pathtracer.cpp

#include "pathtracer.h"

#include <random>

#include <core/message_tags.h>
#include <core/time.h>
#include <pugixml/pugixml.hpp>
#include <util/files.h>

namespace glare
{
	namespace raytrace
	{
		Pathtracer::Pathtracer()
			: Pathtracer(RayGeneratorType::eTrace)
		{

		}

		Pathtracer::Pathtracer(std::shared_ptr<core::GraphNode> graph_root)
			: Pathtracer(std::make_shared<SceneCollector>(graph_root))
		{

		}

		Pathtracer::Pathtracer(std::shared_ptr<core::GraphNode> graph_root, RayGeneratorType ray_generator)
			: Pathtracer(std::make_shared<SceneCollector>(graph_root), ray_generator)
		{

		}

		Pathtracer::Pathtracer(RayGeneratorType ray_generator)
			: Pathtracer(std::shared_ptr<SceneCollector>(nullptr), ray_generator)
		{
		}

		Pathtracer::Pathtracer(std::shared_ptr<SceneCollector> collector)
			: Pathtracer(collector, RayGeneratorType::eTrace)
		{
		}

		Pathtracer::Pathtracer(std::shared_ptr<SceneCollector> collector, RayGeneratorType ray_generator)
		{
			m_bounce_count_thresholds[static_cast<unsigned>(EffectType::eDiffusion)] = 4;
			m_bounce_count_thresholds[static_cast<unsigned>(EffectType::eReflection)] = 6;
			m_bounce_count_thresholds[static_cast<unsigned>(EffectType::eTransmission)] = 12;
			m_bounce_count_thresholds[static_cast<unsigned>(EffectType::eEmission)] = 1;

			m_ls_bounce_count_thresholds[static_cast<unsigned>(EffectType::eDiffusion)] = 1;
			m_ls_bounce_count_thresholds[static_cast<unsigned>(EffectType::eReflection)] = 3;
			m_ls_bounce_count_thresholds[static_cast<unsigned>(EffectType::eTransmission)] = 3;
			m_ls_bounce_count_thresholds[static_cast<unsigned>(EffectType::eEmission)] = 6;

			m_linespace_config.distance_threshold = 8.f;
			m_render_config.bounces = 16;
			Log_Hint << "Pathtracing Shader will now be compiled. This might take a couple of seconds.";
			m_render_shader = std::make_unique<core::Program>(files::shader("/pathtracer/pathtracer.comp"));
			m_generator_type = ray_generator;
			m_trace_buffer = std::make_unique<core::Buffer<gl::BufferType::eShaderStorage>>();

			registerForMessage(tags::scene);

			if (collector)
				initialize(collector);
		}

		Pathtracer::~Pathtracer()
		{
			if (!core::state::window->isClosing())
				unregisterForMessage(tags::scene);
		}

		void Pathtracer::loadSettings(const fs::path &xml_file)
		{
			pugi::xml_document preferences_file;
			Log_Info << "Pathtracer settings file load status: " << preferences_file.load_file(xml_file.c_str()).description();

			//Pathtracer
			const auto pt_child = preferences_file.child("pathtracer");

			//bounces
			const auto bounces_child = pt_child.find_child_by_attribute("group", "name", "bounces");
			m_bounce_count_thresholds[static_cast<unsigned>(EffectType::eDiffusion)] = bounces_child.find_child_by_attribute("item", "name", "diffusion").attribute("value").as_uint(2);
			m_bounce_count_thresholds[static_cast<unsigned>(EffectType::eReflection)] = bounces_child.find_child_by_attribute("item", "name", "reflection").attribute("value").as_uint(4);
			m_bounce_count_thresholds[static_cast<unsigned>(EffectType::eTransmission)] = bounces_child.find_child_by_attribute("item", "name", "transmission").attribute("value").as_uint(4);
			m_bounce_count_thresholds[static_cast<unsigned>(EffectType::eEmission)] = bounces_child.find_child_by_attribute("item", "name", "emission").attribute("value").as_uint(8);

			//ls thresholds
			const auto ls_thresholds_child = pt_child.find_child_by_attribute("group", "name", "ls-thresholds");
			m_ls_bounce_count_thresholds[static_cast<unsigned>(EffectType::eDiffusion)] = ls_thresholds_child.find_child_by_attribute("item", "name", "diffusion").attribute("value").as_uint(2);
			m_ls_bounce_count_thresholds[static_cast<unsigned>(EffectType::eReflection)] = ls_thresholds_child.find_child_by_attribute("item", "name", "reflection").attribute("value").as_uint(4);
			m_ls_bounce_count_thresholds[static_cast<unsigned>(EffectType::eTransmission)] = ls_thresholds_child.find_child_by_attribute("item", "name", "transmission").attribute("value").as_uint(4);
			m_ls_bounce_count_thresholds[static_cast<unsigned>(EffectType::eEmission)] = ls_thresholds_child.find_child_by_attribute("item", "name", "emission").attribute("value").as_uint(8);

