Added feature switch to default Standard Material's new anisotropy texture to off (#14048)

# Objective

- Standard Material is starting to run out of samplers (currently uses
13 with no additional features off, I think in 0.13 it was 12).
- This change adds a new feature switch, modelled on the other ones
which add features to Standard Material, to turn off the new anisotropy
feature by default.

## Solution

- feature + texture define

## Testing

- Anisotropy example still works fine
- Other samples work fine
- Standard Material now takes 12 samplers by default on my Mac instead
of 13

## Migration Guide

- Add feature pbr_anisotropy_texture if you are using that texture in
any standard materials.

---------

Co-authored-by: John Payne <20407779+johngpayne@users.noreply.github.com>

Cargo.toml

@@ -318,6 +318,9 @@ pbr_multi_layer_material_textures = [
   "bevy_internal/pbr_multi_layer_material_textures",
 ]
 
+# Enable support for anisotropy texture in the `StandardMaterial`, at the risk of blowing past the global, per-shader texture limit on older/lower-end GPUs
+pbr_anisotropy_texture = ["bevy_internal/pbr_anisotropy_texture"]
+
 # Enable some limitations to be able to use WebGL2. Please refer to the [WebGL2 and WebGPU](https://github.com/bevyengine/bevy/tree/latest/examples#webgl2-and-webgpu) section of the examples README for more information on how to run Wasm builds with WebGPU.
 webgl2 = ["bevy_internal/webgl"]
 
@@ -3239,7 +3242,7 @@ wasm = true
 name = "anisotropy"
 path = "examples/3d/anisotropy.rs"
 doc-scrape-examples = true
-required-features = ["jpeg"]
+required-features = ["jpeg", "pbr_anisotropy_texture"]
 
 [package.metadata.example.anisotropy]
 name = "Anisotropy"

crates/bevy_gltf/Cargo.toml

@@ -12,6 +12,7 @@ keywords = ["bevy"]
 dds = ["bevy_render/dds"]
 pbr_transmission_textures = ["bevy_pbr/pbr_transmission_textures"]
 pbr_multi_layer_material_textures = []
+pbr_anisotropy_texture = []
 
 [dependencies]
 # bevy

crates/bevy_gltf/src/loader.rs

@@ -1099,7 +1099,9 @@ fn load_material(
             clearcoat_normal_texture: clearcoat.clearcoat_normal_texture,
             anisotropy_strength: anisotropy.anisotropy_strength.unwrap_or_default() as f32,
             anisotropy_rotation: anisotropy.anisotropy_rotation.unwrap_or_default() as f32,
+            #[cfg(feature = "pbr_anisotropy_texture")]
             anisotropy_channel: anisotropy.anisotropy_channel,
+            #[cfg(feature = "pbr_anisotropy_texture")]
             anisotropy_texture: anisotropy.anisotropy_texture,
             ..Default::default()
         }
@@ -1910,11 +1912,14 @@ impl ClearcoatExtension {
 struct AnisotropyExtension {
     anisotropy_strength: Option<f64>,
     anisotropy_rotation: Option<f64>,
+    #[cfg(feature = "pbr_anisotropy_texture")]
     anisotropy_channel: UvChannel,
+    #[cfg(feature = "pbr_anisotropy_texture")]
     anisotropy_texture: Option<Handle<Image>>,
 }
 
 impl AnisotropyExtension {
+    #[allow(unused_variables)]
     fn parse(
         load_context: &mut LoadContext,
         document: &Document,
@@ -1925,6 +1930,7 @@ impl AnisotropyExtension {
             .get("KHR_materials_anisotropy")?
             .as_object()?;
 
+        #[cfg(feature = "pbr_anisotropy_texture")]
         let (anisotropy_channel, anisotropy_texture) = extension
             .get("anisotropyTexture")
             .and_then(|value| value::from_value::<json::texture::Info>(value.clone()).ok())
@@ -1939,7 +1945,9 @@ impl AnisotropyExtension {
         Some(AnisotropyExtension {
             anisotropy_strength: extension.get("anisotropyStrength").and_then(Value::as_f64),
             anisotropy_rotation: extension.get("anisotropyRotation").and_then(Value::as_f64),
+            #[cfg(feature = "pbr_anisotropy_texture")]
             anisotropy_channel: anisotropy_channel.unwrap_or_default(),
+            #[cfg(feature = "pbr_anisotropy_texture")]
             anisotropy_texture,
         })
     }

crates/bevy_internal/Cargo.toml

@@ -111,6 +111,12 @@ pbr_multi_layer_material_textures = [
   "bevy_gltf?/pbr_multi_layer_material_textures",
 ]
 
