Hack to fix GL-specific backend issue where if image atlas grows to a layer depth of 6, GL interprets the texture as a cube map vs a 2d texture array

wgpu/src/image/atlas.rs

@@ -98,6 +98,7 @@ impl Atlas {
     pub fn upload(
         &mut self,
         device: &wgpu::Device,
+        backend: wgpu::Backend,
         encoder: &mut wgpu::CommandEncoder,
         width: u32,
         height: u32,
@@ -109,7 +110,7 @@ impl Atlas {
 
             // We grow the internal texture after allocating if necessary
             let new_layers = self.layers.len() - current_size;
-            self.grow(new_layers, device, encoder);
+            self.grow(new_layers, device, backend, encoder);
 
             entry
         };
@@ -370,18 +371,29 @@ impl Atlas {
         &mut self,
         amount: usize,
         device: &wgpu::Device,
+        backend: wgpu::Backend,
         encoder: &mut wgpu::CommandEncoder,
     ) {
         if amount == 0 {
             return;
         }
 
+        // On the GL backend if layers.len() == 6 we need to help wgpu figure out that this texture
+        // is still a `GL_TEXTURE_2D_ARRAY` rather than `GL_TEXTURE_CUBE_MAP`. This will over-allocate
+        // some unused memory on GL, but it's better than not being able to grow the atlas past a depth
+        // of 6!
+        // https://github.com/gfx-rs/wgpu/blob/004e3efe84a320d9331371ed31fa50baa2414911/wgpu-hal/src/gles/mod.rs#L371
+        let depth_or_array_layers = match backend {
+            wgpu::Backend::Gl if self.layers.len() == 6 => 7,
+            _ => self.layers.len() as u32,
+        };
+
         let new_texture = device.create_texture(&wgpu::TextureDescriptor {
             label: Some("iced_wgpu::image texture atlas"),
             size: wgpu::Extent3d {
                 width: SIZE,
                 height: SIZE,
-                depth_or_array_layers: self.layers.len() as u32,
+                depth_or_array_layers,
             },
             mip_level_count: 1,
             sample_count: 1,

wgpu/src/image/cache.rs

@@ -49,16 +49,19 @@ impl Cache {
     pub fn upload_raster(
         &mut self,
         device: &wgpu::Device,
+        backend: wgpu::Backend,
         encoder: &mut wgpu::CommandEncoder,
         handle: &core::image::Handle,
     ) -> Option<&atlas::Entry> {
-        self.raster.upload(device, encoder, handle, &mut self.atlas)
+        self.raster
+            .upload(device, backend, encoder, handle, &mut self.atlas)
     }
 
     #[cfg(feature = "svg")]
     pub fn upload_vector(
         &mut self,
         device: &wgpu::Device,
+        backend: wgpu::Backend,
         encoder: &mut wgpu::CommandEncoder,
         handle: &core::svg::Handle,
         color: Option<core::Color>,
@@ -67,6 +70,7 @@ impl Cache {
     ) -> Option<&atlas::Entry> {
         self.vector.upload(
             device,
+            backend,
             encoder,
             handle,
             color,

wgpu/src/image/mod.rs

@@ -235,9 +235,12 @@ impl State {
             match &image {
                 #[cfg(feature = "image")]
                 Image::Raster(image, bounds) => {
-                    if let Some(atlas_entry) =
-                        cache.upload_raster(device, encoder, &image.handle)
-                    {
+                    if let Some(atlas_entry) = cache.upload_raster(
+                        device,
+                        pipeline.backend,
+                        encoder,
+                        &image.handle,
+                    ) {
                         add_instances(
                             [bounds.x, bounds.y],
                             [bounds.width, bounds.height],
@@ -265,6 +268,7 @@ impl State {
 
                     if let Some(atlas_entry) = cache.upload_vector(
                         device,
+                        pipeline.backend,
                         encoder,
                         &svg.handle,
                         svg.color,

wgpu/src/image/raster.rs

@@ -66,6 +66,7 @@ impl Cache {
     pub fn upload(
         &mut self,
         device: &wgpu::Device,
+        backend: wgpu::Backend,
         encoder: &mut wgpu::CommandEncoder,
         handle: &image::Handle,
         atlas: &mut Atlas,
@@ -75,7 +76,8 @@ impl Cache {
         if let Memory::Host(image) = memory {
             let (width, height) = image.dimensions();
 
-            let entry = atlas.upload(device, encoder, width, height, image)?;
+            let entry =
+                atlas.upload(device, backend, encoder, width, height, image)?;
 
             *memory = Memory::Device(entry);
         }

wgpu/src/image/vector.rs

@@ -93,6 +93,7 @@ impl Cache {
     pub fn upload(
         &mut self,
         device: &wgpu::Device,
+        backend: wgpu::Backend,
         encoder: &mut wgpu::CommandEncoder,
         handle: &svg::Handle,
         color: Option<Color>,
@@ -167,8 +168,8 @@ impl Cache {
                     });
                 }
 
-                let allocation =
-                    atlas.upload(device, encoder, width, height, &rgba)?;
+                let allocation = atlas
+                    .upload(device, backend, encoder, width, height, &rgba)?;
 
                 log::debug!("allocating {id} {width}x{height}");