engine/src/image.cpp

@@ -8,86 +8,35 @@
 
 namespace sophia {
 
-void Image::transitionLayout(vk::CommandBuffer commandBuffer,
-                             vk::ImageLayout newLayout) {
-  vk::ImageMemoryBarrier barrier{};
-  barrier.oldLayout = this->layout;
-  barrier.newLayout = newLayout;
-  barrier.srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
-  barrier.dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
-  barrier.image = this->get();
-  barrier.subresourceRange.aspectMask = this->aspectMask;
-  barrier.subresourceRange.baseMipLevel = 0;
-  barrier.subresourceRange.levelCount = this->mipLevels;
-  barrier.subresourceRange.baseArrayLayer = 0;
-  barrier.subresourceRange.layerCount = this->arrayLayers;
-
-  vk::PipelineStageFlags srcStage;
-  vk::PipelineStageFlags dstStage;
-
-  if (this->layout == vk::ImageLayout::eUndefined &&
-      newLayout == vk::ImageLayout::eTransferDstOptimal) {
-    barrier.srcAccessMask = {};
-    barrier.dstAccessMask = vk::AccessFlagBits::eTransferWrite;
-    srcStage = vk::PipelineStageFlagBits::eTopOfPipe;
-    dstStage = vk::PipelineStageFlagBits::eTransfer;
-  } else if (this->layout == vk::ImageLayout::eTransferDstOptimal &&
-             newLayout == vk::ImageLayout::eShaderReadOnlyOptimal) {
-    barrier.srcAccessMask = vk::AccessFlagBits::eTransferWrite;
-    barrier.dstAccessMask = vk::AccessFlagBits::eShaderRead;
-    srcStage = vk::PipelineStageFlagBits::eTransfer;
-    dstStage = vk::PipelineStageFlagBits::eFragmentShader;
-  } else if (this->layout == vk::ImageLayout::eUndefined &&
-             newLayout == vk::ImageLayout::eDepthStencilAttachmentOptimal) {
-    barrier.srcAccessMask = {};
-    barrier.dstAccessMask = vk::AccessFlagBits::eDepthStencilAttachmentRead |
-                            vk::AccessFlagBits::eDepthStencilAttachmentWrite;
-    srcStage = vk::PipelineStageFlagBits::eTopOfPipe;
-    dstStage = vk::PipelineStageFlagBits::eEarlyFragmentTests;
-  } else if (this->layout == vk::ImageLayout::eUndefined &&
-             newLayout == vk::ImageLayout::eColorAttachmentOptimal) {
-    barrier.srcAccessMask = {};
-    barrier.dstAccessMask = vk::AccessFlagBits::eColorAttachmentWrite;
-    srcStage = vk::PipelineStageFlagBits::eTopOfPipe;
-    dstStage = vk::PipelineStageFlagBits::eColorAttachmentOutput;
-  } else if (this->layout == vk::ImageLayout::eUndefined &&
-             newLayout == vk::ImageLayout::eGeneral) {
-    barrier.srcAccessMask = {};
-    barrier.dstAccessMask =
-        vk::AccessFlagBits::eShaderRead | vk::AccessFlagBits::eShaderWrite;
-    srcStage = vk::PipelineStageFlagBits::eTopOfPipe;
-    dstStage = vk::PipelineStageFlagBits::eComputeShader;
-  } else if (this->layout == vk::ImageLayout::eColorAttachmentOptimal &&
-             newLayout == vk::ImageLayout::ePresentSrcKHR) {
-    barrier.srcAccessMask = vk::AccessFlagBits::eColorAttachmentWrite;
-    barrier.dstAccessMask = {};
-    srcStage = vk::PipelineStageFlagBits::eColorAttachmentOutput;
-    dstStage = vk::PipelineStageFlagBits::eBottomOfPipe;
-  } else if (this->layout == vk::ImageLayout::eColorAttachmentOptimal &&
-             newLayout == vk::ImageLayout::eShaderReadOnlyOptimal) {
-    barrier.srcAccessMask = vk::AccessFlagBits::eColorAttachmentWrite;
-    barrier.dstAccessMask = vk::AccessFlagBits::eShaderRead;
-    srcStage = vk::PipelineStageFlagBits::eColorAttachmentOutput;
-    dstStage = vk::PipelineStageFlagBits::eFragmentShader;
-  } else if (this->layout == vk::ImageLayout::eShaderReadOnlyOptimal &&
-             newLayout == vk::ImageLayout::eColorAttachmentOptimal) {
-    barrier.srcAccessMask = vk::AccessFlagBits::eShaderRead;
-    barrier.dstAccessMask = vk::AccessFlagBits::eColorAttachmentWrite;
-    srcStage = vk::PipelineStageFlagBits::eFragmentShader;
-    dstStage = vk::PipelineStageFlagBits::eColorAttachmentOutput;
-  } else if (this->layout == vk::ImageLayout::ePresentSrcKHR &&
-             newLayout == vk::ImageLayout::eColorAttachmentOptimal) {
-    barrier.srcAccessMask = {};
-    barrier.dstAccessMask = vk::AccessFlagBits::eColorAttachmentWrite;
-    srcStage = vk::PipelineStageFlagBits::eTopOfPipe;
-    dstStage = vk::PipelineStageFlagBits::eColorAttachmentOutput;
-  } else {
-    log::fatal("Unsupported image layout transition.");
-    throw std::runtime_error("Unsupported image layout transition.");
+vk::ImageSubresourceRange Image::getSubresourceRange() const {
+  return vk::ImageSubresourceRange{this->aspectMask, 0, this->mipLevels, 0,
+                                   this->arrayLayers};
 }
 
