/*
* Vulkan Example - CPU based particle system
* 
* This sample renders a particle system that is updated on the host (by the CPU) and rendered by the GPU using a vertex buffer
*
* Copyright (C) 2016-2023 by Sascha Willems - www.saschawillems.de
*
* This code is licensed under the MIT license (MIT) (http://opensource.org/licenses/MIT)
*/

#include "vulkanexamplebase.h"
#include "VulkanglTFModel.h"

#define PARTICLE_COUNT 512

#define FLAME_RADIUS 8.0f

// The particle system is made from two different particle types
// That type defines how a particle is rendered
#define PARTICLE_TYPE_FLAME 0
#define PARTICLE_TYPE_SMOKE 1

struct Particle {
	glm::vec4 pos;
	glm::vec4 color;
	float alpha;
	float size;
	float rotation;
	uint32_t type;
	glm::vec4 vel;
	float rotationSpeed;
};

class VulkanExample : public VulkanExampleBase
{
public:
	struct {
		struct {
			vks::Texture2D smoke;
			vks::Texture2D fire;
			// Use a custom sampler to change sampler attributes required for rotating the uvs in the shader for alpha blended textures
			VkSampler sampler;
		} particles;
		struct {
			vks::Texture2D colorMap;
			vks::Texture2D normalMap;
		} floor;
	} textures{};

	vkglTF::Model environment;

	// These parameters define the particle system behaviour
	glm::vec3 emitterPos = glm::vec3(0.0f, -FLAME_RADIUS + 2.0f, 0.0f);
	glm::vec3 minVel = glm::vec3(-3.0f, 0.5f, -3.0f);
	glm::vec3 maxVel = glm::vec3(3.0f, 7.0f, 3.0f);

	struct Particles {
		VkBuffer buffer{ VK_NULL_HANDLE };
		VkDeviceMemory memory{ VK_NULL_HANDLE };
		// Store the mapped address of the particle data for reuse
		void *mappedMemory;
		// Size of the particle buffer in bytes
		size_t size{ 0 };
	} particles;

	struct {
		vks::Buffer particles;
		vks::Buffer environment;
	} uniformBuffers;

	struct UniformDataParticles {
		glm::mat4 projection;
		glm::mat4 modelView;
		// The viewport dimension is used by the particle system vertex shader 
		// to calculate the absolute point size based on the current viewport size
		glm::vec2 viewportDim;
		// This is the base point size for all particles
		float pointSize{ 10.0f };
	} uniformDataParticles;

	struct UniformDataEnvironment {
		glm::mat4 projection;
		glm::mat4 modelView;
		glm::mat4 normal;
		glm::vec4 lightPos = glm::vec4(0.0f, 0.0f, 0.0f, 0.0f);
	} uniformDataEnvironment;

	struct {
		VkPipeline particles{ VK_NULL_HANDLE };
		VkPipeline environment{ VK_NULL_HANDLE };
	} pipelines;

	VkPipelineLayout pipelineLayout{ VK_NULL_HANDLE };
	VkDescriptorSetLayout descriptorSetLayout{ VK_NULL_HANDLE };

	struct {
		VkDescriptorSet particles{ VK_NULL_HANDLE };
		VkDescriptorSet environment{ VK_NULL_HANDLE };
	} descriptorSets;

	std::vector<Particle> particleBuffer{};

	std::default_random_engine rndEngine;

	VulkanExample() : VulkanExampleBase()
	{
		title = "CPU based particle system";
		camera.type = Camera::CameraType::lookat;
		camera.setPosition(glm::vec3(0.0f, 0.0f, -75.0f));
		camera.setRotation(glm::vec3(-15.0f, 45.0f, 0.0f));
		camera.setPerspective(60.0f, (float)width / (float)height, 1.0f, 256.0f);
		timerSpeed *= 8.0f;
		rndEngine.seed(benchmark.active ? 0 : (unsigned)time(nullptr));
	}

