Relax render pass color_attachments validation (gfx-rs#2778)

* Make the color attachments `Option`-al in render pipelines, render passes, and render bundles

* vk:  `Option`-al color attachments support

* dx12: sparse color_attachments support

* Only non-hole attachments is supported on wasm target and gl backend

* deno_webgpu: `Option`-al color attachments support

* Follow all suggestions

deno_webgpu/src/bundle.rs

@@ -32,7 +32,7 @@ impl Resource for WebGpuRenderBundle {
 pub struct CreateRenderBundleEncoderArgs {
     device_rid: ResourceId,
     label: Option<String>,
-    color_formats: Vec<wgpu_types::TextureFormat>,
+    color_formats: Vec<Option<wgpu_types::TextureFormat>>,
     depth_stencil_format: Option<wgpu_types::TextureFormat>,
     sample_count: u32,
     depth_read_only: bool,

deno_webgpu/src/command_encoder.rs

@@ -78,7 +78,7 @@ pub fn op_webgpu_command_encoder_begin_render_pass(
     state: &mut OpState,
     command_encoder_rid: ResourceId,
     label: Option<String>,
-    color_attachments: Vec<GpuRenderPassColorAttachment>,
+    color_attachments: Vec<Option<GpuRenderPassColorAttachment>>,
     depth_stencil_attachment: Option<GpuRenderPassDepthStencilAttachment>,
     _occlusion_query_set: Option<u32>, // not yet implemented
 ) -> Result<WebGpuResult, AnyError> {
@@ -89,30 +89,35 @@ pub fn op_webgpu_command_encoder_begin_render_pass(
     let color_attachments = color_attachments
         .into_iter()
         .map(|color_attachment| {
-            let texture_view_resource = state
-                .resource_table
-                .get::<super::texture::WebGpuTextureView>(color_attachment.view)?;
-
-            let resolve_target = color_attachment
-                .resolve_target
-                .map(|rid| {
-                    state
-                        .resource_table
-                        .get::<super::texture::WebGpuTextureView>(rid)
+            let rp_at = if let Some(at) = color_attachment.as_ref() {
+                let texture_view_resource = state
+                    .resource_table
+                    .get::<super::texture::WebGpuTextureView>(at.view)?;
+
+                let resolve_target = at
+                    .resolve_target
+                    .map(|rid| {
+                        state
+                            .resource_table
+                            .get::<super::texture::WebGpuTextureView>(rid)
+                    })
+                    .transpose()?
+                    .map(|texture| texture.0);
+
+                Some(wgpu_core::command::RenderPassColorAttachment {
+                    view: texture_view_resource.0,
+                    resolve_target,
+                    channel: wgpu_core::command::PassChannel {
+                        load_op: at.load_op,
+                        store_op: at.store_op,
+                        clear_value: at.clear_value.unwrap_or_default(),
+                        read_only: false,
+                    },
                 })
-                .transpose()?
-                .map(|texture| texture.0);
-
-            Ok(wgpu_core::command::RenderPassColorAttachment {
-                view: texture_view_resource.0,
-                resolve_target,
-                channel: wgpu_core::command::PassChannel {
-                    load_op: color_attachment.load_op,
-                    store_op: color_attachment.store_op,
-                    clear_value: color_attachment.clear_value.unwrap_or_default(),
-                    read_only: false,
-                },
-            })
+            } else {
+                None
+            };
+            Ok(rp_at)
         })
         .collect::<Result<Vec<_>, AnyError>>()?;
 

deno_webgpu/src/pipeline.rs

@@ -260,7 +260,7 @@ impl From<GpuMultisampleState> for wgpu_types::MultisampleState {
 #[derive(Deserialize)]
 #[serde(rename_all = "camelCase")]
 struct GpuFragmentState {
-    targets: Vec<wgpu_types::ColorTargetState>,
+    targets: Vec<Option<wgpu_types::ColorTargetState>>,
     module: u32,
     entry_point: String,
     // TODO(lucacasonato): constants

deno_webgpu/webgpu.idl

@@ -613,7 +613,7 @@ dictionary GPUMultisampleState {
 };
 
 dictionary GPUFragmentState : GPUProgrammableStage {
-    required sequence<GPUColorTargetState> targets;
+    required sequence<GPUColorTargetState?> targets;
 };
 
 dictionary GPUColorTargetState {
@@ -908,7 +908,7 @@ GPURenderPassEncoder includes GPUBindingCommandsMixin;
 GPURenderPassEncoder includes GPURenderCommandsMixin;
 
