GrXferProcessor is responsible for implementing the xfer mode that blends the src color and dst color, and for applying any coverage. More...

#include <GrXferProcessor.h>

Inheritance diagram for GrXferProcessor:

Classes
struct	BlendInfo

class	DstTexture
	A texture that contains the dst pixel values and an integer coord offset from device space to the space of the texture. More...

Public Types
enum	OptFlags { kSkipDraw_OptFlag = 0x1, kIgnoreColor_OptFlag = 0x2, kIgnoreCoverage_OptFlag = 0x4, kOverrideColor_OptFlag = 0x8, kCanTweakAlphaForCoverage_OptFlag = 0x20 }
	Optimizations for blending / coverage that an OptDrawState should apply to itself. More...

Public Types inherited from GrProcessor
enum	RequiredFeatures { kNone_RequiredFeatures = 0, kFragmentPosition_RequiredFeature = 1 << 0, kSampleLocations_RequiredFeature = 1 << 1 }
	Platform specific built-in features that a processor can request for the fragment shader.

Public Member Functions
void	getGLSLProcessorKey (const GrGLSLCaps &caps, GrProcessorKeyBuilder *b) const
	Sets a unique key on the GrProcessorKeyBuilder calls onGetGLSLProcessorKey(...) to get the specific subclass's key.

virtual GrGLSLXferProcessor *	createGLSLInstance () const =0
	Returns a new instance of the appropriate GL implementation class for the given GrXferProcessor; caller is responsible for deleting the object. More...

	GR_DECL_BITFIELD_OPS_FRIENDS (OptFlags)

OptFlags	getOptimizations (const GrPipelineOptimizations &optimizations, bool doesStencilWrite, GrColor *overrideColor, const GrCaps &caps) const
	Determines which optimizations (as described by the ptFlags above) can be performed by the draw with this xfer processor. More...

GrXferBarrierType	xferBarrierType (const GrRenderTarget *rt, const GrCaps &caps) const
	Returns whether this XP will require an Xfer barrier on the given rt. More...

void	getBlendInfo (BlendInfo *blendInfo) const

bool	willReadDstColor () const

const GrTexture *	getDstTexture () const
	Returns the texture to be used as the destination when reading the dst in the fragment shader. More...

const SkIPoint &	dstTextureOffset () const
	Returns the offset in device coords to use when accessing the dst texture to get the dst pixel color in the shader. More...

bool	dstReadUsesMixedSamples () const
	If we are performing a dst read, returns whether the base class will use mixed samples to antialias the shader's final output. More...

bool	hasSecondaryOutput () const
	Returns whether or not this xferProcossor will set a secondary output to be used with dual source blending.

bool	isEqual (const GrXferProcessor &that) const
	Returns true if this and other processor conservatively draw identically. More...

Public Member Functions inherited from GrProcessor
virtual const char *	name () const =0
	Human-meaningful string to identify this prcoessor; may be embedded in generated shader code. More...

virtual SkString	dumpInfo () const

int	numTextures () const

const GrTextureAccess &	textureAccess (int index) const
	Returns the access pattern for the texture at index. More...

GrTexture *	texture (int index) const
	Shortcut for textureAccess(index).texture();.

int	numBuffers () const

const GrBufferAccess &	bufferAccess (int index) const
	Returns the access pattern for the buffer at index. More...

	GR_DECL_BITFIELD_OPS_FRIENDS (RequiredFeatures)

RequiredFeatures	requiredFeatures () const

void *	operator new (size_t size)

void	operator delete (void *target)

void *	operator new (size_t size, void *placement)

void	operator delete (void target, void placement)

template<typename T >
const T &	cast () const
	Helper for down-casting to a GrProcessor subclass.

uint32_t	classID () const

Public Member Functions inherited from GrProgramElement
void	ref () const

void	unref () const

uint32_t	getUniqueID () const
	Gets an id that is unique for this GrProgramElement object. More...

void	validate () const

Static Public Attributes
static const OptFlags	kNone_OptFlags = (OptFlags)0

Protected Member Functions
	GrXferProcessor (const DstTexture *, bool willReadDstColor, bool hasMixedSamples)

Protected Member Functions inherited from GrProcessor
virtual void	addTextureAccess (const GrTextureAccess *textureAccess)
	Subclasses call these from their constructor to register sampler sources. More...

virtual void	addBufferAccess (const GrBufferAccess *bufferAccess)

bool	hasSameSamplers (const GrProcessor &) const

void	setWillReadFragmentPosition ()
	If the prcoessor will generate code that uses platform specific built-in features, then it must call these methods from its constructor. More...

void	setWillUseSampleLocations ()

void	combineRequiredFeatures (const GrProcessor &other)

template<typename PROC_SUBCLASS >
void	initClassID ()

Protected Member Functions inherited from GrProgramElement
void	addGpuResource (const GrGpuResourceRef *res)
	Subclasses registers their resources using this function. More...

void	addPendingExecution () const

void	completedExecution () const

Private Types
typedef GrFragmentProcessor	INHERITED

Private Member Functions
void	notifyRefCntIsZero () const final
	This will be called when the ref cnt is zero. More...

virtual OptFlags	onGetOptimizations (const GrPipelineOptimizations &optimizations, bool doesStencilWrite, GrColor *overrideColor, const GrCaps &caps) const =0

virtual void	onGetGLSLProcessorKey (const GrGLSLCaps &caps, GrProcessorKeyBuilder *b) const =0
	Sets a unique key on the GrProcessorKeyBuilder that is directly associated with this xfer processor's GL backend implementation.

virtual GrXferBarrierType	onXferBarrier (const GrRenderTarget *, const GrCaps &) const
	Determines the type of barrier (if any) required by the subclass. More...

