.. _program_listing_file_Src_GraphicsEngineVulkan_renderer_PathTracingHistory.hpp:

Program Listing for File PathTracingHistory.hpp
===============================================

|exhale_lsh| :ref:`Return to documentation for file <file_Src_GraphicsEngineVulkan_renderer_PathTracingHistory.hpp>` (``Src/GraphicsEngineVulkan/renderer/PathTracingHistory.hpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   #pragma once
   
   #include <glm/glm.hpp>
   
   namespace Kataglyphis::VulkanRendererInternals {
   
   // Everything that, when changed, invalidates the path tracer's temporal
   // accumulation history: the camera view (an existing check) plus the
   // directional light's direction and colour/radiance, since
   // path_tracing.slang's NEE block - the lightDir/lightColor/lightIntensity
   // reads under its "Next-event estimation toward the directional light"
   // comment - reads sceneUBO.dirLight and a light change makes the running
   // mean blend samples lit by two different lights. The projection is here
   // too: path_tracing.slang builds every primary ray from
   // globalUBO.inv_projection, so a FOV (or near/far/aspect) change changes
   // every ray while the running mean keeps counting frames traced through the
   // old one. Deliberately narrow - cloud/shadow/PCF fields in SceneUBO are not
   // read by path_tracing.slang, so widening this to the whole UBO would reset
   // on changes that do not affect the traced image.
   struct PathTracingHistoryKey
   {
       glm::mat4 view{ 1.0F };
       glm::mat4 projection{ 1.0F };
       glm::vec4 lightDirection{ 0.0F };
       glm::vec4 lightColorAndRadiance{ 0.0F };
       int samplesPerPixel{ 0 };
       int maxBounces{ 0 };
   
       friend auto operator==(const PathTracingHistoryKey &, const PathTracingHistoryKey &) -> bool = default;
   };
   
   }// namespace Kataglyphis::VulkanRendererInternals