fix(gles): Only use sampler2DShadow if comparison samplers are used

naga/src/back/glsl/mod.rs

@@ -911,7 +911,7 @@ impl<'a, W: Write> Writer<'a, W> {
                 TypeInner::Image {
                     mut dim,
                     arrayed,
-                    class,
+                    mut class,
                 } => {
                     // Gather the storage format if needed
                     let storage_format_access = match self.module.types[global.ty].inner {
@@ -959,6 +959,13 @@ impl<'a, W: Write> Writer<'a, W> {
                     // The trailing space is important
                     write!(self.out, "uniform ")?;
 
+                    if self.needs_depth_fix(ep_info, handle, &class) {
+                        class = crate::ImageClass::Sampled {
+                            kind: crate::ScalarKind::Float,
+                            multi: false,
+                        };
+                    }
+
                     // write the type
                     //
                     // This is way we need the leading space because `write_image_type` doesn't add
@@ -1034,6 +1041,30 @@ impl<'a, W: Write> Writer<'a, W> {
         self.collect_reflection_info()
     }
 
+    fn needs_depth_fix(
+        &mut self,
+        ep_info: &valid::FunctionInfo,
+        handle: Handle<crate::GlobalVariable>,
+        class: &crate::ImageClass,
+    ) -> bool {
+        if let crate::ImageClass::Depth { multi: false } = *class {
+            // if any sampler uses the comparison sampler, a fix is not needed. Otherwise, we need to actually sample a regular texture as far as glsl is concerned
+            !ep_info.sampling_set.iter().all(|key| {
+                let data = &self.module.global_variables[key.sampler];
+                if key.image != handle {
+                    return false;
+                }
+
+                matches!(
+                    self.module.types[data.ty].inner,
+                    TypeInner::Sampler { comparison: true }
+                )
+            })
+        } else {
+            false
+        }
+    }
+
     fn write_array_size(
         &mut self,
         base: Handle<crate::Type>,
@@ -3162,6 +3193,14 @@ impl<'a, W: Write> Writer<'a, W> {
                     self.write_expr(expr, ctx)?;
                 }
 
+                let needs_depth_fix =
+                    if let Expression::GlobalVariable(global_handle) = ctx.expressions[image] {
+                        let ep_info = self.info.get_entry_point(self.entry_point_idx as usize);
+                        self.needs_depth_fix(ep_info, global_handle, &class)
+                    } else {
+                        false
+                    };
+
                 match level {
                     // Auto needs no more arguments
                     crate::SampleLevel::Auto => (),
@@ -3180,7 +3219,16 @@ impl<'a, W: Write> Writer<'a, W> {
                     // Exact and bias require another argument
                     crate::SampleLevel::Exact(expr) => {
                         write!(self.out, ", ")?;
+
+                        if needs_depth_fix {
+                            write!(self.out, "float(")?;
+                        }
+
                         self.write_expr(expr, ctx)?;
+
+                        if needs_depth_fix {
+                            write!(self.out, ")")?;
+                        }
                     }
                     crate::SampleLevel::Bias(_) => {
                         // This needs to be done after the offset writing
@@ -3226,7 +3274,12 @@ impl<'a, W: Write> Writer<'a, W> {
                 }
 
                 // End the function
-                write!(self.out, ")")?
+                write!(self.out, ")")?;
+
+                if needs_depth_fix {
+                    // parser thinks it will yield f32, but in reality it yields vec4f
+                    write!(self.out, ".x")?;
+                }
             }
             Expression::ImageLoad {
                 image,