WSGLShaderProgramCapability Class Reference

Base class for all capabilities that can be added to a shader program. More...

#include <Rendering/OpenGL/Shaders/Capabilities/wsglshaderprogramcapability.h>

Inheritance diagram for WSGLShaderProgramCapability:

Public Types
enum	UsageFlags { UpdateOnActivate = 0x01 , UpdateOnRender = 0x02 , UpdatePerGlyph = 0x04 }

Public Member Functions
virtual	~WSGLShaderProgramCapability ()
virtual const WSGLShaderProgramCapabilityId &	capabilityId () const =0
virtual const CapabilityIdList &	dependencies () const =0
virtual QString	getSource (QOpenGLShader::ShaderType type) const =0
virtual UsageFlags	getUsageFlags () const =0
virtual bool	onProgramActivate (WSGLShaderProgram &program, WSGLRenderer &renderer)=0
virtual bool	onProgramDeactivate (WSGLShaderProgram &program, WSGLRenderer &renderer)=0
WSGLShaderProgramCapability &	operator= (const WSGLShaderProgramCapability &)
virtual bool	postProgramLink (WSGLShaderProgram &program)=0
virtual bool	postRenderModel (WSGLShaderProgram &program, WSGLRenderer &renderer, WSGLRenderItem &item)=0
virtual bool	preRenderGlyph (WSGLShaderProgram &program, WSGLRenderer &renderer, WSGLInstancedItem &item, int instanceNumber)=0
virtual bool	preRenderModel (WSGLShaderProgram &program, WSGLRenderer &renderer, WSGLRenderItem &item)=0

Protected Member Functions
	WSGLShaderProgramCapability ()
	WSGLShaderProgramCapability (const WSGLShaderProgramCapability &)
QString	readSourceFromFile (const QString &filename) const

Detailed Description

The WSGLRenderer uses a 'uber' shader model; that is, shaders share a common set of code and are built 'dynamically' when they are compiled in order to minimize the amount of code that a shader developer needs to write.

WSGLShaderImplementation objects are bound to a particular context, and each may instantiate multiple WSGLShaderPrograms. Each one of these programs corresponds to an OpenGL program object, with attached Vertex, Fragment and (potentially) Geometry shaders. In order to make use of commonly used WSGL capabilities such as lighting and transforms, the developer must add WSGLShaderProgramCapability objects to their WSGLShaderProgram. The program will then use these capabilities by invoking the relevant virtual functions at the correct times:

• getSource
• postProgramLink
• onProgramActivate
• onProgramDeactivate
• preRenderModel
• postRenderModel
• preRenderGlyph

This allows the capability to differentiate between when a model is being rendered with glyphs on and the normal case, when it is rendered without glyphs.

Note

When writing the GLSL for the shaders associated with the program, the developer should refer to the relevant capability documentation in order to make use of the correct variables and functions.

Member Enumeration Documentation

UsageFlags

enum UsageFlags

Enumerator
UpdateOnActivate
UpdateOnRender
UpdatePerGlyph

Constructor & Destructor Documentation

WSGLShaderProgramCapability() [1/2]

WSGLShaderProgramCapability ( )

protected

WSGLShaderProgramCapability() [2/2]

WSGLShaderProgramCapability ( const WSGLShaderProgramCapability &  other )

protected

~WSGLShaderProgramCapability()

~WSGLShaderProgramCapability ( )

virtual

Member Function Documentation

capabilityId()

virtual const WSGLShaderProgramCapabilityId & capabilityId ( ) const

pure virtual

Returns

A unique ID object representing this capability.

Implemented in WSGLTypedShaderProgramCapability< Derived >, WSGLTypedShaderProgramCapability< WSGLBlinnPhongLightingCapability >, WSGLTypedShaderProgramCapability< WSGLClippingCapability >, WSGLTypedShaderProgramCapability< WSGLDepthPeelingCapability >, WSGLTypedShaderProgramCapability< WSGLLambertLightingCapability >, WSGLTypedShaderProgramCapability< WSGLScreenSpaceAmbientOcclusionCapability >, and WSGLTypedShaderProgramCapability< WSGLTransformCapability >.

dependencies()

virtual const CapabilityIdList & dependencies ( ) const

pure virtual

Returns

A list of the capabilities that this capability depends on. An error will occur if these capabilities are not also added to a shader program which has this capability added to it.

Implemented in WSGLBlinnPhongLightingCapability, WSGLClippingCapability, WSGLDepthPeelingCapability, WSGLLambertLightingCapability, WSGLScreenSpaceAmbientOcclusionCapability, and WSGLTransformCapability.

getSource()

virtual QString getSource ( QOpenGLShader::ShaderType  type ) const

pure virtual

Returns

The GLSL source code associated with this capability. WSGLShaderPrograms will invoke this function in order to compile a unified shader with all the relevant capabilities.

Implemented in WSGLBlinnPhongLightingCapability, WSGLClippingCapability, WSGLDepthPeelingCapability, WSGLLambertLightingCapability, WSGLScreenSpaceAmbientOcclusionCapability, and WSGLTransformCapability.

getUsageFlags()

virtual UsageFlags getUsageFlags ( ) const

pure virtual

Returns

The usage flags representing how this capability should be used at render time.

