add emissive exposure weight to standard material

bevyengine · May 15, 2024 · 6641f59 · 6641f59
1 parent f91fd32
commit 6641f59
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Showing 3 changed files with 16 additions and 4 deletions.
diff --git a/crates/bevy_pbr/src/pbr_material.rs b/crates/bevy_pbr/src/pbr_material.rs
@@ -90,6 +90,13 @@ pub struct StandardMaterial {
     /// it just adds a value to the color seen on screen.
     pub emissive: Color,
 
+    /// The weight in which the camera exposure influences the emissive color.
+    /// A value of `0.0` means the emissive color is not affected by the camera exposure.
+    /// In opposition, a value of `1.0` means the emissive color is multiplied by the camera exposure.
+    ///
+    /// Defaults to `0.0`
+    pub emissive_exposure_weight: f32,
+
     /// The UV channel to use for the [`StandardMaterial::emissive_texture`].
     ///
     /// Defaults to [`UvChannel::Uv0`].
@@ -683,6 +690,7 @@ impl Default for StandardMaterial {
             base_color_channel: UvChannel::Uv0,
             base_color_texture: None,
             emissive: Color::BLACK,
+            emissive_exposure_weight: 0.0,
             emissive_channel: UvChannel::Uv0,
             emissive_texture: None,
             // Matches Blender's default roughness.
@@ -964,9 +972,12 @@ impl AsBindGroupShaderType<StandardMaterialUniform> for StandardMaterial {
             flags |= StandardMaterialFlags::ATTENUATION_ENABLED;
         }
 
+        let mut emissive = LinearRgba::from(self.emissive).to_f32_array();
+        emissive[3] = self.emissive_exposure_weight;
+
         StandardMaterialUniform {
             base_color: LinearRgba::from(self.base_color).to_f32_array().into(),
-            emissive: LinearRgba::from(self.emissive).to_f32_array().into(),
+            emissive: emissive.into(),
             roughness: self.perceptual_roughness,
             metallic: self.metallic,
             reflectance: self.reflectance,

diff --git a/crates/bevy_pbr/src/render/pbr_fragment.wgsl b/crates/bevy_pbr/src/render/pbr_fragment.wgsl
@@ -178,7 +178,6 @@ fn pbr_input_from_standard_material(
         pbr_input.material.alpha_cutoff = pbr_bindings::material.alpha_cutoff;
 
         // emissive
-        // TODO use .a for exposure compensation in HDR
         var emissive: vec4<f32> = pbr_bindings::material.emissive;
 #ifdef VERTEX_UVS
         if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_EMISSIVE_TEXTURE_BIT) != 0u) {
@@ -191,7 +190,7 @@ fn pbr_input_from_standard_material(
                 uv,
 #endif
                 bias,
-            ).rgb, 1.0);
+            ).rgb, emissive.a);
         }
 #endif
         pbr_input.material.emissive = emissive;

diff --git a/crates/bevy_pbr/src/render/pbr_functions.wgsl b/crates/bevy_pbr/src/render/pbr_functions.wgsl
@@ -564,6 +564,8 @@ fn apply_pbr_lighting(
     emissive_light = emissive_light * (0.04 + (1.0 - 0.04) * pow(1.0 - clearcoat_NdotV, 5.0));
 #endif
 
+    emissive_light = emissive_light * mix(1.0, view_bindings::view.exposure, emissive.a);
+
 #ifdef STANDARD_MATERIAL_SPECULAR_TRANSMISSION
     transmitted_light += transmission::specular_transmissive_light(in.world_position, in.frag_coord.xyz, view_z, in.N, in.V, F0, ior, thickness, perceptual_roughness, specular_transmissive_color, specular_transmitted_environment_light).rgb;
 
@@ -585,7 +587,7 @@ fn apply_pbr_lighting(
 
     // Total light
     output_color = vec4<f32>(
-        view_bindings::view.exposure * (transmitted_light + direct_light + indirect_light + emissive_light),
+        (view_bindings::view.exposure * (transmitted_light + direct_light + indirect_light)) + emissive_light,
         output_color.a
     );