	~VulkanExample()
	{
		if (device) {
			textures.particles.smoke.destroy();
			textures.particles.fire.destroy();
			textures.floor.colorMap.destroy();
			textures.floor.normalMap.destroy();

			vkDestroyPipeline(device, pipelines.particles, nullptr);
			vkDestroyPipeline(device, pipelines.environment, nullptr);

			vkDestroyPipelineLayout(device, pipelineLayout, nullptr);
			vkDestroyDescriptorSetLayout(device, descriptorSetLayout, nullptr);

			vkUnmapMemory(device, particles.memory);
			vkDestroyBuffer(device, particles.buffer, nullptr);
			vkFreeMemory(device, particles.memory, nullptr);

			uniformBuffers.environment.destroy();
			uniformBuffers.particles.destroy();

			vkDestroySampler(device, textures.particles.sampler, nullptr);
		}
	}

	virtual void getEnabledFeatures()
	{
		// Enable anisotropic filtering if supported
		if (deviceFeatures.samplerAnisotropy) {
			enabledFeatures.samplerAnisotropy = VK_TRUE;
		};
	}

	void buildCommandBuffers()
	{
		VkCommandBufferBeginInfo cmdBufInfo = vks::initializers::commandBufferBeginInfo();

		VkClearValue clearValues[2];
		clearValues[0].color = defaultClearColor;
		clearValues[1].depthStencil = { 1.0f, 0 };

		VkRenderPassBeginInfo renderPassBeginInfo = vks::initializers::renderPassBeginInfo();
		renderPassBeginInfo.renderPass = renderPass;
		renderPassBeginInfo.renderArea.offset.x = 0;
		renderPassBeginInfo.renderArea.offset.y = 0;
		renderPassBeginInfo.renderArea.extent.width = width;
		renderPassBeginInfo.renderArea.extent.height = height;
		renderPassBeginInfo.clearValueCount = 2;
		renderPassBeginInfo.pClearValues = clearValues;

		for (int32_t i = 0; i < drawCmdBuffers.size(); ++i)
		{
			// Set target frame buffer
			renderPassBeginInfo.framebuffer = frameBuffers[i];

			VK_CHECK_RESULT(vkBeginCommandBuffer(drawCmdBuffers[i], &cmdBufInfo));

			vkCmdBeginRenderPass(drawCmdBuffers[i], &renderPassBeginInfo, VK_SUBPASS_CONTENTS_INLINE);

			VkViewport viewport = vks::initializers::viewport((float)width, (float)height, 0.0f, 1.0f);
			vkCmdSetViewport(drawCmdBuffers[i], 0, 1, &viewport);

			VkRect2D scissor = vks::initializers::rect2D(width, height, 0,0);
			vkCmdSetScissor(drawCmdBuffers[i], 0, 1, &scissor);

			VkDeviceSize offsets[1] = { 0 };

			// Environment
			vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayout, 0, 1, &descriptorSets.environment, 0, nullptr);
			vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelines.environment);
			environment.draw(drawCmdBuffers[i]);

			// Particle system (no index buffer)
			vkCmdBindDescriptorSets(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelineLayout, 0, 1, &descriptorSets.particles, 0, nullptr);
			vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelines.particles);
			vkCmdBindVertexBuffers(drawCmdBuffers[i], 0, 1, &particles.buffer, offsets);
			vkCmdDraw(drawCmdBuffers[i], static_cast<uint32_t>(particleBuffer.size()), 1, 0, 0);

			drawUI(drawCmdBuffers[i]);

			vkCmdEndRenderPass(drawCmdBuffers[i]);

			VK_CHECK_RESULT(vkEndCommandBuffer(drawCmdBuffers[i]));
		}
	}

	float rnd(float range)
	{
		std::uniform_real_distribution<float> rndDist(0.0f, range);
		return rndDist(rndEngine);
	}

	void initParticle(Particle *particle, glm::vec3 emitterPos)
	{
		particle->vel = glm::vec4(0.0f, minVel.y + rnd(maxVel.y - minVel.y), 0.0f, 0.0f);
		particle->alpha = rnd(0.75f);
		particle->size = 1.0f + rnd(0.5f);
		particle->color = glm::vec4(1.0f);
		particle->type = PARTICLE_TYPE_FLAME;
		particle->rotation = rnd(2.0f * float(M_PI));
		particle->rotationSpeed = rnd(2.0f) - rnd(2.0f);