-  commandBuffer.pipelineBarrier(srcStage, dstStage, {}, nullptr, nullptr,
+AccessState Image::getAccessState() const {
+  AccessState state = getStateForLayout(this->layout);
+
+  // A wrapped (swapchain) image is handed to us by the acquire semaphore, so
+  // whatever we do next has to be ordered after that wait.
+  if (this->isExternal() && (this->layout == vk::ImageLayout::eUndefined ||
+                             this->layout == vk::ImageLayout::ePresentSrcKHR)) {
+    state.stage = SWAPCHAIN_ACQUIRE_STAGE;
+  }
+
+  return state;
+}
+
+void Image::transitionLayout(vk::CommandBuffer commandBuffer,
+                             vk::ImageLayout newLayout) {
+  AccessState from = this->getAccessState();
+  AccessState to = getStateForLayout(newLayout);
+
+  if (needsBarrier(from, to)) {
+    vk::ImageMemoryBarrier barrier =
+        makeImageBarrier(this->get(), this->getSubresourceRange(), from, to);
+    commandBuffer.pipelineBarrier(from.stage, to.stage, {}, nullptr, nullptr,
                                   barrier);
+  }
 
   this->layout = newLayout;
 }

engine/src/image.hpp

@@ -4,6 +4,8 @@
 #include <sophia/types.hpp>
 #include <vulkan/vulkan.hpp>
 
+#include "rendering/access.hpp"
+
 namespace sophia {
 
 class Device;
@@ -28,6 +30,20 @@ class Image {
   vk::Format getFormat() const { return this->format; }
   vk::Extent3D getExtent() const { return this->extent; }
   vk::ImageLayout getLayout() const { return this->layout; }
+  vk::ImageSubresourceRange getSubresourceRange() const;
+
+  /**
+   * The layout this image was last left in, plus the stages and accesses that
+   * a barrier out of it has to wait on.
+   */
+  AccessState getAccessState() const;
+
+  /**
+   * Updates the tracked layout without recording a barrier. For code that
+   * does its own transitions (the RenderGraph) and needs to hand the final
+   * layout back.
+   */
+  void recordLayout(vk::ImageLayout newLayout) { this->layout = newLayout; }
 
   void transitionLayout(vk::CommandBuffer commandBuffer,
                         vk::ImageLayout newLayout);

