From 92fc6a50ee12f9a7af8a7c3a4cb5a593bfabaf49 Mon Sep 17 00:00:00 2001
From: Jacob Hughes <j@distanthills.org>
Date: Wed, 1 Nov 2023 05:20:20 -0700
Subject: [PATCH] debug_printf: Enable debug_printf validation feature

---
 wgpu-hal/src/vulkan/instance.rs | 34 ++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/wgpu-hal/src/vulkan/instance.rs b/wgpu-hal/src/vulkan/instance.rs
index 6910c15a32..b4e1241a48 100644
--- a/wgpu-hal/src/vulkan/instance.rs
+++ b/wgpu-hal/src/vulkan/instance.rs
@@ -611,7 +611,7 @@ impl crate::Instance<super::Api> for super::Instance {
                 },
             );
 
-        let extensions = Self::desired_extensions(&entry, instance_api_version, desc.flags)?;
+        let mut extensions = Self::desired_extensions(&entry, instance_api_version, desc.flags)?;
 
         let instance_layers = {
             profiling::scope!("vkEnumerateInstanceLayerProperties");
@@ -644,6 +644,7 @@ impl crate::Instance<super::Api> for super::Instance {
 
         // Request validation layer if asked.
         let mut debug_utils = None;
+        let mut validation_features = None;
         if desc.flags.contains(wgt::InstanceFlags::VALIDATION) {
             let validation_layer_name =
                 CStr::from_bytes_with_nul(b"VK_LAYER_KHRONOS_validation\0").unwrap();
@@ -689,6 +690,33 @@ impl crate::Instance<super::Api> for super::Instance {
 
                     debug_utils = Some((create_info, vk_create_info));
                 }
+
+                let validation_features_name = vk::ExtValidationFeaturesFn::name();
+                match entry.enumerate_instance_extension_properties(Some(validation_layer_name)) {
+                    Ok(validation_extensions) => {
+                        if validation_extensions.iter().any(|inst_ext| {
+                            cstr_from_bytes_until_nul(&inst_ext.extension_name)
+                                == Some(validation_features_name)
+                        }) {
+                            extensions.push(validation_features_name);
+                            validation_features = Some(
+                                vk::ValidationFeaturesEXT::builder().enabled_validation_features(
+                                    &[vk::ValidationFeatureEnableEXT::DEBUG_PRINTF],
+                                ),
+                            );
+                        } else {
+                            log::info!(
+                                "Unable to find validation layer extension {}, not enabling DEBUG_PRINTF",
+                                validation_features_name.to_string_lossy()
+                            )
+                        }
+                    }
+                    Err(e) => {
+                        log::warn!(
+                            "enumerate_instance_extension_properties() failed for validation layer: {:?}", e
+                        )
+                    }
+                }
             } else {
                 log::warn!(
                     "InstanceFlags::VALIDATION requested, but unable to find layer: {}",
@@ -743,6 +771,10 @@ impl crate::Instance<super::Api> for super::Instance {
                 .enabled_layer_names(&str_pointers[..layers.len()])
                 .enabled_extension_names(&str_pointers[layers.len()..]);
 
+            if let Some(validation_features) = validation_features.as_mut() {
+                create_info = create_info.push_next(validation_features);
+            }
+
             if let Some(&mut (_, ref mut vk_create_info)) = debug_utils.as_mut() {
                 create_info = create_info.push_next(vk_create_info);
             }