glsl::screenSpaceRayTrace_glsl Class Reference

Shader program. More...

Public Member Functions
float	distanceSquared (vec2 A, vec2 B)
bool traceScreenSpaceRay()	numLayers (vec3 csOrigin, vec3 csDirection, mat4x4 projectToPixelMatrix, sampler2D csZBuffer, vec2 csZBufferSize, float csZThickness, const in bool csZBufferIsHyperbolic, vec3 clipInfo, float nearPlaneZ, float stride, float jitterFraction, float maxSteps, in float maxRayTraceDistance, out vec2 hitPixel, out int hitLayer, out vec3 csHitPoint)
	Screen-space ray trace suitable for a "peeled" depth buffer of up to four layers. More...
bool	traceScreenSpaceRay1 (vec3 csOrigin, vec3 csDirection, mat4x4 projectToPixelMatrix, sampler2D csZBuffer, vec2 csZBufferSize, float csZThickness, const in bool csZBufferIsHyperbolic, vec3 clipInfo, float nearPlaneZ, float stride, float jitterFraction, float maxSteps, in float maxRayTraceDistance, out vec2 hitPixel, out int hitLayer, out vec3 csHitPoint)

Detailed Description

Shader program.

Member Function Documentation

distanceSquared()

float glsl::screenSpaceRayTrace_glsl::distanceSquared ( vec2  A, vec2  B  )

inline

numLayers()

bool traceScreenSpaceRay() glsl::screenSpaceRayTrace_glsl::numLayers ( vec3  csOrigin, vec3  csDirection, mat4x4  projectToPixelMatrix, sampler2D  csZBuffer, vec2  csZBufferSize, float  csZThickness, const in bool  csZBufferIsHyperbolic, vec3  clipInfo, float  nearPlaneZ, float  stride, float  jitterFraction, float  maxSteps, in float  maxRayTraceDistance, out vec2  hitPixel, out int  hitLayer, out vec3  csHitPoint  )

inline

Screen-space ray trace suitable for a "peeled" depth buffer of up to four layers.

The common unpeeled, single-layer case is specially optimized below. For traceScreenSpaceRay1, the termination conditions within the inner loop can be moved to the loop condition itself.

traceScreenSpaceRay1()

bool glsl::screenSpaceRayTrace_glsl::traceScreenSpaceRay1 ( vec3  csOrigin, vec3  csDirection, mat4x4  projectToPixelMatrix, sampler2D  csZBuffer, vec2  csZBufferSize, float  csZThickness, const in bool  csZBufferIsHyperbolic, vec3  clipInfo, float  nearPlaneZ, float  stride, float  jitterFraction, float  maxSteps, in float  maxRayTraceDistance, out vec2  hitPixel, out int  hitLayer, out vec3  csHitPoint  )

inline

Parameters

csOrigin	Camera-space ray origin, which must be within the view volume and must have z < -0.01 and project within the valid screen rectangle
csDirection	Unit length camera-space ray direction
projectToPixelMatrix	A projection matrix that maps to pixel coordinates (not [-1, +1] normalized device coordinates). Usually g3d_ProjectToPixelMatrix or gbuffer_camera_projectToPixelMatrix.
csZBuffer	The depth or camera-space Z buffer, depending on the value of csZBufferIsHyperbolic
csZBufferSize	Dimensions of csZBuffer
csZThickness	Camera space thickness to ascribe to each pixel in the depth buffer
csZBufferIsHyperbolic	True if csZBuffer is an OpenGL depth buffer, false (faster) if csZBuffer contains (negative) "linear" camera space z values. Const so that the compiler can evaluate the branch based on it at compile time
clipInfo	See G3D::Camera documentation
nearPlaneZ	Negative number. Doesn't have to be THE actual near plane, just a reasonable value for clipping rays headed towards the camera
stride	Step in horizontal or vertical pixels between samples. This is a float because integer math is slow on GPUs, but should be set to an integer >= 1
jitterFraction	Number between 0 and 1 for how far to bump the ray in stride units to conceal banding artifacts, plus the stride ray offset. It is recommended to set this to at least 1.0 to avoid self-intersection artifacts. Using 1 + float((int(gl_FragCoord.x) + int(gl_FragCoord.y.y)) & 1) * 0.5 gives a nice dither pattern when stride is > 1.0;
maxSteps	Maximum number of iterations. Higher gives better images but may be slow
maxRayTraceDistance	Maximum camera-space distance to trace before returning a miss
hitPixel	Pixel coordinates of the first intersection with the scene
csHitPoint	Camera space location of the ray hit

Single-layer