engine/src/rendering/access.cpp

@@ -0,0 +1,104 @@
+#include "rendering/access.hpp"
+
+#include <array>
+#include <sophia/util/logger.hpp>
+#include <stdexcept>
+
+namespace sophia {
+
+namespace {
+
+constexpr std::array<Access, 7> ALL_ACCESSES = {
+    Access::ColorWrite,       Access::DepthWrite,  Access::SampledRead,
+    Access::StorageReadWrite, Access::TransferSrc, Access::TransferDst,
+    Access::Present,
+};
+
+constexpr vk::AccessFlags WRITE_ACCESSES =
+    vk::AccessFlagBits::eColorAttachmentWrite |
+    vk::AccessFlagBits::eDepthStencilAttachmentWrite |
+    vk::AccessFlagBits::eShaderWrite | vk::AccessFlagBits::eTransferWrite;
+
+}  // namespace
+
+AccessState getAccessState(Access access) {
+  switch (access) {
+    case Access::ColorWrite:
+      return {vk::ImageLayout::eColorAttachmentOptimal,
+              vk::PipelineStageFlagBits::eColorAttachmentOutput,
+              vk::AccessFlagBits::eColorAttachmentRead |
+                  vk::AccessFlagBits::eColorAttachmentWrite};
+    case Access::DepthWrite:
+      return {vk::ImageLayout::eDepthStencilAttachmentOptimal,
+              vk::PipelineStageFlagBits::eEarlyFragmentTests |
+                  vk::PipelineStageFlagBits::eLateFragmentTests,
+              vk::AccessFlagBits::eDepthStencilAttachmentRead |
+                  vk::AccessFlagBits::eDepthStencilAttachmentWrite};
+    case Access::SampledRead:
+      return {vk::ImageLayout::eShaderReadOnlyOptimal,
+              vk::PipelineStageFlagBits::eFragmentShader,
+              vk::AccessFlagBits::eShaderRead};
+    case Access::StorageReadWrite:
+      return {
+          vk::ImageLayout::eGeneral, vk::PipelineStageFlagBits::eComputeShader,
+          vk::AccessFlagBits::eShaderRead | vk::AccessFlagBits::eShaderWrite};
+    case Access::TransferSrc:
+      return {vk::ImageLayout::eTransferSrcOptimal,
+              vk::PipelineStageFlagBits::eTransfer,
+              vk::AccessFlagBits::eTransferRead};
+    case Access::TransferDst:
+      return {vk::ImageLayout::eTransferDstOptimal,
+              vk::PipelineStageFlagBits::eTransfer,
+              vk::AccessFlagBits::eTransferWrite};
+    case Access::Present:
+      return {vk::ImageLayout::ePresentSrcKHR,
+              vk::PipelineStageFlagBits::eBottomOfPipe, vk::AccessFlags{}};
+  }
+
+  log::fatal("Unknown Access value.");
+  throw std::runtime_error("Unknown Access value.");
+}
+
+AccessState getStateForLayout(vk::ImageLayout layout) {
+  if (layout == vk::ImageLayout::eUndefined) {
+    return AccessState{};
+  }
+
+  for (Access access : ALL_ACCESSES) {
+    AccessState state = getAccessState(access);
+    if (state.layout == layout) {
+      return state;
+    }
+  }
+
+  log::fatal("Unsupported image layout:", vk::to_string(layout));
+  throw std::runtime_error("Unsupported image layout.");
+}
+
+bool writesImage(const AccessState& state) {
+  return static_cast<bool>(state.access & WRITE_ACCESSES);
+}
+
+bool needsBarrier(const AccessState& from, const AccessState& to) {
+  return from.layout != to.layout || writesImage(from) || writesImage(to);
+}
+
+vk::ImageMemoryBarrier makeImageBarrier(vk::Image image,
+                                        const vk::ImageSubresourceRange& range,
+                                        const AccessState& from,
+                                        const AccessState& to) {
+  vk::ImageMemoryBarrier barrier{};
+  barrier.oldLayout = from.layout;
+  barrier.newLayout = to.layout;
+  barrier.srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
+  barrier.dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
+  barrier.image = image;
+  barrier.subresourceRange = range;
+  // Only writes need to be made available; reads just need the execution
+  // dependency the stage masks already give.
+  barrier.srcAccessMask = from.access & WRITE_ACCESSES;
+  barrier.dstAccessMask = to.access;
+  return barrier;
+}
+
+}  // namespace sophia

engine/src/rendering/access.hpp

@@ -0,0 +1,63 @@
+#pragma once
+
+#include <vulkan/vulkan.hpp>
+
+namespace sophia {
+
+/**
+ * How an image is used at a point in a frame. Each value implies an image
+ * layout plus the pipeline stages and memory accesses that go with it, so a
+ * barrier between any two of them can be derived instead of hand-written.
+ */
+enum class Access {
+  ColorWrite,
+  DepthWrite,
+  SampledRead,
+  StorageReadWrite,
+  TransferSrc,
+  TransferDst,
+  Present,
+};
+
+/**
+ * The layout, stages and accesses an image is in after some use. Barriers go
+ * from one of these to another.
+ */
+struct AccessState {
+  vk::ImageLayout layout = vk::ImageLayout::eUndefined;
+  vk::PipelineStageFlags stage = vk::PipelineStageFlagBits::eTopOfPipe;
+  vk::AccessFlags access;
+};
+
+/**
+ * The stage RenderContext waits on for the swapchain image-available
+ * semaphore. A barrier that takes a swapchain image out of its
+ * just-acquired state has to use this as its source stage, otherwise the
+ * layout transition isn't ordered after the acquire.
+ */
+inline constexpr vk::PipelineStageFlags SWAPCHAIN_ACQUIRE_STAGE =
+    vk::PipelineStageFlagBits::eColorAttachmentOutput;
+
+AccessState getAccessState(Access access);
+
+/**
+ * The state of an image sitting in `layout` with no outstanding work.
+ * eUndefined maps to "nothing to wait on"; layouts with no matching Access
+ * throw.
+ */
+AccessState getStateForLayout(vk::ImageLayout layout);
+
+bool writesImage(const AccessState& state);
+
+/**
+ * Whether going from `from` to `to` needs a barrier: a layout change, or any
+ * hazard involving a write. Read-after-read in the same layout doesn't.
+ */
+bool needsBarrier(const AccessState& from, const AccessState& to);
+
+vk::ImageMemoryBarrier makeImageBarrier(vk::Image image,
+                                        const vk::ImageSubresourceRange& range,
+                                        const AccessState& from,
+                                        const AccessState& to);
+
+}  // namespace sophia