Render Graph improvements

[yeetari]

• Ensure buffer and texture usage can't be in an invalid state
• Expand BufferResource::upload_data() to allow for dynamically changing data at runtime
• Changeable octree at runtime :)
• Cleanup physical resource/stage system in render graph (use shared_ptr and unique_ptr)
• Cleanup render graph docs
• Switch to 32-bit indices
• ImGUI with render graph (mostly)

This PR adds support to the render graph for dynamic buffers. This allows for changeable octree geometry at runtime, which a small demo has been created for. ImGUI support has also been rewritten to work with the render graph. It now fully uses the render graph for the two buffers and stage, however it still relies on textures being done externally. This brings around a 33% FPS improvement - and that's with the bigger octree. With the original octree, I get an FPS improvement of about 73%.

In terms of the internals of the render graph, the two std::unordered_maps used to map resources&stages to physical resources&stages has been removed. A RenderResource now holds a shared_ptr<PhysicalResource> and a RenderStage now holds a unique_ptr<PhysicalStage>. The reason a RenderResource holds a shared pointer is because, in the future, multiple render resources will be able to point to the same physical resource. This makes accessing the physical resource much easier, and removes the need for the ugly create functions.

Also, instead of storing just a std::vector<std::unique_ptr<RenderResource>>, each different type of resource (BufferResource, TextureResource, etc.) now has its own vector. This makes it faster to iterate each type of resource.

[IAmNotHanni]

Btw I can't seei ImGui. Not on Windows and neither on Ubuntu. I will debug this using RenderDoc.

[IAmNotHanni]

It works now on Ubuntu 20.04 LTS!

[movabo]

2021-05-17 00:48:57.078338 debug 11393 [vulkan-renderer] Running Application.
2021-05-17 00:48:57.079727 debug 11393 [vulkan-renderer] FPS: 0, window size: 800 x 800.
2021-05-17 00:48:57.083832 error 11393 [vulkan-renderer]  [ VUID-vkResetCommandPool-commandPool-00040 ] Object: 0x55f30a994950 (Type = 6) | Attempt to reset command pool with VkCommandBuffer 0x55f30a994950[] which is in use. The Vulkan spec states: All VkCommandBuffer objects allocated from commandPool must not be in the pending state (https://www.khronos.org/registry/vulkan/specs/1.1-extensions/html/vkspec.html#VUID-vkResetCommandPool-commandPool-00040)
2021-05-17 00:48:57.083853 critical 11393 [vulkan-renderer] Command line argument --stop-on-validation-message is enabled.
2021-05-17 00:48:57.083857 critical 11393 [vulkan-renderer] Application will cause a break point now!

Process finished with exit code 134 (interrupted by signal 6: SIGABRT)

caused by

vulkan-renderer/src/vulkan-renderer/application.cpp

Lines 310 to 320 in 60be537

	// Check if --stop-on-validation-message is enabled.
	if (user_data != nullptr) {
	// This feature stops command lines from overflooding with messages in case many validation
	// layer messages are reported in a short amount of time.
	spdlog::critical("Command line argument --stop-on-validation-message is enabled.");
	spdlog::critical("Application will cause a break point now!");
	// Wait for spdlog to shut down before aborting.
	spdlog::shutdown();
	std::abort();
	}

even though no argument was passed. Could not test because of this, also I don't understand at most points what the code should do (on a conceptual level), thus I don't feel fit to give a (full) review, but still gladly test it and read through the code.

[IAmNotHanni]

Fantastic work!

[IceflowRE]

Suggested change

	void load_octree_geometry(bool initial);
	/// @param initialize Initialize worlds with a fixed seed.
	void load_octree_geometry(bool initialize);

[IceflowRE]

Rename variable.