[dxvk] Make emitRenderTargetReadbackBarrier more generic

And also remove the redundant pipeline barrier.

src/d3d9/d3d9_device.cpp

@@ -6084,7 +6084,7 @@ namespace dxvk {
   void D3D9DeviceEx::PrepareDraw(D3DPRIMITIVETYPE PrimitiveType) {
     if (unlikely(m_activeHazardsRT != 0)) {
       EmitCs([](DxvkContext* ctx) {
-        ctx->emitRenderTargetReadbackBarrier();
+        ctx->emitGraphicsBarrier();
       });
 
       if (m_d3d9Options.generalHazards)

src/dxvk/dxvk_context.cpp

@@ -1441,18 +1441,6 @@ namespace dxvk {
   }
 
 
-  void DxvkContext::emitRenderTargetReadbackBarrier() {
-    if (m_flags.test(DxvkContextFlag::GpRenderPassBound))
-      this->spillRenderPass(true);
-
-    emitMemoryBarrier(0,
-      VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT,
-      VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT,
-      VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT,
-      VK_ACCESS_SHADER_READ_BIT);
-  }
-
-
   void DxvkContext::initBuffer(
     const Rc<DxvkBuffer>&           buffer) {
     auto slice = buffer->getSliceHandle();
@@ -1570,6 +1558,12 @@ namespace dxvk {
   }
   
   
+  void DxvkContext::emitGraphicsBarrier() {
+    if (!m_barrierControl.test(DxvkBarrierControl::IgnoreGraphicsBarriers))
+      this->spillRenderPass(true);
+  }
+
+
   void DxvkContext::generateMipmaps(
     const Rc<DxvkImageView>&        imageView,
           VkFilter                  filter) {

src/dxvk/dxvk_context.h

@@ -707,12 +707,14 @@ namespace dxvk {
             uint32_t          counterBias);
     
     /**
-     * \brief Emits barrier for render target readback
+     * \brief Emits graphics barrier
      *
-     * Use between draw calls if the fragment shader
-     * reads one of the currently bound render targets.
+     * Needs to be used when the fragment shader reads a bound
+     * render target, or when subsequent draw calls access any
+     * given resource for writing. It is assumed that no hazards
+     * can happen between storage descriptors and other resources.
      */
-    void emitRenderTargetReadbackBarrier();
+    void emitGraphicsBarrier();
 
     /**
      * \brief Generates mip maps