+# Anisotropy texture in `StandardMaterial`:
+pbr_anisotropy_texture = [
+  "bevy_pbr?/pbr_anisotropy_texture",
+  "bevy_gltf?/pbr_anisotropy_texture",
+]
+
 # Optimise for WebGL2
 webgl = [
   "bevy_core_pipeline?/webgl",

crates/bevy_pbr/Cargo.toml

@@ -13,6 +13,7 @@ webgl = []
 webgpu = []
 pbr_transmission_textures = []
 pbr_multi_layer_material_textures = []
+pbr_anisotropy_texture = []
 shader_format_glsl = ["bevy_render/shader_format_glsl"]
 trace = ["bevy_render/trace"]
 ios_simulator = ["bevy_render/ios_simulator"]

crates/bevy_pbr/src/pbr_material.rs

@@ -215,8 +215,8 @@ pub struct StandardMaterial {
     ///
     /// **Important:** The [`StandardMaterial::diffuse_transmission`] property must be set to a value higher than 0.0,
     /// or this texture won't have any effect.
-    #[texture(19)]
-    #[sampler(20)]
+    #[cfg_attr(feature = "pbr_transmission_textures", texture(19))]
+    #[cfg_attr(feature = "pbr_transmission_textures", sampler(20))]
     #[cfg(feature = "pbr_transmission_textures")]
     pub diffuse_transmission_texture: Option<Handle<Image>>,
 
@@ -256,8 +256,8 @@ pub struct StandardMaterial {
     ///
     /// **Important:** The [`StandardMaterial::specular_transmission`] property must be set to a value higher than 0.0,
     /// or this texture won't have any effect.
-    #[texture(15)]
-    #[sampler(16)]
+    #[cfg_attr(feature = "pbr_transmission_textures", texture(15))]
+    #[cfg_attr(feature = "pbr_transmission_textures", sampler(16))]
     #[cfg(feature = "pbr_transmission_textures")]
     pub specular_transmission_texture: Option<Handle<Image>>,
 
@@ -285,8 +285,8 @@ pub struct StandardMaterial {
     ///
     /// **Important:** The [`StandardMaterial::thickness`] property must be set to a value higher than 0.0,
     /// or this texture won't have any effect.
-    #[texture(17)]
-    #[sampler(18)]
+    #[cfg_attr(feature = "pbr_transmission_textures", texture(17))]
+    #[cfg_attr(feature = "pbr_transmission_textures", sampler(18))]
     #[cfg(feature = "pbr_transmission_textures")]
     pub thickness_texture: Option<Handle<Image>>,
 
@@ -420,8 +420,8 @@ pub struct StandardMaterial {
     /// main [`StandardMaterial::clearcoat`] factor.
     ///
     /// As this is a non-color map, it must not be loaded as sRGB.
-    #[texture(21)]
-    #[sampler(22)]
+    #[cfg_attr(feature = "pbr_multi_layer_material_textures", texture(21))]
+    #[cfg_attr(feature = "pbr_multi_layer_material_textures", sampler(22))]
     #[cfg(feature = "pbr_multi_layer_material_textures")]
     pub clearcoat_texture: Option<Handle<Image>>,
 
@@ -445,8 +445,8 @@ pub struct StandardMaterial {
     /// [`StandardMaterial::clearcoat_perceptual_roughness`] factor.
     ///
     /// As this is a non-color map, it must not be loaded as sRGB.
-    #[texture(23)]
-    #[sampler(24)]
+    #[cfg_attr(feature = "pbr_multi_layer_material_textures", texture(23))]
+    #[cfg_attr(feature = "pbr_multi_layer_material_textures", sampler(24))]
     #[cfg(feature = "pbr_multi_layer_material_textures")]
     pub clearcoat_roughness_texture: Option<Handle<Image>>,
 
@@ -467,8 +467,8 @@ pub struct StandardMaterial {
     /// in both [`StandardMaterial::normal_map_texture`] and this field.
     ///
     /// As this is a non-color map, it must not be loaded as sRGB.
-    #[texture(25)]
-    #[sampler(26)]
+    #[cfg_attr(feature = "pbr_multi_layer_material_textures", texture(25))]
+    #[cfg_attr(feature = "pbr_multi_layer_material_textures", sampler(26))]
     #[cfg(feature = "pbr_multi_layer_material_textures")]
     pub clearcoat_normal_texture: Option<Handle<Image>>,
 
@@ -513,6 +513,7 @@ pub struct StandardMaterial {
     /// The UV channel to use for the [`StandardMaterial::anisotropy_texture`].
     ///
     /// Defaults to [`UvChannel::Uv0`].
+    #[cfg(feature = "pbr_anisotropy_texture")]
     pub anisotropy_channel: UvChannel,
 
     /// An image texture that allows the
@@ -536,8 +537,9 @@ pub struct StandardMaterial {
     ///
     /// [`KHR_materials_anisotropy` specification]:
     /// https://github.com/KhronosGroup/glTF/blob/main/extensions/2.0/Khronos/KHR_materials_anisotropy/README.md
-    #[texture(13)]
-    #[sampler(14)]
+    #[cfg_attr(feature = "pbr_anisotropy_texture", texture(13))]
+    #[cfg_attr(feature = "pbr_anisotropy_texture", sampler(14))]
+    #[cfg(feature = "pbr_anisotropy_texture")]
     pub anisotropy_texture: Option<Handle<Image>>,
 