Implemented in WSGLBlinnPhongLightingCapability, WSGLClippingCapability, WSGLDepthPeelingCapability, WSGLLambertLightingCapability, WSGLScreenSpaceAmbientOcclusionCapability, and WSGLTransformCapability.

onProgramActivate()

virtual bool onProgramActivate ( WSGLShaderProgram &  program, WSGLRenderer &  renderer  )

pure virtual

Invoked when the program is activated. The WSGLShaderProgram is assumed to be bound. Subclasses can override this function to set up any program or other GL state (such as uniform values) that do not change on a per-render-item basis.

Parameters

program	The program which is being activated.
renderer	The renderer on which the program is being activated.

Returns

true if the activation process was successful, false if errors occurred.

See also

onProgramDeactivate

preRenderModel

postRenderModel

Implemented in WSGLBlinnPhongLightingCapability, WSGLClippingCapability, WSGLDepthPeelingCapability, WSGLLambertLightingCapability, WSGLScreenSpaceAmbientOcclusionCapability, and WSGLTransformCapability.

onProgramDeactivate()

virtual bool onProgramDeactivate ( WSGLShaderProgram &  program, WSGLRenderer &  renderer  )

pure virtual

Invoked when the program is deactivated. The WSGLShaderProgram is assumed to be bound. Use this function to clean up any GL state that is common to all items rendered.

Parameters

program	The program which is being deactivated.
renderer	The renderer that the program is being deactivated on.

Returns

true if the deactivation was successful, false if errors occurred.

See also

onProgramActivate

preRenderModel

postRenderModel

Implemented in WSGLBlinnPhongLightingCapability, WSGLClippingCapability, WSGLDepthPeelingCapability, WSGLLambertLightingCapability, WSGLScreenSpaceAmbientOcclusionCapability, and WSGLTransformCapability.

operator=()

WSGLShaderProgramCapability & operator=

(

const WSGLShaderProgramCapability &

rhs

)

Parameters

rhs

postProgramLink()

virtual bool postProgramLink ( WSGLShaderProgram &  program )

pure virtual

Invoked immediately after the program is linked. Use this function to stored uniform locations or other variables which will remain constant for the life of the capability.

Parameters

program

The program which has just been linked.

Implemented in WSGLBlinnPhongLightingCapability, WSGLClippingCapability, WSGLDepthPeelingCapability, WSGLLambertLightingCapability, WSGLScreenSpaceAmbientOcclusionCapability, and WSGLTransformCapability.

postRenderModel()

virtual bool postRenderModel ( WSGLShaderProgram &  program, WSGLRenderer &  renderer, WSGLRenderItem &  item  )

pure virtual

Invoked immediately following the rendering of a WSGLRenderItem (i.e. immediately after a call to glDrawElements or glDrawRangeElements). Use this function to clean up any GL state that changes on a per-item basis. The program is assumed to be bound.

Parameters

program	The program which is rendering the item.
renderer	The renderer which the program has just used to render the item.
item	The render item just drawn.

Returns

true if the postRenderModel process was successful, false if errors occurred.

See also

preRenderModel

onProgramActivate

onProgramDeactivate

Implemented in WSGLBlinnPhongLightingCapability, WSGLClippingCapability, WSGLDepthPeelingCapability, WSGLLambertLightingCapability, WSGLScreenSpaceAmbientOcclusionCapability, and WSGLTransformCapability.

preRenderGlyph()

virtual bool preRenderGlyph ( WSGLShaderProgram &  program, WSGLRenderer &  renderer, WSGLInstancedItem &  item, int  instanceNumber  )

pure virtual

Invoked immediately prior to the rendering of an individual glyph instance (i.e. immediately before a call to glDrawElements or glDrawRangeElements). Use this function to set up any GL state that changes on a per-glyph basis. The program is assumed to be bound.

Note

This function will only be called if the render item is glyphed. For normal rendering, see preRenderModel

Parameters

program	The program which is rendering the item.
renderer	The renderer which the program has just used to render the item.
item	The instanced item we're going to use to render an instance.
instanceNumber	The instance number of the glyph.

Returns

true if the preRenderModel process was successful, false if errors occurred.

See also

preRenderModel

postRenderGlyph

Implemented in WSGLBlinnPhongLightingCapability, WSGLClippingCapability, WSGLDepthPeelingCapability, WSGLLambertLightingCapability, WSGLScreenSpaceAmbientOcclusionCapability, and WSGLTransformCapability.

preRenderModel()

virtual bool preRenderModel ( WSGLShaderProgram &  program, WSGLRenderer &  renderer, WSGLRenderItem &  item  )

pure virtual

Invoked immediately prior to the rendering of a WSGLRenderItem (i.e. immediately before a call to glDrawElements or glDrawRangeElements). Use this function to set up any GL state that changes on a per-item basis. The program is assumed to be bound.

Parameters

program	The program which is rendering the item.
renderer	The renderer which the program is about to use to render the item.
item	The render item about to be drawn.

Returns

true if the preRenderModel process was successful, false if errors occurred.

See also

postRenderModel

onProgramActivate

onProgramDeactivate

Implemented in WSGLBlinnPhongLightingCapability, WSGLClippingCapability, WSGLDepthPeelingCapability, WSGLLambertLightingCapability, WSGLScreenSpaceAmbientOcclusionCapability, and WSGLTransformCapability.

readSourceFromFile()

QString readSourceFromFile ( const QString &  filename ) const

protected

Parameters

filename

The name of the file from which the source is to be read.