		// Get random sphere point
		float theta = rnd(2.0f * float(M_PI));
		float phi = rnd(float(M_PI)) - float(M_PI) / 2.0f;
		float r = rnd(FLAME_RADIUS);

		particle->pos.x = r * cos(theta) * cos(phi);
		particle->pos.y = r * sin(phi);
		particle->pos.z = r * sin(theta) * cos(phi);

		particle->pos += glm::vec4(emitterPos, 0.0f);
	}

	// Change the type of a particle, e.g. from flame to smoke
	void transitionParticle(Particle *particle)
	{
		switch (particle->type)
		{
		case PARTICLE_TYPE_FLAME:
			// Flame particles have a chance of turning into smoke
			if (rnd(1.0f) < 0.05f)
			{
				particle->alpha = 0.0f;
				particle->color = glm::vec4(0.25f + rnd(0.25f));
				particle->pos.x *= 0.5f;
				particle->pos.z *= 0.5f;
				particle->vel = glm::vec4(rnd(1.0f) - rnd(1.0f), (minVel.y * 2) + rnd(maxVel.y - minVel.y), rnd(1.0f) - rnd(1.0f), 0.0f);
				particle->size = 1.0f + rnd(0.5f);
				particle->rotationSpeed = rnd(1.0f) - rnd(1.0f);
				particle->type = PARTICLE_TYPE_SMOKE;
			}
			else
			{
				initParticle(particle, emitterPos);
			}
			break;
		case PARTICLE_TYPE_SMOKE:
			// Respawn at end of life
			initParticle(particle, emitterPos);
			break;
		}
	}

	// Initialize the particle system and create a vertex buffer for rendering the particles
	void prepareParticles()
	{
		particleBuffer.resize(PARTICLE_COUNT);
		for (auto& particle : particleBuffer)
		{
			initParticle(&particle, emitterPos);
			particle.alpha = 1.0f - (abs(particle.pos.y) / (FLAME_RADIUS * 2.0f));
		}

		particles.size = particleBuffer.size() * sizeof(Particle);

		VK_CHECK_RESULT(vulkanDevice->createBuffer(
			VK_BUFFER_USAGE_VERTEX_BUFFER_BIT,
			VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
			particles.size,
			&particles.buffer,
			&particles.memory,
			particleBuffer.data()));

		// Map the memory and store the pointer for reuse
		VK_CHECK_RESULT(vkMapMemory(device, particles.memory, 0, particles.size, 0, &particles.mappedMemory));
	}

	// Update the state of all particles
	void updateParticles()
	{
		float particleTimer = frameTimer * 0.45f;
		for (auto& particle : particleBuffer)
		{
			switch (particle.type)
			{
			case PARTICLE_TYPE_FLAME:
				particle.pos.y -= particle.vel.y * particleTimer * 3.5f;
				particle.alpha += particleTimer * 2.5f;
				particle.size -= particleTimer * 0.5f;
				break;
			case PARTICLE_TYPE_SMOKE:
				particle.pos -= particle.vel * frameTimer * 1.0f;
				particle.alpha += particleTimer * 1.25f;
				particle.size += particleTimer * 0.125f;
				particle.color -= particleTimer * 0.05f;
				break;
			}
			particle.rotation += particleTimer * particle.rotationSpeed;
			// If a particle has faded out, turn it into the other type (e.g. flame to smoke and vice versa)
			if (particle.alpha > 2.0f)
			{
				transitionParticle(&particle);
			}
		}
		