 dictionary GPURenderPassDescriptor : GPUObjectDescriptorBase {
-    required sequence<GPURenderPassColorAttachment> colorAttachments;
+    required sequence<GPURenderPassColorAttachment?> colorAttachments;
     GPURenderPassDepthStencilAttachment depthStencilAttachment;
     GPUQuerySet occlusionQuerySet;
 };
@@ -947,7 +947,7 @@ enum GPUStoreOp {
 };
 
 dictionary GPURenderPassLayout: GPUObjectDescriptorBase {
-    required sequence<GPUTextureFormat> colorFormats;
+    required sequence<GPUTextureFormat?> colorFormats;
     GPUTextureFormat depthStencilFormat;
     GPUSize32 sampleCount = 1;
 };

player/tests/data/quad.ron

@@ -66,9 +66,9 @@
                         entry_point: "fs_main",
                     ),
                     targets: [
-                        (
+                        Some((
                             format: rgba8unorm,
-                        ),
+                        )),
                     ],
                 )),
             ),
@@ -90,7 +90,7 @@
                     push_constant_data: [],
                 ),
                 target_colors: [
-                    (
+                    Some((
                         view: Id(0, 1, Empty),
                         resolve_target: None,
                         channel: (
@@ -104,7 +104,7 @@
                             ),
                             read_only: false,
                         ),
-                    ),
+                    )),
                 ],
                 target_depth_stencil: None,
             ),

player/tests/data/zero-init-texture-rendertarget.ron

@@ -46,7 +46,7 @@
                     push_constant_data: [],
                 ),
                 target_colors: [
-                    (
+                    Some((
                         view: Id(0, 1, Empty),
                         resolve_target: None,
                         channel: (
@@ -57,7 +57,7 @@
                             ),
                             read_only: false,
                         ),
-                    ),
+                    )),
                 ],
                 target_depth_stencil: None,
             ),

wgpu-core/src/command/bundle.rs

@@ -114,7 +114,7 @@ pub struct RenderBundleEncoderDescriptor<'a> {
     pub label: Label<'a>,
     /// The formats of the color attachments that this render bundle is capable to rendering to. This
     /// must match the formats of the color attachments in the renderpass this render bundle is executed in.
-    pub color_formats: Cow<'a, [wgt::TextureFormat]>,
+    pub color_formats: Cow<'a, [Option<wgt::TextureFormat>]>,
     /// Information about the depth attachment that this render bundle is capable to rendering to. The format
     /// must match the format of the depth attachments in the renderpass this render bundle is executed in.
     pub depth_stencil: Option<wgt::RenderBundleDepthStencil>,

wgpu-core/src/command/clear.rs

@@ -408,15 +408,15 @@ fn clear_texture_via_render_passes<A: hal::Api>(
         for depth_or_layer in layer_or_depth_range {
             let color_attachments_tmp;
             let (color_attachments, depth_stencil_attachment) = if is_color {
-                color_attachments_tmp = [hal::ColorAttachment {
+                color_attachments_tmp = [Some(hal::ColorAttachment {
                     target: hal::Attachment {
                         view: dst_texture.get_clear_view(mip_level, depth_or_layer),
                         usage: hal::TextureUses::COLOR_TARGET,
                     },
                     resolve_target: None,
                     ops: hal::AttachmentOps::STORE,
                     clear_value: wgt::Color::TRANSPARENT,
-                }];
+                })];
                 (&color_attachments_tmp[..], None)
             } else {
                 (

wgpu-core/src/command/render.rs

@@ -173,7 +173,7 @@ impl RenderPassDepthStencilAttachment {
 pub struct RenderPassDescriptor<'a> {
     pub label: Label<'a>,
     /// The color attachments of the render pass.
-    pub color_attachments: Cow<'a, [RenderPassColorAttachment]>,
+    pub color_attachments: Cow<'a, [Option<RenderPassColorAttachment>]>,
     /// The depth and stencil attachment of the render pass, if any.
     pub depth_stencil_attachment: Option<&'a RenderPassDepthStencilAttachment>,
 }
@@ -182,7 +182,7 @@ pub struct RenderPassDescriptor<'a> {
 pub struct RenderPass {
     base: BasePass<RenderCommand>,
     parent_id: id::CommandEncoderId,
-    color_targets: ArrayVec<RenderPassColorAttachment, { hal::MAX_COLOR_ATTACHMENTS }>,
+    color_targets: ArrayVec<Option<RenderPassColorAttachment>, { hal::MAX_COLOR_ATTACHMENTS }>,
     depth_stencil_target: Option<RenderPassDepthStencilAttachment>,
 
