RGBMBo Class Reference

Wrapper around a native GBM buffer object (gbm_bo). More...

#include <RGBMBo.h>

Inheritance diagram for RGBMBo:

Public Member Functions
	~RGBMBo () noexcept
	Destroys the underlying gbm_bo if this object owns it.
RDevice *	allocator () const noexcept
	Returns the allocator device used to create this buffer.
bool	hasModifier () const noexcept
	Checks whether the buffer was created with an explicit modifier.
RModifier	modifier () const noexcept
	Returns the DRM format modifier of the buffer.
RFormat	format () const noexcept
	Returns the DRM pixel format of the buffer.
SkISize	size () const noexcept
	Returns the width and height of the buffer in pixels.
int	planeCount () const noexcept
	Returns the number of planes in the buffer.
union gbm_bo_handle	planeHandle (int planeIndex) const noexcept
	Returns the GEM flink handle for a specific plane.
UInt32	planeStride (int planeIndex) const noexcept
	Returns the stride (bytes per row) for a specific plane.
UInt32	planeOffset (int planeIndex) const noexcept
	Returns the byte offset of a specific plane within the buffer.
CZSpFd	planeFd (int planeIndex) const noexcept
	Exports a DMA-BUF file descriptor for a specific plane.
bool	supportsMapRead () const noexcept
	Checks whether the buffer supports memory mapping for read access.
bool	supportsMapWrite () const noexcept
	Checks whether the buffer supports memory mapping for write access.
gbm_bo *	bo () const noexcept
	Returns the raw gbm_bo handle.
std::shared_ptr< RCore >	core () const noexcept
	Returns the internal shared reference to the core instance.
Public Member Functions inherited from RObject
	RObject ()=default
	Constructs a default RObject.

Static Public Member Functions
static std::shared_ptr< RGBMBo >	Make (SkISize size, const RDRMFormat &format, RDevice *allocator=nullptr) noexcept
	Creates a GBM buffer object.

Detailed Description

Wrapper around a native GBM buffer object (gbm_bo).

This class encapsulates a GBM buffer object, providing safe access to its properties and DMA-BUF export information. It manages the lifetime of the gbm_bo handle and related resources.

Use Make() to create an instance. The buffer object is created either with or without modifiers, depending on platform support and requested format.

Constructor & Destructor Documentation

~RGBMBo()

~RGBMBo ( )

noexcept

Destroys the underlying gbm_bo if this object owns it.

Member Function Documentation

Make()

static std::shared_ptr< RGBMBo > Make ( SkISize  size, const RDRMFormat &  format, RDevice *  allocator = nullptr  )

staticnoexcept

Creates a GBM buffer object.

Allocates a new gbm_bo with the specified size and format.

If no allocator is provided, the default device from RCore::mainDevice() is used.

Parameters

size	The width and height of the buffer.
format	The DRM pixel format and modifiers.
allocator	The device to use for allocation (optional).

Returns

A shared pointer to a valid RGBMBo on success, nullptr on failure.

allocator()

RDevice * allocator ( ) const

inlinenoexcept

Returns the allocator device used to create this buffer.

hasModifier()

bool hasModifier ( ) const

inlinenoexcept

Checks whether the buffer was created with an explicit modifier.

If true, the buffer was created using gbm_bo_create_with_modifiers and has a valid modifier. If false, it was created using gbm_bo_create, and the modifier may be DRM_FORMAT_MOD_INVALID or DRM_FORMAT_MOD_LINEAR.

Returns

True if the buffer has an explicit modifier, false otherwise.

modifier()

RModifier modifier ( ) const

noexcept

Returns the DRM format modifier of the buffer.

See also

hasModifier()

format()

RFormat format ( ) const

noexcept

Returns the DRM pixel format of the buffer.

size()

SkISize size ( ) const

noexcept

Returns the width and height of the buffer in pixels.

planeCount()

int planeCount ( ) const

noexcept

Returns the number of planes in the buffer.

Returns

Number of planes (usually 1 for RGB, may be more for YUV).

planeHandle()

union gbm_bo_handle planeHandle ( int  planeIndex ) const

noexcept

Returns the GEM flink handle for a specific plane.

Note

Handles must not be manually closed or used by other device than the allocator. For cross-device sharing, use dmaInfo().

Parameters

planeIndex

Index of the plane (0-based).

Returns

The GEM flink handle (DRM buffer object handle) for the specified plane.

planeStride()

UInt32 planeStride ( int  planeIndex ) const

noexcept

Returns the stride (bytes per row) for a specific plane.

Parameters

planeIndex

Index of the plane (0-based).

Returns

The stride in bytes for the specified plane.

planeOffset()

UInt32 planeOffset ( int  planeIndex ) const

noexcept

Returns the byte offset of a specific plane within the buffer.

Parameters

planeIndex

Index of the plane (0-based).

Returns

The offset in bytes for the specified plane.

planeFd()

CZSpFd planeFd ( int  planeIndex ) const

noexcept

Exports a DMA-BUF file descriptor for a specific plane.

Note

The returned file descriptor is owned by the caller (wrapped in a CZSpFd) and must be closed when no longer needed. For a full export of all planes, use dmaExport().

Parameters

planeIndex

Index of the plane (0-based).

Returns

A CZSpFd wrapping the plane's DMA-BUF file descriptor.

supportsMapRead()

bool supportsMapRead ( ) const

noexcept

Checks whether the buffer supports memory mapping for read access.

Note

The mapping present a linear view of the buffer, independently of the modifier.

Returns

True if gbm_bo_map can be used for reading, false otherwise.

supportsMapWrite()

bool supportsMapWrite ( ) const

noexcept

Checks whether the buffer supports memory mapping for write access.

Note

The mapping present a linear view of the buffer, independently of the modifier.

Returns

True if gbm_bo_map can be used for writing, false otherwise.

bo()

gbm_bo * bo ( ) const

inlinenoexcept

Returns the raw gbm_bo handle.

Note

This handle is owned by the object. Do not manually destroy it.

Returns

Pointer to the underlying gbm_bo.

core()

std::shared_ptr< RCore > core ( ) const

inlinenoexcept

Returns the internal shared reference to the core instance.

This ensures the current RCore instance stays alive while the buffer exists.