[d3d11] Introduce ResetState and use it for ClearState

ClearState gets used a lot in games that use deferred
contexts, so we should make sure it's fast. Since we
apply default state everywhere, there is no need to
perform any expensive RestoreState operations.

Reduces the amount of time spent on ClearState on the
CS thread by ~40%, and by ~90% on the calling thread.

src/d3d11/d3d11_context.cpp

@@ -254,7 +254,7 @@ namespace dxvk {
     m_state.pr.predicateValue  = FALSE;
     
     // Make sure to apply all state
-    RestoreState();
+    ResetState();
   }
   
   
@@ -3775,6 +3775,93 @@ namespace dxvk {
   }
   
   
+  void D3D11DeviceContext::ResetState() {
+    EmitCs([
+      cBlendState         = m_defaultBlendState.prvRef(),
+      cDepthStencilState  = m_defaultDepthStencilState.prvRef(),
+      cRasterizerState    = m_defaultRasterizerState.prvRef()
+    ] (DxvkContext* ctx) {
+      // Reset render targets
+      ctx->bindRenderTargets(DxvkRenderTargets());
+
+      // Reset vertex input state
+      ctx->setInputLayout(0, nullptr, 0, nullptr);
+
+      DxvkInputAssemblyState iaState;
+      InitDefaultPrimitiveTopology(&iaState);
+
+      ctx->setInputAssemblyState(iaState);
+
+      // Reset render states
+      cBlendState->BindToContext(ctx, D3D11_DEFAULT_SAMPLE_MASK);
+      cDepthStencilState->BindToContext(ctx);
+      cRasterizerState->BindToContext(ctx);
+
+      // Reset dynamic states
+      ctx->setBlendConstants(DxvkBlendConstants { 1.0f, 1.0f, 1.0f, 1.0f });
+      ctx->setStencilReference(D3D11_DEFAULT_STENCIL_REFERENCE);
+
+      // Reset viewports
+      auto viewport = VkViewport();
+      auto scissor  = VkRect2D();
+
+      ctx->setViewports(1, &viewport, &scissor);
+
+      // Reset predication
+      ctx->setPredicate(DxvkBufferSlice(), 0);
+
+      // Unbind indirect draw buffer
+      ctx->bindDrawBuffers(DxvkBufferSlice(), DxvkBufferSlice());
+
+      // Unbind index and vertex buffers
+      ctx->bindIndexBuffer(DxvkBufferSlice(), VK_INDEX_TYPE_UINT32);
+
+      for (uint32_t i = 0; i < D3D11_IA_VERTEX_INPUT_RESOURCE_SLOT_COUNT; i++)
+        ctx->bindVertexBuffer(i, DxvkBufferSlice(), 0);
+
+      // Unbind transform feedback buffers
+      for (uint32_t i = 0; i < D3D11_SO_BUFFER_SLOT_COUNT; i++)
+        ctx->bindXfbBuffer(i, DxvkBufferSlice(), DxvkBufferSlice());
+
+      // Unbind per-shader stage resources
+      for (uint32_t i = 0; i < 6; i++) {
+        auto programType = DxbcProgramType(i);
+        ctx->bindShader(GetShaderStage(programType), nullptr);
+
+        // Unbind constant buffers, including the shader's ICB
+        auto cbSlotId = computeConstantBufferBinding(programType, 0);
+
+        for (uint32_t j = 0; j <= D3D11_COMMONSHADER_CONSTANT_BUFFER_API_SLOT_COUNT; j++)
+          ctx->bindResourceBuffer(cbSlotId + j, DxvkBufferSlice());
+
+        // Unbind shader resource views
+        auto srvSlotId = computeSrvBinding(programType, 0);
+
+        for (uint32_t j = 0; j < D3D11_COMMONSHADER_INPUT_RESOURCE_SLOT_COUNT; j++)
+          ctx->bindResourceView(srvSlotId + j, nullptr, nullptr);
+
+        // Unbind texture samplers
+        auto samplerSlotId = computeSamplerBinding(programType, 0);
+
+        for (uint32_t j = 0; j < D3D11_COMMONSHADER_SAMPLER_SLOT_COUNT; j++)
+          ctx->bindResourceSampler(samplerSlotId + j, nullptr);
+
+        // Unbind UAVs for supported stages
+        if (programType == DxbcProgramType::PixelShader
+         || programType == DxbcProgramType::ComputeShader) {
+          auto uavSlotId = computeUavBinding(programType, 0);
+          auto ctrSlotId = computeUavCounterBinding(programType, 0);
+
+          for (uint32_t j = 0; j < D3D11_1_UAV_SLOT_COUNT; j++) {
+            ctx->bindResourceView   (uavSlotId, nullptr, nullptr);
+            ctx->bindResourceBuffer (ctrSlotId, DxvkBufferSlice());
+          }
+        }
+      }
+    });
+  }
+
+
   void D3D11DeviceContext::RestoreState() {
     BindFramebuffer();
     
@@ -4172,4 +4259,12 @@ namespace dxvk {
     return m_parent->AllocCsChunk(m_csFlags);
   }
   
+
+  void D3D11DeviceContext::InitDefaultPrimitiveTopology(
+          DxvkInputAssemblyState*           pIaState) {
+    pIaState->primitiveTopology = VK_PRIMITIVE_TOPOLOGY_MAX_ENUM;
+    pIaState->primitiveRestart  = VK_FALSE;
+    pIaState->patchVertexCount  = 0;
+  }
+
 }

src/d3d11/d3d11_context.h

@@ -838,6 +838,8 @@ namespace dxvk {
             UINT*                             pFirstConstant, 
             UINT*                             pNumConstants);
     
+    void ResetState();
+
     void RestoreState();
     
     template<DxbcProgramType Stage>
@@ -902,6 +904,9 @@ namespace dxvk {
     
     DxvkCsChunkRef AllocCsChunk();
     
+    static void InitDefaultPrimitiveTopology(
+            DxvkInputAssemblyState*           pIaState);
+
     template<typename T>
     const D3D11CommonShader* GetCommonShader(T* pShader) const {
       return pShader != nullptr ? pShader->GetCommonShader() : nullptr;