     // Resource binding dedupe state.
@@ -441,7 +441,7 @@ pub enum RenderPassErrorInner {
     InvalidDepthStencilAttachmentFormat(wgt::TextureFormat),
     #[error("attachment format {0:?} can not be resolved")]
     UnsupportedResolveTargetFormat(wgt::TextureFormat),
-    #[error("necessary attachments are missing")]
+    #[error("missing color or depth_stencil attachments, at least one is required.")]
     MissingAttachments,
     #[error("attachments have differing sizes: {previous:?} is followed by {mismatch:?}")]
     AttachmentsDimensionMismatch {
@@ -646,7 +646,7 @@ impl<'a, A: HalApi> RenderPassInfo<'a, A> {
     fn start(
         device: &Device<A>,
         label: Option<&str>,
-        color_attachments: &[RenderPassColorAttachment],
+        color_attachments: &[Option<RenderPassColorAttachment>],
         depth_stencil_attachment: Option<&RenderPassDepthStencilAttachment>,
         cmd_buf: &mut CommandBuffer<A>,
         view_guard: &'a Storage<TextureView<A>, id::TextureViewId>,
@@ -722,11 +722,15 @@ impl<'a, A: HalApi> RenderPassInfo<'a, A> {
                     expected: sample_count,
                 });
             }
+            if sample_count != 1 && sample_count != 4 {
+                return Err(RenderPassErrorInner::InvalidSampleCount(sample_count));
+            }
             attachment_type_name = type_name;
             Ok(())
         };
 
-        let mut colors = ArrayVec::<hal::ColorAttachment<A>, { hal::MAX_COLOR_ATTACHMENTS }>::new();
+        let mut colors =
+            ArrayVec::<Option<hal::ColorAttachment<A>>, { hal::MAX_COLOR_ATTACHMENTS }>::new();
         let mut depth_stencil = None;
 
         if let Some(at) = depth_stencil_attachment {
@@ -840,6 +844,12 @@ impl<'a, A: HalApi> RenderPassInfo<'a, A> {
         }
 
         for at in color_attachments {
+            let at = if let Some(attachment) = at.as_ref() {
+                attachment
+            } else {
+                colors.push(None);
+                continue;
+            };
             let color_view: &TextureView<A> = cmd_buf
                 .trackers
                 .views
@@ -919,36 +929,38 @@ impl<'a, A: HalApi> RenderPassInfo<'a, A> {
                 });
             }
 
-            colors.push(hal::ColorAttachment {
+            colors.push(Some(hal::ColorAttachment {
                 target: hal::Attachment {
                     view: &color_view.raw,
                     usage: hal::TextureUses::COLOR_TARGET,
                 },
                 resolve_target: hal_resolve_target,
                 ops: at.channel.hal_ops(),
                 clear_value: at.channel.clear_value,
-            });
+            }));
         }
 
-        if sample_count != 1 && sample_count != 4 {
-            return Err(RenderPassErrorInner::InvalidSampleCount(sample_count));
-        }
+        let extent = extent.ok_or(RenderPassErrorInner::MissingAttachments)?;
+        let multiview = detected_multiview.expect("Multiview was not detected, no attachments");
 
         let view_data = AttachmentData {
             colors: color_attachments
                 .iter()
-                .map(|at| view_guard.get(at.view).unwrap())
+                .map(|at| at.as_ref().map(|at| view_guard.get(at.view).unwrap()))
                 .collect(),
             resolves: color_attachments
                 .iter()
-                .filter_map(|at| at.resolve_target)
-                .map(|attachment| view_guard.get(attachment).unwrap())
+                .filter_map(|at| match *at {
+                    Some(RenderPassColorAttachment {
+                        resolve_target: Some(resolve),
+                        ..
+                    }) => Some(view_guard.get(resolve).unwrap()),
+                    _ => None,
+                })
                 .collect(),
             depth_stencil: depth_stencil_attachment.map(|at| view_guard.get(at.view).unwrap()),
         };
-        let extent = extent.ok_or(RenderPassErrorInner::MissingAttachments)?;
 
-        let multiview = detected_multiview.expect("Multiview was not detected, no attachments");
         let context = RenderPassContext {
             attachments: view_data.map(|view| view.desc.format),
             sample_count,
@@ -1076,7 +1088,7 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
         &self,
         encoder_id: id::CommandEncoderId,
         base: BasePassRef<RenderCommand>,
-        color_attachments: &[RenderPassColorAttachment],
+        color_attachments: &[Option<RenderPassColorAttachment>],
         depth_stencil_attachment: Option<&RenderPassDepthStencilAttachment>,
     ) -> Result<(), RenderPassError> {
         profiling::scope!("run_render_pass", "CommandEncoder");