		// Copy the updated particles to the vertex buffer
		size_t size = particleBuffer.size() * sizeof(Particle);
		memcpy(particles.mappedMemory, particleBuffer.data(), size);
	}

	void loadAssets()
	{
		// Particles
		textures.particles.smoke.loadFromFile(getAssetPath() + "textures/particle_smoke.ktx", VK_FORMAT_R8G8B8A8_UNORM, vulkanDevice, queue);
		textures.particles.fire.loadFromFile(getAssetPath() + "textures/particle_fire.ktx", VK_FORMAT_R8G8B8A8_UNORM, vulkanDevice, queue);

		// Floor
		textures.floor.colorMap.loadFromFile(getAssetPath() + "textures/fireplace_colormap_rgba.ktx", VK_FORMAT_R8G8B8A8_UNORM, vulkanDevice, queue);
		textures.floor.normalMap.loadFromFile(getAssetPath() + "textures/fireplace_normalmap_rgba.ktx", VK_FORMAT_R8G8B8A8_UNORM, vulkanDevice, queue);

		// Create a custom sampler to be used with the particle textures
		// Create sampler
		VkSamplerCreateInfo samplerCreateInfo = vks::initializers::samplerCreateInfo();
		samplerCreateInfo.magFilter = VK_FILTER_LINEAR;
		samplerCreateInfo.minFilter = VK_FILTER_LINEAR;
		samplerCreateInfo.mipmapMode = VK_SAMPLER_MIPMAP_MODE_LINEAR;
		// Different address mode
		samplerCreateInfo.addressModeU = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER;
		samplerCreateInfo.addressModeV = samplerCreateInfo.addressModeU;
		samplerCreateInfo.addressModeW = samplerCreateInfo.addressModeU;
		samplerCreateInfo.mipLodBias = 0.0f;
		samplerCreateInfo.compareOp = VK_COMPARE_OP_NEVER;
		samplerCreateInfo.minLod = 0.0f;
		// Both particle textures have the same number of mip maps
		samplerCreateInfo.maxLod = float(textures.particles.fire.mipLevels);

		if (vulkanDevice->features.samplerAnisotropy)
		{
			// Enable anisotropic filtering
			samplerCreateInfo.maxAnisotropy = 8.0f;
			samplerCreateInfo.anisotropyEnable = VK_TRUE;
		}

		// Use a different border color (than the normal texture loader) for additive blending
		samplerCreateInfo.borderColor = VK_BORDER_COLOR_FLOAT_TRANSPARENT_BLACK;
		VK_CHECK_RESULT(vkCreateSampler(device, &samplerCreateInfo, nullptr, &textures.particles.sampler));

		const uint32_t glTFLoadingFlags = vkglTF::FileLoadingFlags::PreTransformVertices | vkglTF::FileLoadingFlags::PreMultiplyVertexColors | vkglTF::FileLoadingFlags::FlipY;
		environment.loadFromFile(getAssetPath() + "models/fireplace.gltf", vulkanDevice, queue, glTFLoadingFlags);
	}

	void setupDescriptors()
	{
		// Pool
		std::vector<VkDescriptorPoolSize> poolSizes = {
			vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 2),
			vks::initializers::descriptorPoolSize(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 4)
		};
		VkDescriptorPoolCreateInfo descriptorPoolInfo = vks::initializers::descriptorPoolCreateInfo(poolSizes, 2);
		VK_CHECK_RESULT(vkCreateDescriptorPool(device, &descriptorPoolInfo, nullptr, &descriptorPool));

		// Layout
		std::vector<VkDescriptorSetLayoutBinding> setLayoutBindings = {
			// Binding 0 : Vertex shader uniform buffer
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, VK_SHADER_STAGE_VERTEX_BIT, 0),
			// Binding 1 : Fragment shader image sampler
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, VK_SHADER_STAGE_FRAGMENT_BIT, 1),
			// Binding 1 : Fragment shader image sampler
			vks::initializers::descriptorSetLayoutBinding(VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, VK_SHADER_STAGE_FRAGMENT_BIT,2)
		};
		VkDescriptorSetLayoutCreateInfo descriptorLayout = vks::initializers::descriptorSetLayoutCreateInfo(setLayoutBindings);
		VK_CHECK_RESULT(vkCreateDescriptorSetLayout(device, &descriptorLayout, nullptr, &descriptorSetLayout));
		
