Avoid binding descriptor sets for layouts without that set

Avoids disturbing necessary descriptor sets while still avoiding the need for full layout compatibility checks.

This is achieved with a basic vector<bool> saying which sets a pipeline layout has and doesn't have, so layouts it doesn't have won't be bound.
This could mean different sets are bound than if a full compatibility check was done, but that should only happen when the scenegraph requested invalid API usage - there should only be one BindDescriptorSet for each slot at the top of the state stacks, and if it's for a slot the current pipeline layout needs, it must be compatible.
Therefore, we only need to worry about compatibility checks for slots the current pipeline layout doesn't use.

Author: AnyOldName3

include/vsg/state/PipelineLayout.h

@@ -34,6 +34,7 @@ namespace vsg
         VkPipelineLayoutCreateFlags flags = 0;
         DescriptorSetLayouts setLayouts;
         PushConstantRanges pushConstantRanges;
+        std::vector<bool> descriptorSetSlots;
 
         /// Vulkan VkPipelineLayout handle
         VkPipelineLayout vk(uint32_t deviceID) const { return _implementation[deviceID]->_pipelineLayout; }

include/vsg/vk/CommandBuffer.h

@@ -56,6 +56,7 @@ namespace vsg
         void setCurrentPipelineLayout(const PipelineLayout* pipelineLayout);
 
         VkPipelineLayout getCurrentPipelineLayout() const { return _currentPipelineLayout; }
+        const std::vector<bool>& getCurrentDescriptorSetSlots() const { return _currentDescriptorSetSlots; }
         VkShaderStageFlags getCurrentPushConstantStageFlags() const { return _currentPushConstantStageFlags; }
 
         ref_ptr<ScratchMemory> scratchMemory;
@@ -73,6 +74,7 @@ namespace vsg
         ref_ptr<Device> _device;
         ref_ptr<CommandPool> _commandPool;
         VkPipelineLayout _currentPipelineLayout;
+        std::vector<bool> _currentDescriptorSetSlots;
         VkShaderStageFlags _currentPushConstantStageFlags;
     };
     VSG_type_name(vsg::CommandBuffer);

src/vsg/state/BindDescriptorSet.cpp

@@ -113,6 +113,13 @@ void BindDescriptorSets::compile(Context& context)
 void BindDescriptorSets::record(CommandBuffer& commandBuffer) const
 {
     //info("BindDescriptorSets::record() ", dynamicOffsets.size(), ", ", dynamicOffsets.data());
+    if (commandBuffer.getCurrentDescriptorSetSlots().size() < firstSet + descriptorSets.size())
+        return;
+    for (size_t slot = firstSet; slot < firstSet + descriptorSets.size(); ++slot)
+    {
+        if (!commandBuffer.getCurrentDescriptorSetSlots()[slot])
+            return;
+    }
     auto& vkd = _vulkanData[commandBuffer.deviceID];
     vkCmdBindDescriptorSets(commandBuffer, pipelineBindPoint, vkd._vkPipelineLayout, firstSet,
                             static_cast<uint32_t>(vkd._vkDescriptorSets.size()), vkd._vkDescriptorSets.data(),
@@ -209,8 +216,11 @@ void BindDescriptorSet::compile(Context& context)
 void BindDescriptorSet::record(CommandBuffer& commandBuffer) const
 {
     //info("BindDescriptorSet::record() ", dynamicOffsets.size(), ", ", dynamicOffsets.data());
-    auto& vkd = _vulkanData[commandBuffer.deviceID];
-    vkCmdBindDescriptorSets(commandBuffer, pipelineBindPoint, vkd._vkPipelineLayout, firstSet,
-                            1, &(vkd._vkDescriptorSet),
-                            static_cast<uint32_t>(dynamicOffsets.size()), dynamicOffsets.data());
+    if (commandBuffer.getCurrentDescriptorSetSlots().size() > firstSet && commandBuffer.getCurrentDescriptorSetSlots()[firstSet])
+    {
+        auto& vkd = _vulkanData[commandBuffer.deviceID];
+        vkCmdBindDescriptorSets(commandBuffer, pipelineBindPoint, vkd._vkPipelineLayout, firstSet,
+                                1, &(vkd._vkDescriptorSet),
+                                static_cast<uint32_t>(dynamicOffsets.size()), dynamicOffsets.data());
+    }
 }

src/vsg/state/PipelineLayout.cpp

@@ -30,7 +30,8 @@ PipelineLayout::PipelineLayout(const PipelineLayout& rhs, const CopyOp& copyop)
     Inherit(rhs, copyop),
     flags(rhs.flags),
     setLayouts(rhs.setLayouts),
-    pushConstantRanges(rhs.pushConstantRanges)
+    pushConstantRanges(rhs.pushConstantRanges),
+    descriptorSetSlots(rhs.descriptorSetSlots)
 {
 }
 
@@ -123,9 +124,13 @@ void PipelineLayout::compile(Context& context)
 {
     if (!_implementation[context.deviceID])
     {
+        descriptorSetSlots.clear();
+        descriptorSetSlots.reserve(setLayouts.size());
+
         for (auto dsl : setLayouts)
         {
             if (dsl) dsl->compile(context);
+            descriptorSetSlots.push_back(dsl != nullptr);
         }
         _implementation[context.deviceID] = PipelineLayout::Implementation::create(context.device, setLayouts, pushConstantRanges, flags);
     }

src/vsg/state/ViewDependentState.cpp

@@ -151,7 +151,7 @@ void BindViewDescriptorSets::compile(Context& context)
 
 void BindViewDescriptorSets::record(CommandBuffer& commandBuffer) const
 {
-    if (commandBuffer.viewDependentState)
+    if (commandBuffer.viewDependentState && commandBuffer.getCurrentDescriptorSetSlots().size() > firstSet && commandBuffer.getCurrentDescriptorSetSlots()[firstSet])
     {
         commandBuffer.viewDependentState->bindDescriptorSets(commandBuffer, pipelineBindPoint, layout->vk(commandBuffer.deviceID), firstSet);
     }

src/vsg/vk/CommandBuffer.cpp

@@ -30,6 +30,7 @@ CommandBuffer::CommandBuffer(CommandPool* commandPool, VkCommandBuffer commandBu
     _device(commandPool->getDevice()),
     _commandPool(commandPool),
     _currentPipelineLayout(VK_NULL_HANDLE),
+    _currentDescriptorSetSlots(),
     _currentPushConstantStageFlags(0)
 {
 }
@@ -45,6 +46,7 @@ CommandBuffer::~CommandBuffer()
 void CommandBuffer::reset()
 {
     _currentPipelineLayout = VK_NULL_HANDLE;
+    _currentDescriptorSetSlots.clear();
     _currentPushConstantStageFlags = 0;
 
     _commandPool->reset();
@@ -59,6 +61,7 @@ void CommandBuffer::setCurrentPipelineLayout(const PipelineLayout* pipelineLayou
         state->dirtyStateStacks();
 
         _currentPipelineLayout = newLayout;
+        _currentDescriptorSetSlots = pipelineLayout->descriptorSetSlots;
         if (pipelineLayout->pushConstantRanges.empty())
             _currentPushConstantStageFlags = 0;
         else