     /// Support two-sided lighting by automatically flipping the normals for "back" faces
@@ -814,7 +816,9 @@ impl Default for StandardMaterial {
             clearcoat_normal_texture: None,
             anisotropy_strength: 0.0,
             anisotropy_rotation: 0.0,
+            #[cfg(feature = "pbr_anisotropy_texture")]
             anisotropy_channel: UvChannel::Uv0,
+            #[cfg(feature = "pbr_anisotropy_texture")]
             anisotropy_texture: None,
             flip_normal_map_y: false,
             double_sided: false,
@@ -999,8 +1003,11 @@ impl AsBindGroupShaderType<StandardMaterialUniform> for StandardMaterial {
             }
         }
 
-        if self.anisotropy_texture.is_some() {
-            flags |= StandardMaterialFlags::ANISOTROPY_TEXTURE;
+        #[cfg(feature = "pbr_anisotropy_texture")]
+        {
+            if self.anisotropy_texture.is_some() {
+                flags |= StandardMaterialFlags::ANISOTROPY_TEXTURE;
+            }
         }
 
         #[cfg(feature = "pbr_multi_layer_material_textures")]
@@ -1207,10 +1214,14 @@ impl From<&StandardMaterial> for StandardMaterialKey {
             StandardMaterialKey::NORMAL_MAP_UV,
             material.normal_map_channel != UvChannel::Uv0,
         );
-        key.set(
-            StandardMaterialKey::ANISOTROPY_UV,
-            material.anisotropy_channel != UvChannel::Uv0,
-        );
+
+        #[cfg(feature = "pbr_anisotropy_texture")]
+        {
+            key.set(
+                StandardMaterialKey::ANISOTROPY_UV,
+                material.anisotropy_channel != UvChannel::Uv0,
+            );
+        }
 
         #[cfg(feature = "pbr_multi_layer_material_textures")]
         {

crates/bevy_pbr/src/render/mesh.rs

@@ -1642,6 +1642,9 @@ impl SpecializedMeshPipeline for MeshPipeline {
         if cfg!(feature = "pbr_multi_layer_material_textures") {
             shader_defs.push("PBR_MULTI_LAYER_MATERIAL_TEXTURES_SUPPORTED".into());
         }
+        if cfg!(feature = "pbr_anisotropy_texture") {
+            shader_defs.push("PBR_ANISOTROPY_TEXTURE_SUPPORTED".into());
+        }
 
         let mut bind_group_layout = vec![self.get_view_layout(key.into()).clone()];
 

crates/bevy_pbr/src/render/pbr_bindings.wgsl

@@ -15,8 +15,10 @@
 @group(2) @binding(10) var normal_map_sampler: sampler;
 @group(2) @binding(11) var depth_map_texture: texture_2d<f32>;
 @group(2) @binding(12) var depth_map_sampler: sampler;
+#ifdef PBR_ANISOTROPY_TEXTURE_SUPPORTED
 @group(2) @binding(13) var anisotropy_texture: texture_2d<f32>;
 @group(2) @binding(14) var anisotropy_sampler: sampler;
+#endif
 #ifdef PBR_TRANSMISSION_TEXTURES_SUPPORTED
 @group(2) @binding(15) var specular_transmission_texture: texture_2d<f32>;
 @group(2) @binding(16) var specular_transmission_sampler: sampler;

crates/bevy_pbr/src/render/pbr_fragment.wgsl

@@ -420,6 +420,7 @@ fn pbr_input_from_standard_material(
         //
         // This code comes from the `KHR_materials_anisotropy` spec:
         // <https://github.com/KhronosGroup/glTF/blob/main/extensions/2.0/Khronos/KHR_materials_anisotropy/README.md#individual-lights>
+#ifdef PBR_ANISOTROPY_TEXTURE_SUPPORTED
 #ifdef VERTEX_TANGENTS
 #ifdef STANDARD_MATERIAL_ANISOTROPY
 
@@ -456,6 +457,7 @@ fn pbr_input_from_standard_material(
 
 #endif  // STANDARD_MATERIAL_ANISOTROPY
 #endif  // VERTEX_TANGENTS
+#endif  // PBR_ANISOTROPY_TEXTURE_SUPPORTED
 
 #endif  // LOAD_PREPASS_NORMALS
 

docs/cargo_features.md

@@ -71,6 +71,7 @@ The default feature set enables most of the expected features of a game engine,
 |meshlet_processor|Enables processing meshes into meshlet meshes for bevy_pbr|
 |minimp3|MP3 audio format support (through minimp3)|
 |mp3|MP3 audio format support|
+|pbr_anisotropy_texture|Enable support for anisotropy texture in the `StandardMaterial`, at the risk of blowing past the global, per-shader texture limit on older/lower-end GPUs|
 |pbr_multi_layer_material_textures|Enable support for multi-layer material textures in the `StandardMaterial`, at the risk of blowing past the global, per-shader texture limit on older/lower-end GPUs|
 |pbr_transmission_textures|Enable support for transmission-related textures in the `StandardMaterial`, at the risk of blowing past the global, per-shader texture limit on older/lower-end GPUs|
 |pnm|PNM image format support, includes pam, pbm, pgm and ppm|