		// Sets
		std::vector<VkWriteDescriptorSet> writeDescriptorSets;

		VkDescriptorSetAllocateInfo allocInfo = vks::initializers::descriptorSetAllocateInfo(descriptorPool, &descriptorSetLayout, 1);

		VK_CHECK_RESULT(vkAllocateDescriptorSets(device, &allocInfo, &descriptorSets.particles));

		// Image descriptor for the color map texture
		VkDescriptorImageInfo texDescriptorSmoke = vks::initializers::descriptorImageInfo(textures.particles.sampler, textures.particles.smoke.view, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL);
		VkDescriptorImageInfo texDescriptorFire = vks::initializers::descriptorImageInfo(textures.particles.sampler, textures.particles.fire.view, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL);

		writeDescriptorSets = {
			// Binding 0: Vertex shader uniform buffer
			vks::initializers::writeDescriptorSet(descriptorSets.particles, VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 0, &uniformBuffers.particles.descriptor),
			// Binding 1: Smoke texture
			vks::initializers::writeDescriptorSet(descriptorSets.particles, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1, &texDescriptorSmoke),
			// Binding 1: Fire texture array
			vks::initializers::writeDescriptorSet(descriptorSets.particles, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 2, &texDescriptorFire)
		};
		vkUpdateDescriptorSets(device, static_cast<uint32_t>(writeDescriptorSets.size()), writeDescriptorSets.data(), 0, nullptr);

		// Environment
		VK_CHECK_RESULT(vkAllocateDescriptorSets(device, &allocInfo, &descriptorSets.environment));
		writeDescriptorSets = {
			// Binding 0: Vertex shader uniform buffer
			vks::initializers::writeDescriptorSet(descriptorSets.environment, VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 0, &uniformBuffers.environment.descriptor),
			// Binding 1: Color map
			vks::initializers::writeDescriptorSet(descriptorSets.environment, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 1, &textures.floor.colorMap.descriptor),
			// Binding 2: Normal map
			vks::initializers::writeDescriptorSet(descriptorSets.environment, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 2, &textures.floor.normalMap.descriptor),
		};
		vkUpdateDescriptorSets(device, static_cast<uint32_t>(writeDescriptorSets.size()), writeDescriptorSets.data(), 0, nullptr);
	}

	void preparePipelines()
	{
		// Layout
		VkPipelineLayoutCreateInfo pipelineLayoutCI = vks::initializers::pipelineLayoutCreateInfo(&descriptorSetLayout, 1);
		VK_CHECK_RESULT(vkCreatePipelineLayout(device, &pipelineLayoutCI, nullptr, &pipelineLayout));

		// Pipelines
		VkPipelineInputAssemblyStateCreateInfo inputAssemblyState = vks::initializers::pipelineInputAssemblyStateCreateInfo(VK_PRIMITIVE_TOPOLOGY_POINT_LIST, 0, VK_FALSE);
		VkPipelineRasterizationStateCreateInfo rasterizationState = vks::initializers::pipelineRasterizationStateCreateInfo(VK_POLYGON_MODE_FILL, VK_CULL_MODE_BACK_BIT, VK_FRONT_FACE_COUNTER_CLOCKWISE, 0);
		VkPipelineColorBlendAttachmentState blendAttachmentState = vks::initializers::pipelineColorBlendAttachmentState(0xf, VK_FALSE);
		VkPipelineColorBlendStateCreateInfo colorBlendState = vks::initializers::pipelineColorBlendStateCreateInfo(1, &blendAttachmentState);
		VkPipelineDepthStencilStateCreateInfo depthStencilState = vks::initializers::pipelineDepthStencilStateCreateInfo(VK_TRUE, VK_TRUE, VK_COMPARE_OP_LESS_OR_EQUAL);
		VkPipelineViewportStateCreateInfo viewportState = vks::initializers::pipelineViewportStateCreateInfo(1, 1, 0);
		VkPipelineMultisampleStateCreateInfo multisampleState = vks::initializers::pipelineMultisampleStateCreateInfo(VK_SAMPLE_COUNT_1_BIT, 0);
		std::vector<VkDynamicState> dynamicStateEnables = {VK_DYNAMIC_STATE_VIEWPORT, VK_DYNAMIC_STATE_SCISSOR};
		VkPipelineDynamicStateCreateInfo dynamicState = vks::initializers::pipelineDynamicStateCreateInfo(dynamicStateEnables);
		std::array<VkPipelineShaderStageCreateInfo, 2> shaderStages;

