which deferred lighting pass should be used for rendering this material, if any.
     deferred_lighting_pass_id: u32,
+    uv_transform: mat3x3<f32>,
 };
 
 // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@@ -74,6 +75,7 @@ fn standard_material_new() -> StandardMaterial {
     material.max_parallax_layer_count = 16.0;
     material.max_relief_mapping_search_steps = 5u;
     material.deferred_lighting_pass_id = 1u;
+    material.uv_transform = mat3x3<f32>(1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0);
 
     return material;
 }

From edbc37b6e9c84a2103ded146107163e6d7187f73 Mon Sep 17 00:00:00 2001
From: Jan Hohenheim <jan@hohenheim.ch>
Date: Fri, 16 Feb 2024 18:36:33 +0100
Subject: [PATCH 02/10] Refactor uv transform retrieval

---
 crates/bevy_gltf/src/loader.rs | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/crates/bevy_gltf/src/loader.rs b/crates/bevy_gltf/src/loader.rs
index 072076030c42e..f3845a026e6be 100644
--- a/crates/bevy_gltf/src/loader.rs
+++ b/crates/bevy_gltf/src/loader.rs
@@ -812,16 +812,16 @@ fn load_material(
 
         // TODO: handle missing label handle errors here?
         let color = pbr.base_color_factor();
-        let (base_color_texture, uv_transform) = pbr
+        let base_color_texture = pbr.base_color_texture().map(|info| {
+            // TODO: handle info.tex_coord() (the *set* index for the right texcoords)
+            texture_handle(load_context, &info.texture())
+        });
+
+        let uv_transform = pbr
             .base_color_texture()
-            .map(|info| {
-                // TODO: handle info.tex_coord() (the *set* index for the right texcoords)
-                let texture = texture_handle(load_context, &info.texture());
-                let uv_transform = info.texture_transform().map(texture_transform_mat3);
-                (texture, uv_transform)
-            })
-            .unzip();
-        let uv_transform = uv_transform.flatten().unwrap_or_default();
+            .map(|info| info.texture_transform().map(texture_transform_mat3))
+            .flatten()
+            .unwrap_or_default();
 
         let normal_map_texture: Option<Handle<Image>> =
             material.normal_texture().map(|normal_texture| {

From b9deafdd9e7b99b3dc7ec9f956f822edc0a4777c Mon Sep 17 00:00:00 2001
From: Jan Hohenheim <jan@hohenheim.ch>
Date: Fri, 16 Feb 2024 18:46:13 +0100
Subject: [PATCH 03/10] Improve error messages

---
 crates/bevy_gltf/src/loader.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/crates/bevy_gltf/src/loader.rs b/crates/bevy_gltf/src/loader.rs
index f3845a026e6be..c410cc3e4b648 100644
--- a/crates/bevy_gltf/src/loader.rs
+++ b/crates/bevy_gltf/src/loader.rs
@@ -833,7 +833,7 @@ fn load_material(
         let metallic_roughness_texture = pbr.metallic_roughness_texture().map(|info| {
             // TODO: handle info.tex_coord() (the *set* index for the right texcoords)
             if info.texture_transform().map(texture_transform_mat3) != Some(uv_transform) {
-                warn!("Only one texture transform is supported");
+                warn!("Only the texture transform on the base color texture is supported, ignoring the texture transform on the metallic/roughness texture");
             }
             texture_handle(load_context, &info.texture())
         });
@@ -849,7 +849,7 @@ fn load_material(
             // TODO: handle occlusion_texture.tex_coord() (the *set* index for the right texcoords)
             // TODO: handle occlusion_texture.strength() (a scalar multiplier for occlusion strength)
             if info.texture_transform().map(texture_transform_mat3) != Some(uv_transform) {
-                warn!("Only one texture transform is supported");
+                warn!("Only the texture transform on the base color texture is supported, ignoring the texture transform on the emissive texture");
             }
             texture_handle(load_context, &info.texture())
         });

From 51642f5b04843c32937ad7dad865bd29fe15bba2 Mon Sep 17 00:00:00 2001
From: Jan Hohenheim <jan@hohenheim.ch>
Date: Fri, 16 Feb 2024 18:50:43 +0100
Subject: [PATCH 04/10] Fix lint

