SoftShadow Class Reference

An implementation of the Percentage-Closer Soft Shadows. More...

#include <easy3d/renderer/soft_shadow.h>

Inheritance diagram for SoftShadow:

Public Types
enum	SamplePattern {   SP_Poisson_25_25 = 0 , SP_Poisson_32_64 = 1 , SP_Poisson_64_128 = 2 , SP_Poisson_100_100 = 3 ,   SP_Regular_49_225 = 4 }
	The sample pattern used for blocker search and PCF filtering. More...

Public Member Functions
	SoftShadow (Camera *cam)
	Constructor.
	~SoftShadow () override=default
	Destructor.
float	softness () const
	Get the softness of the shadow.
void	set_softness (float s)
	Set the softness of the shadow.
SamplePattern	sample_pattern () const
	Get the sample pattern used for blocker search and PCF filtering.
void	set_sample_pattern (SamplePattern pattern)
	Set the sample pattern used for blocker search and PCF filtering.
Public Member Functions inherited from Shadow
	Shadow (Camera *cam)
	Constructor.
bool	virtual_background () const
void	set_virtual_background (bool b)
	Enable/Disable the virtual background.
const vec4 &	virtual_background_color (const vec4 &c)
	Query the virtual background color.
void	set_virtual_background_color (const vec4 &c)
	Set the virtual background color.
int	shadow_map_size () const
	Query the size of the shadow map. The shadow is assumed to be square.
void	set_shadow_map_size (int size)
	Set/Change the size of the shadow map. The shadow is assumed to be square. Default: 1024 by 1024.
float	light_distance () const
	The distance of the light source to the scene (w.r.t. the scene radius).
void	set_light_distance (float dist)
float	darkness () const
void	set_darkness (float darkness)
void	draw (const std::vector< TrianglesDrawable * > &surfaces)
	Rendering the surfaces.

Detailed Description

An implementation of the Percentage-Closer Soft Shadows.

SoftShadow implements the Percentage-Closer Soft Shadows technique. See

• http://developer.download.nvidia.com/shaderlibrary/docs/shadow_PCSS.pdf
• https://http.download.nvidia.com/developer/presentations/2005/SIGGRAPH/Percentage_Closer_Soft_Shadows.pdf

— Overview — This sample demonstrates two techniques for rendering soft shadows: Percentage Closer Filtering (PCS) with a uniform kernel size and Percentage-Closer Soft Shadows (PCSS) with a variable kernel size. This sample is assuming the shadow map is a regular depth buffer (non-linear depths), and the shadow-map is generated using a perspective projection with the center of projection at the center of the area light simulated by PCSS. The sample uses a gradient-based depth bias to scale the depth bias based on the uv-space distance from the center of the kernel. To avoid self-shadowing artifacts, an additional depth bias may also been applied while writing depth into the shadow map.

— Percentage Closer Filtering (PCF) — The Percentage Closer Filtering technique uses a uniform size filter kernel, resulting in shadows with a uniformly soft edge. The PCF algorithm is very straightforward and fast, but does not achieve a realistic contact hardening effect. Also, while the kernel size and penumbra width is uniform, the kernel can be scaled to accommodate different sized lights.

— Percentage-Closer Soft Shadows (PCSS) — Soft shadows are typically rendered in games by using shadow mapping and Percentage Closer Filtering with a uniform kernel size. The Percentage-Closer Soft Shadows (PCSS) algorithm computes a variable kernel size based on the distance between the relative position of the receiver point, an approximation of the blocker, and the area light. It produces perceptually plausible soft shadows that harden on contact.

Optimization tips: rendering with multi-effects (e.g., shadowing, SSAO) can benefit from sharing the same geometry pass.

Examples

Tutorial_503_SoftShadow/main.cpp.

Member Enumeration Documentation

SamplePattern

enum SamplePattern

The sample pattern used for blocker search and PCF filtering.

Enumerator
SP_Poisson_25_25	25 samples for the blocker search, 25 samples in the PCF filtering, all samples using a Poisson disk
SP_Poisson_32_64	32 samples for the blocker search, 64 samples for the PCF filtering, all samples using a Poisson disk
SP_Poisson_64_128	64 samples for the blocker search, 128 samples for the PCF filtering, all samples using a Poisson disk
SP_Poisson_100_100	100 samples for the blocker search, 100 samples for the PCF filtering, all samples using a Poisson disk
SP_Regular_49_225	49 samples for the blocker search, 225 samples for the PCF filtering, all samples using regular sampling (faster than Poisson disk)

Constructor & Destructor Documentation

SoftShadow()

SoftShadow ( Camera * cam )

explicit

Constructor.

Parameters

cam	The camera used in the view.

Member Function Documentation

sample_pattern()

SamplePattern sample_pattern ( ) const

inline

Get the sample pattern used for blocker search and PCF filtering.

Returns

The sample pattern.

set_sample_pattern()

void set_sample_pattern ( SamplePattern pattern )

inline

Set the sample pattern used for blocker search and PCF filtering.

Parameters

pattern

The sample pattern.

set_softness()

void set_softness ( float s )

inline

Set the softness of the shadow.

Parameters

s	The softness of the shadow, must be in the range [0, 1].

softness()

float softness ( ) const

inline

Get the softness of the shadow.

Returns

The softness of the shadow, in the range [0, 1]. Default is 0.5.

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

• G:/3_code/Easy3D/easy3d/renderer/soft_shadow.h
• G:/3_code/Easy3D/easy3d/renderer/soft_shadow.cpp