6.16. OpenGL Interoperability

This section describes the OpenGL interoperability functions of the CUDA runtime application programming interface. Note that mapping of OpenGL resources is performed with the graphics API agnostic, resource mapping interface described in Graphics Interopability.

Enumerations

enum cudaGLDeviceList

Functions

__host__cudaError_t cudaGLGetDevices ( unsigned int* pCudaDeviceCount, int* pCudaDevices, unsigned int  cudaDeviceCount, cudaGLDeviceList deviceList )
Gets the CUDA devices associated with the current OpenGL context.
__host__cudaError_t cudaGraphicsGLRegisterBuffer ( cudaGraphicsResource** resource, GLuint buffer, unsigned int  flags )
Registers an OpenGL buffer object.
__host__cudaError_t cudaGraphicsGLRegisterImage ( cudaGraphicsResource** resource, GLuint image, GLenum target, unsigned int  flags )
Register an OpenGL texture or renderbuffer object.
__host__cudaError_t cudaWGLGetDevice ( int* device, HGPUNV hGpu )
Gets the CUDA device associated with hGpu.

Enumerations

enum cudaGLDeviceList

CUDA devices corresponding to the current OpenGL context

Values
cudaGLDeviceListAll = 1
The CUDA devices for all GPUs used by the current OpenGL context
cudaGLDeviceListCurrentFrame = 2
The CUDA devices for the GPUs used by the current OpenGL context in its currently rendering frame
cudaGLDeviceListNextFrame = 3
The CUDA devices for the GPUs to be used by the current OpenGL context in the next frame

Functions

__host__cudaError_t cudaGLGetDevices ( unsigned int* pCudaDeviceCount, int* pCudaDevices, unsigned int  cudaDeviceCount, cudaGLDeviceList deviceList )
Gets the CUDA devices associated with the current OpenGL context.
Parameters
pCudaDeviceCount
- Returned number of CUDA devices corresponding to the current OpenGL context
pCudaDevices
- Returned CUDA devices corresponding to the current OpenGL context
cudaDeviceCount
- The size of the output device array pCudaDevices
deviceList
- The set of devices to return. This set may be cudaGLDeviceListAll for all devices, cudaGLDeviceListCurrentFrame for the devices used to render the current frame (in SLI), or cudaGLDeviceListNextFrame for the devices used to render the next frame (in SLI).
Description

Returns in *pCudaDeviceCount the number of CUDA-compatible devices corresponding to the current OpenGL context. Also returns in *pCudaDevices at most cudaDeviceCount of the CUDA-compatible devices corresponding to the current OpenGL context. If any of the GPUs being used by the current OpenGL context are not CUDA capable then the call will return cudaErrorNoDevice.

Note:
  • This function is not supported on Mac OS X.

  • Note that this function may also return error codes from previous, asynchronous launches.

See also:

cudaGraphicsUnregisterResource, cudaGraphicsMapResources, cudaGraphicsSubResourceGetMappedArray, cudaGraphicsResourceGetMappedPointer, cuGLGetDevices

__host__cudaError_t cudaGraphicsGLRegisterBuffer ( cudaGraphicsResource** resource, GLuint buffer, unsigned int  flags )
Registers an OpenGL buffer object.
Parameters
resource
- Pointer to the returned object handle
buffer
- name of buffer object to be registered
flags
- Register flags
Description

Registers the buffer object specified by buffer for access by CUDA. A handle to the registered object is returned as resource. The register flags flags specify the intended usage, as follows:

  • cudaGraphicsRegisterFlagsNone: Specifies no hints about how this resource will be used. It is therefore assumed that this resource will be read from and written to by CUDA. This is the default value.

  • cudaGraphicsRegisterFlagsReadOnly: Specifies that CUDA will not write to this resource.

  • cudaGraphicsRegisterFlagsWriteDiscard: Specifies that CUDA will not read from this resource and will write over the entire contents of the resource, so none of the data previously stored in the resource will be preserved.

Note:

Note that this function may also return error codes from previous, asynchronous launches.

See also:

cudaGraphicsUnregisterResource, cudaGraphicsMapResources, cudaGraphicsResourceGetMappedPointer, cuGraphicsGLRegisterBuffer

__host__cudaError_t cudaGraphicsGLRegisterImage ( cudaGraphicsResource** resource, GLuint image, GLenum target, unsigned int  flags )
Register an OpenGL texture or renderbuffer object.
Parameters
resource
- Pointer to the returned object handle
image
- name of texture or renderbuffer object to be registered
target
- Identifies the type of object specified by image
flags
- Register flags
Description

Registers the texture or renderbuffer object specified by image for access by CUDA. A handle to the registered object is returned as resource.

target must match the type of the object, and must be one of GL_TEXTURE_2D, GL_TEXTURE_RECTANGLE, GL_TEXTURE_CUBE_MAP, GL_TEXTURE_3D, GL_TEXTURE_2D_ARRAY, or GL_RENDERBUFFER.

The register flags flags specify the intended usage, as follows:

The following image formats are supported. For brevity's sake, the list is abbreviated. For ex., {GL_R, GL_RG} X {8, 16} would expand to the following 4 formats {GL_R8, GL_R16, GL_RG8, GL_RG16} :

  • GL_RED, GL_RG, GL_RGBA, GL_LUMINANCE, GL_ALPHA, GL_LUMINANCE_ALPHA, GL_INTENSITY

  • {GL_R, GL_RG, GL_RGBA} X {8, 16, 16F, 32F, 8UI, 16UI, 32UI, 8I, 16I, 32I}

  • {GL_LUMINANCE, GL_ALPHA, GL_LUMINANCE_ALPHA, GL_INTENSITY} X {8, 16, 16F_ARB, 32F_ARB, 8UI_EXT, 16UI_EXT, 32UI_EXT, 8I_EXT, 16I_EXT, 32I_EXT}

The following image classes are currently disallowed:

  • Textures with borders

  • Multisampled renderbuffers

Note:

Note that this function may also return error codes from previous, asynchronous launches.

See also:

cudaGraphicsUnregisterResource, cudaGraphicsMapResources, cudaGraphicsSubResourceGetMappedArray, cuGraphicsGLRegisterImage

__host__cudaError_t cudaWGLGetDevice ( int* device, HGPUNV hGpu )
Gets the CUDA device associated with hGpu.
Parameters
device
- Returns the device associated with hGpu, or -1 if hGpu is not a compute device.
hGpu
- Handle to a GPU, as queried via WGL_NV_gpu_affinity
Returns

cudaSuccess

Description

Returns the CUDA device associated with a hGpu, if applicable.

Note:

Note that this function may also return error codes from previous, asynchronous launches.

See also:

WGL_NV_gpu_affinity, cuWGLGetDevice