- Qt 5.15
- Qt 3D
- C++ Classes
- QAlphaCoverage
- Qt 5.15.11 Reference Documentation

# QAlphaCoverage Class

class Qt3DRender::QAlphaCoverage

Enable alpha-to-coverage multisampling mode. More...

Header: | #include <QAlphaCoverage>
qmake: | QT += 3drender
Since: | Qt 5.7
Instantiated By: | AlphaCoverage
Inherits: | Qt3DRender::QRenderState

This class was introduced in Qt 5.7.

- List of all members, including inherited members

## Detailed Description

A Qt3DRender::QAlphaCoverage class enables alpha-to-coverage multisampling mode. When enabled, the fragment alpha value is used as a coverage for the sample and combined with fragment coverage value. Qt3DRender::QAlphaCoverage does nothing if multisampling is disabled. Alpha-to-coverage is most useful when order independent blending is required, for example when rendering leaves, grass and other rich vegetation.

It can be added to a QRenderPass by calling QRenderPass::addRenderState():

     QRenderPass *renderPass = new QRenderPass();

     // Create a alpha coverage render state
     QAlphaCoverage *alphaCoverage = new QAlphaCoverage();
     QMultiSampleAntiAliasing *multiSampleAntialiasing = new QMultiSampleAntiAliasing();

     // Add the render states to the render pass
     renderPass->addRenderState(alphaCoverage);
     renderPass->addRenderState(multiSampleAntialiasing);

Or to a QRenderStateSet by calling QRenderStateSet::addRenderState():

     QRenderStateSet *renderStateSet = new QRenderStateSet();

     // Create a alpha coverage render state
     QAlphaCoverage *alphaCoverage = new QAlphaCoverage();
     QMultiSampleAntiAliasing *multiSampleAntialiasing = new QMultiSampleAntiAliasing();

     // Add the render states to the render state set
     renderStateSet->addRenderState(alphaCoverage);
     renderStateSet->addRenderState(multiSampleAntialiasing);

See also Qt3DRender::QMultiSampleAntiAliasing.