---
 crates/bevy_gltf/src/loader.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/crates/bevy_gltf/src/loader.rs b/crates/bevy_gltf/src/loader.rs
index c410cc3e4b648..c67eca2151137 100644
--- a/crates/bevy_gltf/src/loader.rs
+++ b/crates/bevy_gltf/src/loader.rs
@@ -819,8 +819,7 @@ fn load_material(
 
         let uv_transform = pbr
             .base_color_texture()
-            .map(|info| info.texture_transform().map(texture_transform_mat3))
-            .flatten()
+            .and_then(|info| info.texture_transform().map(texture_transform_mat3))
             .unwrap_or_default();
 
         let normal_map_texture: Option<Handle<Image>> =

From 7298cdbe62891229c8e99edff358a51757ccc941 Mon Sep 17 00:00:00 2001
From: Jan Hohenheim <jan@hohenheim.ch>
Date: Sat, 17 Feb 2024 15:03:05 +0100
Subject: [PATCH 05/10] Use Affine2 instead of Mat3 and improve error messages

---
 crates/bevy_gltf/src/loader.rs      | 64 +++++++++++++++++++++--------
 crates/bevy_pbr/src/pbr_material.rs | 12 +++---
 2 files changed, 53 insertions(+), 23 deletions(-)

diff --git a/crates/bevy_gltf/src/loader.rs b/crates/bevy_gltf/src/loader.rs
index c67eca2151137..e0d32f8c0c39f 100644
--- a/crates/bevy_gltf/src/loader.rs
+++ b/crates/bevy_gltf/src/loader.rs
@@ -8,7 +8,7 @@ use bevy_ecs::entity::EntityHashMap;
 use bevy_ecs::{entity::Entity, world::World};
 use bevy_hierarchy::{BuildWorldChildren, WorldChildBuilder};
 use bevy_log::{error, warn};
-use bevy_math::{Mat3, Mat4, Vec3};
+use bevy_math::{Affine2, Mat4, Vec3};
 use bevy_pbr::{
     AlphaMode, DirectionalLight, DirectionalLightBundle, PbrBundle, PointLight, PointLightBundle,
     SpotLight, SpotLightBundle, StandardMaterial, MAX_JOINTS,
@@ -35,6 +35,7 @@ use bevy_scene::Scene;
 use bevy_tasks::IoTaskPool;
 use bevy_transform::components::Transform;
 use bevy_utils::{HashMap, HashSet};
+use gltf::texture::Info;
 use gltf::{
     accessor::Iter,
     mesh::{util::ReadIndices, Mode},
@@ -791,15 +792,6 @@ async fn load_image<'a, 'b>(
     }
 }
 
-/// Converts [`TextureTransform`] to [`Mat3`].
-fn texture_transform_mat3(texture_transform: TextureTransform) -> Mat3 {
-    Mat3::from_scale_angle_translation(
-        texture_transform.scale().into(),
-        -texture_transform.rotation(),
-        texture_transform.offset().into(),
-    )
-}
-
 /// Loads a glTF material as a bevy [`StandardMaterial`] and returns it.
 fn load_material(
     material: &Material,
@@ -819,7 +811,10 @@ fn load_material(
 
         let uv_transform = pbr
             .base_color_texture()
-            .and_then(|info| info.texture_transform().map(texture_transform_mat3))
+            .and_then(|info| {
+                info.texture_transform()
+                    .map(convert_texture_transform_to_affine2)
+            })
             .unwrap_or_default();
 
         let normal_map_texture: Option<Handle<Image>> =
@@ -831,9 +826,12 @@ fn load_material(
 
         let metallic_roughness_texture = pbr.metallic_roughness_texture().map(|info| {
             // TODO: handle info.tex_coord() (the *set* index for the right texcoords)
-            if info.texture_transform().map(texture_transform_mat3) != Some(uv_transform) {
-                warn!("Only the texture transform on the base color texture is supported, ignoring the texture transform on the metallic/roughness texture");
-            }
+            warn_on_differing_texture_transforms(
+                material,
+                &info,
+                uv_transform,
+                "metallic/roughness",
+            );
             texture_handle(load_context, &info.texture())
         });
 
@@ -847,9 +845,7 @@ fn load_material(
         let emissive_texture = material.emissive_texture().map(|info| {
             // TODO: handle occlusion_texture.tex_coord() (the *set* index for the right texcoords)
             // TODO: handle occlusion_texture.strength() (a scalar multiplier for occlusion strength)
-            if info.texture_transform().map(texture_transform_mat3) != Some(uv_transform) {
-                warn!("Only the texture transform on the base color texture is supported, ignoring the texture transform on the emissive texture");
-            }
+            warn_on_differing_texture_transforms(material, &info, uv_transform, "emissive");
             texture_handle(load_context, &info.texture())
         });
 
