>Psychtoolbox>PsychGLImageProcessing

Psychtoolbox:PsychGLImageProcessing – OpenGL image processing functions.

This subfolder contains subroutines, tests and demos on how to use
the PTB built-in image processing pipeline.

The built in pipeline provides the infrastructure to define image processing
or stimulus image postprocessing operations on stimuli drawn by PTB’s Screen
2D drawing commands or MOGL 3D OpenGL drawing commands.

The pipeline provides the data flow and API to define type and parameterization
of the image processing operations. Operations are usually implemented via
OpenGL GLSL shader plugins, vertex & fragment shader programs written in the
high level OpenGL Shading langugage GLSL and executed directly inside the
graphics processing unit GPU. While this is the most efficient way, operations
may also be defined in standard OpenGL code, Matlab M-Functions or C callable
functions.

Typical applications, realized via plugins are:

* Stereo display algorithms.
* High dynamic range display output drivers.
* Standard operations like 2D convolution, noise, linear superposition.
* Geometric undistortion of displays.
* Per pixel output corrections like gamma, color, gain, display PDF.

This part of PTB is under heavy construction. This intro will get extended
soon with more useful infos…

Files:

Add2DConvolutionToGLOperator - Create and add a shader for 2D image convolution to a GLOperator.
Add2DSeparableConvolutionToGLOperator - Create and add a shader for 2D separable image convolution to a GLOperator.
AddImageUndistortionToGLOperator - Add geometric image correction to a GLOperator.
AddToGLOperator - Add a shader with options to a GLOperator.
BitsPlusPlus - Setup function for imaging pipelines built-in Bits++ support.
CountSlotsInGLOperator - Count number of processing slots in a given GLOperator.
CreateDisplayWarp - Internal helper function for setup of geometric display undistortion.
CreateGLOperator - Create a new GLOperator as container for imaging operations.
CreateProceduralColorGrating - Create a procedural texture for fast drawing of either sinusoidal or square gratings varying between two colors.
CreateProceduralGabor - Create a procedural texture for fast drawing of Gabor patches.
CreateProceduralNoise - Create a procedural texture for fast drawing of random noise patches.
CreateProceduralSineGrating - Create a procedural texture for fast drawing of sine grating patches.
CreateProceduralSmoothedApertureSineGrating - Create a procedural texture for fast drawing of smoothed aperture sine grating patches.
CreateProceduralSmoothedDisc - Create a procedural texture for fast drawing of smoothed edge discs.
CreateProceduralSquareWaveGrating - Create a procedural texture for fast drawing of squarewave grating patches.
CreatePseudoGrayLUT - Create a lookup table for pseudogray conversion - Internal helper function.
CreateResolutionPyramid - Build a mip-map image resolution pyramid for given texture.
CreateSinglePassImageProcessingShader - Create a single pass image processing shader for simple but common operations.
DisplayUndistortionBezier - Interactive geometric display calibration for simple needs.
DisplayUndistortionBVL - Interactive geometric display calibration. Recommended!
DisplayUndistortionCSV - Import ASCII data file with geometric display calibration for NVidia “Warp API”.
DisplayUndistortionHalfCylinder - Interactive geometric display calibration for half-cylinder or spherical projections.
DisplayUndistortionLabRiggerMouseStim - Create display undistortion based on method from LabRigger for mouse visual stims.
DisplayUndistortionSphere - Interactive geometric display calibration for spherical projections.
ImagingStereoDemo - Counterpart to StereoDemo, but using imaging pipeline
for increased fidelity, flexibility, ease of use.
MakeTextureDrawShader - Create GLSL shader for use with Screen(‘DrawTexture’) and Screen(‘MakeTexture’)
to apply on-the-fly texture filtering operations during texture draw.

PsychColorCorrection - Routines for gpu accelerated color correction via PsychImaging().

PsychHDR - Support and control stimulus display to HDR “High dynamic range” displays.

PsychImaging - Generic setup routine for the imaging pipeline. Allows to setup
and initialize the pipeline for many common tasks.

PsychVideoSwitcher - Setup routine for the Xiangru Li et al. “VideoSwitcher” video attenuator device.

PsychVulkan - Interface with the Vulkan graphics and compute api for special purpose tasks.

SetAnaglyphStereoParameters - Function for runtime tuning of Anaglyph stereo parameters,
see ImagingStereoDemo for example of use.
SetStereoBlueLineSyncParameters - Change settings for drawing of stereo sync lines in frame-sequential stereo mode.
SetStereoSideBySideParameters - Change parameters for side-by-side stereo display modes (4 and 5).
SetCompressedStereoSideBySideParameters - Change parameters for compressed side-by-side stereo display modes.

VignetCalibration - Vignetted luminance calibration procedure for undistortion of distorted display luminance.

Constants for use as ‘flipFlags’ with the imaging pipeline function
Screen(‘HookFunction’, windowPtr, ‘SetOneshotFlipFlags’ …, flipFlags):

kPsychDontAutoResetOneshotFlags - Prevent “one-shot” flip flags from being automatically cleared after execution of the next Screen(‘Flip’) operation.
kPsychSkipSwapForFlipOnce - Skip OpenGL double-buffer swap during execution of next Screen(‘Flip’).
kPsychSkipTimestampingForFlipOnce - Skip timestamping of OpenGL double-buffer swap stimulus onset after execution of next Screen(‘Flip’).
kPsychSkipVsyncForFlipOnce - Do not synchronize next OpenGL buffer swap to vertical retrace during execution of next Screen(‘Flip’).
kPsychSkipWaitForFlipOnce - Do not schedule OpenGL buffer swap for specific target time, leave it to some external method.

Constants for imagingmode flag of Screen(‘OpenWindow’, …., imagingmode);
One can ‘or’ them together, e.g., imagingmode = mor(kPsychNeed16BPCFixed, kPsychNeedFastBackingStore);

kPsychNeed16BPCFixed - Request 16 bit per color component, fixed point framebuffer.
kPsychNeed16BPCFloat - Request 16 bit per color component, floating point framebuffer.
kPsychNeed32BPCFloat - Request 32 bit per color component, floating point framebuffer.
kPsychNeedDualPass - Indicate that some of the used image processing plugins will need
at two render passes for processing.
kPsychNeedFastBackingStore - Enable minimal imaging pipeline. This flag is implied when using any
of the other flags.
kPsychNeedFastOffscreenWindows - Only enable support for fast Offscreen windows, nothing else.
kPsychNeedHalfWidthWindow - Tell imaging pipe to create internal buffers half the real window width. Internal flag, not useful for end-user code.
kPsychNeedHalfHeightWindow - Tell imaging pipe to create internal buffers half the real window height. Internal flag, not useful for end-user code.
kPsychNeedImageProcessing - Request explicit support for image processing.
kPsychNeedMultiPass - Indicate that some of the used plugins will need more than two passes.
kPsychNeedOutputConversion - Indicate that display output is going to some special output device that
needs special output formatting, e.g., Bits++ or Brightside HDR.
kPsychNeedTwiceWidthWindow - Tell imaging pipe to create internal buffers twice the real window width. Internal flag, not useful for end-user code.
kPsychNeedTripleWidthWindow - Tell imaging pipe to create internal buffers triple the real window width. Internal flag, not useful for end-user code.

Constants for specialflags of Screen(‘OpenWindow’, …, specialflags);
One can ‘or’ them together:

kPsychSkipSecondaryVsyncForFlip - Disable vsync for bufferswaps on secondary/slave windows.