OpenCV  4.0.0-pre
Open Source Computer Vision
Namespaces | Classes | Enumerations | Functions
OpenGL interoperability

Namespaces

 cv::ogl::ocl
 

Classes

class  cv::ogl::Arrays
 Wrapper for OpenGL Client-Side Vertex arrays. More...
 
class  cv::ogl::Buffer
 Smart pointer for OpenGL buffer object with reference counting. More...
 
class  cv::ogl::Texture2D
 Smart pointer for OpenGL 2D texture memory with reference counting. More...
 

Enumerations

enum  cv::ogl::RenderModes {
  cv::ogl::POINTS = 0x0000,
  cv::ogl::LINES = 0x0001,
  cv::ogl::LINE_LOOP = 0x0002,
  cv::ogl::LINE_STRIP = 0x0003,
  cv::ogl::TRIANGLES = 0x0004,
  cv::ogl::TRIANGLE_STRIP = 0x0005,
  cv::ogl::TRIANGLE_FAN = 0x0006,
  cv::ogl::QUADS = 0x0007,
  cv::ogl::QUAD_STRIP = 0x0008,
  cv::ogl::POLYGON = 0x0009
}
 render mode More...
 

Functions

void cv::ogl::convertFromGLTexture2D (const Texture2D &texture, OutputArray dst)
 Converts Texture2D object to OutputArray. More...
 
void cv::ogl::convertToGLTexture2D (InputArray src, Texture2D &texture)
 Converts InputArray to Texture2D object. More...
 
UMat cv::ogl::mapGLBuffer (const Buffer &buffer, AccessFlag accessFlags=ACCESS_READ|ACCESS_WRITE)
 Maps Buffer object to process on CL side (convert to UMat). More...
 
void cv::ogl::render (const Texture2D &tex, Rect_< double > wndRect=Rect_< double >(0.0, 0.0, 1.0, 1.0), Rect_< double > texRect=Rect_< double >(0.0, 0.0, 1.0, 1.0))
 Render OpenGL texture or primitives. More...
 
void cv::ogl::render (const Arrays &arr, int mode=POINTS, Scalar color=Scalar::all(255))
 
void cv::ogl::render (const Arrays &arr, InputArray indices, int mode=POINTS, Scalar color=Scalar::all(255))
 
void cv::cuda::setGlDevice (int device=0)
 Sets a CUDA device and initializes it for the current thread with OpenGL interoperability. More...
 
void cv::ogl::unmapGLBuffer (UMat &u)
 Unmaps Buffer object (releases UMat, previously mapped from Buffer). More...
 

Detailed Description

This section describes OpenGL interoperability.

To enable OpenGL support, configure OpenCV using CMake with WITH_OPENGL=ON . Currently OpenGL is supported only with WIN32, GTK and Qt backends on Windows and Linux (MacOS and Android are not supported). For GTK backend gtkglext-1.0 library is required.

To use OpenGL functionality you should first create OpenGL context (window or frame buffer). You can do this with namedWindow function or with other OpenGL toolkit (GLUT, for example).

Enumeration Type Documentation

§ RenderModes

render mode

Enumerator
POINTS 
Python: cv.ogl.POINTS
LINES 
Python: cv.ogl.LINES
LINE_LOOP 
Python: cv.ogl.LINE_LOOP
LINE_STRIP 
Python: cv.ogl.LINE_STRIP
TRIANGLES 
Python: cv.ogl.TRIANGLES
TRIANGLE_STRIP 
Python: cv.ogl.TRIANGLE_STRIP
TRIANGLE_FAN 
Python: cv.ogl.TRIANGLE_FAN
QUADS 
Python: cv.ogl.QUADS
QUAD_STRIP 
Python: cv.ogl.QUAD_STRIP
POLYGON 
Python: cv.ogl.POLYGON

Function Documentation

§ convertFromGLTexture2D()

void cv::ogl::convertFromGLTexture2D ( const Texture2D texture,
OutputArray  dst 
)

Converts Texture2D object to OutputArray.

Parameters
texture- source Texture2D object.
dst- destination OutputArray.

§ convertToGLTexture2D()

void cv::ogl::convertToGLTexture2D ( InputArray  src,
Texture2D texture 
)

Converts InputArray to Texture2D object.

Parameters
src- source InputArray.
texture- destination Texture2D object.

§ mapGLBuffer()

UMat cv::ogl::mapGLBuffer ( const Buffer buffer,
AccessFlag  accessFlags = ACCESS_READ|ACCESS_WRITE 
)

Maps Buffer object to process on CL side (convert to UMat).

Function creates CL buffer from GL one, and then constructs UMat that can be used to process buffer data with OpenCV functions. Note that in current implementation UMat constructed this way doesn't own corresponding GL buffer object, so it is the user responsibility to close down CL/GL buffers relationships by explicitly calling unmapGLBuffer() function.

Parameters
buffer- source Buffer object.
accessFlags- data access flags (ACCESS_READ|ACCESS_WRITE).
Returns
Returns UMat object

§ render() [1/3]

void cv::ogl::render ( const Texture2D tex,
Rect_< double >  wndRect = Rect_< double >(0.0, 0.0, 1.0, 1.0),
Rect_< double >  texRect = Rect_< double >(0.0, 0.0, 1.0, 1.0) 
)

Render OpenGL texture or primitives.

Parameters
texTexture to draw.
wndRectRegion of window, where to draw a texture (normalized coordinates).
texRectRegion of texture to draw (normalized coordinates).

§ render() [2/3]

void cv::ogl::render ( const Arrays arr,
int  mode = POINTS,
Scalar  color = Scalar::all(255) 
)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters
arrArray of privitives vertices.
modeRender mode. One of cv::ogl::RenderModes
colorColor for all vertices. Will be used if arr doesn't contain color array.

§ render() [3/3]

void cv::ogl::render ( const Arrays arr,
InputArray  indices,
int  mode = POINTS,
Scalar  color = Scalar::all(255) 
)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters
arrArray of privitives vertices.
indicesArray of vertices indices (host or device memory).
modeRender mode. One of cv::ogl::RenderModes
colorColor for all vertices. Will be used if arr doesn't contain color array.

§ setGlDevice()

void cv::cuda::setGlDevice ( int  device = 0)

Sets a CUDA device and initializes it for the current thread with OpenGL interoperability.

This function should be explicitly called after OpenGL context creation and before any CUDA calls.

Parameters
deviceSystem index of a CUDA device starting with 0.

§ unmapGLBuffer()

void cv::ogl::unmapGLBuffer ( UMat u)

Unmaps Buffer object (releases UMat, previously mapped from Buffer).

Function must be called explicitly by the user for each UMat previously constructed by the call to mapGLBuffer() function.

Parameters
u- source UMat, created by mapGLBuffer().