@@ -943,6 +939,40 @@ fn load_material(
     })
 }
 
+fn convert_texture_transform_to_affine2(texture_transform: TextureTransform) -> Affine2 {
+    Affine2::from_scale_angle_translation(
+        texture_transform.scale().into(),
+        -texture_transform.rotation(),
+        texture_transform.offset().into(),
+    )
+}
+
+fn warn_on_differing_texture_transforms(
+    material: &Material,
+    info: &Info,
+    texture_transform: Affine2,
+    texture_kind: &str,
+) {
+    let has_same_texture_transform = info
+        .texture_transform()
+        .map(convert_texture_transform_to_affine2)
+        == Some(texture_transform);
+    if !has_same_texture_transform {
+        let material_name = material
+            .name()
+            .map(|n| format!("the material \"{n}\""))
+            .unwrap_or_else(|| "an unnamed material".to_string());
+        let texture_name = info
+            .texture()
+            .name()
+            .map(|n| format!("its {texture_kind} texture \"{n}\""))
+            .unwrap_or_else(|| format!("its unnamed {texture_kind} texture"));
+        warn!(
+            "Only texture transforms on base color textures are supported, but {material_name} has a texture transform on {texture_name}, which will be ignored.",
+        );
+    }
+}
+
 /// Loads a glTF node.
 #[allow(clippy::too_many_arguments, clippy::result_large_err)]
 fn load_node(
diff --git a/crates/bevy_pbr/src/pbr_material.rs b/crates/bevy_pbr/src/pbr_material.rs
index 574468cc00053..5534ab3aef7d6 100644
--- a/crates/bevy_pbr/src/pbr_material.rs
+++ b/crates/bevy_pbr/src/pbr_material.rs
@@ -1,5 +1,5 @@
 use bevy_asset::{Asset, Handle};
-use bevy_math::{Mat3, Vec4};
+use bevy_math::{Affine2, Mat3, Vec4};
 use bevy_reflect::{std_traits::ReflectDefault, Reflect};
 use bevy_render::{
     color::Color, mesh::MeshVertexBufferLayout, render_asset::RenderAssets, render_resource::*,
@@ -473,8 +473,8 @@ pub struct StandardMaterial {
     /// PBR deferred lighting pass. Ignored in the case of forward materials.
     pub deferred_lighting_pass_id: u8,
 
-    /// Texture UV transform.
-    pub uv_transform: Mat3,
+    /// The transform applied to the UVs of the material before sampling. Default is identity.
+    pub uv_transform: Affine2,
 }
 
 impl Default for StandardMaterial {
@@ -523,7 +523,7 @@ impl Default for StandardMaterial {
             parallax_mapping_method: ParallaxMappingMethod::Occlusion,
             opaque_render_method: OpaqueRendererMethod::Auto,
             deferred_lighting_pass_id: DEFAULT_PBR_DEFERRED_LIGHTING_PASS_ID,
-            uv_transform: Mat3::IDENTITY,
+            uv_transform: Affine2::IDENTITY,
         }
     }
 }
@@ -636,7 +636,7 @@ pub struct StandardMaterialUniform {
     pub max_relief_mapping_search_steps: u32,
     /// ID for specifying which deferred lighting pass should be used for rendering this material, if any.
     pub deferred_lighting_pass_id: u32,
-    /// Texture UV transform.
+    /// The transform applied to the UVs of the material before sampling. Default is identity.
     pub uv_transform: Mat3,
 }
 
@@ -735,7 +735,7 @@ impl AsBindGroupShaderType<StandardMaterialUniform> for StandardMaterial {
             lightmap_exposure: self.lightmap_exposure,
             max_relief_mapping_search_steps: self.parallax_mapping_method.max_steps(),
             deferred_lighting_pass_id: self.deferred_lighting_pass_id as u32,
-            uv_transform: self.uv_transform,
+            uv_transform: self.uv_transform.into(),
         }
     }
 }

From 598452a55400c241a9e88c15e4e04dbce65c2516 Mon Sep 17 00:00:00 2001
From: Jan Hohenheim <jan@hohenheim.ch>
Date: Sat, 17 Feb 2024 15:54:48 +0100
Subject: [PATCH 06/10] Allow having no texture transform on non base color
 textures

---
 crates/bevy_gltf/src/loader.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/crates/bevy_gltf/src/loader.rs b/crates/bevy_gltf/src/loader.rs
index e0d32f8c0c39f..74d15b7f9e125 100644
--- a/crates/bevy_gltf/src/loader.rs
+++ b/crates/bevy_gltf/src/loader.rs
@@ -953,11 +953,11 @@ fn warn_on_differing_texture_transforms(
     texture_transform: Affine2,
     texture_kind: &str,
 ) {
-    let has_same_texture_transform = info
+    let has_differing_texture_transform = info
         .texture_transform()
         .map(convert_texture_transform_to_affine2)
-        == Some(texture_transform);
-    if !has_same_texture_transform {
+        .is_some_and(|t| t != texture_transform);
+    if has_differing_texture_transform {
         let material_name = material
             .name()
             .map(|n| format!("the material \"{n}\""))