			m_linespace_config.accuracy_threshold = ls_thresholds_child.find_child_by_attribute("item", "name", "accuracy").attribute("value").as_float(0.5f);
			m_linespace_config.shadow_threshold = ls_thresholds_child.find_child_by_attribute("item", "name", "shadow").attribute("value").as_float(0.5f);
			m_linespace_config.distance_threshold = ls_thresholds_child.find_child_by_attribute("item", "name", "distance").attribute("value").as_float(10.f);

			m_render_config.clamp_direct = pt_child.find_child_by_attribute("item", "name", "clamp-direct").attribute("value").as_float(8);
			m_render_config.clamp_indirect = pt_child.find_child_by_attribute("item", "name", "clamp-indirect").attribute("value").as_float(8);
		}

		void Pathtracer::reset()
		{
			m_render_config.current_sample = 0;
			if (m_color_store)
				gl::clearTextureImage(m_color_store->id(), 0, gl::TextureFormat::eRGBA, gl::Type::eFloat, glm::value_ptr(glm::vec4(0)));

			m_collector->apply(*m_render_shader);

			m_render_shader->uniform("u_render_config.num_bounces", m_render_config.bounces);
			m_render_shader->uniform("u_render_config.clamp_direct", m_render_config.clamp_direct);
			m_render_shader->uniform("u_render_config.clamp_indirect", m_render_config.clamp_indirect);

			m_render_shader->uniform("u_linespace_properties.accuracy_quality", m_linespace_config.accuracy_threshold);
			m_render_shader->uniform("u_linespace_properties.shadow_quality", m_linespace_config.shadow_threshold);
			m_render_shader->uniform("u_linespace_properties.distance_threshold", m_linespace_config.distance_threshold);

			unsigned bounce_thresholds = 0;
			for (int i = 0; i < 4; ++i)
			{
				bounce_thresholds |= (m_bounce_count_thresholds[i] & 0xff) << (8 * i);
			}
			m_render_shader->uniform("u_render_config.bounce_thresholds", bounce_thresholds);

			m_linespace_config.bounce_thresholds = 0;
			for (int i = 0; i < 4; ++i)
			{
				m_linespace_config.bounce_thresholds |= (m_ls_bounce_count_thresholds[i] & 0xff) << (8 * i);
			}
			m_render_shader->uniform("u_linespace_properties.bounce_thresholds", m_linespace_config.bounce_thresholds);

			m_render_shader->bindSubroutine(gl::ShaderType::eCompute, "u_light_sample[0]", "samplePoint");
			m_render_shader->bindSubroutine(gl::ShaderType::eCompute, "u_light_sample[1]", "sampleSpot");
			m_render_shader->bindSubroutine(gl::ShaderType::eCompute, "u_light_sample[2]", "sampleDirectional");
			m_render_shader->bindSubroutine(gl::ShaderType::eCompute, "u_light_sample[3]", "sampleAmbient");
		}

		const core::TextureRGBA_32F &Pathtracer::render(uint32_t width, uint32_t height)
		{
			if (width != m_last_width || height != m_last_height) {
				m_last_width = width;
				m_last_height = height;

				m_trace_buffer->reserve<Trace>(width * height, gl::BufferUsage::eDynamicCopy);
				m_render_target = std::make_unique<core::TextureRGBA_32F>(width, height);
				m_color_store = std::make_unique<core::TextureRGBA_32F>(width, height);

				m_render_shader->uniform("u_render_target", m_render_target->makeImageResident(gl::Access::eReadWrite));
				m_render_shader->uniform("u_color_store", m_color_store->makeImageResident(gl::Access::eReadWrite));
				m_render_shader->storageBuffer("trace_buffer", *m_trace_buffer);
				m_render_config.current_sample = 0;
			}

			if (m_skybox && m_skybox->isInitialized())
			{
				m_render_shader->uniform("u_environment.cubemap", m_skybox->makeResident());
				m_render_shader->uniform("u_environment.has_cubemap", 1);
			}
			else
			{
				m_render_shader->uniform("u_environment.color", glm::vec4(0.7f, 0.9f, 0.97f, 1));
				m_render_shader->uniform("u_environment.has_cubemap", 0);
			}

			for (unsigned sample = 0; sample < m_render_config.samples_per_frame; sample++) {

				if (m_render_config.current_sample >= m_render_config.max_samples)
					return *m_render_target;

				const static std::unique_ptr<RayGenerator> ray_generator = std::make_unique<RayGenerator>();
				ray_generator->generate(*this);

				m_render_shader->use();
				m_render_shader->uniform("u_render_config.current_sample", m_render_config.current_sample);
				m_render_shader->dispatch2d(width, 4, height, 4);

				++m_render_config.current_sample;
			}

			return *m_render_target;
		}

		void Pathtracer::renderToScreen(uint32_t width, uint32_t height)
		{
			static const std::shared_ptr<core::TextureRenderer> texture_renderer = core::DefaultTextureRenderers::makeSimpleRenderer();
			texture_renderer->draw(render(width, height));
		}

		void Pathtracer::saveRender(fs::path target) const
		{
			core::textures::saveTexture(target, *m_render_target);
		}

		void Pathtracer::setGenerator(RayGeneratorType generator)
		{
			m_generator_type = generator;
			reset();
		}