virtual bool	onHasSecondaryOutput () const
	If we are not performing a dst read, returns whether the subclass will set a secondary output. More...

virtual void	onGetBlendInfo (BlendInfo *) const
	If we are not performing a dst read, retrieves the fixed-function blend state required by the subclass. More...

virtual bool	onIsEqual (const GrXferProcessor &) const =0

Private Attributes
bool	fWillReadDstColor

bool	fDstReadUsesMixedSamples

SkIPoint	fDstTextureOffset

GrTextureAccess	fDstTexture

Additional Inherited Members
Protected Attributes inherited from GrProcessor
uint32_t	fClassID

SkSTArray< 4, const GrTextureAccess *, true >	fTextureAccesses

SkSTArray< 2, const GrBufferAccess *, true >	fBufferAccesses

Detailed Description

GrXferProcessor is responsible for implementing the xfer mode that blends the src color and dst color, and for applying any coverage.

It does this by emitting fragment shader code and controlling the fixed-function blend state. When dual-source blending is available, it may also write a seconday fragment shader output color. GrXferProcessor has two modes of operation:

Dst read: When allowed by the backend API, or when supplied a texture of the destination, the GrXferProcessor may read the destination color. While operating in this mode, the subclass only provides shader code that blends the src and dst colors, and the base class applies coverage.

No dst read: When not performing a dst read, the subclass is given full control of the fixed- function blend state and/or secondary output, and is responsible to apply coverage on its own.

A GrXferProcessor is never installed directly into our draw state, but instead is created from a GrXPFactory once we have finalized the state of our draw.

Member Enumeration Documentation

enum GrXferProcessor::OptFlags

Optimizations for blending / coverage that an OptDrawState should apply to itself.

Enumerator
kSkipDraw_OptFlag	The draw can be skipped completely.
kIgnoreColor_OptFlag	GrXferProcessor will ignore color, thus no need to provide.
kIgnoreCoverage_OptFlag	GrXferProcessor will ignore coverage, thus no need to provide.
kOverrideColor_OptFlag	Clear color stages and override input color to that returned by getOptimizations.
kCanTweakAlphaForCoverage_OptFlag	Can tweak alpha for coverage. Currently this flag should only be used by a batch

Member Function Documentation

virtual GrGLSLXferProcessor* GrXferProcessor::createGLSLInstance ( ) const

pure virtual

Returns a new instance of the appropriate GL implementation class for the given GrXferProcessor; caller is responsible for deleting the object.

bool GrXferProcessor::dstReadUsesMixedSamples ( ) const

inline

If we are performing a dst read, returns whether the base class will use mixed samples to antialias the shader's final output.

If not doing a dst read, the subclass is responsible for antialiasing and this returns false.

const SkIPoint& GrXferProcessor::dstTextureOffset ( ) const

inline

Returns the offset in device coords to use when accessing the dst texture to get the dst pixel color in the shader.

This value is only valid if getDstTexture() != NULL.

const GrTexture* GrXferProcessor::getDstTexture ( ) const

inline

Returns the texture to be used as the destination when reading the dst in the fragment shader.

If the returned texture is NULL then the XP is either not reading the dst or we have extentions that support framebuffer fetching and thus don't need a copy of the dst texture.

OptFlags GrXferProcessor::getOptimizations	(	const GrPipelineOptimizations &	optimizations,
		bool	doesStencilWrite,
		GrColor *	overrideColor,
		const GrCaps &	caps
	)		const

Determines which optimizations (as described by the ptFlags above) can be performed by the draw with this xfer processor.

If this function is called, the xfer processor may change its state to reflected the given blend optimizations. If the XP needs to see a specific input color to blend correctly, it will set the OverrideColor flag and the output parameter overrideColor will be the required value that should be passed into the XP. A caller who calls this function on a XP is required to honor the returned OptFlags and color values for its draw.

bool GrXferProcessor::isEqual ( const GrXferProcessor & that ) const

inline

Returns true if this and other processor conservatively draw identically.

It can only return true when the two processor are of the same subclass (i.e. they return the same object from from getFactory()).

A return value of true from isEqual() should not be used to test whether the processor would generate the same shader code. To test for identical code generation use getGLSLProcessorKey

void GrXferProcessor::notifyRefCntIsZero ( ) const

inlinefinalprivatevirtual

This will be called when the ref cnt is zero.

The object may or may not have pending executions.

Implements GrProgramElement.

virtual void GrXferProcessor::onGetBlendInfo ( BlendInfo * ) const

inlineprivatevirtual

If we are not performing a dst read, retrieves the fixed-function blend state required by the subclass.

When using dst reads, the base class controls the fixed-function blend state and this method will not be called. The BlendInfo struct comes initialized to "no blending".

virtual bool GrXferProcessor::onHasSecondaryOutput ( ) const

inlineprivatevirtual

If we are not performing a dst read, returns whether the subclass will set a secondary output.

When using dst reads, the base class controls the secondary output and this method will not be called.

virtual GrXferBarrierType GrXferProcessor::onXferBarrier	(	const GrRenderTarget *	,
		const GrCaps &
	)		const

inlineprivatevirtual

Determines the type of barrier (if any) required by the subclass.

Note that the possibility that a kTexture type barrier is required is handled by the base class and need not be considered by subclass overrides of this function.

GrXferBarrierType GrXferProcessor::xferBarrierType	(	const GrRenderTarget *	rt,
		const GrCaps &	caps
	)		const

Returns whether this XP will require an Xfer barrier on the given rt.

If true, outBarrierType is updated to contain the type of barrier needed.

The documentation for this class was generated from the following file:

include/gpu/GrXferProcessor.h

Classes

Public Types

Public Member Functions

Static Public Attributes

Protected Member Functions

Private Types

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

Member Function Documentation