From 47567f6faea1bf631ca0ed52134239b916746aca Mon Sep 17 00:00:00 2001
From: Jan Hohenheim <jan@hohenheim.ch>
Date: Sun, 18 Feb 2024 00:05:13 +0100
Subject: [PATCH 07/10] Report index on texture transform warnings

Co-authored-by: Kanabenki <lucien.menassol@gmail.com>
---
 crates/bevy_gltf/src/loader.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/crates/bevy_gltf/src/loader.rs b/crates/bevy_gltf/src/loader.rs
index 74d15b7f9e125..4b552591568c4 100644
--- a/crates/bevy_gltf/src/loader.rs
+++ b/crates/bevy_gltf/src/loader.rs
@@ -967,8 +967,13 @@ fn warn_on_differing_texture_transforms(
             .name()
             .map(|n| format!("its {texture_kind} texture \"{n}\""))
             .unwrap_or_else(|| format!("its unnamed {texture_kind} texture"));
+        let material_index = material
+            .index()
+            .map(|i| format!("index {i}"))
+            .unwrap_or_else(|| "default".to_string());
         warn!(
-            "Only texture transforms on base color textures are supported, but {material_name} has a texture transform on {texture_name}, which will be ignored.",
+            "Only texture transforms on base color textures are supported, but {material_name} ({material_index}) \
+            has a texture transform on {texture_name} (index {}), which will be ignored.", info.texture().index()
         );
     }
 }

From ed54b875ea601a94e2cb47f7a99096413f504abb Mon Sep 17 00:00:00 2001
From: Jan Hohenheim <jan@hohenheim.ch>
Date: Sun, 18 Feb 2024 00:06:58 +0100
Subject: [PATCH 08/10] Improve docs

---
 crates/bevy_pbr/src/pbr_material.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/crates/bevy_pbr/src/pbr_material.rs b/crates/bevy_pbr/src/pbr_material.rs
index 5534ab3aef7d6..0387feb942b2a 100644
--- a/crates/bevy_pbr/src/pbr_material.rs
+++ b/crates/bevy_pbr/src/pbr_material.rs
@@ -473,7 +473,7 @@ pub struct StandardMaterial {
     /// PBR deferred lighting pass. Ignored in the case of forward materials.
     pub deferred_lighting_pass_id: u8,
 
-    /// The transform applied to the UVs of the material before sampling. Default is identity.
+    /// The transform applied to the UVs corresponding to ATTRIBUTE_UV_0 on the mesh before sampling. Default is identity.
     pub uv_transform: Affine2,
 }
 
@@ -636,7 +636,7 @@ pub struct StandardMaterialUniform {
     pub max_relief_mapping_search_steps: u32,
     /// ID for specifying which deferred lighting pass should be used for rendering this material, if any.
     pub deferred_lighting_pass_id: u32,
-    /// The transform applied to the UVs of the material before sampling. Default is identity.
+    /// The transform applied to the UVs corresponding to ATTRIBUTE_UV_0 on the mesh before sampling. Default is identity.
     pub uv_transform: Mat3,
 }
 

From 2d40a37776b7636750eb3803f316252fc1eeb109 Mon Sep 17 00:00:00 2001
From: Jan Hohenheim <jan@hohenheim.ch>
Date: Tue, 20 Feb 2024 17:25:22 +0100
Subject: [PATCH 09/10] Optimize packing of standard material

---
 crates/bevy_pbr/src/pbr_material.rs           | 20 ++++++---
 .../bevy_pbr/src/render/mesh_functions.wgsl   |  6 +--
 crates/bevy_pbr/src/render/mesh_types.wgsl    |  2 +-
 crates/bevy_pbr/src/render/pbr_fragment.wgsl  |  4 +-
 .../src/render/pbr_prepass_functions.wgsl     |  4 +-
 crates/bevy_pbr/src/render/pbr_types.wgsl     | 43 ++++++++++---------
 crates/bevy_render/src/maths.wgsl             | 10 ++++-
 .../src/mesh2d/mesh2d_functions.wgsl          |  4 +-
 .../bevy_sprite/src/mesh2d/mesh2d_types.wgsl  |  2 +-
 crates/bevy_sprite/src/render/sprite.wgsl     |  4 +-
 10 files changed, 60 insertions(+), 39 deletions(-)

