OpacityMask Class

class Kuesa::OpacityMask

Masks onscreen content based on the alpha color value of a mask texture. More...

Header:	#include <OpacityMask>
Inherits:	Kuesa::AbstractPostProcessingEffect

List of all members, including inherited members

Properties

mask : Qt3DRender::QAbstractTexture*
premultipliedAlpha : bool

Public Functions

Qt3DRender::QAbstractTexture *	mask() const
bool	premultipliedAlpha() const
void	setMask(Qt3DRender::QAbstractTexture *mask)
void	setPremultipliedAlpha(bool premultipliedAlpha)

Signals

void	maskChanged(Qt3DRender::QAbstractTexture *mask)
void	premultipliedAlphaChanged(bool premultipliedAlpha)

Detailed Description

Given an RGBA mask texture, content of the backbuffer will be rendered as:

 vec4 pixelColor = vec4(inputColor.rgb, inputColor.a * maskColor.a)

A premultiplied alpha variant of the algorithm is also available which can be of use when combining Qt 3D / Kuesa content with 2D QtQuick content (Scene3D). It performs rendering doing:

 vec4 pixelColor = vec4(inputColor.rgb / maskColor.a, inputColor.a * maskColor.a);

 #include <Qt3DExtras/Qt3DWindow>
 #include <ForwardRenderer>
 #include <SceneEntity>
 #include <OpacityMask>

 Qt3DExtras::Qt3DWindow win;
 Kuesa::SceneEntity *root = new Kuesa::SceneEntity();
 Kuesa::ForwardRenderer *frameGraph = new Kuesa::ForwardRenderer();
 Kuesa::OpacityMask *opacityMask = new Kuesa::OpacityMask();

 Qt3DRender::QTextureLoader *texture = new Qt3DRender::QTextureLoader();
 texture->setSource(QUrl("file:///opacityMask.png"));
 opacityMask->setMask(texture);

 frameGraph->addPostProcessingEffect(opacityMask);

 win->setRootEntity(root);
 win->setActiveFrameGraph(forwardRenderer);
 ...

Property Documentation

mask : Qt3DRender::QAbstractTexture*

The RGBA texture to use as a mask.

Access functions:

Qt3DRender::QAbstractTexture *	mask() const
void	setMask(Qt3DRender::QAbstractTexture *mask)

Notifier signal:

void	maskChanged(Qt3DRender::QAbstractTexture *mask)

premultipliedAlpha : bool

Specifies whether the masking should be performed using premultipliedAlpha. This can be useful when combining Kuesa and QtQuick with a Scene3D element. It is false by default.