Write to depth buffer in alpha mask mode

CHANGELOG.md

@@ -37,6 +37,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - The following modifiers' `via_property()` function now takes a `PropertyHandle` instead of a property name: `AccelModifier`, `RadialAccelModifier`, `TangentAccelModifier`.
 - `Expr` is now `Copy`, making it even more lightweight.
 - `ExprWriter::prop()` now panics if the property doesn't exist. This ensures the created `WriterExpr` is well-formed, which was impossible to validate at expression write time previously.
+- Effects rendered with `AlphaMode::Mask` now write to the depth buffer. Other effects continue to not write to it. This fixes particle flickering for alpha masked effects only.
 
 ### Removed
 
@@ -54,6 +55,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Fixed a panic in rendering randomly occurring when no effect is present.
 - Fixed invalid WGSL being generated for large `u32` values.
+- Fixed particle flickering, only for particles rendered through the `AlphaMask3d` render pass (`EffectAsset::alpha_mode == AlphaMode::Mask`). (#183)
 
 ## [0.10.0] 2024-02-24
 

src/render/mod.rs

@@ -1184,7 +1184,8 @@ impl SpecializedRenderPipeline for ParticlesRenderPipeline {
             PipelineMode::Camera2d => None,
             PipelineMode::Camera3d => Some(DepthStencilState {
                 format: TextureFormat::Depth32Float,
-                depth_write_enabled: false,
+                // Use depth buffer with alpha-masked particles, not with transparent ones
+                depth_write_enabled: key.use_alpha_mask,
                 // Bevy uses reverse-Z, so Greater really means closer
                 depth_compare: CompareFunction::Greater,
                 stencil: StencilState::default(),
@@ -1198,7 +1199,8 @@ impl SpecializedRenderPipeline for ParticlesRenderPipeline {
         #[cfg(all(feature = "3d", not(feature = "2d")))]
         let depth_stencil = Some(DepthStencilState {
             format: TextureFormat::Depth32Float,
-            depth_write_enabled: false,
+            // Use depth buffer with alpha-masked particles, not with transparent ones
+            depth_write_enabled: key.use_alpha_mask,
             // Bevy uses reverse-Z, so Greater really means closer
             depth_compare: CompareFunction::Greater,
             stencil: StencilState::default(),