i think fixed logic in access conflict?

crates/renderer/src/render_graph/commands.rs

@@ -308,6 +308,11 @@ pub struct BeginRendering {
 impl Command for BeginRendering {
     fn side_effects(&self, mut map: SideEffectMap) {
         for attachment in &self.color_attachments {
+            // The dependencies declared here need to be barrier'd before the
+            // render pass: the spec says pipelineBarrier inside of a render
+            // pass instance referencing framebuffer-local stages must contain
+            // only framebuffer-local stages.
+
             // TODO: consider loadop and storeop?
             attachment.side_effect(map.reborrow().into_side_effect_map2(
                 vk::PipelineStageFlags2::COLOR_ATTACHMENT_OUTPUT,

crates/renderer/src/render_graph/resources.rs

@@ -201,7 +201,13 @@ impl ResourceAccess {
                     ..
                 },
             ) => {
-                if aspect != aspect_b
+                // two accesses conflict if they overlap;
+                // they overlap if they share mip levels or array layers with
+                // the same aspects.
+                // If one access contains the other, we can merge them (i
+                // think), however: if a previous access requires a less general
+                // barrier, then is it better to split?
+                if !aspect.contains(*aspect_b)
                     || layout != layout_b
                     || !mip_level.intersects(mip_level_b)
                     || !array_layers.intersects(array_layers_b)
@@ -209,6 +215,7 @@ impl ResourceAccess {
                     return false;
                 }
 
+                *aspect = *aspect | *aspect_b;
                 *mip_level = mip_level.union(mip_level_b);
                 *array_layers = array_layers.union(array_layers_b);
                 // let lower_left = Offset::from(*origin).min(Offset::from(*origin_b));
@@ -245,7 +252,7 @@ impl ResourceAccess {
                     return false;
                 }
 
-                // must be a read/write conflict, check if subresources intersect
+                // must be a read/write conflict, check if sub-resources intersect
                 !(*offset > *offset_b + *size_b || *offset_b > *offset + *size)
             }
             (
@@ -264,21 +271,23 @@ impl ResourceAccess {
                     ..
                 },
             ) => {
-                // layouts differing means we need a layout transition, which is a conflict
+                //  check if sub-resources intersect
+                let overlaps = aspect.intersects(*aspect_b)
+                    && (mip_level.intersects(mip_level_b)
+                        || array_layers.intersects(array_layers_b));
+
+                // non-overlapping sub-resources never conflict
+                if !overlaps {
+                    return false;
+                }
+
+                // layout transition required even on reads
                 if layout != layout_b {
                     return true;
                 }
 
                 // two reads don't conflict
-                // TODO: two writes may conflict if the user cares about the order of writes.
+                access_flag_is_read(self.access) != access_flag_is_read(other.access)
-                if access_flag_is_read(self.access) == access_flag_is_read(other.access) {
-                    return false;
-                }
-
-                // must be a read/write conflict, check if subresources intersect
-                aspect.intersects(*aspect_b)
-                    && (mip_level.intersects(mip_level_b)
-                        || array_layers.intersects(array_layers_b))
             }
         }
     }