Add INDIRECT_FIRST_INSTANCE feature (#2206)

wgpu-hal/src/dx12/adapter.rs

@@ -170,6 +170,7 @@ impl super::Adapter {
 
         let mut features = wgt::Features::empty()
             | wgt::Features::DEPTH_CLIP_CONTROL
+            | wgt::Features::INDIRECT_FIRST_INSTANCE
             | wgt::Features::MAPPABLE_PRIMARY_BUFFERS
             //TODO: Naga part
             //| wgt::Features::TEXTURE_BINDING_ARRAY

wgpu-hal/src/metal/adapter.rs

@@ -872,6 +872,7 @@ impl super::PrivateCapabilities {
 
         let mut features = F::empty()
             | F::TEXTURE_COMPRESSION_BC
+            | F::INDIRECT_FIRST_INSTANCE
             | F::MAPPABLE_PRIMARY_BUFFERS
             | F::VERTEX_WRITABLE_STORAGE
             | F::TEXTURE_ADAPTER_SPECIFIC_FORMAT_FEATURES

wgpu-hal/src/vulkan/adapter.rs

@@ -104,6 +104,9 @@ impl PhysicalDeviceFeatures {
                 .image_cube_array(
                     downlevel_flags.contains(wgt::DownlevelFlags::CUBE_ARRAY_TEXTURES),
                 )
+                .draw_indirect_first_instance(
+                    requested_features.contains(wgt::Features::INDIRECT_FIRST_INSTANCE),
+                )
                 //.dual_src_blend(requested_features.contains(wgt::Features::DUAL_SRC_BLENDING))
                 .multi_draw_indirect(
                     requested_features.contains(wgt::Features::MULTI_DRAW_INDIRECT),
@@ -339,6 +342,10 @@ impl PhysicalDeviceFeatures {
             self.core.fragment_stores_and_atomics != 0,
         );
 
+        features.set(
+            F::INDIRECT_FIRST_INSTANCE,
+            self.core.draw_indirect_first_instance != 0,
+        );
         //if self.core.dual_src_blend != 0
         features.set(F::MULTI_DRAW_INDIRECT, self.core.multi_draw_indirect != 0);
         features.set(F::POLYGON_MODE_LINE, self.core.fill_mode_non_solid != 0);

wgpu-types/src/lib.rs

@@ -189,6 +189,15 @@ bitflags::bitflags! {
         ///
         /// This is a web and native feature.
         const TEXTURE_COMPRESSION_BC = 1 << 1;
+        /// Allows non-zero value for the "first instance" in indirect draw calls.
+        ///
+        /// Supported Platforms:
+        /// - Vulkan (mostly)
+        /// - DX12
+        /// - Metal
+        ///
+        /// This is a web and native feature.
+        const INDIRECT_FIRST_INSTANCE = 1 << 2;
         /// Enables use of Timestamp Queries. These queries tell the current gpu timestamp when
         /// all work before the query is finished. Call [`CommandEncoder::write_timestamp`],
         /// [`RenderPassEncoder::write_timestamp`], or [`ComputePassEncoder::write_timestamp`] to
@@ -206,7 +215,7 @@ bitflags::bitflags! {
         /// - DX12 (works)
         ///
         /// This is a web and native feature.
-        const TIMESTAMP_QUERY = 1 << 2;
+        const TIMESTAMP_QUERY = 1 << 3;
         /// Enables use of Pipeline Statistics Queries. These queries tell the count of various operations
         /// performed between the start and stop call. Call [`RenderPassEncoder::begin_pipeline_statistics_query`] to start
         /// a query, then call [`RenderPassEncoder::end_pipeline_statistics_query`] to stop one.
@@ -221,7 +230,7 @@ bitflags::bitflags! {
         /// - DX12 (works)
         ///
         /// This is a web and native feature.
-        const PIPELINE_STATISTICS_QUERY = 1 << 3;
+        const PIPELINE_STATISTICS_QUERY = 1 << 4;
         /// Webgpu only allows the MAP_READ and MAP_WRITE buffer usage to be matched with
         /// COPY_DST and COPY_SRC respectively. This removes this requirement.
         ///

wgpu/src/lib.rs

@@ -2591,8 +2591,9 @@ impl<'a> RenderPass<'a> {
     /// struct DrawIndirect {
     ///     vertex_count: u32, // The number of vertices to draw.
     ///     instance_count: u32, // The number of instances to draw.
-    ///     base_vertex: u32, // The Index of the first vertex to draw.
-    ///     base_instance: u32, // The instance ID of the first instance to draw.
+    ///     first_vertex: u32, // The Index of the first vertex to draw.
+    ///     first_instance: u32, // The instance ID of the first instance to draw.
+    ///     // has to be 0, unless [`Features::INDIRECT_FIRST_INSTANCE`] is enabled.
     /// }
     /// ```
     pub fn draw_indirect(&mut self, indirect_buffer: &'a Buffer, indirect_offset: BufferAddress) {
@@ -2612,9 +2613,10 @@ impl<'a> RenderPass<'a> {
     /// struct DrawIndexedIndirect {
     ///     vertex_count: u32, // The number of vertices to draw.
     ///     instance_count: u32, // The number of instances to draw.
-    ///     base_index: u32, // The base index within the index buffer.
+    ///     first_index: u32, // The base index within the index buffer.
     ///     vertex_offset: i32, // The value added to the vertex index before indexing into the vertex buffer.
-    ///     base_instance: u32, // The instance ID of the first instance to draw.
+    ///     first_instance: u32, // The instance ID of the first instance to draw.
+    ///     // has to be 0, unless [`Features::INDIRECT_FIRST_INSTANCE`] is enabled.
     /// }
     /// ```
     pub fn draw_indexed_indirect(