diff --git a/crates/bevy_pbr/src/pbr_material.rs b/crates/bevy_pbr/src/pbr_material.rs
index 0387feb942b2a..3c017fbc4be79 100644
--- a/crates/bevy_pbr/src/pbr_material.rs
+++ b/crates/bevy_pbr/src/pbr_material.rs
@@ -1,5 +1,5 @@
 use bevy_asset::{Asset, Handle};
-use bevy_math::{Affine2, Mat3, Vec4};
+use bevy_math::{Affine2, Vec2, Vec4};
 use bevy_reflect::{std_traits::ReflectDefault, Reflect};
 use bevy_render::{
     color::Color, mesh::MeshVertexBufferLayout, render_asset::RenderAssets, render_resource::*,
@@ -594,9 +594,17 @@ pub struct StandardMaterialUniform {
     /// Doubles as diffuse albedo for non-metallic, specular for metallic and a mix for everything
     /// in between.
     pub base_color: Vec4,
-    // Use a color for user friendliness even though we technically don't use the alpha channel
+    // Use a color for user-friendliness even though we technically don't use the alpha channel
     // Might be used in the future for exposure correction in HDR
     pub emissive: Vec4,
+    /// Color white light takes after travelling through the attenuation distance underneath the material surface
+    pub attenuation_color: Vec4,
+    /// The x-axis of the mat2 of the transform applied to the UVs corresponding to ATTRIBUTE_UV_0 on the mesh before sampling. Default is [1, 0].
+    pub uv_transform_x_axis: Vec2,
+    /// The y-axis of the mat2 of the transform applied to the UVs corresponding to ATTRIBUTE_UV_0 on the mesh before sampling. Default is [0, 1].
+    pub uv_transform_y_axis: Vec2,
+    /// The translation of the transform applied to the UVs corresponding to ATTRIBUTE_UV_0 on the mesh before sampling. Default is [0, 0].
+    pub uv_transform_translation: Vec2,
     /// Linear perceptual roughness, clamped to [0.089, 1.0] in the shader
     /// Defaults to minimum of 0.089
     pub roughness: f32,
@@ -615,8 +623,6 @@ pub struct StandardMaterialUniform {
     pub ior: f32,
     /// How far light travels through the volume underneath the material surface before being absorbed
     pub attenuation_distance: f32,
-    /// Color white light takes after travelling through the attenuation distance underneath the material surface
-    pub attenuation_color: Vec4,
     /// The [`StandardMaterialFlags`] accessible in the `wgsl` shader.
     pub flags: u32,
     /// When the alpha mode mask flag is set, any base color alpha above this cutoff means fully opaque,
@@ -636,8 +642,6 @@ pub struct StandardMaterialUniform {
     pub max_relief_mapping_search_steps: u32,
     /// ID for specifying which deferred lighting pass should be used for rendering this material, if any.
     pub deferred_lighting_pass_id: u32,
-    /// The transform applied to the UVs corresponding to ATTRIBUTE_UV_0 on the mesh before sampling. Default is identity.
-    pub uv_transform: Mat3,
 }
 
 impl AsBindGroupShaderType<StandardMaterialUniform> for StandardMaterial {
@@ -735,7 +739,9 @@ impl AsBindGroupShaderType<StandardMaterialUniform> for StandardMaterial {
             lightmap_exposure: self.lightmap_exposure,
             max_relief_mapping_search_steps: self.parallax_mapping_method.max_steps(),
             deferred_lighting_pass_id: self.deferred_lighting_pass_id as u32,
-            uv_transform: self.uv_transform.into(),
+            uv_transform_x_axis: self.uv_transform.matrix2.x_axis,
+            uv_transform_y_axis: self.uv_transform.matrix2.y_axis,
+            uv_transform_translation: self.uv_transform.translation,
         }
     }
 }
diff --git a/crates/bevy_pbr/src/render/mesh_functions.wgsl b/crates/bevy_pbr/src/render/mesh_functions.wgsl
index 170c2f916ae26..e94b4f763306d 100644
--- a/crates/bevy_pbr/src/render/mesh_functions.wgsl
+++ b/crates/bevy_pbr/src/render/mesh_functions.wgsl
@@ -6,15 +6,15 @@
     mesh_types::MESH_FLAGS_SIGN_DETERMINANT_MODEL_3X3_BIT,
     view_transformations::position_world_to_clip,
 }
-#import bevy_render::maths::{affine_to_square, mat2x4_f32_to_mat3x3_unpack}
+#import bevy_render::maths::{affine3_to_square, mat2x4_f32_to_mat3x3_unpack}
 
 
 fn get_model_matrix(instance_index: u32) -> mat4x4<f32> {
-    return affine_to_square(mesh[instance_index].model);
+    return affine3_to_square(mesh[instance_index].model);
 }
 
 fn get_previous_model_matrix(instance_index: u32) -> mat4x4<f32> {
-    return affine_to_square(mesh[instance_index].previous_model);
+    return affine3_to_square(mesh[instance_index].previous_model);
 }
 
