From 797d3f5c398f32238fe8649e5fb185dfa6ea686d Mon Sep 17 00:00:00 2001
From: Jakub Arnold <darthdeus@gmail.com>
Date: Mon, 1 Jan 2024 17:00:22 +0100
Subject: [PATCH] Add y_sort_offset

---
 comfy-core/src/lib.rs      | 1 +
 comfy-core/src/quad.rs     | 5 +++++
 comfy-wgpu/src/batching.rs | 4 +++-
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/comfy-core/src/lib.rs b/comfy-core/src/lib.rs
index 9f690d0..a7f9751 100644
--- a/comfy-core/src/lib.rs
+++ b/comfy-core/src/lib.rs
@@ -633,6 +633,7 @@ pub struct Mesh {
     pub indices: SmallVec<[u32; 6]>,
     pub z_index: i32,
     pub texture: Option<TextureHandle>,
+    pub y_sort_offset: f32,
 }
 
 #[repr(C)]
diff --git a/comfy-core/src/quad.rs b/comfy-core/src/quad.rs
index b58b63c..ee19b55 100644
--- a/comfy-core/src/quad.rs
+++ b/comfy-core/src/quad.rs
@@ -185,6 +185,10 @@ pub struct DrawTextureProParams {
     pub blend_mode: BlendMode,
     /// Rotation around the x axis for creating a 3d effect.
     pub rotation_x: f32,
+    /// Offset for y-sorting in world-space. This is useful for when sprites have different
+    /// sizes and pivots, for example when a tree should be "behind" something based on its bottom-most
+    /// pixel, and not based on its size.
+    pub y_sort_offset: f32,
 }
 
 impl Default for DrawTextureProParams {
@@ -199,6 +203,7 @@ impl Default for DrawTextureProParams {
             flip_y: false,
             blend_mode: Default::default(),
             rotation_x: 0.0,
+            y_sort_offset: 0.0,
         }
     }
 }
diff --git a/comfy-wgpu/src/batching.rs b/comfy-wgpu/src/batching.rs
index 139a0d6..60d4629 100644
--- a/comfy-wgpu/src/batching.rs
+++ b/comfy-wgpu/src/batching.rs
@@ -40,7 +40,9 @@ pub fn run_batched_render_passes(
 
         // TODO: add this back later
         if get_y_sort(key.z_index) {
-            meshes.sort_by_key(|mesh| OrderedFloat::<f32>(-mesh.origin.y));
+            meshes.sort_by_key(|mesh| {
+                OrderedFloat::<f32>(-(mesh.origin.y + mesh.y_sort_offset))
+            });
         }
 
         render_meshes(