		RayGeneratorType Pathtracer::getGenerator() const
		{
			return m_generator_type;
		}

		void Pathtracer::initialize(std::shared_ptr<SceneCollector> collector)
		{
			m_collector = collector;
			m_collector->collect();

			m_skybox = core::state::skybox;
			reset();
		}

		void Pathtracer::reload(std::shared_ptr<core::GraphNode> graph_root)
		{
			if (!m_collector)
			{
				m_collector = std::make_shared<SceneCollector>(graph_root);
			}
			else
			{
				m_collector->setDirty(DirtyFlags::eAll);
				m_collector->collect(graph_root);
			}

			m_skybox = core::state::skybox;
			reset();
		}

		void Pathtracer::handle(messaging::message_t& message)
		{
			switch (message.name)
			{
			case tags::scene:
				reset();
				break;
			}
		}

		const core::Program& Pathtracer::shader() const
		{
			return *m_render_shader;
		}

		uint32_t Pathtracer::width() const
		{
			return m_last_width;
		}

		uint32_t Pathtracer::height() const
		{
			return m_last_height;
		}

		core::Buffer<gl::BufferType::eShaderStorage>& Pathtracer::traceBuffer() const
		{
			return *m_trace_buffer;
		}

		const core::TextureRGBA_32F& Pathtracer::renderTarget() const
		{
			return *m_render_target;
		}

		std::shared_ptr<SceneCollector> Pathtracer::collector() const
		{
			return m_collector;
		}

		unsigned Pathtracer::currentSample() const
		{
			return m_render_config.current_sample;
		}

		void Pathtracer::setEffectBounces(EffectType type, uint8_t bounces)
		{
			uint8_t clamped = bounces & 0xff;

			if (clamped != bounces)
			{
				Log_Warn << bounces << " - value larger than 15 (0xf). Result of " << clamped << " may be unintended.";
			}

			m_bounce_count_thresholds[static_cast<unsigned>(type)] = clamped;
			reset();
		}

		uint8_t Pathtracer::getEffectBounces(EffectType type)
		{
			return m_bounce_count_thresholds[static_cast<unsigned>(type)];
		}

		void Pathtracer::setLinespaceBounceThresholds(EffectType type, uint8_t bounces)
		{
			uint8_t clamped = bounces & 0xff;

			if (clamped != bounces)
			{
				Log_Warn << bounces << " - value larger than 15 (0xf). Result of " << clamped << " may be unintended.";
			}

			m_ls_bounce_count_thresholds[unsigned(type)] = clamped;
			reset();
		}

		uint8_t Pathtracer::getLinespaceBounceThreshold(EffectType type)
		{
			return m_ls_bounce_count_thresholds[static_cast<unsigned>(type)];
		}

		void Pathtracer::setSkybox(std::shared_ptr<core::Skybox> skybox)
		{
			m_skybox = skybox;
			reset();
		}

		std::shared_ptr<core::Skybox> Pathtracer::getSkybox() const
		{
			return m_skybox;
		}

		void Pathtracer::setBounces(unsigned count)
		{
			reset();
			m_render_config.bounces = count;
		}

		unsigned Pathtracer::getBounces() const
		{
			return m_render_config.bounces;
		}

		void Pathtracer::setMaxSamples(unsigned count)
		{
			m_render_config.max_samples = count;
		}

		unsigned Pathtracer::getMaxSamples() const
		{
			return m_render_config.max_samples;
		}

		void Pathtracer::setSamplesPerFrame(unsigned count)
		{
			m_render_config.samples_per_frame = count;
		}

		unsigned Pathtracer::getSamplesPerFrame() const
		{
			return m_render_config.samples_per_frame;
		}

		void Pathtracer::setClampDirect(float clamp_direct)
		{
			m_render_config.clamp_direct = clamp_direct; reset();
		}

		float Pathtracer::getClampDirect() const
		{
			return m_render_config.clamp_direct;
		}

		void Pathtracer::setClampIndirect(float clamp_indirect)
		{
			m_render_config.clamp_indirect = clamp_indirect; reset();
		}

		float Pathtracer::getClampIndirect() const
		{
			return m_render_config.clamp_indirect;
		}

		void Pathtracer::setAccuracyThreshold(float accuracy_threshold)
		{
			m_linespace_config.accuracy_threshold = accuracy_threshold; reset();
		}

		float Pathtracer::getAccuracyThreshold() const
		{
			return m_linespace_config.accuracy_threshold;
		}

		void Pathtracer::setShadowThreshold(float shadow_threshold)
		{
			m_linespace_config.shadow_threshold = shadow_threshold; reset();
		}

		float Pathtracer::getShadowThreshold() const
		{
			return m_linespace_config.shadow_threshold;
		}

		void Pathtracer::setDistanceThreshold(float distance_threshold)
		{
			m_linespace_config.distance_threshold = distance_threshold; reset();
		}

		float Pathtracer::getDistanceThreshold() const
		{
			return m_linespace_config.distance_threshold;
		}
	}
}