 fn mesh_position_local_to_world(model: mat4x4<f32>, vertex_position: vec4<f32>) -> vec4<f32> {
diff --git a/crates/bevy_pbr/src/render/mesh_types.wgsl b/crates/bevy_pbr/src/render/mesh_types.wgsl
index 89b73be2bd6f1..6580941c96acd 100644
--- a/crates/bevy_pbr/src/render/mesh_types.wgsl
+++ b/crates/bevy_pbr/src/render/mesh_types.wgsl
@@ -2,7 +2,7 @@
 
 struct Mesh {
     // Affine 4x3 matrices transposed to 3x4
-    // Use bevy_render::maths::affine_to_square to unpack
+    // Use bevy_render::maths::affine3_to_square to unpack
     model: mat3x4<f32>,
     previous_model: mat3x4<f32>,
     lightmap_uv_rect: vec2<u32>,
diff --git a/crates/bevy_pbr/src/render/pbr_fragment.wgsl b/crates/bevy_pbr/src/render/pbr_fragment.wgsl
index 1b43d4a912cba..b484e9691a879 100644
--- a/crates/bevy_pbr/src/render/pbr_fragment.wgsl
+++ b/crates/bevy_pbr/src/render/pbr_fragment.wgsl
@@ -11,6 +11,7 @@
     parallax_mapping::parallaxed_uv,
     lightmap::lightmap,
 }
+#import bevy_render::maths::affine2_to_square
 
 #ifdef SCREEN_SPACE_AMBIENT_OCCLUSION
 #import bevy_pbr::mesh_view_bindings::screen_space_ambient_occlusion_texture
@@ -73,7 +74,8 @@ fn pbr_input_from_standard_material(
     let NdotV = max(dot(pbr_input.N, pbr_input.V), 0.0001);
 
 #ifdef VERTEX_UVS
-    var uv = (pbr_bindings::material.uv_transform * vec3(in.uv, 1.0)).xy;
+    let uv_transform = affine2_to_square(pbr_bindings::material.uv_transform);
+    var uv = (uv_transform * vec3(in.uv, 1.0)).xy;
 
 #ifdef VERTEX_TANGENTS
     if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_DEPTH_MAP_BIT) != 0u) {
diff --git a/crates/bevy_pbr/src/render/pbr_prepass_functions.wgsl b/crates/bevy_pbr/src/render/pbr_prepass_functions.wgsl
index ee1bb45f3ebc0..7a8dbb8a19d7e 100644
--- a/crates/bevy_pbr/src/render/pbr_prepass_functions.wgsl
+++ b/crates/bevy_pbr/src/render/pbr_prepass_functions.wgsl
@@ -7,6 +7,7 @@
     pbr_bindings,
     pbr_types,
 }
+#import bevy_render::maths::affine2_to_square
 
 // Cutoff used for the premultiplied alpha modes BLEND and ADD.
 const PREMULTIPLIED_ALPHA_CUTOFF = 0.05;
@@ -18,7 +19,8 @@ fn prepass_alpha_discard(in: VertexOutput) {
     var output_color: vec4<f32> = pbr_bindings::material.base_color;
 
 #ifdef VERTEX_UVS
-    let uv = (pbr_bindings::material.uv_transform * vec3(in.uv, 1.0)).xy;
+    let uv_transform = affine2_to_square(pbr_bindings::material.uv_transform);
+    let uv = (uv_transform * vec3(in.uv, 1.0)).xy;
     if (pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_BASE_COLOR_TEXTURE_BIT) != 0u {
         output_color = output_color * textureSampleBias(pbr_bindings::base_color_texture, pbr_bindings::base_color_sampler, uv, view.mip_bias);
     }
diff --git a/crates/bevy_pbr/src/render/pbr_types.wgsl b/crates/bevy_pbr/src/render/pbr_types.wgsl
index b90631380cefc..f3fc79a30c835 100644
--- a/crates/bevy_pbr/src/render/pbr_types.wgsl
+++ b/crates/bevy_pbr/src/render/pbr_types.wgsl
@@ -1,27 +1,29 @@
 #define_import_path bevy_pbr::pbr_types
 
