Add support for KHR_texture_transform

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",

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,
@@ -808,6 +817,11 @@ fn load_material(
             texture_handle(load_context, &info.texture())
         });
 
+        let uv_transform = pbr
+            .base_color_texture()
+            .and_then(|info| info.texture_transform().map(texture_transform_mat3))
+            .unwrap_or_default();
+
         let normal_map_texture: Option<Handle<Image>> =
             material.normal_texture().map(|normal_texture| {
                 // TODO: handle normal_texture.scale
@@ -817,6 +831,9 @@ 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 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())
         });
 
@@ -830,6 +847,9 @@ 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 the texture transform on the base color texture is supported, ignoring the texture transform on the emissive texture");
+            }
             texture_handle(load_context, &info.texture())
         });
 
@@ -917,6 +937,7 @@ fn load_material(
             ),
             unlit: material.unlit(),
             alpha_mode: alpha_mode(material),
+            uv_transform,
             ..Default::default()
         }
     })

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,
         }
     }
 }

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) {

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
 

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;
 }