PathTracer Class Reference

Unidirectional path tracer. Generates renderings of a scene by emitting rays from the user viewpoint and letting them bounce in the scene, forming paths. Lighting and materials contributions are accumulated along each path to compute the color of the associated sample. More...

#include <PathTracer.hpp>

Public Member Functions
	PathTracer ()=default
	PathTracer (const std::shared_ptr< Scene > &scene)
void	render (const Camera &camera, size_t samples, size_t depth, Image &render)
const Raycaster &	raycaster () const

Private Member Functions
bool	checkVisibility (const glm::vec3 &startPos, const glm::vec3 &rayDir, float maxDist) const
glm::vec3	evalBackground (const glm::vec3 &rayDir, const glm::vec3 &rayPos, const glm::vec2 &ndcPos, bool directHit) const

Static Private Member Functions
static glm::ivec2	getSampleGrid (size_t samples)
static glm::vec2	getSamplePosition (size_t sid, const glm::ivec2 &cellCount, const glm::vec2 &cellSize)
static glm::mat3	buildLocalFrame (const Object &obj, const Raycaster::Hit &hit, const glm::vec3 &rayDir, const glm::vec2 &uv)

Private Attributes
Raycaster	_raycaster
	The internal raycaster.
std::shared_ptr< Scene >	_scene
	The scene.

Detailed Description

Unidirectional path tracer. Generates renderings of a scene by emitting rays from the user viewpoint and letting them bounce in the scene, forming paths. Lighting and materials contributions are accumulated along each path to compute the color of the associated sample.

Constructor & Destructor Documentation

PathTracer() [1/2]

PathTracer::PathTracer ( )

default

Empty constructor.

PathTracer() [2/2]

PathTracer::PathTracer ( const std::shared_ptr< Scene > &  scene )

explicit

Constructor. Initializes the internal raycaster with the scene data.

Parameters

scene

the scene to path trace against

Member Function Documentation

buildLocalFrame()

glm::mat3 PathTracer::buildLocalFrame ( const Object &  obj, const Raycaster::Hit &  hit, const glm::vec3 &  rayDir, const glm::vec2 &  uv  )

staticprivate

Build the local frame at an intersection on an object surface.

Parameters

obj	the intersected object
hit	the intersection record
rayDir	the direction of the ray that intersected
uv	the local texture coordinates (if valid)

Returns

the local tangent space frame. \

checkVisibility()

bool PathTracer::checkVisibility ( const glm::vec3 &  startPos, const glm::vec3 &  rayDir, float  maxDist  ) const

private

Check visibility from a point along a ray in the scene, taking into account object opacity masks.

Parameters

startPos	the point to test visibility for
rayDir	the ray direction to follow
maxDist	the maximum distance to travel along the ray

Returns

true if the point has clear visibility along the ray

evalBackground()

glm::vec3 PathTracer::evalBackground ( const glm::vec3 &  rayDir, const glm::vec3 &  rayPos, const glm::vec2 &  ndcPos, bool  directHit  ) const

private

Evalutation the contribution from the scene background.

Parameters

rayDir	the direction of the ray that intersected
rayPos	the ray world space position
ndcPos	the current pixel in the final image
directHit	was it a direct hit or a hit after bounces

Returns

the background contribution

getSampleGrid()

glm::ivec2 PathTracer::getSampleGrid ( size_t  samples )

staticprivate

Compute the dimensions of a grid that contains a given number of samples.

Parameters

samples

the number of samples to place on a regular grid

Returns

the number of samples on each axis

getSamplePosition()

glm::vec2 PathTracer::getSamplePosition ( size_t  sid, const glm::ivec2 &  cellCount, const glm::vec2 &  cellSize  )

staticprivate

Get the local location of a sample in a pixel.

Parameters

sid	the sample ID for the pixel
cellCount	the number of samples on each grid axis
cellSize	the spacing between two samples on an axis

Returns

the local sample location in [0,1]

Note

The sample will be randomly jittered.

raycaster()

const Raycaster & PathTracer::raycaster ( ) const

inline

Returns

the internal raycaster.

render()

void PathTracer::render	(	const Camera &	camera,
		size_t	samples,
		size_t	depth,
		Image &	render
	)

Performs a rendering of the scene.

Parameters

camera	the viewpoint to use
samples	the number of samples per-pixel
depth	the maximum number of bounces for each path
render	the image, will be filled with the (gamma-corrected) result

Todo:

Support dieletric specular on top.

Todo:

Support all materials from the PBR demo.

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The documentation for this class was generated from the following files:

• src/apps/pathtracer/PathTracer.hpp
• src/apps/pathtracer/PathTracer.cpp