+// Alignments and sizes taken from <https://www.w3.org/TR/WGSL/#alignment-and-size>.
+// Since this is a hot path, try to keep the alignment and size of the struct members in mind.
 struct StandardMaterial {
-    base_color: vec4<f32>,
-    emissive: vec4<f32>,
-    perceptual_roughness: f32,
-    metallic: f32,
-    reflectance: f32,
-    diffuse_transmission: f32,
-    specular_transmission: f32,
-    thickness: f32,
-    ior: f32,
-    attenuation_distance: f32,
-    attenuation_color: vec4<f32>,
+    base_color: vec4<f32>, // alignment 16, size 16
+    emissive: vec4<f32>, // alignment 16, size 16
+    attenuation_color: vec4<f32>, // alignment 16, size 16
+    uv_transform: mat3x2<f32>, // alignment 8, size 24
+    perceptual_roughness: f32, // alignment 4, size 4
+    metallic: f32, // alignment 4, size 4
+    reflectance: f32, // alignment 4, size 4
+    diffuse_transmission: f32, // alignment 4, size 4
+    specular_transmission: f32, // alignment 4, size 4
+    thickness: f32, // alignment 4, size 4
+    ior: f32, // alignment 4, size 4
+    attenuation_distance: f32, // alignment 4, size 4
     // 'flags' is a bit field indicating various options. u32 is 32 bits so we have up to 32 options.
-    flags: u32,
-    alpha_cutoff: f32,
-    parallax_depth_scale: f32,
-    max_parallax_layer_count: f32,
-    lightmap_exposure: f32,
-    max_relief_mapping_search_steps: u32,
+    flags: u32, // alignment 4, size 4
+    alpha_cutoff: f32, // alignment 4, size 4
+    parallax_depth_scale: f32, // alignment 4, size 4
+    max_parallax_layer_count: f32, // alignment 4, size 4
+    lightmap_exposure: f32, // alignment 4, size 4
+    max_relief_mapping_search_steps: u32, // alignment 4, size 4
     /// ID for specifying which deferred lighting pass should be used for rendering this material, if any.
-    deferred_lighting_pass_id: u32,
-    uv_transform: mat3x3<f32>,
+    deferred_lighting_pass_id: u32, // alignment 4, size 4
 };
 
 // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@@ -75,7 +77,8 @@ fn standard_material_new() -> StandardMaterial {
     material.max_parallax_layer_count = 16.0;
     material.max_relief_mapping_search_steps = 5u;
     material.deferred_lighting_pass_id = 1u;
-    material.uv_transform = mat3x3<f32>(1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0);
+    // scale 1, translation 0, rotation 0
+    material.uv_transform = mat3x2<f32>(1.0, 0.0, 0.0, 1.0, 0.0, 0.0);
 
     return material;
 }
diff --git a/crates/bevy_render/src/maths.wgsl b/crates/bevy_render/src/maths.wgsl
index af79c88c9a150..17d045154a317 100644
--- a/crates/bevy_render/src/maths.wgsl
+++ b/crates/bevy_render/src/maths.wgsl
@@ -1,6 +1,14 @@
 #define_import_path bevy_render::maths
 
-fn affine_to_square(affine: mat3x4<f32>) -> mat4x4<f32> {
+fn affine2_to_square(affine: mat3x2<f32>) -> mat3x3<f32> {
+    return mat3x3<f32>(
+        vec3<f32>(affine[0].xy, 0.0),
+        vec3<f32>(affine[1].xy, 0.0),
+        vec3<f32>(affine[2].xy, 1.0),
+    );
+}
+
+fn affine3_to_square(affine: mat3x4<f32>) -> mat4x4<f32> {
     return transpose(mat4x4<f32>(
         affine[0],
         affine[1],
diff --git a/crates/bevy_sprite/src/mesh2d/mesh2d_functions.wgsl b/crates/bevy_sprite/src/mesh2d/mesh2d_functions.wgsl
index b66b34e88896d..d76a88ab03832 100644
--- a/crates/bevy_sprite/src/mesh2d/mesh2d_functions.wgsl
+++ b/crates/bevy_sprite/src/mesh2d/mesh2d_functions.wgsl
@@ -4,10 +4,10 @@
     mesh2d_view_bindings::view,
     mesh2d_bindings::mesh,
 }
-#import bevy_render::maths::{affine_to_square, mat2x4_f32_to_mat3x3_unpack}
+#import bevy_render::maths::{affine3_to_square, mat2x4_f32_to_mat3x3_unpack}
 
 fn get_model_matrix(instance_index: u32) -> mat4x4<f32> {
-    return affine_to_square(mesh[instance_index].model);
+    return affine3_to_square(mesh[instance_index].model);
 }
 
 fn mesh2d_position_local_to_world(model: mat4x4<f32>, vertex_position: vec4<f32>) -> vec4<f32> {
diff --git a/crates/bevy_sprite/src/mesh2d/mesh2d_types.wgsl b/crates/bevy_sprite/src/mesh2d/mesh2d_types.wgsl
index f855707790001..4b14b919f3a26 100644
--- a/crates/bevy_sprite/src/mesh2d/mesh2d_types.wgsl
+++ b/crates/bevy_sprite/src/mesh2d/mesh2d_types.wgsl
@@ -2,7 +2,7 @@
 