		VkGraphicsPipelineCreateInfo pipelineCI = vks::initializers::pipelineCreateInfo(pipelineLayout, renderPass);
		pipelineCI.pInputAssemblyState = &inputAssemblyState;
		pipelineCI.pRasterizationState = &rasterizationState;
		pipelineCI.pColorBlendState = &colorBlendState;
		pipelineCI.pMultisampleState = &multisampleState;
		pipelineCI.pViewportState = &viewportState;
		pipelineCI.pDepthStencilState = &depthStencilState;
		pipelineCI.pDynamicState = &dynamicState;
		pipelineCI.stageCount = static_cast<uint32_t>(shaderStages.size());
		pipelineCI.pStages = shaderStages.data();

		// Particle rendering pipeline
		{
			// Vertex input state
			VkVertexInputBindingDescription vertexInputBinding =
				vks::initializers::vertexInputBindingDescription(0, sizeof(Particle), VK_VERTEX_INPUT_RATE_VERTEX);

			std::vector<VkVertexInputAttributeDescription> vertexInputAttributes = {
				vks::initializers::vertexInputAttributeDescription(0, 0, VK_FORMAT_R32G32B32A32_SFLOAT,	offsetof(Particle, pos)),	// Location 0: Position
				vks::initializers::vertexInputAttributeDescription(0, 1, VK_FORMAT_R32G32B32A32_SFLOAT,	offsetof(Particle, color)),	// Location 1: Color
				vks::initializers::vertexInputAttributeDescription(0, 2, VK_FORMAT_R32_SFLOAT, offsetof(Particle, alpha)),			// Location 2: Alpha
				vks::initializers::vertexInputAttributeDescription(0, 3, VK_FORMAT_R32_SFLOAT, offsetof(Particle, size)),			// Location 3: Size
				vks::initializers::vertexInputAttributeDescription(0, 4, VK_FORMAT_R32_SFLOAT, offsetof(Particle, rotation)),		// Location 4: Rotation
				vks::initializers::vertexInputAttributeDescription(0, 5, VK_FORMAT_R32_SINT, offsetof(Particle, type)),				// Location 5: Particle type
			};

			VkPipelineVertexInputStateCreateInfo vertexInputState = vks::initializers::pipelineVertexInputStateCreateInfo();
			vertexInputState.vertexBindingDescriptionCount = 1;
			vertexInputState.pVertexBindingDescriptions = &vertexInputBinding;
			vertexInputState.vertexAttributeDescriptionCount = static_cast<uint32_t>(vertexInputAttributes.size());
			vertexInputState.pVertexAttributeDescriptions = vertexInputAttributes.data();

			pipelineCI.pVertexInputState = &vertexInputState;

			// Don t' write to depth buffer
			depthStencilState.depthWriteEnable = VK_FALSE;

			// Premulitplied alpha
			blendAttachmentState.blendEnable = VK_TRUE;
			blendAttachmentState.srcColorBlendFactor = VK_BLEND_FACTOR_ONE;
			blendAttachmentState.dstColorBlendFactor = VK_BLEND_FACTOR_ONE_MINUS_SRC_ALPHA;
			blendAttachmentState.colorBlendOp = VK_BLEND_OP_ADD;
			blendAttachmentState.srcAlphaBlendFactor = VK_BLEND_FACTOR_ONE;
			blendAttachmentState.dstAlphaBlendFactor = VK_BLEND_FACTOR_ZERO;
			blendAttachmentState.alphaBlendOp = VK_BLEND_OP_ADD;
			blendAttachmentState.colorWriteMask = VK_COLOR_COMPONENT_R_BIT | VK_COLOR_COMPONENT_G_BIT | VK_COLOR_COMPONENT_B_BIT | VK_COLOR_COMPONENT_A_BIT;

			shaderStages[0] = loadShader(getShadersPath() + "particlesystem/particle.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
			shaderStages[1] = loadShader(getShadersPath() + "particlesystem/particle.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
			VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCI, nullptr, &pipelines.particles));
		}

