[WebGPU] Add indirect draw / dispatch

This CL adds `dispatchIndirect` to GPUComputePassEncoder and
`drawIndirect` and `drawIndexedIndirect` to GPURenderPassEncoder.

Bug: 877147
Change-Id: Idd5344c112fc2df6564e5091ca0ef86dc8f8bcc9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1731113Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: François Beaufort <beaufort.francois@gmail.com>
Cr-Commit-Position: refs/heads/master@{#683138}

third_party/blink/renderer/modules/webgpu/gpu_buffer_usage.h

@@ -23,6 +23,7 @@ class GPUBufferUsage : public ScriptWrappable {
   static constexpr uint32_t kVertex = 32;
   static constexpr uint32_t kUniform = 64;
   static constexpr uint32_t kStorage = 128;
+  static constexpr uint32_t kIndirect = 256;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(GPUBufferUsage);

third_party/blink/renderer/modules/webgpu/gpu_buffer_usage.idl

@@ -17,4 +17,5 @@ typedef unsigned long GPUBufferUsageFlags;
     const unsigned long VERTEX = 32;
     const unsigned long UNIFORM = 64;
     const unsigned long STORAGE = 128;
+    const unsigned long INDIRECT = 256;
 };

third_party/blink/renderer/modules/webgpu/gpu_compute_pass_encoder.cc

@@ -47,6 +47,12 @@ void GPUComputePassEncoder::dispatch(uint32_t x, uint32_t y, uint32_t z) {
   GetProcs().computePassEncoderDispatch(GetHandle(), x, y, z);
 }
 
+void GPUComputePassEncoder::dispatchIndirect(GPUBuffer* indirectBuffer,
+                                             uint64_t indirectOffset) {
+  GetProcs().computePassEncoderDispatchIndirect(
+      GetHandle(), indirectBuffer->GetHandle(), indirectOffset);
+}
+
 void GPUComputePassEncoder::endPass() {
   GetProcs().computePassEncoderEndPass(GetHandle());
 }

third_party/blink/renderer/modules/webgpu/gpu_compute_pass_encoder.h

@@ -6,6 +6,7 @@
 #define THIRD_PARTY_BLINK_RENDERER_MODULES_WEBGPU_GPU_COMPUTE_PASS_ENCODER_H_
 
 #include "third_party/blink/renderer/modules/webgpu/dawn_object.h"
+#include "third_party/blink/renderer/modules/webgpu/gpu_buffer.h"
 
 namespace blink {
 
@@ -29,6 +30,7 @@ class GPUComputePassEncoder : public DawnObject<DawnComputePassEncoder> {
                     const Vector<uint64_t>& dynamicOffsets);
   void setPipeline(GPUComputePipeline* pipeline);
   void dispatch(uint32_t x, uint32_t y, uint32_t z);
+  void dispatchIndirect(GPUBuffer* indirectBuffer, uint64_t indirectOffset);
   void endPass();
 
  private:

third_party/blink/renderer/modules/webgpu/gpu_compute_pass_encoder.idl

@@ -15,6 +15,8 @@
     void dispatch(unsigned long x,
                   optional unsigned long y = 1,
                   optional unsigned long z = 1);
+    void dispatchIndirect(GPUBuffer indirectBuffer,
+                          unsigned long long indirectOffset);
 
     void endPass();
 };

third_party/blink/renderer/modules/webgpu/gpu_render_pass_encoder.cc

@@ -113,6 +113,18 @@ void GPURenderPassEncoder::drawIndexed(uint32_t indexCount,
                                           firstInstance);
 }
 
+void GPURenderPassEncoder::drawIndirect(GPUBuffer* indirectBuffer,
+                                        uint64_t indirectOffset) {
+  GetProcs().renderPassEncoderDrawIndirect(
+      GetHandle(), indirectBuffer->GetHandle(), indirectOffset);
+}
+
+void GPURenderPassEncoder::drawIndexedIndirect(GPUBuffer* indirectBuffer,
+                                               uint64_t indirectOffset) {
+  GetProcs().renderPassEncoderDrawIndexedIndirect(
+      GetHandle(), indirectBuffer->GetHandle(), indirectOffset);
+}
+
 void GPURenderPassEncoder::endPass() {
   GetProcs().renderPassEncoderEndPass(GetHandle());
 }

third_party/blink/renderer/modules/webgpu/gpu_render_pass_encoder.h

@@ -55,6 +55,8 @@ class GPURenderPassEncoder : public DawnObject<DawnRenderPassEncoder> {
                    uint32_t firstIndex,
                    int32_t baseVertex,
                    uint32_t firstInstance);
+  void drawIndirect(GPUBuffer* indirectBuffer, uint64_t indirectOffset);
+  void drawIndexedIndirect(GPUBuffer* indirectBuffer, uint64_t indirectOffset);
 
   void endPass();
 

third_party/blink/renderer/modules/webgpu/gpu_render_pass_encoder.idl

@@ -30,6 +30,10 @@
                      unsigned long firstIndex,
                      long baseVertex,
                      unsigned long firstInstance);
+    void drawIndirect(GPUBuffer indirectBuffer,
+                      unsigned long long indirectOffset);
+    void drawIndexedIndirect(GPUBuffer indirectBuffer,
+                             unsigned long long indirectOffset);
 
     void endPass();
 };