Fix missing 4X MSAA support on some OpenGL backends (#3780)

* Always support 4x MSAA on GL * Update changelog
gfx-rs · May 19, 2023 · b0dfd11 · b0dfd11
1 parent dafc189
commit b0dfd11
Show file tree

Hide file tree

Showing 2 changed files with 6 additions and 3 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -57,6 +57,7 @@ Bottom level categories:
 ### Bug Fixes
 
 - Fix order of arguments to glPolygonOffset by @komadori in [#3783](https://github.com/gfx-rs/wgpu/pull/3783).
+- Fix missing 4X MSAA support on some OpenGL backends. By @emilk in [#3780](https://github.com/gfx-rs/wgpu/pull/3780)
 
 #### General
 

diff --git a/wgpu-hal/src/gles/adapter.rs b/wgpu-hal/src/gles/adapter.rs
@@ -713,10 +713,12 @@ impl crate::Adapter<super::Api> for super::Adapter {
  | Tfc::MULTISAMPLE_X16
  } else if max_samples >= 8 {
  Tfc::MULTISAMPLE_X2 | Tfc::MULTISAMPLE_X4 | Tfc::MULTISAMPLE_X8
- } else if max_samples >= 4 {
- Tfc::MULTISAMPLE_X2 | Tfc::MULTISAMPLE_X4
  } else {
- Tfc::MULTISAMPLE_X2
+ // The lowest supported level in GLE3.0/WebGL2 is 4X
+ // (see GL_MAX_SAMPLES in https://registry.khronos.org/OpenGL-Refpages/es3.0/html/glGet.xhtml).
+ // On some platforms, like iOS Safari, `get_parameter_i32(MAX_SAMPLES)` returns 0,
+ // so we always fall back to supporting 4x here.
+ Tfc::MULTISAMPLE_X2 | Tfc::MULTISAMPLE_X4
  }
  };