From b4afa01e74375446c12e4bd7472412df7f0d6e48 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 16 Mar 2022 13:29:09 +0200
Subject: [PATCH] Skip binding of low-numbered descriptor sets if they haven't
 changed

---
 source/backends/vulkan/pipelinestate_backend.cpp | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/source/backends/vulkan/pipelinestate_backend.cpp b/source/backends/vulkan/pipelinestate_backend.cpp
index a6a548af..02e7993c 100644
--- a/source/backends/vulkan/pipelinestate_backend.cpp
+++ b/source/backends/vulkan/pipelinestate_backend.cpp
@@ -374,6 +374,7 @@ void VulkanPipelineState::apply(VkCommandBuffer command_buffer, const VulkanPipe
 	const PipelineState &self = *static_cast<const PipelineState *>(this);
 	const VulkanFunctions &vk = device.get_functions();
 
+	unsigned first_changed_desc_set = 0;
 	if(!last)
 		unapplied = ~0U;
 	else if(last!=this)
@@ -387,6 +388,7 @@ void VulkanPipelineState::apply(VkCommandBuffer command_buffer, const VulkanPipe
 			if(descriptor_set_slots[i]!=last->descriptor_set_slots[i])
 			{
 				unapplied |= PipelineState::UNIFORMS;
+				first_changed_desc_set = i;
 				break;
 			}
 		if(self.viewport!=last_ps.viewport)
@@ -420,12 +422,13 @@ void VulkanPipelineState::apply(VkCommandBuffer command_buffer, const VulkanPipe
 	if((unapplied&PipelineState::UNIFORMS) && !descriptor_set_slots.empty())
 	{
 		vector<VkDescriptorSet> descriptor_set_handles;
-		descriptor_set_handles.reserve(self.descriptor_set_slots.size());
-		for(unsigned i=0; i<self.descriptor_set_slots.size(); ++i)
-			descriptor_set_handles.push_back(device.get_descriptor_pool().get_descriptor_set(self.descriptor_set_slots[i], self, i, frame));
+		descriptor_set_handles.reserve(descriptor_set_slots.size()-first_changed_desc_set);
+		for(unsigned i=first_changed_desc_set; i<descriptor_set_slots.size(); ++i)
+			descriptor_set_handles.push_back(device.get_descriptor_pool().get_descriptor_set(
+				self.descriptor_set_slots[i], self, i, frame));
 
 		vk.CmdBindDescriptorSets(command_buffer, VK_PIPELINE_BIND_POINT_GRAPHICS, self.shprog->layout_handle,
-			0, descriptor_set_handles.size(), descriptor_set_handles.data(), 0, 0);
+			first_changed_desc_set, descriptor_set_handles.size(), descriptor_set_handles.data(), 0, 0);
 	}
 
 	if(unapplied&(PipelineState::VIEWPORT|PipelineState::SCISSOR))
-- 
2.43.0