		// Environment rendering pipeline (normal mapped)
		{
			// Vertex input state is taken from the glTF model loader
			pipelineCI.pVertexInputState = vkglTF::Vertex::getPipelineVertexInputState({ vkglTF::VertexComponent::Position, vkglTF::VertexComponent::UV, vkglTF::VertexComponent::Normal, vkglTF::VertexComponent::Tangent });

			blendAttachmentState.blendEnable = VK_FALSE;
			depthStencilState.depthWriteEnable = VK_TRUE;
			inputAssemblyState.topology = VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;

			shaderStages[0] = loadShader(getShadersPath() + "particlesystem/normalmap.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
			shaderStages[1] = loadShader(getShadersPath() + "particlesystem/normalmap.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
			VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCI, nullptr, &pipelines.environment));
		}
	}

	// Prepare and initialize uniform buffer containing shader uniforms
	void prepareUniformBuffers()
	{
		// Vertex shader uniform buffer block
		VK_CHECK_RESULT(vulkanDevice->createBuffer(VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT, &uniformBuffers.particles, sizeof(UniformDataParticles)));
		// Vertex shader uniform buffer block
		VK_CHECK_RESULT(vulkanDevice->createBuffer(VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT, &uniformBuffers.environment, sizeof(UniformDataEnvironment)));
		// Map persistent
		VK_CHECK_RESULT(uniformBuffers.particles.map());
		VK_CHECK_RESULT(uniformBuffers.environment.map());
	}

	void updateUniformBuffers()
	{
		// Particle system fire
		uniformDataParticles.projection = camera.matrices.perspective;
		uniformDataParticles.modelView = camera.matrices.view;
		uniformDataParticles.viewportDim = glm::vec2((float)width, (float)height);
		memcpy(uniformBuffers.particles.mapped, &uniformDataParticles, sizeof(UniformDataParticles));

		// Environment
		uniformDataEnvironment.projection = camera.matrices.perspective;
		uniformDataEnvironment.modelView = camera.matrices.view;
		uniformDataEnvironment.normal = glm::inverseTranspose(uniformDataEnvironment.modelView);
		// Update light position
		if (!paused) {
			uniformDataEnvironment.lightPos.x = sin(timer * 2.0f * float(M_PI)) * 1.5f;
			uniformDataEnvironment.lightPos.y = 0.0f;
			uniformDataEnvironment.lightPos.z = cos(timer * 2.0f * float(M_PI)) * 1.5f;
		}
		memcpy(uniformBuffers.environment.mapped, &uniformDataEnvironment, sizeof(UniformDataEnvironment));
	}

	void prepare()
	{
		VulkanExampleBase::prepare();
		loadAssets();
		prepareParticles();
		prepareUniformBuffers();
		setupDescriptors();
		preparePipelines();
		buildCommandBuffers();
		prepared = true;
	}

	void draw()
	{
		VulkanExampleBase::prepareFrame();
		submitInfo.commandBufferCount = 1;
		submitInfo.pCommandBuffers = &drawCmdBuffers[currentBuffer];
		VK_CHECK_RESULT(vkQueueSubmit(queue, 1, &submitInfo, VK_NULL_HANDLE));
		VulkanExampleBase::submitFrame();
	}

	virtual void render()
	{
		if (!prepared)
			return;
		updateUniformBuffers();
		if (!paused) {
			updateParticles();
		}
		draw();
	}
};

VULKAN_EXAMPLE_MAIN()