 struct Mesh2d {
     // Affine 4x3 matrix transposed to 3x4
-    // Use bevy_render::maths::affine_to_square to unpack
+    // Use bevy_render::maths::affine3_to_square to unpack
     model: mat3x4<f32>,
     // 3x3 matrix packed in mat2x4 and f32 as:
     // [0].xyz, [1].x,
diff --git a/crates/bevy_sprite/src/render/sprite.wgsl b/crates/bevy_sprite/src/render/sprite.wgsl
index 1f5c0125e17ae..48f0235155856 100644
--- a/crates/bevy_sprite/src/render/sprite.wgsl
+++ b/crates/bevy_sprite/src/render/sprite.wgsl
@@ -3,7 +3,7 @@
 #endif
 
 #import bevy_render::{
-    maths::affine_to_square,
+    maths::affine3_to_square,
     view::View,
 }
 
@@ -37,7 +37,7 @@ fn vertex(in: VertexInput) -> VertexOutput {
         0.0
     );
 
-    out.clip_position = view.view_proj * affine_to_square(mat3x4<f32>(
+    out.clip_position = view.view_proj * affine3_to_square(mat3x4<f32>(
         in.i_model_transpose_col0,
         in.i_model_transpose_col1,
         in.i_model_transpose_col2,

From 6c4297ba4ff3c00865f5d3a67116f9eca4a152a1 Mon Sep 17 00:00:00 2001
From: Jan Hohenheim <jan@hohenheim.ch>
Date: Tue, 20 Feb 2024 17:33:14 +0100
Subject: [PATCH 10/10] Remove comment noise

---
 crates/bevy_pbr/src/render/pbr_types.wgsl | 40 +++++++++++------------
 1 file changed, 20 insertions(+), 20 deletions(-)

diff --git a/crates/bevy_pbr/src/render/pbr_types.wgsl b/crates/bevy_pbr/src/render/pbr_types.wgsl
index f3fc79a30c835..c08245034c222 100644
--- a/crates/bevy_pbr/src/render/pbr_types.wgsl
+++ b/crates/bevy_pbr/src/render/pbr_types.wgsl
@@ -1,29 +1,29 @@
 #define_import_path bevy_pbr::pbr_types
 
-// Alignments and sizes taken from <https://www.w3.org/TR/WGSL/#alignment-and-size>.
 // Since this is a hot path, try to keep the alignment and size of the struct members in mind.
+// You can find the alignment and sizes at <https://www.w3.org/TR/WGSL/#alignment-and-size>.
 struct StandardMaterial {
-    base_color: vec4<f32>, // alignment 16, size 16
-    emissive: vec4<f32>, // alignment 16, size 16
-    attenuation_color: vec4<f32>, // alignment 16, size 16
-    uv_transform: mat3x2<f32>, // alignment 8, size 24
-    perceptual_roughness: f32, // alignment 4, size 4
-    metallic: f32, // alignment 4, size 4
-    reflectance: f32, // alignment 4, size 4
-    diffuse_transmission: f32, // alignment 4, size 4
-    specular_transmission: f32, // alignment 4, size 4
-    thickness: f32, // alignment 4, size 4
-    ior: f32, // alignment 4, size 4
-    attenuation_distance: f32, // alignment 4, size 4
+    base_color: vec4<f32>,
+    emissive: vec4<f32>,
+    attenuation_color: vec4<f32>,
+    uv_transform: mat3x2<f32>,
+    perceptual_roughness: f32,
+    metallic: f32,
+    reflectance: f32,
+    diffuse_transmission: f32,
+    specular_transmission: f32,
+    thickness: f32,
+    ior: f32,
+    attenuation_distance: f32,
     // 'flags' is a bit field indicating various options. u32 is 32 bits so we have up to 32 options.
-    flags: u32, // alignment 4, size 4
-    alpha_cutoff: f32, // alignment 4, size 4
-    parallax_depth_scale: f32, // alignment 4, size 4
-    max_parallax_layer_count: f32, // alignment 4, size 4
-    lightmap_exposure: f32, // alignment 4, size 4
-    max_relief_mapping_search_steps: u32, // alignment 4, size 4
+    flags: u32,
+    alpha_cutoff: f32,
+    parallax_depth_scale: f32,
+    max_parallax_layer_count: f32,
+    lightmap_exposure: f32,
+    max_relief_mapping_search_steps: u32,
     /// ID for specifying which deferred lighting pass should be used for rendering this material, if any.
-    deferred_lighting_pass_id: u32, // alignment 4, size 4
+    deferred_lighting_pass_id: u32,
 };
 
 // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!